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1
Mohammed, Hassan J., and Ammar S. Khazzl. "Optimum Design of Tunnels." Tikrit Journal of Engineering Sciences 14, no. 3 (September 30, 2007): 50–68. http://dx.doi.org/10.25130/tjes.14.3.03.
Повний текст джерелаАнотація:
This study is an application of optimization method to the structural design of tunnels, considering the total cost of the tunnels as an objective function with the properties of the tunnel and soil unit weight, height of soil above tunnel, height of water above tunnel and tunnel radius, as design variables. A computer program has been developed to solve numerical examples using the ACI code equations , requirements and criteria in concrete design. The results shown that the minimum total cost of the tunnel increases with the increase of the soil unit weight and tunnel radius, and decreases with the increase of the height of water above tunnel.
2
Gong, Wenping, Hongwei Huang, C. Hsein Juang, Sez Atamturktur, and Andrew Brownlow. "Improved shield tunnel design methodology incorporating design robustness." Canadian Geotechnical Journal 52, no. 10 (October 2015): 1575–91. http://dx.doi.org/10.1139/cgj-2014-0458.
Повний текст джерелаАнотація:
This paper presents an improved design methodology for shield tunnels. Here, a new framework for three-dimensional analysis of shield tunnel “performance” (defined herein as the structural safety and serviceability of each tunnel ring) is developed, which considers the effect of the longitudinal variation of input parameters on the tunnel performance. Within this framework, random fields are used to simulate the longitudinal variation of input parameters, and the three-dimensional problem of shield tunnel performance is solved through a two-stage solution involving a one-dimensional model (for tunnel longitudinal behavior) and a two-dimensional model (for performance of segment rings). Furthermore, the robust design concept is integrated into the design of shield tunnels to guard against the longitudinal variation of tunnel performance caused by the longitudinal variation of input parameters. In the context of robust design, a new measure is developed for determining the robustness of the tunnel performance against the longitudinal variation of noise factors. A multi-objective optimization is then performed to optimize the design with respect to the design robustness and the cost efficiency, while satisfying the safety and serviceability requirements. Through an illustrative example, the effectiveness and significance of the improved shield tunnel design methodology is demonstrated.
3
Zhao, Hongbo, Shaojun Li, and Bingrui Chen. "The Reliability-Based Design Optimization of considering Rock-Support Interaction for Rock Tunnels." Advances in Civil Engineering 2021 (May 25, 2021): 1–13. http://dx.doi.org/10.1155/2021/9921881.
Повний текст джерелаАнотація:
Uncertainty is critical to the tunnel design. In this study, a novel reliability-based design (RBD) method was developed by integrating the rock-support interaction and its uncertainties for rock tunnels. In this method, the rock-support interactions were analyzed based on a convergence-confinement method. Uncertainties were estimated by reliability analysis using Excel Solver. Chaotic particle swarm optimization (CPSO) was adopted to search the optimal tunnel design parameters based on the rock-support interaction analysis. The proposed method for estimating the reliability index and determining the tunnel support parameters was introduced in detail. To illustrate the proposed method, it was applied to two tunnels with rock-bolt and combined support systems. The results indicated that the method could obtain accurate solutions with a dramatically improved computing efficiency, guaranteeing the tunnel stability at the same time. The developed method provides an excellent way to deal with the uncertainty in tunnel design. It was proved to be an efficient and effective method for the support designs of rock tunnels.
4
Wu, Huajun. "Numerical Simulation Algorithm Design of Influence on Existing Tunnel by Underpass Construction of New Tunnel." Scientific Programming 2021 (December 16, 2021): 1–12. http://dx.doi.org/10.1155/2021/1734308.
Повний текст джерелаАнотація:
Simulation is a powerful tool that can be used for systematic planning, analysis, and decision-making. Proper designing is preliminary required to construct a new tunnel over an existing tunnel to ensure safety and durability. Once an underpass tunnel completes, the interaction between the tunnel structure and the nearby soil gains a stable state and the stress of the tunnel is balanced. However, the stability of an existing tunnel is affected if the construction in the nearby area is not properly analyzed. This article proposes a numerical simulation model to empirically analyze lining force and surface settlement in order to ensure safety in engineering practice. The existing tunnel structure working condition is simulated under the new tunnel. The artificial honeybee colony algorithm is used to extract the parameter fusion characteristic value of tunnel influence and the model of estimating the bending moment of group piles. The structural mechanics of existing tunnels under new tunnels are analyzed using the triple bend model to improve the bearing capacity of existing tunnels under new tunnels. Based on the above analysis, numerical simulation experiments are designed. The proposed method has high accuracy and strong fitting ability and can effectively reduce the displacement of existing tunnels. Moreover, the method can improve the bearing capacity of tunnels. For tunneling operation, the results of the simulation may be used as a recommendation.
5
Mohammed Asadullah, Sher Afghan Khan, Parvathy Rajendran, and Ervin Sulaeman. "Design Intent of Future Tunnels." Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 88, no. 2 (November 1, 2021): 50–63. http://dx.doi.org/10.37934/arfmts.88.2.5063.
Повний текст джерелаАнотація:
The sound barrier for bullet trains remains a challenge due to the piston effect causing compression waves at the entry and exit of the tunnel. The air ahead of the train nose is compressed, and the wave propagates through the tunnel at the speed of sound and exits with the generation of micro pressure waves. It gives rise to a complex wave pattern comprising compression at the train nose & expansion at the train tail leading to the positive pressure around the nose and suction around the tail. This is intended to provide exhaustive input for the proper design of a futuristic tunnel. The cross-sectional shapes of the tunnel, whether square, rectangular, circular, or semi-circular, will experience pressure compression wave generated by high-speed train but will influence the flow pattern and hence the compression wave. This paper presents the pressure load on the walls of long and short tunnels for subsonic compressible and transonic flows. The experimental investigation is carried out only for length parameters to study short and long tunnels. Further, flow visualization is also provided after the formation of the sonic boom. The results of this investigation can be an essential data source for optimum design of high-speed tunnels so as to suppress or break the sound barriers, thus, resulting in a safer high-speed train network.
6
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.
7
Humphries, R. W., and L. T. Jory. "Underground design at Andekaleka Hydroelectric Development." Canadian Geotechnical Journal 22, no. 1 (February 1, 1985): 25–31. http://dx.doi.org/10.1139/t85-004.
Повний текст джерелаАнотація:
Andekaleka Hydroelectric Development, Republic of Malagasy (Madagascar), comprises an 8 m high intake dam, a 4 km long unlined power tunnel, a surge shaft, a concrete-lined penstock, four steel-lined branch penstocks, an underground powerhouse, and a 0.5 km long tailrace tunnel. The scheme develops a 235 m fall in the Vohitra River. Two 29 MW Francis turbines have been installed, with space left for two more identical units.This paper describes the geotechnical aspects of the underground design for the scheme. The predominant rock type is good quality granitic gneiss, which required minimal underground support and lining. Where the power tunnel 'daylights' and crosses the Sahantsiva River, steel and concrete lining and drainage tunnels have been provided.The length and design of the steel and concrete lining and the system of underground drainage are described along with the design and support for the powerhouse cavern and the support of the powerhouse crane beams on rock shoulders. Key words: tunnels, penstocks, underground powerhouse, underground drainage, underground support, tunnel lining, Madagascar.
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Uchanski, Mark E., Dawn M. VanLeeuwen, Steven J. Guldan, Constance L. Falk, Manoj Shukla, and Juliette Enfield. "Temperature and Light Characterization during Winter Production Season in High Tunnels in the Southwestern United States." HortTechnology 30, no. 2 (April 2020): 259–67. http://dx.doi.org/10.21273/horttech04486-19.
Повний текст джерелаАнотація:
Replicated temperature data from passively heated high tunnels are lacking, especially in the southwestern United States. Field studies were conducted over three seasons in two locations in New Mexico—a southern site in Las Cruces and a northern site in Alcalde—to characterize the crop environment in three high-tunnel designs during the winter growing season (October–March). High tunnels were 16 × 32 ft and oriented with the long edge running east to west. Heavyweight woven plastic covered the single-layer (SL) high-tunnel design. Double-layer designs (DL) were covered with a lightweight woven plastic on the bottom, followed by a second layer of the heavyweight plastic inflated with a fan. A heat sink was created using 16 55-gal barrels painted black, filled with water, and aligned along the north side of the double layer for the DL+B design. Soil temperature (3 inches deep) and air temperature (1 ft above the soil surface) were recorded inside the high tunnel, inside the high tunnel under a floating rowcover, and outside the high tunnel. In addition, photosynthetically active radiation (PAR) was recorded inside and outside the high tunnels during or near the winter solstice each year of the study. Daily air and soil temperature minimums were highest in the DL+B design and lowest in the SL design. Maximum air and soil temperatures did not significantly differ between high-tunnel designs, although the DL+B design measurements were consistently lower. During season 1, the SL design had significantly higher PAR transmission than the other two designs. In the northern location, the difference became insignificant during seasons 2 and 3, likely due to dust accumulation and plastic aging. In the southern location, the SL design maintained higher PAR transmission throughout the study, possibly due to plastic cleaning. Data collected in this study can help inform the decisions of high-tunnel growers and researchers in the region.
9
Valenti, Robert, Alex Brudno, Michael Bertoulin, and Ian Davis. "Fort Point Channel: Concrete Immersed-Tube and Ventilation Building Design." Transportation Research Record: Journal of the Transportation Research Board 1541, no. 1 (January 1996): 147–52. http://dx.doi.org/10.1177/0361198196154100119.
Повний текст джерелаАнотація:
The Central Artery/Third Harbor Tunnel Project in Boston, Massachusetts, is one of the largest highway projects over undertaken in the country. It requires the replacement of the existing elevated artery, I-93, with an underground tunnel extending through downtown Boston and an extension of the Massachusetts Turnpike Authority (MTA) I-90 from its existing termination at the I-93 interchange to Boston's Logan International Airport. The I-90 extension tunnels east under the existing South Station intercity and commuter railroad tracks, under historic Fort Point Channel while crossing above the 1915 twin subway tunnels, and continues through industrial South Boston with ramps surfacing in a new South Boston interchange, the heart of tremendous growth in Boston. From there the tunnel connects to the recently completed Ted Williams Tunnel harbor crossing to East Boston and Logan International Airport. The unique design challenges and solutions relating to the Fort Point Channel crossing, particularly the use of in-the-wet construction with concrete immersed-tube tunnels and the design interface to the ventilation structures, are presented. Structures required for the I-90 extension are concrete immersed tubes and jacked tunnels, as well as more conventional cut-and-cover tunnels, bridges, surface roads, and ancillary buildings. The geometric and physical restraints of the alignment initially required the placement of the ventilation building, which serves the tunnels, on a cut-and-cover tunnel transition section between the jacked tunnels and the concrete immersed tubes. Ultimately, placement of the ventilation building on the immersed tubes created a substantial cost and schedule benefit.
10
Kuang, Jiang Hong, and Bin Yu. "Discuss on Tunnel Design for High Speed Metro Line." Applied Mechanics and Materials 723 (January 2015): 364–67. http://dx.doi.org/10.4028/www.scientific.net/amm.723.364.
Повний текст джерелаАнотація:
When trains with high speed pass through the tunnel, there is pressure fluctuation in the tunnel which will cause discomfort of the driver and the passengers. Using unsteady one dimensional flow model, the aerodynamic effect caused by the train with speed of 120km/s running through the tunnel was calculated and analyzed. The results show that the routine tunnel size of Ф5.5m for metro lines can not meet the standard for comfort level. Instead, tunnels with inner diameters of 6.8m and 10.36m were recommended.
11
Chao KONG and Xinqiang Gao. "Zoning of mutual influence of approach rock tunnels based on a safety factor." Electronic Journal of Structural Engineering 21 (November 30, 2021): 46–54. http://dx.doi.org/10.56748/ejse.21290.
Повний текст джерелаАнотація:
For multiple approach tunnels, the construction of the new tunnel near the existing tunnel modifies the state of stresses and movements around the existing tunnel in an area called the “influence zone”. In this study, new method is developed to optimize the relative position of approach tunnels and guide their design via the zoning of mutual influence of the approach tunnels based on a safety factor. The strength reduction method is applied to calculate the global safety factor of multiple approach tunnels in limit state. According to quantitative laws of variation in the safety factor from single tunnel to multiple tunnels, the strong influence, weak influence, and no influence have been zoning to guide the design and construction of approach tunnels. By changing the relative position of the new tunnel complex, the safety factor and failure shapes of the tunnel complex in several cases are obtained through numerical simulation. The results are based on dividing the influence zone of approach construction of the new tunnel complex. Combining the influence zone with failure shapes, the relative position of the tunnel complex is optimized. Special support countermeasures for weak tunnel complex parts and parameters of support are initially determined.
12
Shang, Ting, Hongjiao Qi, An Huang, and Tangzhi Liu. "A comparative driving safety study of mountainous expressway individual tunnel and tunnel group based on eye gaze behavior." PLOS ONE 17, no. 2 (February 14, 2022): e0263835. http://dx.doi.org/10.1371/journal.pone.0263835.
Повний текст джерелаАнотація:
The traffic environment of a tunnel group is more complex than that of a single tunnel, which increases the driving risk. The eye gaze behavior of drivers can be used to evaluate driving safety and comfort. To analyze the fixation characteristics of drivers in a single tunnel and tunnel group of mountainous expressways, an actual vehicle test is conducted. The test area has a total length of 160 km and 38 tunnels, including 8 tunnel groups and 16 single tunnels. In the test, the difference in the gaze time of five drivers between single tunnels and tunnel groups is compared. The k-means method is used to cluster driver’s gaze points dynamically. Based on the Markov theory, the attributes related to gaze transfer are obtained. The results show that when tunnels are of short or medium length, there is no significant difference in the gaze time and gaze point transfer between the tunnel group and a single tunnel. In contrast, when tunnels have long or extra-long length, the repeated fixation probability and the two-step transition probability of looking back of a driver in a tunnel group are higher than those in a single tunnel. The design and management method of a single tunnel cannot be directly used, especially for extra-long tunnels located at the back of a tunnel group with a long upstream tunnel length and a short interval distance from the upstream tunnel. Therefore, it is necessary to focus on the design and management methods of tunnel groups.
13
Lamont, William J., Martin R. McGann, Michael D. Orzolek, Nymbura Mbugua, Bruce Dye, and Dayton Reese. "Design and Construction of the Penn State High Tunnel." HortTechnology 12, no. 3 (January 2002): 447–53. http://dx.doi.org/10.21273/horttech.12.3.447.
Повний текст джерелаАнотація:
Plasticulture technology, especially high tunnels for extending the production period of a wide variety of horticultural crops, is an accepted production practice worldwide. In particular, high tunnels offer a production system that minimizes the effect of the environment on crop production and allows growers to continue to farm in densely populated areas. Only recently has the use of high tunnels in the U.S. been investigated and this research has been centered in the northeastern U.S. In 1999 the High Tunnel Research and Education Facility was established at Pennsylvania State University that resulted in the development of a unique high tunnel design. A detailed description of the new design and construction is presented in this report.
14
Jin, Liguo, Xujin Liu, Hongyang Sun, and Zhenghua Zhou. "An Analytical Solution for 2D Dynamic Structure-Soil-Structure Interaction for Twin Flexible Tunnels Embedded in a Homogeneous Half-Space." Applied Sciences 11, no. 21 (November 3, 2021): 10343. http://dx.doi.org/10.3390/app112110343.
Повний текст джерелаАнотація:
The interaction between subway tunnels is investigated by using a 2D analytic model of a twin tunnels system embedded in a homogenous half-space. The closed-form analytical solution for tunnel displacement response is derived through the wave function expansion method and the mirror method, and the correctness of the solution is verified through residuals convergence and comparison with the published results. The analysis focuses on the effects of tunnel relative stiffness on tunnel–soil–tunnel interaction. Tunnel relative stiffness has a great influence on tunnel displacement response. For small tunnel relative stiffness, tunnel displacement amplitude can be enlarged by 3.3 times that of single rigid tunnel model. The response of the tunnel–soil–tunnel interaction system depends not only on the distances between tunnels but also on the frequency of the incident wave and the incident angle. The strength of the interaction between the tunnels is highly related to the tunnel spacing distance. The smaller the distance between tunnels, the stronger the interaction between them. When the distance between tunnels reaches s/a = 20, the interaction between tunnels can be ignored. It is worth pointing out that the seismic design of underground tunnels should consider the interaction between tunnels when the tunnel distance is small.
15
Hu, Hui, and Wen Ge Qiu. "Study on Earthquake Damage Characteristic on Mountain Tunnel and Analysis." Applied Mechanics and Materials 94-96 (September 2011): 1078–81. http://dx.doi.org/10.4028/www.scientific.net/amm.94-96.1078.
Повний текст джерелаАнотація:
This paper collects earthquake damage data and research on tunnel in recent years(Wenchuan earthquake,Ms 8.0;Yushu earthquake, Ms 7.1, Chi-Chi Earthquake,Ms 7.6 and so on). Damage patterns and characteristics of mountain tunnels in severe earthquake region are classified: Slope failure near tunnel portal; Spalling and collapse of tunnel portal and end wall; Lining collapse; Longitudinal and transverse cracks of lining; Slant and transverse fracture of lining; Sheared off lining in fault region; Steel frame damage of primary support; pavement or bottom cracks. The damage mechanisms are analyzed and some proposals are put forward for tunnel rehabilitation and new tunnel construction: It is suggested that in strong earthquake areas, a comprehensive aseismic design should be conducted considering tunnel portal structure and slope. Line selection should avoid or reduce passing through active faults and avoid placing tunnels too close to slope faces when planning future tunnels. The paper provides a reference for seismic design and construction procedures of tunnel.
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Chen, Hong Juan, Wei Ming Yan, and Shi Cai Chen. "Construction of Zhoutouzui Immersed Tunnel in China." Applied Mechanics and Materials 353-356 (August 2013): 1657–61. http://dx.doi.org/10.4028/www.scientific.net/amm.353-356.1657.
Повний текст джерелаАнотація:
Immersed tunnel was constructed in the year 1910 at the first time. The next few decades, there were more than one hundred immersed tunnels constructed in the world. Zhoutouzui Immersed Tunnel of Guangzhou City is the seventh underwater tunnel in Chinese Mainland. It is one concrete tunnel with rectangular cross-section which is variable because of the constraint conditions at overpass. It has distinct feature in Chinas tunnel design. The overall design and technical characteristics of Zhoutouzui Immersed Tunnel are described in detail.
17
Mařík, Libor, and Matěj Bůžek. "Design of Concrete Pavement in the Považský Chlmec Tunnel." Solid State Phenomena 272 (February 2018): 305–12. http://dx.doi.org/10.4028/www.scientific.net/ssp.272.305.
Повний текст джерелаАнотація:
Construction of the Považský Chlmec Tunnel on the D3 Highway in the stretch Žilina (Strážov) – Žilina (Brodno) is being finished and the last structure before installation of the technological equipment has been a concrete pavement and construction works related to design and construction of the pavement. The paper describes not only the issue of road structural layers according to the regulation TP098 Design of Cement Concrete Pavements on Roads, but especially on a specific example of a tunnel already built we demonstrate general particularities of road surfaces in road and highway tunnels. These are, in particular, engineering requirements on the subgrade and possibilities of its drainage, design of joints of the cement concrete pavement in relation to the tunnel lining design, ensuring the necessary long-term roughness of the road surface, design of entries of utility lines (cables, drains) below the road surface, structural details connected with placement of kerbs and channel drains, lay-bys, impacts of use of self-extinguishing road drainage components in the load bearing system of the tunnel lining and other seemingly independent structures, which, however, in the confined tunnel space influence each other substantially. The paper focuses also on construction of the individual road courses with a recommendation for measures to adopt in order to eliminate damage to the tunnel structures completed (in particular, pavements, channel drains and kerbs), coordination of the other works in the tunnel ensuring safety of all workers, logistics (transport of pavers and cement concrete mix) and other apparently tiny details, which result in safe and fast work when placing the road courses in a restricted tunnel space. In the paper, the authors have taken into account requirements of the road engineering segment and also geotechnical requirements and particularities of the tunnel construction and point out the necessity of a multi-professional approach to the design to achieve an optimal solution. Based on their own experience, at the end of the paper, the authors give recommendations on amending the standards and regulations, which in some cases do not allow for construction of road surfaces in tunnels (i.e. deep under the ground).
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Shang, Shi Yu. "Aanalyse on the Causation and Classification of Usual Damages of Highway Tunnel." Applied Mechanics and Materials 204-208 (October 2012): 1297–300. http://dx.doi.org/10.4028/www.scientific.net/amm.204-208.1297.
Повний текст джерелаАнотація:
There are long spans and various types of lining of highway tunnels under different geological conditions. It is challenging to obtain accurate geological condition data of tunnel, the existing tunnel design theories and methods are not mature either. Meantime, the stresses of tunnel during the stage of design, construction, operation and maintenance are also changing with time. Therefore, it is difficult to discover the root causes of the highway tunnels defeats, also because of the joint influence of the above factors. Through the broadly investigations of defeats of highway tunnel, the reasons of these defeats was analyzed and classified from four aspects, external forces, design methods, construction phase and deterioration of materials. More important, the general rules and association between the defeats and causes was studied and suggested following the brief introduction of the highway tunnel defeats.
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Liu, Li Yu, Zhi Yi Chen, and Yong Yuan. "Seismic Design and Analysis of Large-Size Shield Tunnels. Part I: Parametric Study." Applied Mechanics and Materials 105-107 (September 2011): 1299–303. http://dx.doi.org/10.4028/www.scientific.net/amm.105-107.1299.
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According to the extensive application of shield tunnel, large-diameter shield tunnel in particular, structure stiffness of shield tunnels varies in a large rang. In this paper, shield tunnels with different diameters and thicknesses are analyzed and calculated by time-history method. Stiffness ratio is identified to measure the relationship of structure’s stiffness and soil’s stiffness. The results indicate that dynamic moment and shear forces of shield tunnels have positive correlation with the stiffness ratio. Axial forces have positive correlation with thickness and diameter of lining structure.
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Lara, Andrés, Jonathan Toledo, and Robert Paul Salazar Romero. "Characterization, Design Testing and Numerical Modeling of a Subsonic-Low Speed Wind Tunnel." Ingeniería 27, no. 1 (January 4, 2022): e17973. http://dx.doi.org/10.14483/23448393.17973.
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Context: Wind tunnels are essential devices in the study of flow properties through objects and scaled prototypes. This work presents a numerical study to characterize an existing wind tunnel, proposing modifications with the aim to improve the quality of the flow in the test chamber. Method: Experimental measurements of the inlet velocity and pressure distribution of a wind tunnel are nperformed. These empirical values are used as parameters to define boundary conditions in simulations. The Finite Element Method (FEM) at low speeds is implemented to determine the stream function by using a standard Galerkin method. Polynomial interpolations are employed to modify the contraction section design, and numerical simulations are performed in order to compare the numerical results of the flow for the existing and the modified wind tunnels. Results: Experimental measurements of the flow at the wind tunnel entrance are presented. The velocity field and distribution of thermodynamic variables inside the tunnel are numerically determined. This computations are useful since it is experimentally difficult to make measurements inside the channel. Additionally, numerical calculations of these variables are presented under modifications in the tunnel geometry. Conclusions: A comparison between these simulations show that laminar flow at low velocities can be modeled as incompressible and irrotational fluid under a bidimensional approximation along its longitudinal section. It is observed that modifications in the geometry of the tunnel can improve the flow in the test section of the wind tunnel in the laminar regime.
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CHEN, Dan, Zhong WANG, Xiang LU, Chenlong LIN, and Haitao PEI. "The control system design and study for continuous supersonic wind tunnel." Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 40, no. 1 (February 2022): 167–74. http://dx.doi.org/10.1051/jnwpu/20224010167.
Повний текст джерелаАнотація:
As the first continuous supersonic wind tunnel in China, Mach number and total pressure are the most important flow field parameters of the wind tunnel, how to precise control and rapid and stable adjustment of total pressure and Mach number is the key in the design and construction of the wind tunnel control system. By analyzing the principle of parameter control of the wind tunnel flow field and the coupling relationship of each adjustment methods, the construction of continuous supersonic wind tunnel control system is constructed, and the solution measure of each key technical problem is given. The total pressure is precisely controlled by the segmented variable parameter fuzzy PI control algorithm, and then the wind tunnel operation control process design is carried out. Finally the wind tunnel blowing test is verified. The result shows that the accuracy of total pressure accuracy is better than 0.05%, the Mach number accuracy is better than 0.167 3, all the flow field parameter is greatly better than the design index, which proves that the design idea proposed in this paper is effective and can provide reference for the design and debugging of continuous supersonic wind tunnels.
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Lee, Dong-Hee. "A study on effects of landscape design of road tunnel portal to interior lighting of tunnels." Journal of Korean Tunnelling and Underground Space Association 15, no. 5 (2013): 497. http://dx.doi.org/10.9711/ktaj.2013.15.5.497.
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Zhang, Yong Tao. "Analysis of Seepage Field of Highway Tunnel Excavation by Finite Difference Method." Applied Mechanics and Materials 638-640 (September 2014): 798–803. http://dx.doi.org/10.4028/www.scientific.net/amm.638-640.798.
Повний текст джерелаАнотація:
As the excavation of tunnels, there are new channels of the groundwater drainage. The original supply of the circulatory system has been destroyed. The effects of groundwater to rock mass of surrounding rock are aggravated. In this paper, combined with a new highway tunnel project, the model is built according to the design parameters and the site engineering geological conditions of the tunnel. The fluid-structure interaction module of the finite difference software FLAC3D is used for the research on tunnel excavation. The distribution of seepage field, the stability of surrounding rock and rock deformation under saturated conditions during the tunnel excavation have been analyzed. The simulation results have certain guiding meaning on fracture development, the stability design of tunnels in water-rich stratum and the design and construction of anti-drainage.
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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.
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Wu, Yan Kai, and Wei Feng. "Research of Surface Deformation with Metro Double Tunnels Construction and the Relative Position Change." Key Engineering Materials 462-463 (January 2011): 732–37. http://dx.doi.org/10.4028/www.scientific.net/kem.462-463.732.
Повний текст джерелаАнотація:
With the rapid development of our economy, the urban traffic becomes increasingly busy. To ease traffic congestion, underground rail transportation is becoming one of the main modes of transportation in city. At present in order to relieve the traffic congestion most major cities in China are accelerating the construction of subway tunnels. The relative position change of metro double tunnels and construction of the sequence will affect the surface subsidence deformation and the interaction of the tunnel lining. It is more concerned about these issues in tunnel design. It is the main purposes, in this paper, to analyze the metro double tunnels surface deformation, which affect by the position changes of new construction double and the sequence of construction. From the numerical simulating results, in order to reduce surface subsidence and ensure the structural safety over the subway tunnel, it should try to make double-tunnels at the same horizontal plane in design. If the double tunnels could not be located at the same horizontal plane, the double-hole tunnel construction sequence of the deformation of the surface subsidence effects are obvious it is obvious that the double tunnels construction sequence differently make the deformation of the surface subsidence. To reduce the deformation of the surface subsidence, it should be first excavated the shallow tunnels and then excavated the tunnel buried deeply. The ideal distance of the double tunnels center is greater than 4 times the tunnel diameter. It can make the surface subsidence reduce to the minimum during the metro tunnel construction.
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Wang, Xiangbin, Yushan Sun, Lei Wan, Hongyu Bian, and Xiangrui Ran. "Design and Reliability Analysis of a Tunnel-Detection AUV Based on a Heterogeneous Dual CPU Hot Redundancy System." Electronics 10, no. 1 (December 25, 2020): 22. http://dx.doi.org/10.3390/electronics10010022.
Повний текст джерелаАнотація:
A water conveyance tunnel is narrow and enclosed with a complex distribution of flow field. The performance of sensors such as Doppler log, magnetic compass, sonar, and depth gauge used by conventional underwater vehicles in the tunnel is greatly affected and can even fail. Aiming at the special operating environment and operational requirements of water conveyance tunnels, this paper designed an architecture suitable for pressurized water conveyance tunnel-detection autonomous underwater vehicles (AUVs). The tunnel-detection AUV (called AUV-T in this paper) with the architecture proposed in this paper could easily and smoothly complete inspection tasks in water conveyance tunnels, and field tests have verified the effectiveness of the architecture. Since an AUV in a water conveyance tunnel cannot go to the surface to rescue itself, in order to ensure its safety we designed the heterogeneous dual-CPU (Central Processing Unit) hot redundancy system based on dual communication lines. The reliability analysis showed that the system can significantly reduce the probability of AUV failure and ensure that the AUV can still be recovered even if it fails in the tunnel.
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Wang, Haozheng, Qiang Wang, Junli Zhai, Dongyang Yuan, Weikang Zhang, Xiongyao Xie, Biao Zhou, Jielong Cai, and Yuanshuai Lei. "Design of Fast Acquisition System and Analysis of Geometric Feature for Highway Tunnel Lining Cracks Based on Machine Vision." Applied Sciences 12, no. 5 (February 28, 2022): 2516. http://dx.doi.org/10.3390/app12052516.
Повний текст джерелаАнотація:
Under the dual effects of the rapid growth of tunnel mileage and operating years, the application and research of tunnel crack identification based on machine vision are increasing with the vigorous development of machine vision. However, due to the complex environment in tunnels, it is difficult to quickly obtain tunnel lining cracks via computer visions in the tunnel. Therefore, this paper presents the design of a fast acquisition system with the geometric feature analysis for tunnel lining cracks, which has been integrated into a tunnel fast inspection vehicle with a machine vision module. Through the research on the image acquisition system of the tunnel lining, the parameter selection of the crack shooting hardware system is determined, and the fast calculation method of shooting parameters is proposed. The geometric characteristic analysis of the tunnel lining crack image is employed to calculate crack width and determine the optimal gray value of crack extraction. Field tests have been conducted in the highway tunnels in Zhejiang and Yunnan provinces in China and the result indicates that the proposed approach yields much better performance in the detection efficiency, whose time of detection is only 1%, and the number of personnel required is only 40% of the traditional pure manual method. Compared with similar systems, it also has significant advantages in crack resolution and detection speed. This research provides a means of rapid acquisition of tunnel cracks and laying a foundation for the evaluation of the service performance of the tunnel.
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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.
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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.
Повний текст джерелаАнотація:
<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, Li Yu, Zhi Yi Chen, and Yong Yuan. "Seismic Design and Analysis of Large-Size Shield Tunnels. Part II: Modified Stiffness Solution." Applied Mechanics and Materials 105-107 (September 2011): 1308–12. http://dx.doi.org/10.4028/www.scientific.net/amm.105-107.1308.
Повний текст джерелаАнотація:
According to the extensive application of shield tunnel, large-diameter shield tunnel in particular, a simplified seismic design method is in urgent need. The equivalent static method is more suitable for the rigid underground structure, rather than flexible structure such as large-diameter shield tunnel. In this paper, shield tunnels with different diameters and thicknesses are analyzed and calculated by time-history method and free field deformation method. The calculation and analysis above help to identify the stiffness ratio to measure the relationship of structure’s stiffness and soil’s stiffness and the derivation of a revised stiffness solution based on the free field deformation method. The results indicate that this method can calculate seismic stress of shield tunnels with different diameters and thicknesses accurately.
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Song, He, Chao Liang Ye, and Jun Feng Mi. "Numerical Analysis of Optimization Design for Insulation Layer in Cold Regions Tunnel." Advanced Materials Research 1065-1069 (December 2014): 368–72. http://dx.doi.org/10.4028/www.scientific.net/amr.1065-1069.368.
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Setting of insulation layer is widely recognized to prevent frost damage for tunnels constructed in cold region. Optimization design of insulation layers, however, still need deeply investigate. In this paper, taking Houanshan tunnel as example, two-dimensional finite element analysis on the optimization design of insulation layers has been carried out by ABAQUS. The tunnel temperature fields due to various thickness and length of insulation layer are numerically analyzed. It shows that ,1)4.85°C increased at backside of insulation layer with thickness of 5cm, while 5.8°C increased for thickness of 7cm;2) frozen depth of surrounding rock decrease with the increase of insulation layer thickness. The farther distance to tunnel portal, the smaller thickness of insulation layer required to prevent the surrounding rock from freezing;3)According to analysis, frost penetration length should be 450~500m before tunnel holing-through ,while 720m~830m after tunnel holing-through.
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Zhu, Duan, Zhende Zhu, Cong Zhang, and Xinghua Xie. "Shaking Table Test on the Tunnel Dynamic Response under Different Fault Dip Angles." Symmetry 13, no. 8 (July 28, 2021): 1375. http://dx.doi.org/10.3390/sym13081375.
Повний текст джерелаАнотація:
Fault-crossing tunnels are often severely damaged under seismic dynamics. Study of the dynamic response characteristics of tunnels crossing faults is thus of great engineering significance. Here, the Xianglushan Tunnel of the Central Yunnan Water Diversion Project was studied. A shaking table experimental device was used, and four sets of dynamic model tests of deep-buried tunnels with different fault inclination angles were conducted. Test schemes of model similarity ratio, similar material selection, model box design, and sine wave loading were introduced. The acceleration and strain data of the tunnel lining were monitored. Analysis of the acceleration data showed that when the input PGA was 0.6 g, compared with the ordinary tunnel, the acceleration increases by 117% when the inclination angle was 75°, 127% when the inclination angle was 45°, and 144% when the inclination angle was 30°. This indicates that the dynamic response of the cross-fault tunnel structure was stronger than that of the ordinary tunnel, and the effect was more obvious as the fault dip angle decreased. Analysis of the strain data showed that the strain response of the fault-crossing tunnels was more sensitive to the fault dip. The peak strain and increase in fault-crossing tunnels were much larger than those of ordinary tunnels, and smaller fault dips led to larger increases in the strain peak; consequently, the tunnel would reach the ultimate strain and break down when the input PGA was smaller. Generally, the influence of fault inclination on the dynamic response of the tunnel lining should receive increased consideration in the seismic design of tunnels.
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Gao, He, Chen, and Li. "A Novel Calculation Method of Process Load for Extra-Large Section Tunnels." Symmetry 11, no. 10 (October 2, 2019): 1228. http://dx.doi.org/10.3390/sym11101228.
Повний текст джерелаАнотація:
The calculation of load and surrounding rock pressure of extra-large-section tunnels serves as an important premise for the design and construction of tunnel projects with extra-large sections. Based on the large-span section of the Shenzhen Liantang Tunnel (China), which is the largest highway tunnel in the world to date, this paper discusses the challenges existing in the calculation method of state load and surrounding rock pressure for extra-large-section tunnels and puts forward a novel calculation method for process load, which is suitable for extra-large-section highway tunnels. In the current work, we derived the related application correlations and improved the specific application steps, methods, and project models of the proposed calculation method. Both the rationality and feasibility of the calculation method were verified from a practical perspective by comparing the on-site data of surrounding rock pressure at the Liantang Tunnel with the calculated load, which provides a fundamental basis for the process design of tunnels.
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Lee, Jae Kook, Hankyu Yoo, Hoki Ban, and Won-Jun Park. "Estimation of Rock Load of Multi-Arch Tunnel with Cracks Using Stress Variable Method." Applied Sciences 10, no. 9 (May 8, 2020): 3285. http://dx.doi.org/10.3390/app10093285.
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In multi-arch tunnels, the increased rock load on the concrete lining of the main tunnel and side walls due to the excavation of adjacent tunnels is critical and must be considered in the design stage. Therefore, this study estimates the rock load of a multi-arch tunnel using two-dimensional numerical analysis, considering rock mass classifications, overburden, and construction steps. The rock load is estimated using two criteria: the factor of safety and stress variable. The rock load is underestimated when the factor of safety is applied to rock mass class III. However, the stress variable method reveals a reasonable rock load as overburden increases. Particularly, the rock load is estimated to be equal to the overburden in shallow tunnels and approximately 0.7 times the tunnel width in deep tunnels. Additionally, the crack-induced rock load is computed using back analysis at the excavation completion stage of adjacent tunnels, yielding the relation between the rock load height and the deformation modulus of the rock mass. Therefore, an accurate estimation of the rock load of multi-arch tunnels emphasizes the importance of a more economical and realistic design and must be addressed in the process of performance-based tunnel design.
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Liu, Yan, Jian Ping Gao, and Min Tang. "Study on Urban Tunnel CO Control Criteria Based on Human Capacity." Applied Mechanics and Materials 253-255 (December 2012): 1864–68. http://dx.doi.org/10.4028/www.scientific.net/amm.253-255.1864.
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Carbon monoxide has a significant impact on human health, and a special attention should be given in the tunnel management. But the existing tunnel design standard about carbon monoxide concentration is mainly for rural highway especially for expressway, there is no urban road tunnel carbon monoxide concentration control criteria promulgated in China up to now. By analyze the character of human blood carboxy hemoglobin concentration which expose in different environment concentration of carbon monoxide according to a certain time, and take carboxyhaemoglobin that accounts for 2.0 percent in the hemoglobin as the carbon monoxide concentration control threshold for the model development to establish the basis for carbon monoxide concentration of both pedestrian and vehicle mixed tunnel and vehicle only tunnel with different lengths, put forwards the length limit of pedestrian and vehicle mixed tunnel and the recommend criteria for carbon monoxide concentration control of urban tunnels. The result of the study can has a support for urban tunnels design and management decision making especially in ventilation.
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Lidström, Mats. "Using Advanced Driving Simulator as Design Tool in Road Tunnel Design." Transportation Research Record: Journal of the Transportation Research Board 1615, no. 1 (January 1998): 51–55. http://dx.doi.org/10.3141/1615-07.
Повний текст джерелаАнотація:
To obtain more information for tunnel design problems, a virtual model of some proposed tunnel designs was developed to demonstrate the design in advance and to be used as a platform for future tunnel research projects. By combining this model with an advanced driving simulator, the designers can virtually drive through their drawings before construction work is started. In comparison with traditional animation techniques, an interactive virtual model combined with a driving simulator has proved to be useful in many aspects. It is an excellent tool for testing proposed positions of road signs in the tunnel. It is easier to compare alternative sign positions with the three-dimensional virtual tunnel model than with ordinary drawings. Some visual traps not foreseen in the original sign-position design were corrected after detection in the simulator. Traffic engineers reported that they became involved in the tunnel design process at an earlier stage than before, enabling them to work in the final tunnel environment long before the actual tunnel was built. The ability to work early in the design process makes it possible for traffic engineers, architects, and safety engineers to evaluate their designs while other solutions still can be considered.
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Zhou, Xiao Jun, Bo Jiang, Rui Yang, and Chao Ning. "Design of High Speed Railway Tunnel and its Construction Method in Abrupt Slope with Loose Rockmass." Applied Mechanics and Materials 580-583 (July 2014): 1096–99. http://dx.doi.org/10.4028/www.scientific.net/amm.580-583.1096.
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This paper mainly deals with the structural design of high speed railway tunnel and its driving method in abrupt slope with loose rockmass, meanwhile summarizes the connection between tunnel portal and bridge abutment in loose rockmass according to complicated landform and geology. The anti-slide piles are adopted to retain the stability of abrupt slope near the tunnel portal. In order to eliminate the risk and cost in tunnel construction, four bench cut method is invented to satisfy the safe excavation of loose rockmass in the tunnel. Composite fiber rockbolt is also employed to keep the stability of working face while driving the tunnel. The innovative tunneling method presented in the paper can be applied to guide the rational design and economical construction of high speed railway tunnels in loose surrounding rock under harsh geological conditions.
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Wu, Peng, Feng Yang, Jinlong Zheng, and Yanqing Wei. "Evaluating the Highway Tunnel Construction in Western Sichuan Plateau Considering Vocational Health and Environment." International Journal of Environmental Research and Public Health 16, no. 23 (November 23, 2019): 4671. http://dx.doi.org/10.3390/ijerph16234671.
Повний текст джерелаАнотація:
Oxygen deficiency and coldness are the main challenges for highway tunnel construction in high-altitude areas such as western Sichuan plateau. The artificial oxygen supply and anti-freezing structure in the tunnel construction process has a significant impact on vocational health and the environment. Thus, the conditions of tunnels need to be carefully evaluated before construction. However, the current design code for tunnel construction contains few instructions about these aspects. This paper attempts to establish a simple evaluation method to guide the construction design by analyzing the oxygen partial pressure of trachea, the mean temperature of the coldest month, and the maximum freezing depth for tunnel projects in western Sichuan plateau. Based on the on-site meteorological monitoring at different altitudes of three typical tunnels in the western Sichuan plateau and the comparative analysis of the existing meteorological data, the corresponding relationships between the three parameters and the altitude were investigated. The thresholds by altitude for grading the tunnels are identified as 2100 m and 4200 m, respectively. The highway tunnels in the western Sichuan plateau are graded in three categories, namely, general-altitude tunnels, high-altitude tunnels, and ultra-high-altitude tunnels. The corresponding measures of oxygen supply and freezing prevention for different graded tunnels are recommended. The results would provide a basis for the design and construction of new tunnels and enhance the service life and operations safety of the tunnels in western Sichuan plateau and other similar high-altitude areas.
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Sun, Haili, Zhengwen Xu, Lianbi Yao, Ruofei Zhong, Liming Du, and Hangbin Wu. "Tunnel Monitoring and Measuring System Using Mobile Laser Scanning: Design and Deployment." Remote Sensing 12, no. 4 (February 22, 2020): 730. http://dx.doi.org/10.3390/rs12040730.
Повний текст джерелаАнотація:
The common statistical methods for rail tunnel deformation and disease detection usually require a large amount of equipment and manpower to achieve full section detection, which are time consuming and inefficient. The development trend in the industry is to use laser scanning for full section detection. In this paper, a design scheme for a tunnel monitoring and measuring system with laser scanning as the main sensor for tunnel environmental disease and deformation analysis is proposed. The system provides functions such as tunnel point cloud collection, section deformation analysis, dislocation analysis, disease extraction, tunnel and track image generation, roaming video generation, etc. Field engineering indicated that the repeatability of the convergence diameter detection of the system can reach ±2 mm, dislocation repeatability can reach ±3 mm, the image resolution is about 0.5 mm/pixel in the ballast part, and the resolution of the inner wall of the tunnel is about 1.5 mm/pixel. The system can include human–computer interaction to extract and label diseases or appurtenances and support the generation of thematic disease maps. The developed system can provide important technical support for deformation and disease detection of rail transit tunnels.
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Zhao, Huiling, Yuheng Ma, and Xupeng Yao. "Dynamic Response of Curved Tunnels under Vertical Incidence of Transversal SV Waves." Shock and Vibration 2023 (April 25, 2023): 1–15. http://dx.doi.org/10.1155/2023/8561647.
Повний текст джерелаАнотація:
Long tunnels often have curved sections when alignment designs are influenced by topography, adverse geology, and environmental factors. When the transversal SV wave is incident vertically, the curved section of the tunnel is subject to a connection between longitudinal and transversal loads, which are asymmetrical about the tunnel longitudinal axis. Compared to straight tunnels, curved tunnels are more complex in terms of forces and deformations and may become a key control section limiting the seismic safety of curved tunnels. To investigate the seismic response of curved tunnels, numerical simulations of curved tunnels with different radii of curvature under transversal SV seismic waves were carried out in this study. Local artificial boundaries were programmed and used for the 3D rock tunnel interaction system model to simulate semi-infinite rock and to eliminate fake reflections of seismic waves on local boundaries. The results show that longitudinal deformation and cross-sectional deformation occurred simultaneously in curved tunnels when the transversal SV wave was incident vertically. As the curvature increased, the longitudinal deformation of the curved tunnel increased. The cross-section of the tunnel was in oblique compression, and the cross-sectional internal force showed significant asymmetry. When the radius of curvature was 250 m, the difference in bending moment between the left and right haunch was 35.2%. These characteristics differ from those of straight tunnels and should be paid attention in the seismic design of curved tunnels.
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Wang, Jie, Xin Hou, Xujie Deng, Huichao Han, and Liuliu Zhang. "Application of BIM in Tunnel Design with Compaction Pile Reinforced Foundation Carrying Carbon Assessment Based on Advanced Dynamo Visual Programming: A Case Study in China." Sustainability 14, no. 23 (December 5, 2022): 16222. http://dx.doi.org/10.3390/su142316222.
Повний текст джерелаАнотація:
Carbon emission assessment in civil engineering has gained worldwide attention due to the negative effects of greenhouse gases on the environment. Significant amounts of building materials and electric power are consumed during the construction of tunnels, causing the release of greenhouse gases into the atmosphere. In addition, building information modeling (BIM) can be utilized to realize the computerized design of tunnels, and improve construction efficiency. However, the traditional BIM software (Autodesk Revit) lacks tunnel components and is unable to directly create a three-dimensional tunnel axis. This paper adopted BIM to build a three-dimensional model of the tunnel components for tunnel and carried out batch parameterization and component lofting based on Dynamo visual programming. The BIM of the tunnel guided the construction procedures and improved the construction efficiency. Based on the emission coefficient method, we calculated the carbon emissions from each component and loaded them into the BIM during the parameterization process. After the tunnel modeling design was completed, a bill of quantities was obtained. Then, the carbon emissions from the whole tunnel construction were calculated according to the bill. Thus, the combination of BIM technology and tunnel engineering was realized; this has practical significance for reductions in emissions, and cleaner construction in relation to tunnel engineering.
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Cheng, Yuh-Jiuh, Bor-Tauo Chen, Cheng-Ping Wu, and Yu-Yun Lee. "Design of Optical Tunnel Switching Networks for Big Data Applications." Applied Sciences 10, no. 6 (March 20, 2020): 2098. http://dx.doi.org/10.3390/app10062098.
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In this paper, we proposed large-scale optical tunnel switching networks based on the Torus topology network with WSS (Wavelength Selective Switch) for future big data applications. All nodes of the large-scale optical tunnel switching networks use WSS switch modules, and the communications between nodes use multiple λs (wavelengths), where a tunnel is established with a wavelength which can be reused. The widely used MEMS (Micro-Electro-Mechanical Systems) and LCoS (Liquid Crystal on Silicon) technologies are all millisecond-level switching speeds, so the frame size of the optical frame switch is very large, and this will reduce switching performance. Therefore, they are only suitable for optical tunnel switching networks design, but are not suitable for optical frame switch design. This multi-plane Torus topology network architecture not only increases network throughput, but also has fault tolerance to increase network reliability. When the traffic is changed, the number of tunnels between nodes can be scheduled in time to balance the load traffic and avoid traffic loss. Therefore, it can not only schedule the number of tunnels in time to balance the load traffic, in order to avoid traffic loss, but also because the channel is fixedly established, this does not generate any buffer delay, and this because of the transmission using optical transmission unlimited speed, so it is a good choice for future big data applications that require high speed, high bandwidth and low latency.
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Mori, Lomere, Mustafa Gül, Roger Cheng, and Ved Sharma. "An investigation of the ambient temperature field and thermal response of the Calgary Airport Trail Tunnel." Canadian Journal of Civil Engineering 45, no. 12 (December 2018): 1015–26. http://dx.doi.org/10.1139/cjce-2017-0039.
Повний текст джерелаАнотація:
Currently, there is a lack of direct design provisions in structural codes and literature that address design temperatures in tunnel structures and thus it is common practice for designers to resort to bridge codes. The main focus of this paper is the study of the temperature distribution in concrete road tunnels due to ambient temperature. In this context, the temperature distributions of the Airport Trail Tunnel in Calgary, Alberta is studied using numerical modelling and long-term temperature monitoring data collected from the tunnel. The overall aim is to evaluate findings from the numerical analysis and sensor data with current Canadian structural code provisions considered in tunnel design in regards to temperature loads. From the investigation, it is determined that the design temperature range was within CSA S6, however CSA S6 underestimates the temperature gradient effect in the walls and slabs of the tunnel under study.
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Wu, Lin, Xiedong Zhang, Wei Wang, Xiancong Meng, and Hong Guo. "Comparison of Dynamic Characteristics between Small and Super-Large Diameter Cross-River Twin Tunnels under Train Vibration." Applied Sciences 11, no. 16 (August 18, 2021): 7577. http://dx.doi.org/10.3390/app11167577.
Повний текст джерелаАнотація:
Train vibration from closely aligned adjacent tunnels could cause safety concerns, especially given the soaring size of the tunnel diameter. This paper established a two-dimensional discrete element model (DEM) of small (d = 6.2 m) and super-large (D = 15.2 m) diameter cross-river twin tunnels and discussed the dynamic characteristics of adjacent tunnels during the vibration of a train that runs through the tunnel at a speed of 120 km/h. Results in the D tunnel showed that the horizontal walls have the same horizontal displacement (DH) and the vertical walls have the same vertical displacement (DV). The stress state of the surroundings of the D tunnel is the decisive factor for DH, and the distance from the vibration point to the measurement point is the decisive factor for DV. Results in the comparison of the d and D tunnels showed that the D tunnel is more stable than the d tunnel with respect to two aspects: the time the tunnel reaches the equilibrium state and the vibration amplitude of the structure’s dynamic and static responses. The dynamic characteristic of the d and D tunnel is significantly different. This research is expected to guide the design and construction of large diameter twin tunnels.
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Baker, Dirk V., and K. Beck George. "The Weed Tunnel: Building an Experimental Wind Tunnel." Weed Technology 22, no. 3 (September 2008): 549–52. http://dx.doi.org/10.1614/wt-07-162.1.
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Dispersal is a key component of plant population and community dynamics and the spread of weeds. Although many species of economic concern disperse via tumbleweed mechanisms, our ability to estimate relevant dispersal parameters can be hindered by the lack of a controlled environment that can be provided by a wind tunnel. Established wind tunnels are typically closed-circuit, clean systems and are therefore unsuitable for biological or ecological research. We designed and constructed a wind tunnel to estimate dispersal parameters for diffuse knapweed. Our design was a tunnel that utilizes the Venturi effect to obtain maximum flow velocity while pulling, rather than pushing, air through the test section. Flow velocity was continuously variable from 0 to 8 m/s, and the tunnel was equipped with instrumentation for measuring the force exerted on plants by wind. Our modular design provided a way to effectively estimate key parameters that govern the dispersal of tumbleweeds, and was readily constructed and stored in research facilities.
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Zhao, Jinpeng, Zhongsheng Tan, and Zhenliang Zhou. "Discussion on the Waterproof and Drainage System of the Coastal Tunnel and Analysis of Water Pressure Law outside Lining: A Case Study of the Gongbei Tunnel." Advances in Civil Engineering 2021 (February 26, 2021): 1–18. http://dx.doi.org/10.1155/2021/6610601.
Повний текст джерелаАнотація:
With the orderly promotion of the infrastructure construction in China, the number of coastal tunnels is increasing, but the coastal environment is accompanied by a large amount of groundwater and the designs of the waterproof and drainage system of coastal tunnels have always been a hot topic in the industry. If the waterproof and drainage system designs of the coastal tunnels are improper, the tunnel structure will easily be damaged and the stability and service life of the whole project will be affected. Based on the Gongbei tunnel project of the Hong Kong-Zhuhai-Macao Bridge, this paper discusses the designs of the waterproof and drainage system, and the waterproof detail structures of the Gongbei tunnel. Indoor similarity tests were carried out to study the law of the free water discharge of the tunnel under variable water heads, the relationship between the water pressure outside the lining and the water discharge, the relationship between the water pressure outside the pipe roof and the water discharge, and the distribution of water pressure around the tunnel. The reliability of the indoor similarity test was verified by the field test. The results show that the whole waterproof system should be adopted in the Gongbei tunnel, that is, grouting ring + pipe roof freezing ring + initial lining + waterproof board + tertiary lining. In a certain range, the greater the water head, the greater the free water discharge of the tunnel. When the water head is large, the free drainage tends to a fixed value. When the tunnel is completely plugged, the water pressure outside the tunnel is distributed from the hydrostatic pressure. When the tunnel adopts drainage measures, the water pressure outside the lining will be reduced to a certain extent even the water discharge is very small. The above research can provide a reference for the design of the waterproof and drainage system similar to the coastal tunnel in the future.
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Hrúz, Michal, Pavol Pecho, and Martin Bugaj. "Design procedure and honeycomb screen implementation to the air transtport department’s subsonic wind tunnel." AEROjournal 16, no. 2 (2020): 3–8. http://dx.doi.org/10.26552/aer.c.2020.2.1.
Повний текст джерелаАнотація:
Wind tunnels are the most widely used tools when comes to validation of Reynold number. Most of wind tunnels use various air straighteners or flow conditioners to achieve as most unified air flow as it’s possible. This article deals with design and creation procedure of air flow straightener – honeycomb screen. Based on mathematical relations and empirical experience defines dimensions and characteristics for subsonic wind tunnel of the Air Transport Department of University of Žilina. Wind tunnel equipped with a suitable screen provides more relevant and accurate data, which are crucial for final validation of results of test objects.
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Yamamoto, Kentaro, Andrei V. Lyamin, Daniel W. Wilson, Scott W. Sloan, and Andrew J. Abbo. "Stability of dual square tunnels in cohesive-frictional soil subjected to surcharge loading." Canadian Geotechnical Journal 51, no. 8 (August 2014): 829–43. http://dx.doi.org/10.1139/cgj-2013-0481.
Повний текст джерелаАнотація:
The stability of dual square tunnels in cohesive-frictional soils subjected to surcharge loading has been investigated theoretically and numerically assuming plane strain conditions. From the viewpoint of the efficient utilization of underground space for human activities, noncircular openings and tunnels should be preferred in the design stage. Despite the importance of this issue, previous research on the subject is very limited. At present, no generally accepted design or analysis method is available to evaluate the stability of multiple tunnels–openings in cohesive-frictional soils. In the design stage, it is important to consider the interaction effects of dual tunnels. Unlike the case of a single tunnel, the centre-to-centre distance appears as a new parameter that must be considered and plays a key role in tunnel stability. In this study, continuous loading is applied to the ground surface and a smooth interface condition is modelled. For a series of tunnel size-to-depth ratios and material properties, rigorous lower- and upper-bound solutions for the ultimate surcharge loading are obtained by applying finite element limit analysis techniques. For practical suitability, the results are presented in the form of dimensionless stability charts and a table with the actual tunnel stability numbers closely bracketed from above and below. As an additional verification of the solutions, upper-bound rigid-block mechanisms have been developed, and the predicted collapse loads from these mechanisms are compared with those from finite element limit analysis. Finally, a discussion is presented regarding the location of the critical tunnel spacing between dual square tunnels where interaction no longer occurs.
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Kiekara, Tommi, Antti Paakkala, Piia Suomalainen, Heini Huhtala, and Timo Järvelä. "Femoral and Tibial Tunnel Diameter and Bioabsorbable Screw Findings After Double-Bundle ACL Reconstruction in 5-Year Clinical and MRI Follow-up." Orthopaedic Journal of Sports Medicine 5, no. 2 (February 1, 2017): 232596711668552. http://dx.doi.org/10.1177/2325967116685525.
Повний текст джерелаАнотація:
Background: Tunnel enlargement is frequently seen in short-term follow-up after anterior cruciate ligament reconstruction (ACLR). According to new evidence, tunnel enlargement may be followed by tunnel narrowing, but the long-term evolution of the tunnels is currently unknown. Hypothesis/Purpose: The hypothesis was that tunnel enlargement is followed by tunnel narrowing caused by ossification as seen in follow-up using magnetic resonance imaging (MRI). The purpose of this study was to evaluate the ossification pattern of the tunnels, the communication of the 2 femoral and 2 tibial tunnels, and screw absorption findings in MRI. Study Design: Case series; Level of evidence, 4. Methods: Thirty-one patients underwent anatomic double-bundle ACLR with hamstring grafts and bioabsorbable interference screw fixation and were followed with MRI and clinical evaluation at 2 and 5 years postoperatively. Results: The mean tunnel enlargement at 2 years was 58% and reduced to 46% at 5 years. Tunnel ossification resulted in evenly narrowed tunnels in 44%, in conical tunnels in 48%, and fully ossified tunnels in 8%. Tunnel communication increased from 13% to 23% in the femur and from 19% to 23% in the tibia between 2 and 5 years and was not associated with knee laxity. At 5 years, 54% of the screws were not visible, with 35% of the screws replaced by a cyst and 19% fully ossified. Tunnel cysts were not associated with worse patient-reported outcomes or knee laxity. Patients with a tibial anteromedial tunnel cyst had higher Lysholm scores than patients without a cyst (93 and 84, P = .03). Conclusion: Tunnel enlargement was followed by tunnel narrowing in 5-year follow-up after double-bundle ACLR. Tunnel communication and tunnel cysts were frequent MRI findings and not associated with adverse clinical evaluation results.
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Zhou, Xiao Jun, and Xiao Feng Wang. "Design of Shallow Depth Tunnel with Asymmetric Twin Arches and its Construction Procedure in Poor Rock Mass." Applied Mechanics and Materials 353-356 (August 2013): 1321–24. http://dx.doi.org/10.4028/www.scientific.net/amm.353-356.1321.
Повний текст джерелаАнотація:
An asymmetric twin arched tunnel is designed to meet the line development of triple track railway in accordance with ground geological condition and topography in this paper. A partition wall is adopted to support the double arches of the tunnel, and the pilot drift and bench cut method is utilized to preserve the safe excavation of the double arch tunnel in poor rock mass in the paper. The design technique and construction method may guide the driving of such tunnels under similar condition.