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1
Qiu, Jiadong, and Fan Feng. "Effect of Different Tunnel Distribution on Dynamic Behavior and Damage Characteristics of Non-Adjacent Tunnel Triggered by Blasting Disturbance." Mathematics 10, no. 19 (October 10, 2022): 3705. http://dx.doi.org/10.3390/math10193705.
Повний текст джерелаАнотація:
When a blasting is executed near two tunnels, the blasting wave will trigger a dynamic response and damage to the tunnels. Depending on the tunnel distribution, the path of the blasting wave to the remote non-adjacent tunnels will change. The aim of this study is to analyze the effect of the tunnel distribution on the dynamic response characteristics of a remote non-adjacent tunnel. Numerical models of two tunnels were established by PFC2D and three different tunnel distributions were considered. The two tunnels were divided into the adjacent tunnel and the non-adjacent tunnel according to their relative distance to the blasting source. The dynamic stress evolution, damage characteristics and the evolution of strain energy of the non-adjacent tunnel were initially analyzed. The results show that the stress wave amplitude of the non-adjacent tunnel is closely related to the tunnel distribution, but only near the sidewalls of the non-adjacent tunnel is the stress wave waveform sensitive to the tunnel distribution. The larger the tunnel dip, the more severe the damage to the non-adjacent tunnel. In addition, as the tunnel dip increases, the maximum strain energy densities (SEDs) in the roof, floor and sidewalls of the non-adjacent tunnel exhibit different trends. The influence of the wavelength of the blasting wave is further discussed. It is shown that the dynamic stress amplification factor and damage degree around the non-adjacent tunnel is usually positively correlated with the wavelength of the blasting wave. Moreover, the release of strain energy around the non-adjacent tunnel has a positive correlation with the wavelength. The SED variations in different areas around the non-adjacent tunnel also exhibit different trends with the increase of tunnel dip.
2
Li, Zheng, and Gerald H. Pollack. "Surface-induced flow: A natural microscopic engine using infrared energy as fuel." Science Advances 6, no. 19 (May 2020): eaba0941. http://dx.doi.org/10.1126/sciadv.aba0941.
Повний текст джерелаАнотація:
Fluid commonly flows in response to an external pressure gradient. However, when a tunnel-containing hydrogel is immersed in water, spontaneous flow occurs through the tunnel without any pressure gradient. We confirmed this flow in a wide range of plant- and animal-derived hydrogels. The flow appears to be driven by axial concentration gradients originating from surface activities of the tunnel wall. Those activities include (i) hydrogel-water interaction and (ii) material exchange across the tunnel boundary. Unlike pressure-driven flow, this surface-induced flow has two distinct features: incident infrared energy substantially increases flow velocity, and narrower tunnels generate faster flow. Thus, surface activities in hydrogel-lined tunnels may confer kinetic energy on the enclosed fluid, with infrared as an energy source.
3
Yang, Tao, Yunkang Rao, Honggang Wu, Junyun Zhang, Hao Lei, and Haojiang Ding. "Dynamic Response of Parallel Overlapped Tunnel under Seismic Loading by Shaking Table Tests." Shock and Vibration 2021 (June 7, 2021): 1–15. http://dx.doi.org/10.1155/2021/2535762.
Повний текст джерелаАнотація:
Potential earthquake-induced damage to overlapped tunnels probably occurs during the operation and maintenance of mountain tunnel engineering, especially in the seismically active zone. This study investigated the dynamic response and the failure characteristics of the parallel overlapped tunnel under seismic loadings by employing shaking table tests. The failure mode of the parallel overlapped tunnels was analyzed through macroscopic test phenomena. The dynamic responses of the surrounding rock and tunnel lining were evaluated by acceleration and dynamic strain, respectively. In particular, wavelet packets were used to investigate the spectrum characteristics of the tunnel structure in depth. The failure process of the model can be divided into three stages. The upper-span and the under-crossing tunnels showed different failure characteristics. Additionally, the lining damage on the outer surface of the tunnel mainly occurred on the right side arch waist and the left side wall, whereas the lining damage on the inner surface of the tunnel mainly appeared on the crown and invert. Wavelet packet energy results showed that the energy characteristic distributions of the upper-span and the under-crossing tunnels were not consistent. Specifically, the energy eigenvalues of the crown of the upper-span tunnel and the invert of the under-crossing tunnel were the largest, which should be considered to be the weak parts in the seismic design.
4
Guo, Jinnan, and Angui Li. "Modelling ventilation and convective heat transfer in deeply buried underground tunnels based on boundary layer theory." E3S Web of Conferences 356 (2022): 02009. http://dx.doi.org/10.1051/e3sconf/202235602009.
Повний текст джерелаАнотація:
Underground traffic tunnels serve as the entry and exit buildings for underground spaces. Most of the ventilation and air-conditioning systems in underground spaces rely on traffic tunnels for cooling or preheating to save energy. The temperature distribution of traffic tunnels has always attracted the attention of researchers. In this study, a heat transfer model of a traffic tunnel was established based on energy conservation and boundary layer theory, and the field test was carried out. The calculation model provided in this study was in good agreement with the field measurement results. It is found that the dimensionless air temperature of the traffic tunnel decays exponentially along the tunnel at the same time. The air temperature in the traffic tunnel fluctuates with time, and the simple harmonic fluctuation decreases along the tunnel. In summer, the air temperature decreases and increases exponentially along the tunnel during the day and night, respectively. In this study, a heat transfer model for calculating the temperature distribution of underground traffic tunnels was theoretically established, which provided an important theoretical support for underground traffic tunnels as natural air conditioners. The establishment of heat transfer model of underground traffic tunnel has significant economic and environmental benefits.
5
Sekularac, Milan. "Experimental determination of tunnel ventilation axial ducted fan performance." Thermal Science 20, no. 1 (2016): 209–21. http://dx.doi.org/10.2298/tsci140624108s.
Повний текст джерелаАнотація:
To investigate traffic tunnel ventilation flows, a scaled model of a traffic tunnel with longitudinal ventilation system based on ducted fans is used. Flows in tunnels are influenced by tunnel geometry, fan characteristics, ventilation operation scenario, vehicle traffic, atmospheric factors, etc. To analyze flow fields of tunnels in detail, knowledge of tunnel jet-fan properties and turbulent flow characteristics at the fan exit are required, and can be used as input data for CFD boundary conditions of tunnel flow computation. For this purpose experimental measurements were done using the hot wire anemometry technique. The obtained results, trough ensemble-averaged and time averaged profiles of all velocity components, turbulence intensity, turbulent kinetic energy, integral flow length scales, available Reynolds stresses, Turbulent kinetic energy production rates and the fan thrust performance, are presented. These data allow us to analyze in more detail the influence of fan flow on energy and pollutant removal efficiencies of the tunnel ventilation and to evaluate accuracy of CFD studies on fan improvements.
6
Chai, Lunlei, Xing Wang, Xingbo Han, Yongxu Xia, Yongdong Wang, and Ping Lei. "Optimization Method for Twin-Tunnel Complementary Ventilation Design and Its Energy Saving Effect." Mathematical Problems in Engineering 2019 (May 22, 2019): 1–19. http://dx.doi.org/10.1155/2019/6301041.
Повний текст джерелаАнотація:
Based on the compensation principle and optimization theory, an energy conservation optimization mode for twin-tunnels complementary ventilation design was proposed. And, compensation concept utilization in energy conservation of long tunnels ventilation was discussed. The energy consumption for long tunnels can be reduced significantly by remoulding longitudinal ventilation to complementary ventilation of single U-type mode or normal mode. The short-term and long-term ventilation systems of the Qingniling Tunnel, Dabieshan Tunnel, and Lianghekou Tunnel were redesigned using the optimization method, and the new scheme was compared to the original design in terms of ventilation effects, and energy consumption. In redesign, the energy consumption of short-term ventilation systems decreased 240 kW, 150 kW, and 390 kW, and energy efficiency increased by 40%, 50%, and 68.4%, respectively. In the long term, the numbers of those were 1185 kW, 1185kW, and 540 kW, and 42.5%, 58.09%, and 45%, while the pollutants concentration increased a little. The study can provide a reference for the energy efficient design of ventilation systems in long and extra-long highway tunnels.
7
Rustemli, Sabir, Behcet Kocaman, and Suat Avcil. "Comparative Analysis of High-Pressure Sodium Vapor Luminaires with LED Luminaires in Tunnel Illumination." Light & Engineering, no. 04-2022 (August 2022): 87–96. http://dx.doi.org/10.33383/2022-003.
Повний текст джерелаАнотація:
Nowadays, some roads pass through underground tunnels due to technical inadequacy and high economic costs in constructing highways, railways, and pedestrians. Tunnels are opened to pass through obstacles on the route (mountain, hill, etc.) to force the driver, disturb him, reduce the ramps that could endanger safety depending on nature’s state, and shorten travel distances. In this way, number of tunnels along with the road increases, and illuminating these tunnels with different characteristics varies day and night. Tunnel illumination calculations and applications are essential as good tunnel illumination ensures the same flow of comfort, speed, and safety as on the approaching road. Moreover, with the advancement of tunnel technology, many types of equipment are used inside and outside the tunnel, and electricity needs vary according to these types of equipment. In this research, the importance of tunnel illumination was discussed and comparative illumination analysis in 8 August tunnel in Bitlis was conducted. Illumination for the Bitlis 8 August tunnel was done using luminaires with high-pressure sodium vapor lamps, and the grid was used to generate all the energy required. In this study, the energy used by the Bitlis 8 August tunnel for illumination was obtained from the accurate data and the results were compared with the initial situation when the same system was installed using light emitting diode (LED) illumination technology.
8
Li, Ting Chun, Yun Teng Yin, and Jian Zhang Liu. "Analysis on Seismic Damage Mechanism and Anti-Seismic Measures of Tunnels in Fault Fracture Zone." Advanced Materials Research 446-449 (January 2012): 2110–17. http://dx.doi.org/10.4028/www.scientific.net/amr.446-449.2110.
Повний текст джерелаАнотація:
Fault fracture zone is an important factor that leads to tunnel seismic damage. In order to research failure mechanism and anti-seismic measures of tunnels across large fault fracture zone, theoretical analysis and numerical simulation has been done to Jiaozhou Bay submarine tunnel in Qingdao. The research results indicate that: in fault fracture zones, surrounding rocks instability resulting from ground motion, the huge earthquake inertial force, and the deformation energy by bedrock surface wave with macro energy all can cause damage to tunnel lining, yet the latter is the primary reason; when the differences of mass density and stiffness between tunnel lining and wall rocks become big, ductile tunnels with light weight will aggravate damage to tunnels rather than improve their anti-seismic capability; keeping stability of surrounding rocks and guaranteeing mass density and stiffness of tunnel lining to be the same as or similar to that of surrounding rocks could prevent tunnel damages in fault fracture zone, yet the latter is the most effective way. This research achievement can set particular examples for research on seismic damage mechanism and for anti-seismic design of tunnel structure in highly seismic regions.
9
Chai, Lunlei, Xing Wang, Xingbo Han, Jing Song, Ping Lei, Yongxu Xia, and Yongdong Wang. "Complementary Ventilation Design Method for a Highway Twin-Tunnel Based on the Compensation Concept." Mathematical Problems in Engineering 2018 (October 14, 2018): 1–13. http://dx.doi.org/10.1155/2018/2393272.
Повний текст джерелаАнотація:
Based on the compensation concept, an improved method for twin-tunnel complementary ventilation design considering differences in key pollutants in the uphill and downhill tunnels was proposed. The results demonstrate that the scheme developed using the improved method is more energy efficient when the energy consumption of the interchange channel is included. Here, a larger design of air volume is allocated to the uphill tunnel, and the admissible pollutant concentration for its exits. The complementary ventilation system of the Qingniling Tunnel, Dabieshan Tunnel, and Lianghekou Tunnel was redesigned for long-term performance using the improved method, and the resulting scheme was compared to that designed using the current method in terms of the total required air volume, interchange air volume, ventilation effects, and energy consumption. The results show that these factors in improved method are significantly smaller than that of the current method with an allowable reduction of ventilation effects. Moreover, the total airflow required in the Qingniling Tunnel was reduced from 889.31 to 796.74 m3/s, with a decrease rate of 10.4%; the interchange air volume was reduced from 203 to 175 m3/s, and the estimated energy consumption was decreased from 2760 to 2065.9 kW. This represents a 26% improvement in energy efficiency. The proposed method can provide a reference for the energy efficient design of ventilation systems in extra-long highway tunnels.
10
Han, Feng, Jigang Li, Yuancheng Cai, Qiang Wang, and Junling Qiu. "Application of Energy-Concentrated Hydraulic Blasting Technology in Tunnel Construction in China." Shock and Vibration 2022 (May 2, 2022): 1–17. http://dx.doi.org/10.1155/2022/4724343.
Повний текст джерелаАнотація:
The construction of traffic network brings opportunities to the development of tunnel construction technology. At present, the construction of rock tunnels is still dominated by drilling and blasting. There are some problems in conventional blasting, such as over and underexcavation, damage of surrounding rock, large blasting vibration, and high content of tunnel dust. The energy-concentrated hydraulic blasting technology (ECHBT) combines the advantages of energy-concentrated blasting technology (ECBT) and hydraulic blasting technology (HBT) and makes up for the defects of conventional blasting. This paper summarizes the principle of ECHBT and its application effect in tunnel construction in China. In addition to solving the problems existing in conventional blasting technology, ECHBT can also improve tunneling efficiency, can be used in special stratum tunnels, and can save construction costs. However, there are also some factors affecting the blasting effect in practical applications, which need to be paid attention to. At present, there is little theoretical research on ECHBT; with the further improvement of optimization research, it can be expected to be more widely used in the field of tunnel construction.
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Lombardi, Mara, Davide Berardi, Marta Galuppi, and Maurizio Barbieri. "Green Tunnel Solutions: An Overview of Sustainability Trends in the Last Decade (2013–2022)." Buildings 13, no. 2 (February 1, 2023): 392. http://dx.doi.org/10.3390/buildings13020392.
Повний текст джерелаАнотація:
In the last decade, green solutions for road tunnels have steadily emerged in the field of engineering. The focus has been on using renewable energy sources to conserve energy and address issues of disaster risk management, territorial resilience and vulnerability, especially as these issues relate to critical infrastructures (CIs), such as roads and railways. Focusing on the equilibrium of the infrastructure through integrated system services and their external effects guarantees a better evaluation of both effects as they relate to other systems and energy consumption optimisation. To this end, a systematic literature review has been conducted herein that collects and analyses studies carried out in the last decade that relate to green energy solutions in tunnels. Upon a review of the Scopus database from 2013 to 2022, 46 conceptual and empirical studies were selected. Classifications and discussions were then developed according to the main issues identified (e.g., energy saving in road tunnels, zero-energy tunnels, renewable energy sources, tunnel safety lighting, and sustainable infrastructure). Each contribution constitutes a part of the current literature that combines the problems of tunnel safety (as represented by the energy costs of safety devices, e.g., tunnel lighting systems) with issues of renewable energy sources in tunnels. The results of this systematic review offer ideas for future directions of the ‘green’ vision for tunnel infrastructure. This study represents the state-of-the-art of renewable energy solutions currently present worldwide. Gaps in the literature that have yet to be addressed include how to build a green system as well as how to balance its life costs. The review supports the claim that the integration of renewable energy sources can exploit innovative solutions related to the concept of resilience.
12
Zhuang, Duanyang, Ke Ma, Chunan Tang, Zhengzhao Liang, and Zhenwei Wang. "Microseismic Monitoring of Energy Changes in Deep Tunnels during the TBM Tunneling of the Jinping II Hydropower Station." Advances in Civil Engineering 2018 (July 18, 2018): 1–15. http://dx.doi.org/10.1155/2018/5364628.
Повний текст джерелаАнотація:
The TBM tunneling at the Jinping II hydropower station in Southwest China has received extensive concerns around the world because of its large engineering scale and the high rockburst risks faced in the tunnel advancement. The associated energy changes of rockbursts and control method for safe TBM tunneling are to be further investigated. A movable microseismic (MS) monitoring system was established to capture the MS events and rockbursts when the TBM excavated the headrace tunnel #1 at the Jinping II hydropower station. The spatial and temporal patterns of the energy changes in the tunnel rock masses were studied. Meanwhile, the evolution of a rockburst encountered in front of the TBM excavation face was revealed, and the performance of the top pilot tunnel method on the reduction of the rockburst risks in the headrace tunnel #1 was evaluated based on the energy changes of the surrounding rock masses. It can be concluded that energy accumulation and energy release firstly occurred in the surrounding rock masses at the southern end of the top pilot tunnel section of the headrace tunnel #1. Then, energy transference of the rock masses took place from the southern end to northwest of the top pilot tunnel giving rise to the occurrence of a moderate rockburst about 30 m in front of the tunnel. However, no rockbursts appeared when the TBM excavated through the top pilot tunnel section of the headrace tunnel #1. Therefore, the top pilot tunnel method really works in reducing the risks of rockbursts during the TBM tunneling in deep tunnels.
13
Meng, Kun, Chunyi Cui, Cheng Zhang, and Hailong Liu. "The Ontology-Based Approach Supporting Holistic Energy-Tunnel Design considering Cost, Heat Flux, and System Feasibility." Advances in Materials Science and Engineering 2021 (November 29, 2021): 1–13. http://dx.doi.org/10.1155/2021/8919599.
Повний текст джерелаАнотація:
As an emerging geothermal structure, the energy tunnel has been an important part of geothermal engineering. However, the conventional methods for designing energy tunnels mostly rely on complex numerical models. Furthermore, a macrolevel multidomain collaborative design method to consider multiple areas and design indicators is unavailable. This study combined ontology and semantic Web rule language to establish the domain knowledge of energy tunnels which is an enrichment of the conventional ground source heat pump domain knowledge and develop a comprehensive decision-making tool named OntoETS for the design of energy-tunnel systems. The tool can promote the optimal design scheme with an optimal combination of multiple indexes through an analysis of the economy, heat flux, and system feasibility of the energy-tunnel system from a macroperspective by combining multiple domains. Furthermore, a case study was conducted to demonstrate the effectiveness and practicability of the developed holistic decision-making system.
14
Liu, Weiwei, Jianxun Chen, Yanbin Luo, Zhou Shi, Xiang Ji, and Haoyang Zhu. "Study on the Annual Reduction Rate of Vehicle Emission Factors for Carbon Monoxide: A Case Study of Urban Road Tunnels in Shenzhen, China." Advances in Civil Engineering 2020 (September 3, 2020): 1–17. http://dx.doi.org/10.1155/2020/1686753.
Повний текст джерелаАнотація:
Environmental pollution and energy conservation in urban tunnels have become important issues that affect the scientific design and sustainable development of urban tunnels. The carbon monoxide (CO) concentration in urban road tunnels is regarded as a direct reflection and a useful tracer of the intensity of anthropogenic transportation activities. Previous studies in recent years have paid more attention to pollutant emission factors, but less to the calculation parameters of ventilation design for tunnels. This paper aims to study a reasonable annual reduction rate of CO base emission factors. Therefore, a detailed field measurement was carried out in the four typical urban road tunnels, Henglongshan Tunnel, Cejiexian Tunnel, Jiuweiling Tunnel, and Dameisha Tunnel in Shenzhen, China, from March 29 to September 16, 2014. Measurement results showed that the traffic flow of the four urban tunnels had been approaching the design value, or even beyond the limit. The average daily air velocities in the four tunnels were all within 5 m/s, whereas the maximum air velocity had exceeded the limit of 10 m/s. The CO concentrations in Henglongshan Tunnel, Cejiexian Tunnel, Jiuweiling Tunnel, and Dameisha Tunnel were 17 ppm, 7 ppm, 39 ppm, and 8 ppm, respectively. Moreover, it was found that the average CO emission factors of Henglongshan Tunnel, Cejiexian Tunnel, Jiuweiling Tunnel, and Dameisha Tunnel were 1.075 g/(km·veh), 1.245 g/(km·veh), 4.154 g/(km·veh), and 1.739 g/(km·veh), respectively. Based on the statistical data, the CO emission factors of mixed traffic and passenger cars decrease by an average of 16.4% and 33.3%, respectively, per year through the regression method and by an average of 17.4% and 29.0%, respectively, per year through the extremum method. Finally, when considering the safety factor of 20%, it is more reasonable for the CO base emission to adopt 4% as an annual reduction rate for ventilation design in urban tunnels.
15
Tian, Haigang, Tianyi Hao, Chao Liu, Han Cao, and Xiaobiao Shan. "Investigation of a Portable Wind Tunnel for Energy Harvesting." Aerospace 8, no. 12 (December 9, 2021): 386. http://dx.doi.org/10.3390/aerospace8120386.
Повний текст джерелаАнотація:
Current wind tunnels possess a large space volume and high manufacturing cost, which are not suitable for investigating micro energy harvesters. This paper aims to design and fabricate a small, portable and low-speed wind tunnel for energy harvesting. A wind tunnel structure was first designed, a finite element analyses is then utilized to obtain the airflow velocity and turbulence intensity at the testing section, and the influence of the structural parameters of the wind tunnel on the flow field performance is finally investigated to achieve better performance. An experimental prototype of the wind tunnel was fabricated to verify the simulation results. Results demonstrated that the distribution uniformity and average turbulence intensity at the test section decrease first and then increase with the increase of both the diffuser and contraction lengths. The rectifying and damping effect of the honeycomb increase with increasing porosity and thickness. When the diffuser and contraction lengths are 850 mm and 480 mm, respectively, a better distribution uniformity and a lower turbulence intensity can be achieved. Experimental results were in good agreement with the simulation values. The maximum airflow velocity can reach up to 24.74 m/s, and the minimum error was only 1.23%. The designed wind tunnel achieved low-speed, small, portable and stable functions. This work provides an important guidance for further investigating the piezoelectric energy harvesting.
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Liang, Shu Ying, and Chun Yu Yang. "Study of the Lighting of Entrance/Exit Segments of Urban Tunnels and Outside-Tunnel Roads Based on Visual Efficiency Theory." Applied Mechanics and Materials 470 (December 2013): 871–75. http://dx.doi.org/10.4028/www.scientific.net/amm.470.871.
Повний текст джерелаАнотація:
In order to avoid the black-hole effect, illumination of higher luminance should be installed at the entrance/exit segments of urban tunnels during the day because the luminance of outside urban tunnels is relatively high. But it basically remains the same higher (current status in China) during the night while the illuminating brightness of outside-tunnel urban roads is relatively lower, which is not conducive to driving safety and wastes lots of energy. Through the comparison research of domestic and foreign relevant standards of tunnel and road lighting, as well as measurement and analysis of the present status of entrance/exit segments lighting of 11 tunnels in Fujian, Guizhou, Chongqing, and the present status of some roads lighting in Beijing, Shanghai, Chengdu and Chongqing, it is found that there are significant differences between the luminance of tunnels entrance/exit segments and the luminance of outside-tunnel roads. Especially when drive from the bright inside to the outside, that is from the inside photopic vision environment to the outside scotopic vision and mesopic vision environment. Due to high speed and poor visual fitness, there exist potential safety hazards. At present, there is no visual fitness standard for lighting of entrance/exit segments of urban tunnels and outside-tunnel roads in china, the domestic and foreign relative researches are still not enough. Based on visual features, with response time as parameter, this article applies the visual efficiency method to study the lighting of entrance/exit segments of urban tunnels and outside-tunnel roads. In this thesis, the method of weakening illumination of entrance/exit segments of urban tunnels on the basis of existing standards and enhancing illumination of outside-tunnel roads has been provided. Thus the reduced value of entrance/exit segments of urban tunnels illumination and outside-tunnel roads illumination can be controlled from 3:1 to 5:1 to adapt to visual features. This thesis provides a new research approaches for achieving driving safety and lighting energy saving.
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Gonzalez, F. J., P. K. Kaiser, and M. S. Diederichs. "Energy Release Resulting from Sudden Excavation Shape Changes during Two-sided Strainbursts." IOP Conference Series: Earth and Environmental Science 1124, no. 1 (January 1, 2023): 012082. http://dx.doi.org/10.1088/1755-1315/1124/1/012082.
Повний текст джерелаАнотація:
Abstract When tunnels in underground hard rock mines experience strainbursts, the effective shape of the tunnel suddenly changes as part of the rock fails, notches form and the broken rock bulks inside the strainburst volume. For circular tunnels, this dynamic rupture and bulking process causes a shape change with associated displacements and velocities in the surrounding elastic rockmass and at the excavation walls. This process can be approximated for circular tunnel bursting in elastic rock by a shape change from circular to elliptical and Maugi’s solution [1] can be adapted to estimate related displacements and average ground velocities. If these velocities are imposed on a volume of rock or shotcrete with a given mass, the mass can be ejected, and the corresponding kinetic energy can be estimated. When combined with the sudden bulking of the fractured rock, displacements and velocities are magnified between the elliptical shape and the pre-burst (circular) shape of the tunnel. This study focuses on the effect of the combined excavation response with elastic and bulking deformations to assess frequently observed excavation damage processes involving ‘shotcrete rain’ and heave of floor slabs caused by these shape changes. An analytical solution is presented for circular tunnels to estimate the elastic and bulking displacements, the resulting velocities, and energy demands.
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Peeling, James, Matthew Wayman, Isabela Mocanu, Philippe Nitsche, John Rands, and John Potter. "Energy Efficient Tunnel Solutions." Transportation Research Procedia 14 (2016): 1472–81. http://dx.doi.org/10.1016/j.trpro.2016.05.221.
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Belskikh, Yu S., N. K. Shandala, A. V. Titov, D. V. Isaev, М. P. Semenova, V. А. Seregin, T. A. Doroneva, Yu V. Gushchina, and A. A. Filonova. "Current Radiation Situation at the Remedied Dumps of Mine No. 2 of the Lermontov Production Association Almaz." MEDICAL RADIOLOGY AND RADIATION SAFETY 67, no. 3 (July 2022): 21–25. http://dx.doi.org/10.33266/1024-6177-2022-67-3-21-25.
Повний текст джерелаАнотація:
Purpose: Assessment of the current radiation situation around dumps of mine No. 2 of the Lermontov Production Association Almaz after remediation. Material and methods: The methods of pedestrian gamma survey using the portable spectrometric complex MKS-01A “Multirad-M”. Soil sampling was used to measure radionuclide specific activities. Activities of gamma emitting radionuclides were measured by a stationary gamma spectrometer of the CANBERRA Company. Activities of 210Po and 210Pb following radiochemical separation of these radionuclides were measured using the radiometric installation UMF-2000. Short-term measurements of radon EEC were carried out with aerosol alpha-radiometer RAA-20P2 Poisk. Results: After remediation, gamma ambient dose equivalent rate does not exceed 0,5 μSv/h at all dumps, with the exception of local areas around tunnels No. 9, 10 and 11. In the area around tunnel No. 9, gamma ambient dose equivalent rate reaches 0,55 μSv/h, in the area of tunnel No. 10–5 μSv/h and higher, and in the area of tunnel No. 11 – up to 0,9 μSv/h. In the areas around all tunnels, except for tunnel No.11, soil does not belong to solid radioactive waste. In a small area near tunnel No. 11, the content of radionuclides in the soil exceeds the criteria for classifying as solid radioactive waste. Radon EEC in the surveyed area generally did not exceed 30 Bq/m3. Increased values up to 200 Bq/m3 were registered in the area of tunnel dumps, the mouths of which were not fully isolated (tunnels No. 6, 7 and 10). Moreover, directly at the mouth of tunnel No. 10, radon EEC values reached 65000±11000 Bq/m3. Conclusions: At all surveyed remedied dumps, except for dumps of tunnels No. 10 and 11, the radiation situation in some areas does not meet the requirements established in the remediation project in accordance with the “Health Care Rules for the Closure, Conservation and Conversion of Enterprises for the Mining and Milling Radioactive Ores” and stay in these territories does not pose a hazard to the population.
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Wang, Lin Feng, Hong Mei Tang, and Hong Kai Chen. "Energy Analysis for Energy Dissipation Shed-Tunnel’s Rockfall Impact Signal." Advanced Materials Research 261-263 (May 2011): 1054–57. http://dx.doi.org/10.4028/www.scientific.net/amr.261-263.1054.
Повний текст джерелаАнотація:
Shed-tunnel is one of common prevention measures along the highway. First, denoised the rockfall impact signal when the rock impact the ordinary shed-tunnel and the energy dissipation shed-tunnel by the wavelet theory. The calculation result indicated that the wavelet theory’s denoise effect is very good. Then, pick-up each frequency band’s the rockfall impact signal, and analysed the energy for each frequency band’s impact signal. The result indicated that the energy dissipation shed-tunnel’s impact energy concentrate in the low frequency part. There are only 0.4% impact energy in the high frequency part. Besides, the energy dissipation shed-tunnel’s impact energy in the low frequency part is higher than the the ordinary shed-tunnel, and the energy dissipation shed-tunnel’s impact energy depressed velocity when the impact frequency increase is fast than the ordinary shed-tunnel. So the energy dissipation shed-tunnel’s design must consider the low frequency impact,and could ignore the high frequency impact.
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Xing, Yan Ying. "Approach on Pollution Gases Diffusion Path of Small Spacing Tunnel Entrance Based on CFD." Applied Mechanics and Materials 580-583 (July 2014): 1254–57. http://dx.doi.org/10.4028/www.scientific.net/amm.580-583.1254.
Повний текст джерелаАнотація:
Small spacing tunnel due to the special structure form and two tubes are only separated by a thin wall. This structure form is likely to cause secondary pollution, pollution gas discharged into the adjacent tunnel. This phenomenon will lead to increased ventilation system energy consumption. This paper analysis gas diffusion path between two adjacent tunnels, using CFD (Ansys Fluent). To relieve the pollution gases secondary pollution of tunnel portal area, using CFD analyzed gas diffusion path under different circumstances, for opening hole on the top of sunshades, extended of the wall between two adjacent tunnels and other programs, and identify more comprehensive disposal program.
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Panthi, Krishna Kanta. "Predicting Tunnel Squeezing: A Discussion based on Two Tunnel Projects." Hydro Nepal: Journal of Water, Energy and Environment 12 (October 28, 2013): 20–25. http://dx.doi.org/10.3126/hn.v12i0.9027.
Повний текст джерелаАнотація:
Tunnel squeezing is a phenomenon, which is frequently confronted while tunneling through Himalayan rock mass. Weak and schistose rocks like mudstone, shale, slate, phyllite, schist, highly schistose mica gneiss and the rock mass of the tectonic fault zones are incapable of sustaining high stresses. A reliable and trustworthy prediction on the extent of squeezing is therefore essential. The reliable prediction results help to make strategy regarding stabilizing measures and optimization of tunnel rock support well in advance. This paper is mainly focused in analyzing the tunnel squeezing that took place in connection with the two tunnel cases; i.e. Kali Gandaki 'A' and Middle Marsyangdi headrace tunnels. The main focus is given to look on the applicability of squeezing analysis using Hoek and Marinos approach in combination with the equation proposed by Panthi for the estimation of rock mass strength for highly schistose rocks of the Himalaya. The measured tunnel convergence (squeezing) and lab tested mechanical properties of the rocks from these two headrace tunnels have been used to verify the applicability of the proposed methods and also the uncertainty analysis approach on squeezing introduced by Panthi.Hydro Nepal; Journal of Water, Energy and EnvironmentVol. 12, 2013, JanuaryPage: 20-25DOI: http://dx.doi.org/10.3126/hn.v12i0.9027Uploaded Date : 10/28/2013
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Zhu, Huangda, Feng Liu, Jiawei Cui, and Wangbin Peng. "Research on tunnel damage process based on acoustic emission technology." Journal of Physics: Conference Series 2196, no. 1 (February 1, 2022): 012001. http://dx.doi.org/10.1088/1742-6596/2196/1/012001.
Повний текст джерелаАнотація:
Abstract For a long time, it is generally believed that the tunnel has excellent seismic performance and can resist earthquake damage, so it will not be damaged. However, according to the survey of tunnels after the Wenchuan earthquake in China, 110 tunnels were damaged to varying degrees. In this paper, a series of shaking table tests were carried out on the proportional tunnel model under seismic excitation. Acoustic emission technology is combined with seismic excitation to identify and describe the damage of tunnel lining. The tunnel lining strain and acoustic emission signals are collected in the test. In addition, this paper also introduces the use of acoustic emission technology to describe the damage of tunnel lining. Taking the crown as an example, through the correlation analysis of amplitude, counts and energy, it is preliminarily judged that the crown is damaged under working conditions 7 and 8; Then combined with strain analysis, it is proved that the correlation analysis is reasonable. Finally, the rationality of correlation analysis is further explained by the changes of counts, energy, and its cumulative parameters with time. At the same time, the damage process of tunnel lining under seismic excitation is described by defining damage variables, which can be divided into three stages: initial compression elastic stage, yield failure stage and residual stage.
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Jearsiripongkul, Thira, Suraparb Keawsawasvong, Chanachai Thongchom, and Chayut Ngamkhanong. "Prediction of the Stability of Various Tunnel Shapes Based on Hoek–Brown Failure Criterion Using Artificial Neural Network (ANN)." Sustainability 14, no. 8 (April 11, 2022): 4533. http://dx.doi.org/10.3390/su14084533.
Повний текст джерелаАнотація:
In this paper, artificial neural network (ANN) models are presented in order to enable a prompt assessment of the stability factor of tunnels in rock masses based on the Hoek–Brown (HB) failure criterion. Importantly, the safety assessment is one of the serious concerns for constructing tunnels and requires a reliable and accurate stability analysis. However, it is challenging for engineers to construct finite element limit analysis (FELA) algorithms with the HB failure criterion for tunnel stability solutions in rock masses. For the first time, a machine-learning-aided prediction of tunnel stability based on the HB failure criterion is proposed in this paper. Three different shapes of tunnels, i.e., heading tunnel, dual square tunnels, and dual circular tunnels, are considered. The inputs include four dimensionless parameters for the heading tunnel including the cover-depth ratio, the normalized uniaxial compressive strength, the geological strength index (GSI), and the mi parameter. Moreover, dual square and circular tunnels include one more additional parameter namely the distance ratio. The results present the best ANN models for each tunnel shape, providing very reliable solutions for predicting the tunnel stability based on the HB failure criterion.
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Hasan, Mohammed Munif, and Shabudin Mat. "Data Reduction Analysis on UTM-LST External Balance." International Journal for Research in Applied Science and Engineering Technology 10, no. 10 (October 31, 2022): 952–59. http://dx.doi.org/10.22214/ijraset.2022.47097.
Повний текст джерелаАнотація:
Abstract: The effective use of wind-tunnel testing in determining aerodynamic properties of a body is very much dependent upon the reliability and speed with which wind-tunnel data can be reduced. The operating efficiency of the wind tunnels is substantially improved by the capability of providing lower aerodynamic coefficients in real time, or online, which decreases the expensive wind-tunnel time necessary for each test. This paper describes a system for presenting reduced wind-tunnel data in real time for UTM-LST. The requirements for data-handling equipment and data reduction procedures for wind tunnels are quite diverse, and depend upon the wind tunnel design and the type of tests for which they are used. The supersonic wind tunnels mentioned in this description have a variety of force-balance systems and are used for force tests, pressure tests, and other research projects. Consequently, the problems associated with in order to solve this diversity we build a computerized program where we can find the transformation of axis and aerodynamic characteristics at ease. This program can find the values of different aerodynamic coefficients with certain angle of attacks.
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Tang, Min, Hong Li, and Chun’an Tang. "Study on Preliminarily Estimating Performance of Elementary Deep Underground Engineering Structures in Future Large-Scale Heat Mining Projects." Geofluids 2019 (June 13, 2019): 1–10. http://dx.doi.org/10.1155/2019/3456307.
Повний текст джерелаАнотація:
Geothermal energy will become an important part of energy in the future because of its advantages in source stability, sustainability, and potential high utilization ratio. In particular, the development and utilization of deep geothermal energy from HDR have gradually attracted people’s attention. Aiming at solution to the bottleneck of EGS-D, a new EGS-E based on excavation technology is proposed. In this paper, a concise and direct method for estimating the early performance of this disruptive and innovative geothermal development scheme is established as a viable alternative to supercomputing for the subsequent quantitative research of the corresponding relationship between a typical deep engineering structure and its heat extraction efficiency. Firstly, the effects of the fixed temperature at a tunnel wall, the radius of a tunnel, and the rock type on the annual heat extraction rate of the tunnel are studied based on the analytical solution of a one-dimensional radial plane problem of the transient heat conduction through high-temperature surrounding rock to the tunnel wall covering 30 years. Then, three different estimation methods of EGS-E efficiency with comb-shaped and chessboard-shaped underground tunnels, respectively, are studied, and the research ideas for the estimation of the EGS-E system with more complicated cobweb-shaped tunnels are pointed out.
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Shafagh, Ida, Simon Rees, and Fleur Loveridge. "Investigations into thermal resistance of tunnel lining heat exchangers." E3S Web of Conferences 205 (2020): 06006. http://dx.doi.org/10.1051/e3sconf/202020506006.
Повний текст джерелаАнотація:
Geothermal energy is a promising and sustainable source that can reduce current dependence on conventional fuels for thermal energy production. To exploit this source of energy thermo-active geostructures such as tunnel lining heat exchangers are being investigated theoretically as well as experimentally. These geostructures are composed of concrete panels embedded with reinforcement cages fitted with absorber pipes. Several engineering projects in China, Finland and Italy have deployed such heat exchangers in tunnels. To achieve efficient energy production, characterisation of these systems require realistic models of the substructure heat exchanger. Therefore investigations into thermal resistance of the heat exchanger is vital. The present study is concerned with quantifying the thermal resistance of tunnel lining heat exchangers where the thermal boundary surfaces are applied at surfaces representing the adjacent ground and the exposed concrete, in addition to the pipe surface. Steady state temperature distribution in a two dimensional cross section of a tunnel lining heat exchanger is investigated using the boundary collocation least squares method. Design parameters including pipe and tunnel lining specifications are used as model inputs.
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Sharaf-Eldin, Mohamed A., Zaher Mundher Yaseen, Adel H. Elmetwalli, Salah Elsayed, Miklas Scholz, Zainab Al-Khafaji, and Genesia F. Omar. "Modifying Walk-In Tunnels through Solar Energy, Fogging, and Evaporative Cooling to Mitigate Heat Stress on Tomato." Horticulturae 9, no. 1 (January 6, 2023): 77. http://dx.doi.org/10.3390/horticulturae9010077.
Повний текст джерелаАнотація:
Global warming is by far the most significant issue caused by climate change. Over the past few decades, heat stress has intensified into a serious issue that has a negative impact on crop production. Hence, it is crucial to modify cultivation systems to cope with this kind of stress, particularly in arid dry regions. In comparison to open-field cultivation, tomato production under protected cultivation techniques in walk-in tunnels that are suited for different farmers’ financial abilities was evaluated during the late summer season. The studied tunnels included a shaded net tunnel with natural ventilation, net tunnel with a fogging system and plastic tunnel with evaporative cooling (wet pad and fans). For the operation of fogging and evaporative cooling systems, solar energy was used as a sustainable, eco-friendly energy source. The results indicated that the solar energy system successfully operated the studied cooling systems. All studied protective cultivation techniques mitigated heat stress on tomato plant and improved the microclimate under walk-in tunnels. Moreover, evaporative cooling and fogging systems significantly increased plant leaf area, cell membrane efficiency and the contents of chlorophyll, relative water and proline compared to the net tunnel with natural ventilation. Furthermore, a marked reduction in physiological disorders was noticed. Improved physiological and biochemical parameters and limited physiological diseases led to higher fruit set, marketable fruit yield and total productivity. The percentage of marketable fruit yield increased by around 31.5% with an evaporative cooling system, 28.8% with a fogging system and 17% with a shaded net tunnel with no positive cooling as compared to an open field. However, the plants grown in open-field cultivation without protection significantly deteriorated from heat stress and had a high incidence of physiological disorders. The most incident physiological disorders were blossom-end rot, cracking, internal white tissues, sunscald, puffiness, blotchy ripening, cat face and exserted stigma. It is recommended to use a solar energy system to modify microclimate conditions through fogging or evaporative cooling under walk-in tunnels to ameliorate heat stress on grown tomato in the late summer season for higher fruit yield and fewer physiological disorders.
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Zhang, Kun, Xi Chen, Wei Yin, Kun Hu, and ShengXue Zhu. "Analysis of Shear Stagger Deformation of Existing Shield Tunnel below Induced by Quasirectangular Shield Tunneling." Geofluids 2023 (January 25, 2023): 1–15. http://dx.doi.org/10.1155/2023/3195453.
Повний текст джерелаАнотація:
To use urban underground space more efficiently is a research hotspot of urban underground development. Compared with conventional circular tunnels, quasirectangular tunnels have the characteristics of larger space utilization and higher economic benefits, gradually used in urban rail engineering in recent years. But the ground disturbance induced by the quasirectangular tunneling needs further researches. This paper derives the calculation formula of the additional stress of existing shield tunnel below caused by the quasirectangular shield tunneling by mirror image method and Mindlin solution. The existing shield tunnel is simplified as an elastic foundation short beam connected by tensile springs and shear springs. This paper establishes the energy-deformation coupling equation by principle of minimum potential energy so that the disturbance induced by quasirectangular tunneling to the existing shield tunnel below can be analyzed. The FEM is established with the actual engineering as the background. It is by comparing the numerical simulation results and field monitoring data that the theoretical prediction formula is verified. The research results show that the theoretical calculation results consist highly with numerical simulation results and field monitoring data, verifying practicality of formulas in this paper. Calculation results of shear stagger model are more accurate, which can be also used to analyze the staggered and splayed amount between segments. As the tunnel construction proceeds, uplift deformation, segment stagger, shear force, and segment splay of existing shield tunnel gradually increase, which are symmetrical about the central axis of new tunnel. After the shield machine passes through the central axis of the existing shield tunnel for 20 meters, stable disturbance to the existing shield tunnel occurs. Stagger amount and shear force between segments reach the minimum at the position with maximum uplift deformation of existing shield tunnel and reach the maximum at inflection point of the uplift deformation curve.
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Peña-García, Antonio, Luisa-María Gil-Martín, Roberto Escribano, and Antonio Espín-Estrella. "A Scale Model of Tension Structures in Road Tunnels to Optimize the Use of Solar Light for Energy Saving." International Journal of Photoenergy 2011 (2011): 1–9. http://dx.doi.org/10.1155/2011/313952.
Повний текст джерелаАнотація:
Shifting the threshold zone of road tunnels with semitransparent tension structures has shown itself to be an effective way of saving energy in regards to electricity consumption, maintenance, and construction materials used in the electrical lighting, thus lessening negative environmental impacts. Even though the shape of the tension structure has a major influence on energy savings, the optimal type of structure for each tunnel is often difficult to determine, because experiments using real tunnels are extremely expensive. It is thus necessary to find methods of doing this that are both reliable as well as economical. In this research study, three candidate structures were set up at the portal of a scale model of a real tunnel. The energy savings in each case were analyzed and compared. As a result, it was possible to formulate a new equation that calculates the energy savings in the threshold zone.
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Priyadarshini, Kompala, Nisanth Sai, Peddi Sai Krishna, and Dr Shruti Bhargava Choubey. "Automatic Tunnel Lighting System for Road Traffic with Auto Exhaust Fan." International Journal for Research in Applied Science and Engineering Technology 10, no. 6 (June 30, 2022): 1254–68. http://dx.doi.org/10.22214/ijraset.2022.44035.
Повний текст джерелаАнотація:
Abstract: The main objective of this project work is to provide intelligent lighting scheme for the tunnels of hill station roads. Tunnel means tubular passage cut through the hill or underground, these tunnels remain in dark always and inside the tunnels proper lighting system are essential to avoid the accidents. In this regard our government is arranging lights and they are glowing continuously irrespective of traffic and lot of energy is wasted. To avoid energy losses at these places, this efficient and intelligent lighting scheme is developed, which works automatically depending up on the road traffic and minimizes the energy consumption. In addition, all the vehicles release the waste (exhaust) gases that may be stagnated in the tunnel, due to lack of circulation with the outside environment. So, a gas detector/sensor is used for sensing these exhaust gases released from the automobiles and pump them outside the tunnel through an exhaust fan automatically. The process begins from the sensors; optical sensors are used for sensing the vehicles and depending up on the traffic density, inside lights of tunnel are controlled automatically. For example, many vehicles entered in to the tunnel from both the sides, all the lights are energized and as the traffic moving forward depending up on the clearance, required lights are energized, during the clearance means no vehicle is inside, all the lights remain in off condition automatically. The system is designed with Microcontroller, four sets of Infra Red sensors are used and they can be arranged either side of the tunnel in by directional mode. All the sensors are interfaced with Microcontroller and the program is prepared such that, depending up on the interrupted signals obtained from the sensors. The sensor used in the project work can detect all types of petroleum gases; in addition, it can detect smoke also. The sensor interfaced with the controller can energize exhaust fan automatically when it detects any type of gas or smoke.
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Qin, Li, Antonio Peña-García, Arturo S. Leon, and Jian-Cheng Yu. "Comparative Study of Energy Savings for Various Control Strategies in the Tunnel Lighting System." Applied Sciences 11, no. 14 (July 9, 2021): 6372. http://dx.doi.org/10.3390/app11146372.
Повний текст джерелаАнотація:
Tunnel lighting is the most significant component in total energy consumption in the whole infrastructure. Hence, various lighting control strategies based on light-emitting diode (LED) technology have been investigated to conserve energy by decreasing luminaires’ operating time. In this study, four kinds of tunnel lighting control strategies and the development of their associated technologies are evaluated: no-control low-consumption lamps (LCL), time-scheduling control strategy (TSCS), daylight adaptation control strategy (DACS), and intelligent control strategy (ICS). This work investigates the relationship between initial investment and electrical costs as a function of tunnel length (L) and daily traffic volume (N) for the four control strategies. The analysis was performed using 100-day data collected in eleven Chinese tunnels. The tunnel length (L) ranged from 600 m to 3300 m and the daily traffic volume (N) ranged from 700 to 2500. The results showed that initial investment costs increase with L for all control strategies. Also, the electricity costs for the LCL, TSCS, and DACS strategies increased linearly with L, whereas the electricity cost for the ICS strategy has an exponential growth with L and N. The results showed that for a lifetime equal to or shorter than 218 days, the LCL strategy offered the best economical solution; whereas for a lifetime longer than 955 days, the ICS strategy offered the best economical solution. For a lifetime between 218 and 955 days, the most suitable strategy varies with tunnel length and traffic volume. This study’s results can guide the decision-making process during the tunnel lighting system’s design stage.
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Weijiang, Zhang. "Design of tunnel illumination control system with solar energy." MATEC Web of Conferences 173 (2018): 02003. http://dx.doi.org/10.1051/matecconf/201817302003.
Повний текст джерелаАнотація:
In order to solve the unmanned tunnel illumination in remote areas, control system is designed for tunnel lighting. Meanwhile, solar energy is used to solve the energy problem of tunnel lighting. Based on the specific requirements of the highway tunnel, the intelligent control algorithm is designed. On the basis of the algorithm, the intelligent control tunnel lighting system is realized. Control system for tunnel lighting is stable and reliable, unmanned operation can be realized. Practice shows that the intelligent tunnel lighting control system can be successfully applied in remote areas.
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Song, Ao, Bin Song, and Rongyi Qian. "Experiment of 3D Seismic Reflection Technique for Forward Probing on TBM Tunnel Face." Journal of Environmental and Engineering Geophysics 24, no. 4 (December 2019): 609–19. http://dx.doi.org/10.2113/jeeg24.4.609.
Повний текст джерелаАнотація:
Geophysical technologies are used to mitigate geological hazard caused by adverse geological conditions in front of a tunnel face. The prevailing method for forward probing for tunnels constructed by a tunnel boring machine (TBM) for advance prediction is based on seismic detection. Conventional tunnel seismic prediction technology uses P- and S-waves with sources fired on the tunnel wall or face and layout receivers on the tunnel wall to acquire the reflected waves. However, the results show that most of these methods have different deficiencies that are in either low detection accuracy, short detection depth, and/or multiplicity in imaging. This paper proposes a new high resolution tunnel advance prediction technology on the face based on 3D seismic wave detection. It arranges the 3D high-density source and recording geometry on the tunnel face to receive reflected P-waves for 3D imaging. By using the 3D numerical simulation, we first analyze the energy distribution and propagation characteristics of the wave field, which proves that our method is feasible. Compared with the conventional technologies, the seismic energy propagating towards the tunnel face is stronger and produces rich reflected information. The reflected wave has the advantages of bandwidth, strong energy and little interferences from surface wave, so that the seismic phases are easy to be identified. On this basis, we present the high resolution true 3D prediction technology to obtain more comprehensive and abundant azimuth information. Our approach is further validated by an application experiment in a real-world engineering project of water conveyance tunnel. The results show that the new technique has a greater detection length, higher detection accuracy and more reliable imaging results.
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Zhang, Heng, Shou Gen Chen, and Liang Chen. "A Study on Large Power Jet Ventilation Technology in Long Tunnel Construction." Applied Mechanics and Materials 94-96 (September 2011): 1800–1804. http://dx.doi.org/10.4028/www.scientific.net/amm.94-96.1800.
Повний текст джерелаАнотація:
One of difficulties in super long tunnels’ construction is the construction ventilation to meet the requirement of normal construction environment and assure the workers’ health. Using traditional tunnelling ventilation is very difficult to meet the need of super long tunnel construction. As the energy assumption is high and it is very expensive. This paper investigated the simulation of tunnel construction ventilation with large power jet fans during the construction of Jinping Auxiliary Tunnels by using the computational fluid code FLUENT, the layout of jet fans in the tunnels is optimized. It is found that the best layout of the jet fan is aroud the transverse channel under the direction of airflow and jet fan should not be too far away from the transverse channel. The CO mainly distributes in the upper part of the tunnel when the jet fan is installed at a higher position, this layout of the jet fan is beneficial to construction of tunnels.
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Insana, Alessandra, Marco Barla, and Jean Sulem. "Energy tunnel linings thermo-mechanical performance: comparison between field observations and numerical modelling." E3S Web of Conferences 205 (2020): 06008. http://dx.doi.org/10.1051/e3sconf/202020506008.
Повний текст джерелаАнотація:
Energy linings are receiving great interest due to their potential to transform a tunnel into a smart energy system for enhancing thermal comfort of buildings and metro stations, as well as to absorb waste heat from the tunnel environment. Yet, besides their thermal performance, the impacts of equipping segments with a net of pipes are still challenging in the framework of energy tunnels structural design. Indeed, the thermal regime of the concrete members is altered due to heat carrier fluid circulation. Hence, the need to shed some light on the possible limit states attainment arises. In this paper, field monitoring of stresses and strains are presented for the first time in relation to a full scale monitored prototype of Enertun energy tunnel lining installed in Turin, Italy. Experimental data are compared to the results of a coupled thermo-mechanical numerical model, showing to be in good agreement. Criticalities from the ultimate limit state do not emerge, although a deeper analysis of serviceability limit states attainment should be performed.
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Zhang, Qian, Li Li Dong, Wen Hai Xu, and Li Qin. "The Design of Tunnel Lighting Intelligent Control System." Applied Mechanics and Materials 734 (February 2015): 984–93. http://dx.doi.org/10.4028/www.scientific.net/amm.734.984.
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<p class="p0">It is serious that the electric energy waste exists in highway tunnel operation. Operators and institutes of scientific research pay more and more attention that how to reduce the energy consumption of lighting system of highway tunnels, improve the effect of tunnel lighting and ensure traffic safety. In order to solve the problem of the current tunnel lighting system with high energy consumption, a tunnel lighting intelligent control system based on environmental information perception and vehicle behavior information perception is proposed in this paper for ChiBai tunnel project. In this system, the existence of the vehicle or not is the basis of lighting state switching, environmental information and vehicle behavior information are the basis for calculation of the lighting brightness, pavement illuminance is real-time monitored by the monitoring cameras, closed-loop feedback control of the lighting brightness is achieved through real-time monitoring of pavement illuminance and PID algorithm. The intelligent control system is composed of five parts, in this paper, there are detailed introductions about the function of various parts of the system, including hardware structure, connecting method and the system of dimming control strategy, software functions and the equipment layout position.</p>
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Liu, Xiaohua, Chenglin Li, Guozhu Zhang, Linfeng Zhang, and Bin Wei. "Numerical Investigation on Energy Efficiency of Heat Pump with Tunnel Lining Ground Heat Exchangers under Building Cooling." Buildings 11, no. 12 (December 4, 2021): 611. http://dx.doi.org/10.3390/buildings11120611.
Повний текст джерелаАнотація:
For mountain tunnels, ground heat exchangers can be integrated into the tunnel lining to extract geothermal energy for building heating and cooling via a heat pump. In recent decades, many researchers only focused on the thermal performance of tunnel lining Ground Heat Exchangers (GHEs), ignoring the energy efficiency of the heat pump. A numerical model combining the tunnel lining GHEs and heat pump was established to investigate the energy efficiency of the heat pump. The inlet temperature of an absorber pipe was coupled with the cooling load of GHEs in the numerical model, and the numerical results were calibrated using the in situ test data. The energy efficiency ratio (EER) of the heat pump was calculated based on the correlation of the outlet temperature and EER. The heat pump energy efficiencies under different pipe layout types, pipe pitches and pipe lengths were evaluated. The coupling effect of ventilation and groundwater flow on the energy efficiency of heat pump was investigated. The results demonstrate that (i) the absorber pipes arranged along the axial direction of the tunnel have a greater EER than those arranged along the cross direction; (ii) the EER increases exponentially with increasing absorber pipe pitch and length (the influence of the pipe pitch and length on the growth rate of EER fades gradually as wind speed and groundwater flow rate increase); (iii) the influence of groundwater conditions on the energy efficiency of heat pumps is more obvious compared with ventilation conditions. Moreover, abundant groundwater may lead to a negative effect of ventilation on the heat pump energy efficiency. Hence, the coupling effect of ventilation and groundwater flow needs to be considered for the tunnel lining GHEs design.
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van, Maele, and Bart Merci. "Fire safety case study of a railway tunnel: Smoke evacuation." Thermal Science 11, no. 2 (2007): 207–22. http://dx.doi.org/10.2298/tsci0702207v.
Повний текст джерелаАнотація:
When a fire occurs in a tunnel, it is of great importance to assure the safety of the occupants of the tunnel. This is achieved by creating smoke-free spaces in the tunnel through control of the smoke gases. In this paper, results are presented of a study concerning the fire safety in a real scale railway tunnel test case. Numerical simulations are performed in order to examine the possibility of natural ventilation of smoke in inclined tunnels. Several aspects are taken into account: the length of the simulated tunnel section, the slope of the tunnel and the possible effects of external wind at one portal of the tunnel. The Fire Dynamics Simulator of the National Institute of Standards and Technology, USA, is applied to perform the simulations. The simulations show that for the local behavior of the smoke during the early stages of the fire, the slope of the tunnel is of little importance. Secondly, the results show that external wind and/or pressure conditions have a large effect on the smoke gases inside the tunnel. Finally, some idea for the value of the critical ventilation velocity is given. The study also shows that computational fluid dynamics calculations are a valuable tool for large scale, real life complex fire cases. .
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Omar, Priyanka, MVN Siva Kumar, and Subbarao Yarramsetty. "Management of Various Safety Parameters in Tunnel Construction: A Critical Review." E3S Web of Conferences 170 (2020): 06003. http://dx.doi.org/10.1051/e3sconf/202017006003.
Повний текст джерелаАнотація:
Population is growing rapidly and so are vehicles on roads. This leads to enormous need of tunnels and subways for easy locomotion and mobilization. From conventional tunnels, for sewage and water facilities to modern electrified tunnels, for mass transit and underwater highways, method of construction of a tunnel to its safety inspection and maintenance has taken a wide leap. Tunnel construction requires wide range of resources like human, technology, machinery, materials, energy, and finance. To handle all these resources simultaneously becomes complex and requires good management. Even with good management, accidents and hazards might occur. A critical review of various safety parameters while constructing a tunnel and its management is presented in this paper. This review paper discusses the history of safety of tunnels till present safety measures and techniques adopted around the world for different tunnels; various critical factors which affect the safety in tunnels; the extent of damage occurring due to these factors; numerous preventive measures which are adopted around the world to prevent loss of property and lives in tunnels; and advanced technology and software, which are being used in modern era to enhance safety in tunnel construction. The study from manual horse drawn-tramway to autonomous robotic system has been done. This paper also considers various tunnels around the world and gives a summary of factors for safety focused on for making these tunnels, with its adopted remedy.
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Bomford, Michael K., and Anthony Silvernail. "(34) Energy and Capital Costs of High Tunnel Construction." HortScience 41, no. 4 (July 2006): 1077A—1077. http://dx.doi.org/10.21273/hortsci.41.4.1077a.
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Commercial vegetable growers in Kentucky have used high tunnels for year-round production for the past decade. They suggest it is a more energy-efficient and economical means of supplying off-season vegetables to the region than trucking field-grown produce from warmer regions. In 2005, we erected a 9 × 12-m high tunnel, designed to comply with National Organic Program standards, at the Kentucky State University Research Farm. We recorded the retail cost of each component, and estimated its embodied energy using published figures for common building materials. The materials used for construction were valued at $2830, and contained 59 GJ of embodied energy. The frame and plastic cladding accounted for 36% and 24% of the total capital cost, and 28% and 37% of the embodied energy, respectively, with other components accounting for the remainder. Assuming that the frame, plastic cladding and other components last 20, 4, and 10 years, respectively, the average cost of the tunnel is $328/year, and the average energy input is 8 GJ/year. The plastic cladding accounts for 50% of the annual amortized cost, and 66% of the embodied energy. If the structure is used to grow 2000 heads of lettuce each winter, and 450 kg of early market tomatoes each spring, it could generate sufficient income to recover the total cost of construction materials in its first year. Trucking this amount of produce from California to Kentucky would consume approximately 8 GJ. We conclude that there is an economic incentive for growers to adopt this technology, but no energy efficiency advantage to society. Longer tunnels, such as the 9 × 29-m models more commonly used by commercial vegetable growers in Kentucky, will be more energy- and capital-efficient.
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Aygar, Ebu Bekir, and Candan Gokceoglu. "Problems Encountered during a Railway Tunnel Excavation in Squeezing and Swelling Materials and Possible Engineering Measures: A Case Study from Turkey." Sustainability 12, no. 3 (February 6, 2020): 1166. http://dx.doi.org/10.3390/su12031166.
Повний текст джерелаАнотація:
The T3 railway tunnel—under construction within the scope of the Bursa-Yenişehir high-speed train project—is located in northwestern Turkey and has a length of 1250 m. The tunnel is being constructed entirely in silty clay/clayey silt, sand, and clay units, and it is designed in accordance with the principles of weak ground tunneling described by the new Austrian tunneling method (NATM). When the tunnel excavations began in 2013, during and after portal excavations, a failure occurred at the entrance of the tunnel; thus, a revision of the support systems became mandatory. While the excavation works proceeded after the revision phase, a collapse occurred again at the tunnel face where the overburden thickness was low. This study presents the mechanisms of the collapse that took place at the portal location and in the middle of the tunnel. The proposed tunnel support systems and their numerical analyses are also discussed, because the case is interesting for the tunnel community and will inform future tunnel construction work. For this reason, the relationship between portal excavation and tunnel excavation stability is described. Consequently, tunnels excavated through weak ground conditions are considered, and the importance of considering the face stability of tunnels in tunneling studies is underlined.
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Feng, Guohui, Qingsheng Chen, Changjie Xu, Peng Wan, Feng Sun, Yujie Li, and Zhihao Sun. "Improved Theoretical Solutions for Estimating the Tunnel Response Induced by Overlying Excavation." Sustainability 15, no. 3 (February 1, 2023): 2589. http://dx.doi.org/10.3390/su15032589.
Повний текст джерелаАнотація:
As a result of China’s urbanization, it has been a common phenomenon that adjacent deep excavations were constructed near underground structures, which can have a series of detrimental effects on existing tunnels. Thus, it is crucial to assess the tunnel response induced by the overlying excavation, with the aim of maintaining the safety and serviceability of operating tunnels. The shield tunnel is idealized as an infinite beam lying upon a three parameter Kerr-model and the vertical force equilibrium equation of the tunnel element is established. Then, a theoretical solution is derived for capturing the soil–tunnel interaction. To prove the accuracy of the proposed method, the calculation results are compared with field measurements, along with the data of finite element studies. Thereafter, a parametric analysis will be conducted to assess some characteristic factors for tunnel responses caused by overlying excavations, such as tunnel-excavation horizontal distance, tunnel bending stiffness, and the buried depth of the tunnel. The results indicate that the increase in the bending stiffness and the buried depth of tunnel, as well as the tunnel-excavation horizontal distance, will significantly alleviate the tunnel deformation. However, the inner force will be increased when increasing the tunnel bending stiffness.
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Epple, Philipp, Michael Steppert, and Michael Steber. "The Impact of Pressure Regulators on the Runtime and Energy Savings of Supersonic Blowdown Wind Tunnels." Applied Mechanics and Materials 856 (November 2016): 238–43. http://dx.doi.org/10.4028/www.scientific.net/amm.856.238.
Повний текст джерелаАнотація:
Pressure regulators have a great impact on the runtime and energy savings of supersonic wind tunnels. In order to investigate this impact quantitatively the theoretical isentropic (ideal) equations for the supersonic wind tunnel flow were compared with viscous CFD computations. The theoretical model was extended include the flow from the outflow from the pressure vessel up to the wind tunnel. This theoretical model was solved with and without pressure regulation valve using a Runge-Kutta method. The differences in runtime and energy consumption for both configurations with and without pressure regulator as well as the derivation of the analytical model and the numerical solution are presented in detail in this paper.
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Pan, Guo Bing, Ling Na Shi, Bo Liang, and Yu Hang Pi. "Illumination Energy Conservation Analysis of Reflective Material on the Tunnel Sidewall." Advanced Materials Research 594-597 (November 2012): 1197–200. http://dx.doi.org/10.4028/www.scientific.net/amr.594-597.1197.
Повний текст джерелаАнотація:
This paper endeavors to analyze road lighting quality with the influence of luminous coefficients of the tunnel wall, with lighting design software DIALUX which simulates tunnel lighting, by improving the reflection coefficient of the tunnel wall materials. The result of Analysis shows that high-tunnel side wall reflection coefficient not only helps to improve the tunnel intensity of illumination, but also improves the luminance of the tunnel; under certain circumstances of the road surface luminance, high reflective coefficient of the tunnel walls is helpful to tunnel lighting energy consumption reduction.
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Wen, Tao, Zheng Hu, Yankun Wang, Zihan Zhang, and Jinshan Sun. "Monitoring and Analysis of Geotemperature during the Tunnel Construction." Energies 15, no. 3 (January 20, 2022): 736. http://dx.doi.org/10.3390/en15030736.
Повний текст джерелаАнотація:
High geotemperatures are encountered during tunnel construction in areas with complex geological structures, which can seriously affect personnel and equipment in the process of tunnel construction and operation. The Nige tunnel, a deep-buried extra-long tunnel, was selected to monitor the geotemperature during construction. The air, rock, and water temperatures during the tunnel construction were measured at the tunnel face, and the actual temperatures of the rock or water body at the tunnel face were measured by advanced drilling. The variation trends of the water temperature, air temperature, and flow of water with the tunnel mileage were analyzed. The differences in three measured rock temperatures in three advanced drillings were revealed. The results showed that the Nige tunnel had a maximum water temperature of 63.4 °C, maximum rock temperature (Rock T) of 88.8 °C, and maximum air temperature (Air T) of 56.4 °C. Increasing trends of the air, rock, and water temperatures with the tunnel’s horizontal distance and the buried depth (vertical depth) were obvious, and the geotemperature gradient was approximately 7.6 °C per 100 m. Additionally, the variation laws of the construction ambient temperature with time in a complete construction cycle showed four stage characteristics, and each stage presented different mathematical relationships. These findings will provide guidance for the construction of high geotemperature tunnels in future.
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Khattri, Sanjay Kumar, Torgrim Log, and Arjen Kraaijeveld. "Tunnel Fire Dynamics as a Function of Longitudinal Ventilation Air Oxygen Content." Sustainability 11, no. 1 (January 3, 2019): 203. http://dx.doi.org/10.3390/su11010203.
Повний текст джерелаАнотація:
Longitudinal ambient air ventilation is the most common methodology for maintaining an amicable environment in tunnels during normal operations while providing an evacuation path during tunnel fire emergencies. The present work investigates the influence of forced ventilation air oxygen concentrations on tunnel fire dynamics. Mixing inert gasses such as nitrogen, argon, or carbon dioxide with ambient air changes the ventilation air oxygen concentration. In order to quantify the influence of the oxygen content on the critical tunnel safety parameters, multiple computational fluid dynamics (CFD) simulations were done on a reduced-size tunnel while preserving the system Froude number. Analytical expressions were developed to describe the importance of oxygen content on the tunnel fire dynamics. By employing Froude scaling, the resulting relations were extrapolated to real scale tunnels. For the ambient air ventilation, the extrapolated expressions displayed good agreement with experimental literature data. By adjusting the oxygen concentration, parameters such as maximum tunnel ceiling temperature, fire growth rate, maximum heat flux to the tunnel floor, maximum flux on the tunnel ceiling, and maximum heat release rate can be controlled. This is the case also for oxygen levels where people can survive. This may increase the possibility for evacuation and improve the conditions for firefighting, significantly improving tunnel fire safety.
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Shi, Jian-Xun, Zhao-Hui Li, Yong-Qiang He, Guo-Ming Zhang, and Ming-Qiang Wei. "The Influence of Physical and Chemical Reactions on Water Leakage in a Multiarch Tunnel." Advances in Civil Engineering 2020 (September 23, 2020): 1–8. http://dx.doi.org/10.1155/2020/8830739.
Повний текст джерелаАнотація:
In many tunnels in China, the groundwater is acidic and carbonated, causing in challenges in the prevention and control of leakages of the existing tunnels and tunnels under construction. Research on tunnel leakage and the physical and chemical effects of water due to water-rock interactions is a trending topic. In addition, there is a big difference between the waterproof and drainage of multiarch tunnels and separate tunnels. In this study, the mechanism of the interaction between the groundwater and the surrounding rock of a multiarch tunnel were analyzed. The relationship between the leakage of a multiarch tunnel and the interaction between the surrounding rocks and groundwater was determined by analyzing the interaction between the chemical components in the groundwater, rocks, and the concrete lining. A mathematical model was established based on the physical and chemical reactions in the rock surrounding the tunnel, and the RNCDX.FOR program was compiled using the simplex Monte Carlo method. The total free energy in the entire system varied significantly, and the value of objective function (J) reflected the trend of the system's spontaneous reaction. As J decreased, the reaction power of the system increased. The more significant the erosion of the rocks was by the groundwater, the more channels were created by the groundwater in the rock, and the more likely the water leakage was.
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Yang, Chao, and Shi Juan Fan. "Energy-Saving Performance Studies of Road Tunnel Luminaries." Applied Mechanics and Materials 291-294 (February 2013): 654–60. http://dx.doi.org/10.4028/www.scientific.net/amm.291-294.654.
Повний текст джерелаАнотація:
Reasonable choice of light sources was the key to achieve energy-saving of tunnel lighting. Performance comparisons of light sources were completed, tunnel model was designed with lighting software-DIAlux based on characteristics and design demands of tunnel lighting. Simulation experiments for HPS (high pressure sodium) and LED (light-emitting diode) were made in the tunnel model, lighting effects of HPS and LED in each zone of the tunnel were analyzed, the results show that LED has higher lighting efficiency and can save more 40% power energy than HPS under the same lighting condition and the same road surface average-luminance, and LED has better road surface lighting effects and better color rendering than HPS.
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Chen, Lijun, Jianxun Chen, Yanbin Luo, Yalong Guo, Yongjun Mu, Daochuan Zhong, Weiwei Liu, Tielun Yang, and Weixiang Chen. "Propagation Laws of Blasting Seismic Waves in Weak Rock Mass: A Case Study of Muzhailing Tunnel." Advances in Civil Engineering 2020 (May 25, 2020): 1–15. http://dx.doi.org/10.1155/2020/8818442.
Повний текст джерелаАнотація:
In order to study the propagation laws of blasting vibration waves in weak rock tunnels, the longitudinal and circumferential blasting vibration tests in Muzhailing Tunnel were carried out, and the measured data were analyzed and studied using the methods of Sadov’s nonlinear regression, Fourier transform, and Hilbert–Huang transform (HHT) to provide a reference for the optimization of blasting design of Muzhailing Tunnel or similar weak rock tunnels. The results showed that the tangential main frequency decreases rapidly and the radial main frequency decreases slowly with the increase of proportionate charge quantity. Under a certain charge quantity, as the distance from the explosion source increases, the spectrum width of the blasting vibration frequency becomes narrower, the overall energy is more concentrated, and the vibration frequency tends to be closer to the low frequency. At a certain distance from the explosive source, the frequency of blasting vibration decreases gradually, and the amplitude of low-frequency region increases with the increase of charge quantity. The vibration velocity on the left side of the tunnel is larger than that on the right side, and the vibration velocity at the vault and the arch foot of lower bench decreases rapidly, while the vibration velocity at the arch feet of upper bench and middle bench decreases slowly. The vibration frequencies of the left arch foot of the middle bench and the right arch foot of the upper bench are higher than those of other positions, while the frequencies of the left arch foot of the upper bench are the lowest. During tunnel blasting, the energy input to the strata media is mainly concentrated in the stage of the blasting of the cut hole. The blasting has more energy input to the left arch foot of the upper bench and the tunnel vault, which is consistent with the conclusion of frequency analysis.