Artykuły w czasopismach: „Tunnels - Blast”

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Senthil, Kasilingam, Muskaan Sethi i Loizos Pelecanos. "A review on the performance of the underground tunnels against blast loading". Journal of Structural Engineering & Applied Mechanics 4, nr 1 (30.03.2021): 1–17. http://dx.doi.org/10.31462/jseam.2021.01001017.

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The tunneling system has become an important part of the present infrastructure system in all over the world. Therefore, it has become important to ensure the safety of the tunnels against any type of man-made blasting activities or other accidental blasting occurrence. In order to evaluate the performance of the tunnels against blast loading, a detailed review is carried out. Based on the review in the last couple of decades, the various parameters such as tunnel lining materials, tunnel shapes, tunnel lining thickness, tunnel burial depth, charge weight and standoff distance are high influences on the performance of underground tunnels against blast loading. It was observed that the tunnel roof and the tunnel wall center are most vulnerable to the blast loads. Also, it was found that more of the tunnel lining thickness results in lesser deformation at the tunnel roof and the tunnel wall center. The increase in the burial depth of the tunnel would reduce the extent of damage to the tunnel caused by effects of surface blast loading. The stiffness and strength of the ground media may be enhanced against the effects of blast loading by grouting measures. The studies revealed that the lining materials possessing blast waves absorbing properties can be best suited to be used in tunnel linings. Further, it was observed that more damage was caused to the tunnels due to the magnitude of the charge weight. An increase in the blast load causes a significant increase in the fracture area, residual stress and lateral displacement caused to the tunnel by the action of blast load. The standoff distance of the blast load from the tunnel also plays a significant role in the damage of the tunnel. More is the distance between the charge and the tunnel, lesser damage caused to the tunnels. In addition to that, the lining thickness was predicted and the trend was calibrated and fitted logarithmically with the available results. Based on the observation from the literature, it is concluded that the use of a single lining material in the tunnel against blast loading was studied predominantly in the couple of decades. Further, the performance of the tunnels in combination of different tunnel lining materials against blast loading was found limited. The influence of barriers to save the underground tunnels against blast loading was found limited.

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Zhang, Qingbin, Zongxian Zhang, Congshi Wu, Junsheng Yang i Zhenyu Wang. "Characteristics of Vibration Waves Measured in Concrete Lining of Excavated Tunnel during Blasting in Adjacent Tunnel". Coatings 12, nr 7 (5.07.2022): 954. http://dx.doi.org/10.3390/coatings12070954.

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The effect of a blasting vibration from an excavating tunnel on an adjacent excavated tunnel is of great importance for the stability and security of twin tunnels. Due to the relatively small distance between the tunnel face of the excavating tunnel and the concrete lining of the excavated tunnel, the impact of blasting could be significant and should be considered in a practical project. In order to control the blasting scales during the excavation of one tunnel and minimize the effect of blasting on the adjacent one, research based on field-blasting tests performed on twin tunnels is presented in this study. The particle velocities on the concrete lining of the excavating tunnel caused by blasting from the adjacent excavated tunnel were measured and analysed during six rounds of blasts. According to the measured vibration waves, it was clear that the peak particle velocity (PPV) from each blast was always induced by cut blasting, therefore, the maximum vibration due to each blast was mainly dependent on cut blasting. The measured maximum PPV for all the blasts was 15.55 cm/s, corresponding to a maximum tensile stress of 1.44 MPa observed on the concrete lining, which was smaller than the tensile strength of the concrete lining, in accordance with the one-dimensional elastic-wave theory. Moreover, the attenuation of the vibration waves varied in different regions, and they could be utilized to demonstrate the impact characteristics of the blasting; e.g., the particle velocities in the region along the excavating direction were 1.12 to 1.79 times larger than those in the region opposite to the excavating direction, and the difference increased with the increasing distance to the blasting source. The particle velocities on the side of the excavated tunnel close to the excavating tunnel were larger than those on the other side of the excavated tunnel. However, the particle velocities of the two aforementioned regions were similar when the distance between the measuring point and the blasting source was more than 6 m in the longitudinal direction of the tunnels. Furthermore, the measured vibration waves could be used to evaluate and improve the blast designs of tunnelling with the drill-and-blast method.

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Nawar, Mahmoud, Alaa Ata, Marwa Nabil i Sally Hassan. "Numerical analysis of underground tunnels subjected to surface blast loads". Frattura ed Integrità Strutturale 15, nr 55 (28.12.2020): 159–73. http://dx.doi.org/10.3221/igf-esis.55.12.

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The increased terrorist attacks on important public structures and utilities have raised the vital necessity for the investigation of performance of structures under blast loads to improve the design and enhance the behavior of structures subjected to such threats. In this study, 3-D ﬁnite element analysis is used to study the effect of surface explosions on the response of RC bored tunnels. The soil behavior is modelled using Drucker-Prager Cap model. Two types of soil are investigated, and the blast load is considered through various weights of TNT explosive charges at heights of 0.50 m and 1.0 m from ground surface. To study the effect of horizontal standoff distance, six different horizontal distances are considered. The results show that the soil type has a significance effect on tunnel response due to surface blasts. Also the weight and the location of charge have a great effect on the safety of the tunnel. Finally, a parametric study is established to define the borders of the restricted area around the tunnel location to be safe.

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Mandal, Jagriti, i Manmohan Dass Goel. "Effect of Geo-Material on Dynamic Response of Tunnel Subjected to Surface Explosion". Geotechnics 2, nr 3 (11.08.2022): 635–48. http://dx.doi.org/10.3390/geotechnics2030031.

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Prime materials involved in a problem such as underground structures are concrete, reinforcement steel, and geo-material surrounding the tunnel. Among these three materials, concrete and steel are manufactured materials and their properties can be controlled up to a certain extent. However, geo-material is a naturally occurring material whose constitutive properties vary from region to region, making it highly unpredictable. Findings from one study cannot be applied to other geotechnical problems directly, especially in the case of tunnels subjected to surface explosions. The blast wave generated has to travel through the geo-material before it interacts with the tunnel. As the shock wave propagates radially, its characteristics are likely to be altered by the geo-material. Limited study has been carried out considering this problem. In the present study, the effect of various types of geo-material on the blast response of tunnels subjected to surface explosions is investigated. Finite element analysis has been carried out using LS-DYNA®, wherein the problem has been modeled using the multi-material arbitrary Lagrangian–Eulerian (MM-ALE) method. Materials with fluid behavior such as air, explosives, and soil are modeled using ALE formulation. Other materials including tunnel lining, reinforcement steel, and rock are modeled using Lagrangian formulation. Blast loading is simulated using the Jones–Wilkins–Lee (JWL) equation of state. Geo-materials considered for the comparative study are sandy loam, saturated clayey soil, sandstone, and granite. Vertical displacement measured at the crown of the tunnel is used to determine the response of the tunnel. Sandy loam soil, being a highly compressible soil, exhibits non-linear and fluid-like behavior under high-strain loading such as explosions. Tunnels undergo extreme deformation in the case of sandy loam soil and clayey soil compared to rock cases. Further, the effect of saturation in sandy loam on tunnel stability is studied. It is observed that with the increase in saturation of soil, more blast energy is transmitted to the structure, which results in higher deformation. Lastly, the effect of the weathering of rock on the tunnel’s response is investigated in the case of sandstone and granite. It was observed that weathering in rock led to more displacement of tunnel crown when compared to intact rock.

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Mandal, Jagriti, ManmohanDass Goel i AjayKumar Agarwal. "Effect of Horizontal Curve on the Response of Road Tunnels under Internal Explosion". Proceedings of the 12th Structural Engineering Convention, SEC 2022: Themes 1-2 1, nr 1 (19.12.2022): 1293–97. http://dx.doi.org/10.38208/acp.v1.653.

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Internal explosion in a tunnel is a complex loading phenomenon where the tunnel lining is subjected to not only direct impact of explosion but also loading due to multiple reflection of blast waves which could be of magnitude higher than that of incident blast wave. This kind of loading is complex in nature and difficult to predict using simple analysis tools. Further, it poses a serious threat to its structural integrity. Studies have been conducted in the past to understand the behaviour of tunnel under internal explosion. However, they have been focused on straight tunnels ignoring the convex and concave shapes introduced due to horizontal and vertical curves. Shape of the target surface has significant effect on the characteristics of blast wave. This study investigates the effect of horizontal curves on the damage behaviour of tunnel lining due to internal explosion. A series of numerical simulation are performed on box-shaped tunnel with varying curvature radius and the results are compared with that of straight tunnel adopting Multi-Material Arbitrary Lagrangian-Eulerian (MM-ALE) method using LS-DYNA®. Explosive and air are modeled using ALE formulation, whereas, tunnel and soil are modeled using Lagrangian formulation. Further, Jones-Wilkins-Lee equation of state is used to model the explosion. Damage to the tunnel lining is measured in terms of peak particle velocity (PPV) and von-Mises stress. It is observed that walls of curved tunnels undergo more PPV compared with straight tunnel wherein concave wall show the highest PPV. Propagation of blast wave along the tunnel length is significantly affected due to the introduction of curvature resulting in change in reflection patterns. This further leads to variation in stress contours on tunnel lining with higher concentration of stress in curved tunnels than in straight tunnel.

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Bai, Fengtao, Qi Guo, Kyle Root, Clay Naito i Spencer Quiel. "Blast Vulnerability Assessment of Road Tunnels with Reinforced Concrete Liners". Transportation Research Record: Journal of the Transportation Research Board 2672, nr 41 (28.09.2018): 156–64. http://dx.doi.org/10.1177/0361198118798458.

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Tunnels are a critical component of our transportation infrastructure, and unexpected damage to a tunnel can significantly and adversely impact the functionality of a transportation network. Tunnel systems are vulnerable to potential threats of intentional and accidental blast events because of their relatively unrestricted public access. These events can lead to spalling and breach of the tunnel liner which, depending on the surrounding media, can result in local damage and progressive collapse of the tunnel. Current approaches for evaluating blast-induced damage to a tunnel liner either require significant computational effort or oversimplification such that accurate spatial distributions of damage cannot be obtained. This study presents an effective approach to predict and map the damage to a reinforced concrete liner of a roadway tunnel from various explosive threat sizes and tunnel geometries. A literature review of existing studies is conducted, and potential scenarios of blast events are examined with varying charge position and size. Rectangular, horseshoe, and circular tunnel geometries, each with the same traffic throughput, are evaluated. An efficient analytical approach to determine the spatial distribution of blast-induced spall and breach damage is presented and shows good agreement with numerical models analyzed in LS-DYNA. The proposed approach is then used to examine the relationship between increasing blast hazard intensity and the extent of spall and breach damage. Inflection points in this relationship can be used to identify hazard levels at which a progressive collapse evaluation would be warranted.

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Liu, Zichao, Jun Wu, Qinyi Chen, Shutao Li, Qiushi Yan i Haitao Yu. "Analysis on the Vulnerability of a Tunnel Entrance under Internal Explosion". Sensors 22, nr 24 (12.12.2022): 9727. http://dx.doi.org/10.3390/s22249727.

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Tunnels play an essential role in the transportation network. Tunnel entrances are usually buried at a shallow depth. In the event of an internal explosion, the blast pressure will cause severe damage or even collapse of the tunnel entrance, paralyzing the traffic system. Therefore, an accurate assessment of the damage level of tunnel entrances under internal blast loading can provide effective assistance for the anti-blast design of tunnels, post-disaster emergency response, and economic damage assessment. In this paper, four tunnel entrance specimens were designed and fabricated with a scale ratio of 1/5.5, and a series of field blast tests were carried out to examine the damage pattern of the tunnel entrances under internal explosion. Subsequently, static loading tests were conducted to obtain the maximum bearing capacity of the intact specimen and residual bearing capacities of the post-blast specimens. After that, an explicit non-linear analysis was carried out and a numerical finite element (FE) model of the tunnel entrance under internal blast loading was established by adopting the arbitrary Lagrangian–Eulerian (ALE) method and validated based on the data obtained from the field blast and static loading tests. A probabilistic vulnerability analysis of a typical tunnel entrance subjected to stochastic internal explosions (assuming various charge weights and detonation points) was then carried out with the validated FE model. For the purpose of damage assessment, the residual bearing capacity of the tunnel entrance was taken as the damage criterion. The vulnerability curves corresponding to various damage levels were further developed based on the stochastic data from the probabilistic vulnerability analysis. When the charge weight was 200 kg, the tunnel entrance exhibited slight or moderate damage, while the tunnel entrance suffered severe or even complete damage as the charge weight increased to 1000 kg. However, the tunnel entrance’s probability of complete damage was less than 10% when the TNT charge weight did not exceed 1000 kg.

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Shin, Jinwon, Seungki Pang i Dong-Keon Kim. "Effects of Entrance Shape and Blast Pocket on Internal Overpressure Mitigation for Protective Tunnels Exposed to External Detonation on the Ground". Applied Sciences 13, nr 3 (30.01.2023): 1759. http://dx.doi.org/10.3390/app13031759.

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This study presents a numerical analysis to reduce the overpressure inside protective tunnels for external detonations. A three-dimensional computational fluid dynamics model of a tunnel subjected to detonation for a hemispherical charge with a charge weight of 555 kg and a standoff distance of 7.6 m was established, based on a mesh sensitivity study to obtain an optimal element size, stability analysis of overpressure, and validation study to evaluate the accuracy of the numerical results based on Unified Facilities Criteria (UFC) 3-340-02. A parametric analysis was performed using the validated numerical model to investigate the effects of the entrance shape and blast pockets on the reduction in the maximum overpressure. The maximum overpressures were effectively reduced as the slope angle of the tunnel entrance decreased and the length of the blast pocket divided by the tunnel width decreased. An optimized shape of the tunnel was proposed based on the numerical results, where the peak overpressures were reduced by a maximum of 64.5%. This study aims to protect facilities, personnel, and equipment and further reduce construction costs by lowering the overpressure rating of blast valves in protective tunnels.

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Langdon, Geneive, Gerald Nurick, Neil Du Plessis i Ian Rossiter. "Using Perforated Plates as a Blast Wave Shielding Technique for Application to Tunnels". Applied Mechanics and Materials 82 (lipiec 2011): 467–72. http://dx.doi.org/10.4028/www.scientific.net/amm.82.467.

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Tunnels are vulnerable to devastating explosions, due to the concentration of explosive energy that would be many times greater than in an unconfined blast. One way to mitigate the damage resulting from an explosion is to disrupt the blast wave as it propagates along a tunnel. This paper presents the results of an investigation into the performance of perforated plates as a blast wave mitigation method in tunnel-like structures. Plastic explosive was detonated at the open end of a small-scale rigid steel tube and the blast wave propagated down the tube towards a thin, steel target plate. Increasing the separation distance between the perforated plate and target plate decreased the target plate deformation and increased the impulse at which tearing initiated. Large plastic displacement of the perforated plates was observed. Ansys Autodyn was used to model the experiments and provide additional insight into the blast wave propagation.

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Li, Ao, Dingli Zhang, Qian Fang, Jiwei Luo, Liqiang Cao i Zhenyu Sun. "Safety Distance of Shotcrete Subjected to Blasting Vibration in Large-Span High-Speed Railway Tunnels". Shock and Vibration 2019 (14.10.2019): 1–14. http://dx.doi.org/10.1155/2019/2429713.

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The drill and blast method is widely used in constructing tunnels in rock. Unfortunately, blasting vibration can damage newly performed shotcrete layers which are major support structures to stabilize surrounding structures. Therefore, investigation of the influence of blasting on shotcrete and determining reasonable distance between blasting work face and shotcrete position is of great importance. In this paper, a large-span tunnel excavated by drill and blast method acting as a high-speed railway station has been investigated. Blast vibration in the tunnel was recorded using microseismic monitoring technique. Empirical prediction equations for peak particle velocity (PPV) were obtained through regression analysis based on the obtained monitoring data. The attenuation law of tensile stress imposed on shotcrete layer due to blasting and bond strength of shotcrete-rock interface was also investigated. Minimum safety distance between shotcrete and blasting positions was calculated based on bond failure criterion. Evolution law considering different factors including blasting charge, rock mass class, and setting time of shotcrete was also obtained, which could be applied to determine blast charge shotcrete arrangements for tunnel constructions in future. The obtained results showed that the safety of shotcrete could be ensured and shotcrete falling off the rock could be prevented under current blast constructions.

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Colombo, Matteo, Paolo Martinelli i Marco di Prisco. "Underground Tunnels Exposed to Internal Blast: Effect of the Explosive Source Position". Key Engineering Materials 711 (wrzesień 2016): 852–59. http://dx.doi.org/10.4028/www.scientific.net/kem.711.852.

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The design procedure recently proposed by the same authors and based on a simplified FE model for underground tunnels subjected to internal explosion is extended in this work taking into account different possible positions of the explosive source inside the tunnel. The situation in which the internal explosion is preceded by fire accidents is also analyzed. The reference situation is represented by the explosive source located at the center of the tunnel cross–section. The tunnel geometry considered is that of the metro line in Brescia, Italy. It has an internal diameter of about 8.15 m and is located about 23.1 m below the surface. Six segments and a smaller key segment (6+1) make up the tunnel. The ring has an average width of about 1.5 m. Dynamic analyses were carried out in order to reproduce the blast scenario. The aim of this work is to evaluate the influence of the position of the explosive source on the tunnel dynamic response. An ultimate limit state criterion based on the eccentric ultimate flexural capacity and capable of including fire–blast interaction is adopted. An innovative layered precast tunnel segment solution made of different fiber–reinforced cementitious composites is considered.

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Dey, Kaushik, i V. M. S. R. Murthy. "Investigations on Impact of Blasting in Tunnels". International Journal of Geotechnical Earthquake Engineering 1, nr 2 (lipiec 2010): 59–71. http://dx.doi.org/10.4018/jgee.2010070105.

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Blasting with longer advance per round leaves an impact both visible (in the form of overbreak) and invisible (cracks) in the surrounding rockmass, however, a number of controlled-blasting techniques, that is line drilling, pre-splitting, and smooth blasting, have been developed to minimise this problem. These techniques require additional drilling, controlled charging, and detonation, and thus, are not preferred in regular development activities. Investigations have been carried out in five different horizontal development drivages of metal mines to assess the blasting impact using burn cut and arrive at the blast-induced rock damage (BIRD) model. Vibration monitoring close to the blast was carried out using accelerometers for the first time in India to develop vibration predictors and overbreak threshold levels for individual sites. This paper reports the development of the overbreak predictive model (BIRD) for burn cut blasting in hard rock drivages by combining the relevant rock, blast design, and explosive parameters. A multivariate statistical model has been developed and validated and the same can find ready application in tunnels and mines for exercising suitable engineering controls both in blast design and explosive selection for reduced basting impacts.

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Verma, H. K., N. K. Samadhiya, M. Singh, R. K. Goel i P. K. Singh. "Blast induced rock mass damage around tunnels". Tunnelling and Underground Space Technology 71 (styczeń 2018): 149–58. http://dx.doi.org/10.1016/j.tust.2017.08.019.

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Smith, P. D., P. Vismeg, L. C. Teo i L. Tingey. "Blast wave transmission along rough-walled tunnels". International Journal of Impact Engineering 21, nr 6 (czerwiec 1998): 419–32. http://dx.doi.org/10.1016/s0734-743x(98)00003-7.

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Zhou, Xianshun, Xuemin Zhang, Tianhe Ren, Xuefeng Ou, Wenchao Xiong, Liming Zhang i Lei Zhang. "Waveform Characteristics of Tunnel Blast Waves and a Wave-Blocking Method". Shock and Vibration 2022 (16.08.2022): 1–11. http://dx.doi.org/10.1155/2022/3013130.

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The impact of blast wave air overpressure (AOp) may cause damage to nearby structures and significant noise pollution. In order to minimize the impact of the blast wave on the buildings around the tunnel, a new wave-blocking trolley (NWBT) was proposed to control the AOp during the construction of the Baitacun tunnel, as the nearby villages were located less than 100 m from the tunnel portal. In the study, the characteristics of the blast wave pressure profiles were studied by field measurements and numerical simulations and the Friedlander equation parameters were obtained. Second, the controlling effect and working mechanism of the NWBT were verified to be effective. The measured peak AOp was weakened from 2.49 kPa to 0.55 kPa with the operating NWBT, which meets the requirements of Chinese specifications. Furthermore, a numerical simulation for the impact process of the NWBT was established using the ANSYS/LS-DYNA software. Finally, it was found that a shorter distance from the NWBT to the source of the blast makes a better contribution to its wave-blocking effect. The waveform characteristics obtained in the study contribute to the design of tunnel surrounding structures; the application of the NWBT is a successful wave-blocking method for tunnels adjacent to environmentally sensitive areas.

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Lu, Hong Qin, Wei Qing Liu i Tong Zhao. "Study on the Arrangement of Baffles Attenuating Blast Waves inside Tunnels". Applied Mechanics and Materials 204-208 (październik 2012): 1380–84. http://dx.doi.org/10.4028/www.scientific.net/amm.204-208.1380.

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Explosion inside the entrance of a tunnel may produce strong blast wave in the tunnel. Taking effective measures to attenuate the air blast wave is very important. Numerical simulations were done on explosion inside the entrance of a tunnel in three different cases, no baffles, symmetrical baffles and stagger baffles arranged along the tunnel. It is found that the arrangement of baffles can attenuate the air blast wave effectively. The best arrangement of baffles is given and it is a reference for tunnel protective design and study.

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Zhang, Pei, Jianhua Cai, Feng Zong, Yanpeng He i Qiong Wang. "Dynamic Response Analysis of Underground Double-Line Tunnel under Surface Blasting". Shock and Vibration 2021 (29.07.2021): 1–13. http://dx.doi.org/10.1155/2021/9226615.

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Blasting has been widely used for economical and rapid rock excavation in civil and mining engineering. In order to study the influence of relative horizontal distance and relative vertical distance between two tunnels on the dynamical response of the two tunnels, 10 numerical simulation cases are done by LS-DYNA 3D models under surface explosion by controlling the clear distance and height difference of double-line tunnel, and the ALE multimaterial fluid structure coupling algorithm is applied to analyze the dynamic response characteristics of double-line tunnel under different conditions. The numerical results show that the dynamic response characteristics of the tunnel lining are affected by the change of the clear distance and height difference of the tunnel. With the increase of the height difference between adjacent tunnels, the peak value of vibration velocity at the top of the lining on the blast face increases, which is due to the upward elevation of the right tunnel, which is more conducive to the reflection and superposition of stress waves. When the height difference of tunnel is 4–6 m, the vibration velocity and displacement of monitoring point C on the back blasting side will change abruptly, and the variation range of vibration velocity is about 25%, while the variation range of displacement is about 60%.

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Li, Zhipeng, Shunchuan Wu, Ziqiao Cheng i Yibo Jiang. "Numerical Investigation of the Dynamic Responses and Damage of Linings Subjected to Violent Gas Explosions inside Highway Tunnels". Shock and Vibration 2018 (8.10.2018): 1–20. http://dx.doi.org/10.1155/2018/2792043.

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The linings of structures suffer severe damage when subjected to internal explosions, which cause numerous casualties and incalculable economic losses. In this paper, a violent gas explosion that occurred inside a highway tunnel in the city of Chengdu, China, is studied through numerical simulations. The evaluated energy of the gas explosion was equivalent to 2428.9 kg of TNT. A fully coupled numerical model consisting of five parts is established with dimensions consistent with the real prototype dimensions and by considering fluid-structure interaction (FSI) effects. Then, a detailed modelling process is presented and validated through a comparison with empirical formulas. This paper investigates the strength and propagation characteristics of a blast shock wave inside the tunnel, and both the effective stresses and dynamic responses of the lining are analysed under the blast impact loading. The damage mechanism is studied, and the evolution of the lining damage is reproduced, the results of which show good agreement with the actual conditions. Moreover, in terms of the responses and damage of the lining, the fully coupled blast loading model has obvious advantages in comparison with the simplified blast loading model. Furthermore, the damage assessment of the lining conducted using the single degree of freedom (SDOF) method agrees well with the results of the numerical simulation and site investigations. The comprehensive numerical simulation technique used in the present paper and its results could represent valuable references for future research on violent explosions within tunnels or very large underground structures and provide relevant information for the blast-resistant design of such structures.

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Wu, Bo, Weixing Qiu, Wei Huang, Guowang Meng, Jingsong Huang i Shixiang Xu. "Dynamic risk evaluation method for collapse disasters of drill-and-blast tunnels: a case study". Mathematical Biosciences and Engineering 19, nr 1 (2022): 309–30. http://dx.doi.org/10.3934/mbe.2022016.

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<abstract> <p>The tunnel collapse is one of the most frequent and harmful geological hazards during the construction of highway rock tunnels. As for reducing the occurrence probability of tunnel collapse, a new dynamic risk assessment methodology for the tunnel collapse was established, which combines the Cloud model (CM), the Membership function, and the Bayesian network (BN). During the preparation phase, tunnel collapse risk factors are identified and an index system is constructed. Then, the proposed novel assessment method is used to evaluate the probability of tunnel collapse risk for on-site construction. The probability of tunnel collapse risk in the dynamic process of construction can provide real-time guidance for tunnel construction. Moreover, a typical case study of the Yutangxi tunnel is performed, which belongs to the Pu-Yan Highway Project (Fujian, China). The results show that the dynamic evaluation model is well validated and applied. The risk value of tunnel collapse in a construction cycle is predicted successfully, and on-site construction is guided to reduce the occurrence of tunnel collapse. Besides, it also proves the feasibility of the dynamic evaluation method and its application potential.</p> </abstract>

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Zhang, Su Min, i Yong Quan Zhu. "Management Criterion for Large Deformation Tunnels". Applied Mechanics and Materials 204-208 (październik 2012): 1468–71. http://dx.doi.org/10.4028/www.scientific.net/amm.204-208.1468.

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The limit displacement was calculated with regard to a large deflection tunnel. The continuum calculation model was established with actual parameters of the surrounding rock of the tunnel as input. In the simulation calculation, the action occasion of the support structure was determined based on the ratio of the measured rock pressure to the geo-stress, and the bearing capacity of the R.C. compressive bending component of the support was expressed with the axial force and bending moment on losing capacity of the support structure in loading; The limit displacement of the tunnel wais determined finally combined with the measured displacement of control points on collapsed or gauge-intrusive sections and cracked primary support or secondary lining sections. Since the deforming rate is more concerned than the displacement in drill and blast tunnel construction, three-level-management of deflection and deforming rate was proposed based on the statistical analysis of measured deforming rate, and the safety requirement for deflection control in construction. The management criterion has reference value to other similar tunnels where difficulty is encountered due to large deflection occurring in construction.

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Ouyang, Ziyan, Aerik Carlton, Qi Guo, Clay Naito i Spencer Quiel. "Blast Vulnerability of Drop Ceilings in Roadway Tunnels". Journal of Performance of Constructed Facilities 34, nr 6 (grudzień 2020): 04020121. http://dx.doi.org/10.1061/(asce)cf.1943-5509.0001526.

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Shin, Jinwon, i Seungki Pang. "Blast Overpressure Reduction Using Entrance Shape and Blast Pocket Depth of Protective Tunnels". Journal of Korean Society of Steel Construction 34, nr 1 (27.01.2022): 25–33. http://dx.doi.org/10.7781/kjoss.2022.34.1.025.

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Chen, Juntao, Haitao Yu, Antonio Bobet i Yong Yuan. "Shaking table tests of transition tunnel connecting TBM and drill-and-blast tunnels". Tunnelling and Underground Space Technology 96 (luty 2020): 103197. http://dx.doi.org/10.1016/j.tust.2019.103197.

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Xue, Fei, Caichu Xia, Guoliang Li, Baocheng Jin, Yongwang He i Yapeng Fu. "Safety Threshold Determination for Blasting Vibration of the Lining in Existing Tunnels under Adjacent Tunnel Blasting". Advances in Civil Engineering 2019 (19.09.2019): 1–10. http://dx.doi.org/10.1155/2019/8303420.

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The effects of tunnel blast excavation on the lining structures of adjacent tunnels are comprehensively studied for the Xinling highway tunnel project. First, the LS-DYNA software is applied to obtain the characteristics of vibration velocities and dynamic stresses at different positions of the tunnel liner. The results indicate that the maximum peak particle velocity (PPV) is located on the haunch of the lining facing the blasting source and that the PPV and peak tensile stress decrease with the increase in the surrounding rock grade. Second, a site test on blasting vibration is conducted to verify the simulation results. By using regression analysis of the measured vibration data, the calculation method of maximum charge per delay for optimizing blasting excavation under different surrounding rock grades is obtained. Finally, based on the statistical relationship between crack alteration and PPV on the lining before and after blasting, the safety thresholds of PPV for different portions of the tunnel are determined. The recommended safety threshold of PPV is 10 cm/s for intact lining and for B-grade and V-grade linings of the surrounding rock tunnel. However, if the lining crack grade falls between 1A and B, then the recommended safety thresholds of PPV for the III-grade and IV-grade surrounding rock tunnel are 5 cm/s and 6 cm/s, respectively. The threshold PPV proposed in this study has been successfully applied to restrict blast-induced damage during new tunnel excavation of the Xinling tunnel project.

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ZHAO, ZHIYE, YUN ZHANG i HUIRONG BAO. "TUNNEL BLASTING SIMULATIONS BY THE DISCONTINUOUS DEFORMATION ANALYSIS". International Journal of Computational Methods 08, nr 02 (czerwiec 2011): 277–92. http://dx.doi.org/10.1142/s0219876211002599.

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Drill and blast method has been widely used as an effective excavation method for underground rock caverns or tunnels. To achieve a good blast design, an understanding on the rock dynamic response and rock fragmentation process is important. In this paper, numerical simulations are performed on a typical parallel hole cut blasting based on the discontinuous deformation analysis (DDA). The blast loading is obtained from the explicit FEM code LS-DYNA and the dynamic response of the rock mass is modeled by the DDA. Different influence factors on rock fragmentation under the blast loading are investigated, including the different delay time and various rock mass properties. Such a study will have potential applications for better drill and blast designs.

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Frenelus, Wadslin, Hui Peng i Jingyu Zhang. "Long-term degradation, damage and fracture in deep rock tunnels: A review on the effect of excavation methods". Frattura ed Integrità Strutturale 15, nr 58 (25.09.2021): 128–50. http://dx.doi.org/10.3221/igf-esis.58.10.

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Rocks are frequently host materials for underground structures, particularly for deep Tunnels. Their behavior plays a fundamental role in the overall stability of these structures. In fact, the erection of deep tunnels imposes rocks excavations around the defined routes. These excavations are generally carried out by various methods of which the most used are Drill-and-Blast (DB) and Tunnel Boring Machine (TBM). However, regardless of the tunnelling method used, the impacts such as the perturbation of the initial stress field in rocks and the release of the stored energy are always significant. The impacts produce damage, fractures and deformations which are generally time-dependent and influence the long-term stability of deep tunnels built in rocks. Thus, by considering the aforementioned excavation methods, this paper identifies, reviews and describes the relevant factors generated during and after rock excavations. Interestingly, such factors directly or indirectly influence the long-term stability and therefore the structural integrity of deep rock tunnels. In addition, some recommendations and proposals for future works are presented. This paper can provide useful references in understanding the degradations, damage and fractures generated by tunnelling methods and facilitate suitable actions to ensure long-term stability of deep underground structures.

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Jasipto, Alio, Nuhindro Priagung Widodo, Ganda Marihot Simangunsong, Simon Heru Prasesetyo, Made Astawa Rai, Dhika Noor Pradhana i Dimas Agung Saputra. "Dynamic Analysis of Blasting Effect on Nanjung Tunnel Stability". Indonesian Mining Professionals Journal 2, nr 1 (28.11.2020): 1–10. http://dx.doi.org/10.36986/impj.v2i1.17.

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This study aims to dynamically analyze blasting conducted in the Nanjung tunnel. Nanjung Tunnel is a twin tunnel that has a horseshoe-shaped section with each tunnel having a dimension of 10.2 m x 9.2 m, and 230 meters in length. The layers rock of this tunnel include silty clay, sandstone and dacite. Blasting was carried out on one of the tunnels consisting of dacite rock, having a 75-90% RQD and UCS 49-61 MPa. During the blast, PPV measurements were taken at several points around the tunnel using a minimate.Dynamic analysis is done by building a Nanjung Tunnel model on the RS2 software with the finite element method. Input data in this modeling is endeavored to approach actual conditions in the field, such as tunnel geometry, rock mass properties, and blasting plans carried out at STA 30-32 tunnels 2. This modeling is expected to produce PPV that is close to actual PPV and the results of this model will be continued to the stability analysis tunnel 1.Modeling results indicate that the tunnel 1 condition is stable during blasting. The stability of tunnel 1 based on smallest strength factor on the roof is around 2.6. Stability also seen from the strain level in dacite and sandstone rocks which are 0.07% and 0.38%. These strain levels are still permissible according to the Sakurai strain level diagram, 1983.

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Koneshwaran, Sivalingam, David P. Thambiratnam i Chaminda Gallage. "Response of segmented bored transit tunnels to surface blast". Advances in Engineering Software 89 (listopad 2015): 77–89. http://dx.doi.org/10.1016/j.advengsoft.2015.02.007.

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Zhou, Xianshun, Xuemin Zhang, Han Feng, Shenglin Zhang, Junsheng Yang, Jinwei Mu i Tao Hu. "Study on Dominant Frequency Attenuation of Blasting Vibration for Ultra-Small-Spacing Tunnel". Applied Sciences 12, nr 3 (20.01.2022): 1058. http://dx.doi.org/10.3390/app12031058.

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The middle rock pillar in ultra-small-spacing tunnels is significantly narrow, and the stability of the primary support and lining are easily influenced by the blasting vibration wave from an adjacent tunnel. Therefore, understanding the vibration frequency characteristics is essential for the blasting vibration control. Based on the blasting works on a double-track roadway tunnel (Jiuwuji tunnel in Guizhou, China), this study investigates the dominant frequency attenuation in the preceding tunnel with the middle rock pillar spacing ranging from 4.0 m to 9.4 m. The results show that the ranges of the dominant frequency distributions on the primary support and lining are widely within 200 Hz, but there are varieties in their propagation laws. The distribution of the dominant frequencies on the primary support is broader than that on the lining; and the dominant frequencies are concentrated on a specific range when the lining is far from the blast face beside a particular value, which is not present on the primary support. As the presence of cavity and changing medium between the lining and the primary support, it made a significant contribution to the filtering the vibration waves. Furthermore, on the primary support, the high-frequency part of the vibration waves attenuates rapidly with distance, and then, the practical prediction equations describing dominant frequency attenuation were proposed. The comparison on frequency characteristics per delay for the millisecond delay blasting shows that multiple delay sequences blast contributes to a multi-structured amplitude spectrum of blast vibration waves; and the varies of the equivalent explosion sources dimensions and numbers of free surfaces in each blast delay resulting in diverse vibration waveforms. Finally, the dominant frequencies determined by different methods were compared, and the results show a nonlinear relationship between the ZCFs and DFs. The above research conclusion expands the understanding of blasting vibration in tunnel engineering, particularly in the frequency distribution.

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Khomenko, Oleh, Maksym Kononenko, Inna Myronova i Mykola Savchenko. "Application of the emulsion explosives in the tunnels construction". E3S Web of Conferences 123 (2019): 01039. http://dx.doi.org/10.1051/e3sconf/201912301039.

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The analysis has been made of the technical parameters of the existing passport for drilling and blasting operations (DBO) in terms of compliance with labour safety requirements and scientific-technical standards. The methodology for constructing the DBO passport has been developed, which takes into account the areas of blast-hole groups and the properties of emulsion explosives. The type of the cut has been analysed, modelled and accepted for use, which corresponds to the conditions of tunnelling as much as possible. The zones of deformation and fracturing in the massif around blast-hole charges have been simulated. The level of decrease in the hazard index for atmospheric air has been set when using the emulsion explosive Ukrainit-PP instead of TNT-containing charge – Ammonite No.6 ZhV.

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Basaligheh, Farnoosh, Hamidreza Karimi Tabar i Majid Nikkhah. "Evaluating the Safety and the Effect of Blast Loading on the Shotcrete together with lattice girder Support of Tunnels". Frattura ed Integrità Strutturale 17, nr 64 (21.03.2023): 121–36. http://dx.doi.org/10.3221/igf-esis.64.08.

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Damage to tunnels caused by explosions may damage the support structure and the stability. This damage is due to either blasting the working face for drilling progress or an explosion inside the tunnel. The present study investigates the dynamic parameters resulting from the blasting pattern on the temporary support structure of the tunnel considered as a lattice girder and shotcrete equivalent cross-section. For this purpose, LS-DYNA finite element software was used to assess the dynamic response of the structure to the vibration of the blasting-induced explosion. The peak particle velocity (PPV) was considered to evaluate the safety of the tunnel under dynamic loads. According to the results of this study, by exceeding the velocity of 0.9 m/s in the elements, some levels of destruction will occur. Regarding the elements of the temporary support structure of the tunnel, it is found that the damage occurs near the face and 2 m from the tunnel.

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Soheyli, Mohamad Reza, A. H. Akhaveissy i S. M. Mirhosseini. "Large-Scale Experimental and Numerical Study of Blast Acceleration Created by Close-In Buried Explosion on Underground Tunnel Lining". Shock and Vibration 2016 (2016): 1–9. http://dx.doi.org/10.1155/2016/8918050.

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Despite growing demands for structures in water transportation tunnels, underground installations, subsurface dams, and subterranean channels, there is limited field knowledge about the dynamic behavior of these structures in the face of near-fault earthquakes or impulse excitations. This study conducted a large-scale test on underground tunnel excited by two close-in subsurface explosions. The horizontal and vertical acceleration were recorded on the vertical wall of the tunnel and the free field data including the acceleration on the ground surface at 11-meter distance from the tunnel. The frequency domain analysis of recorded results determined the frequency 961 Hz and 968 Hz for 1.69 kg and 2.76 kg equivalent T.N.T., respectively. Then, finite element analysis results were compared with the test data. The comparisons demonstrated a good correlation and satisfied the field data. Finally, based on numerical modeling, a parametric study was applied to determine the effects of shear wave velocity distance of the crater with respect to the tunnel on impulse response of the tunnel.

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Pelecanos, Loizos, SENTHIL KASILINGAM i Muskaan Sethi. "Techniques to safeguard the Underground Tunnels against Surface Blast load". International Journal of Critical Infrastructures 20, nr 1 (2024): 1. http://dx.doi.org/10.1504/ijcis.2024.10046185.

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Zhang, Z. X. "Blast-induced dynamic rock fracture in the surfaces of tunnels". International Journal of Rock Mechanics and Mining Sciences 71 (październik 2014): 217–23. http://dx.doi.org/10.1016/j.ijrmms.2014.05.020.

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Colombo, Matteo, Paolo Martinelli i Marco di Prisco. "A design approach for tunnels exposed to blast and fire". Structural Concrete 16, nr 2 (czerwiec 2015): 262–72. http://dx.doi.org/10.1002/suco.201400052.

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Senthil, K., Muskaan Sethi i Loizos Pelecanos. "Techniques to safeguard the underground tunnels against surface blast load". International Journal of Critical Infrastructures 19, nr 4 (2023): 301–22. http://dx.doi.org/10.1504/ijcis.2023.132212.

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Yu, Jianxin, Zhibin Zhou, Xin Zhang, Xiaolin Yang, Jinxing Wang i Lianhao Zhou. "Vibration Response Characteristics of Adjacent Tunnels under Different Blasting Schemes". Shock and Vibration 2021 (28.12.2021): 1–13. http://dx.doi.org/10.1155/2021/5121296.

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The vibration caused by the tunnel blasting and excavation will harm the surrounding rock and lining structure of the adjacent existing tunnels. This paper takes a two-lane large-span highway tunnel as the research object, conducts on-site monitoring tests on the impact of vibration caused by the blasting and excavation of new tunnels on the existing tunnels under different blasting schemes, and analyses in detail the three-dimension vibration velocity by different excavation footages. From the vibration speed, it is concluded that the influence of the existing tunnel of the newly built tunnel blasting team is affected by various factors, such as distance, free surface, charge, and blasthole distribution. With different blasting schemes, the greater the amount of charge, the greater the vibration caused by blasting. Existing tunnels correspond to the front of the tunnel, and the axial and radial vibration peaks are greater than the vertical. Although the cut segment uses a less amount of explosive and has a less blasthole layout, there is only one free surface. Because of the clamping of the rock, it is compared with the other two segments. The vibration caused is the largest. Although the peripheral holes are filled with a large amount of explosive, the arrangement of the blast holes is relatively scattered and there are many free surfaces. Hence, the vibration caused is the smallest. Corresponding to the back of the tunnel face, since there is no rock clamp, the vibration caused by the cut segment is the smallest, and the vibration caused by the peripheral segment and the floor segment is relatively large. The vibration caused by the front explosion side is significantly greater than the vibration caused by the back explosion side. The vibration velocity caused by the unit charge of 1.5 m footage is greater than that of the 3.0 m footage. The vibration velocity caused by the unit charge of the cut segment is the largest, and the vibration velocity caused by the peripheral segment and the floor segment is smaller. The research results provide a reference for the blasting control of similar engineering construction.

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Adhikari, Govind Raj, R. Balachander i A. I. Theresraj. "Execution of Safe Blasting Under Adverse Conditions of a Powerhouse Complex: A Revisit to Sardar Sarovar Project, India". Technical Journal 2, nr 1 (10.11.2020): 56–67. http://dx.doi.org/10.3126/tj.v2i1.32832.

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When the excavation of the underground powerhouse of the Sardar Sarovar Project, India was nearly complete, cracks were observed on the upstream and downstream walls of the powerhouse, and the installed instrumentation readings sounded an alert for the instability of the powerhouse cavern that could possibly derail the project, further excavation in the powerhouse cavern was halted. After completing stabilisation measures, the remaining underground excavations by drill and blast method were to be completed. This paper revisits case studies of controlled blasting for the remaining excavations, namely a construction ramp, turbine pits, draft tube tunnels connecting the powerhouse, and the concrete plugs erected at the exit ends of the draft tube tunnels. To ensure overall stability around the excavations, blast vibration was controlled by planning the excavations in proper sequences. The damage outside the planned line of excavations was controlled by adopting modified line drilling/smooth blasting techniques. The details of the sequence of excavations, drilling and blasting parameters, compiled from previous publications, are presented in this paper. This paper also describes the reasons why concrete plugs were erected in the draft tube tunnels, the details of the concrete plugs, the optimised drilling and blasting procedure for safe removal of the plugs, and the method adopted to quantify the damage.

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Zhang, Yu, Yuanxue Liu, Runze Wu, Jichang Zhao, Ming Hu i Yizhong Tan. "A Blast-Resistant Method Based on Wave Converters with Spring Oscillator for Underground Structures". Shock and Vibration 2017 (2017): 1–13. http://dx.doi.org/10.1155/2017/2014726.

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Researches on blast-resistant measures for underground structures such as tunnels and underground shopping malls are of great importance for their significant role in economic and social development. In this paper, a new blast-resistant method based on wave converters with spring oscillator for underground structures was put forward, so as to convert the shock wave with high frequency and high peak pressure to the periodic stress wave with low frequency and low peak pressure. The conception and calculation process of this new method were introduced. The mechanical characteristics and motion evolution law of wave converters were deduced theoretically. Based on the theoretical deduction results and finite difference software FLAC3D, the dynamic responses of the new blast-resistant structure and the traditional one were both calculated. Results showed that, after the deployment of wave converters, the peak absolute values of the bending moment, shear force, and axial force of the structure decreased generally, which verified the good blast-resistant effect of the new blast-resistant method.

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Insam, Romed, Stefan Mössmer, Nedim Radončić, Anton Priller, Oliver Staffel i Marco Reith. "Brenner Basistunnel, Baulos H41 Sillschlucht–Pfons: Herausforderungen aufbauend auf den Vorlosen im betroffenen Projektbereich". Geomechanics and Tunnelling 16, nr 4 (sierpień 2023): 353–69. http://dx.doi.org/10.1002/geot.202300022.

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AbstractThe construction lot H41 Sill Gorge–Pfons is one of the biggest construction lots of the Brenner base tunnel and carries out the work on the Austrian side between Austria and Italy. It is situated between the Sill Gorge in Innsbruck and the small mountain village of Pfons. Here, tunnel excavation and inner lining concrete works are carried out based on existing caverns and tunnels made by previous construction lots E41, Sill Gorge and H33 Tulfes–Pfons. The construction lot H41 Sill Gorge–Pfons started in January 2022 with preparation works, and will take 80 months of continuous construction work to complete. All together about 22.5 km of main tubes, 38 bypasses and the remaining parts of the underground Innsbruck emergency station/stop will be excavated by the drill and blast method and by mechanised means (TBM). Additionally, concrete inner lining works will be executed partly alongside the excavation works. In the connection tunnels which are already finished and link the existing Innsbruck bypass with the new Brenner base tunnel, barrier walls are being erected and a new long‐distance water flushing system is being implemented. The limited surface areas in this mountainous region present a huge challenge for logistics and storage as well as on‐site operations for the execution of this complex underground construction lot.

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Wu, Zu Song, Guang Qi Chen, Kouki Zen, Kiyonobu Kasama i Dao Liang Wang. "Effect of Blasting on the Adjacent Underground Tunnels". Applied Mechanics and Materials 90-93 (wrzesień 2011): 1870–78. http://dx.doi.org/10.4028/www.scientific.net/amm.90-93.1870.

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The blasting method is regarded as a simple, convenient and economical method for constructing the underground structure, so it is advisable method for many underground structures to construct. But the investigation of the effect of the blasting dynamic load on the vicinal tunnel structure is rare, and the effect of blasting on the vicinal structures cannot be ignored either; sometimes, the effect will cause crack and even collapse in the tunnel liner and surrounding rock. So this paper presented the effect of blasting on the vicinal underground structure in differential cases using the finite element software Midas GTS. The investigation in this paper indicated which case will suffer the more severe effect caused by blast and let us know the vibration principle of the underground structure in differential case, and that will provide the knowledge about the vibration caused by blasting to the design and construction by numerical simulation; additionally, this paper has presented the reinforcement method about inserting the bolt into the surrounding rock to analyze how to resist the effect of the blast load. So from this analysis, it can be noted that the blasting method or the explosive energy will be chosen on the basis of different construction shape, and the reasonable location of the bolt will be adopted in order to reduce the effect of the dynamic on the vicinal tunnel structure.

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Shin, Jong-Ho, Hoon-Gi Moon i Sung-Eun Chae. "Effect of blast-induced vibration on existing tunnels in soft rocks". Tunnelling and Underground Space Technology 26, nr 1 (styczeń 2011): 51–61. http://dx.doi.org/10.1016/j.tust.2010.05.004.

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Walton, Gabriel, Mark S. Diederichs, Klaus Weinhardt, Dani Delaloye, Matthew J. Lato i Allan Punkkinen. "Change detection in drill and blast tunnels from point cloud data". International Journal of Rock Mechanics and Mining Sciences 105 (maj 2018): 172–81. http://dx.doi.org/10.1016/j.ijrmms.2018.03.004.

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Tiwari, Rohit, Tanusree Chakraborty i Vasant Matsagar. "Analysis of curved tunnels in soil subjected to internal blast loading". Acta Geotechnica 15, nr 2 (13.07.2018): 509–28. http://dx.doi.org/10.1007/s11440-018-0694-x.

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Liu, Xiang, Annan Jiang, Xinping Guo i Lu Hai. "Effect of Excavation Blasting in the Arch Cover Method on Adjacent Existing Pipelines in a Subway Station". Applied Sciences 12, nr 3 (31.01.2022): 1529. http://dx.doi.org/10.3390/app12031529.

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The dynamic responses of existing pipelines are of great significance to be studied in blasting excavation in the arch cover method. In this paper, the Shi Kui Subway Station Line 5 in Dalian, China, is selected as a case study. A 3D numerical simulation model is established to analyze the dynamics characteristics of the existing pipelines subjected to blasting vibration, with a triangular pattern describing the blast hole pressure. The numerical simulation is verified by comparing the existing pipelines’ PPVs of the numerical model and field monitored points. Then, the dynamic responses of the pilot tunnels, existing pipelines, and secondary lining are discussed. The effects of the later pilot tunnel on the earlier pilot tunnel are remarkable when the relative distance between them is small. Extensive blasting areas and many charges will result in large peak velocities of the existing pipelines in a short time, as well as a decreased distance from the pilot tunnels. However, the hollow effect can change these dynamic characteristics. The implementation of a secondary lining can reduce the existing pipelines’ dynamic responses when the lower rock is blasted. The most adverse position of the secondary lining is the arch foot rather than the arch crown and arch waist; thus, blasting should be carried out at a suitable age for the concrete to ensure the safety of the structures and pipelines.

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Zou, Baoping, Zhanyou Luo, Jianxiu Wang i Lisheng Hu. "Development and Application of an Intelligent Evaluation and Control Platform for Tunnel Smooth Blasting". Geofluids 2021 (9.02.2021): 1–15. http://dx.doi.org/10.1155/2021/6669794.

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Many tunnels around the world are still being constructed by drilling and blasting because these methods have an unmatched degree of flexibility relative to machine excavations using tunnel boring machines. At present, a large gap exists between evaluation theory and the control application of tunnel smooth blasting (TSB) quality. In this study, a handheld mobile platform that is based on the Android system and is written in the Java language is proposed to evaluate and control the performance of TSB. The function of this handheld mobile platform mainly includes data input, data modification, data deletion, weight setting for smooth blasting evaluation, smooth blasting quality assessment, and smooth blasting quality control. Using the proposed mobile platform, end users can evaluate and control TSB quality after each blast. The proposed handheld mobile platform is also applied to the real case history of line 6 in Guangzhou, China.

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van Eldert, Jeroen, Håkan Schunnesson, Daniel Johansson i David Saiang. "Application of Measurement While Drilling Technology to Predict Rock Mass Quality and Rock Support for Tunnelling". Rock Mechanics and Rock Engineering 53, nr 3 (9.10.2019): 1349–58. http://dx.doi.org/10.1007/s00603-019-01979-2.

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Abstract A tunnelling project is normally initiated with a site investigation to determine the in situ rock mass conditions and to generate the basis for the tunnel design and rock support. However, since site investigations often are based on limited information (surface mapping, geophysical profiles, few bore holes, etc.), the estimation of the rock mass conditions may contain inaccuracies, resulting in underestimating the required rock support. The study hypothesised that these inaccuracies could be reduced using Measurement While Drilling (MWD) technology to assist in the decision-making process. A case study of two tunnels in the Stockholm bypass found the rock mass quality was severely overestimated by the site investigation; more than 45% of the investigated sections had a lower rock mass quality than expected. MWD data were recorded in 25 m grout holes and 6 m blast holes. The MWD data were normalised so that the long grout holes with larger hole diameters and the shorter blast holes with smaller hole diameters gave similar results. With normalised MWD data, it was possible to mimic the tunnel contour mapping; results showed good correlation with mapped Q-value and installed rock support. MWD technology can improve the accuracy of forecasting the rock mass ahead of the face. It can bridge the information gap between the early, somewhat uncertain geotechnical site investigation and the geological mapping done after excavation to optimise rock support.

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Ngoc, Minh Nguyen, Ping Cao i Duc Thang Pham. "Establishment automatically contour blasting passport for tunnel in AutoCAD by VOLVN 3.0 software". E3S Web of Conferences 174 (2020): 01021. http://dx.doi.org/10.1051/e3sconf/202017401021.

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The smooth blasting method has been researched, developed and strongly applied for long-term underground construction, such as principal mining excavations, tunnels and hydroelectric projects... with the main purpose of minimizing the explosion impact on rock and creating a well-shaped boundary. In this research, a software was developed to establish automatically the tunnel contour blasting passport in AutoCAD. Using the software in each blast design model, it is quickly possible to determine number of blastholes, specific charge, specific drilling and drawing automatically of blasting passport in AutoCAD. The interaction between the software and AutoCAD is a new and important factor that helps to complete an automatically closed cycle on computer from introducing parameters to designing blasting passport in AutoCAD, thereby contributing to increase efficiency of production and minimize risks in blasting works.

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Jingmao, Xu, Gu Jincai, Chen Anmin, Zhang Xiangyang i Wang Tao. "Model Test on Failure Modes of Anchorage Tunnels Subjected to Blast Loading". Journal of Engineering Science and Technology Review 11, nr 4 (sierpień 2018): 118–25. http://dx.doi.org/10.25103/jestr.114.15.

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Koneshwaran, Sivalingam, David P. Thambiratnam i Chaminda Gallage. "Performance of Buried Tunnels Subjected to Surface Blast Incorporating Fluid-Structure Interaction". Journal of Performance of Constructed Facilities 29, nr 3 (czerwiec 2015): 04014084. http://dx.doi.org/10.1061/(asce)cf.1943-5509.0000585.

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