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1
Luo, Yan-ping, Quan Feng, Tao Zhou, Tao Liu, Zheng-yong Xiao, and Sheng Wang. "The Seismic Response of a Lined Tunnel under Plane P-wave in a Slope Site." Journal of Physics: Conference Series 2230, no. 1 (2022): 012014. http://dx.doi.org/10.1088/1742-6596/2230/1/012014.
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Abstract The indirect boundary element method (IBEM) is adopted to solve the 2D scattering problem of circular underground lining tunnels near canyons and slopes to the P-wave. The numerical results show that the canyon and slope topography near the underground lining tunnel has an evident influence on the surface displacement. The horizontal displacement amplification reaches nearly two times. The presence of slopes has a shielding effect on the nearby underground tunnels. The stress concentration exists at the top and bottom of the arch of the lining tunnel. The dynamic interaction between the slope and the tunnel should be considered when building a tunnel close to the slope.
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Humphries, R. W., and L. T. Jory. "Underground design at Andekaleka Hydroelectric Development." Canadian Geotechnical Journal 22, no. 1 (1985): 25–31. http://dx.doi.org/10.1139/t85-004.
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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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Senthil, Kasilingam, Muskaan Sethi, and Loizos Pelecanos. "A review on the performance of the underground tunnels against blast loading." Journal of Structural Engineering & Applied Mechanics 4, no. 1 (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.
4
Nabizadeh, Ali, and Alireza Seghateh Mojtahedi. "Centrifuge modeling of normal faulting and underground tunnel in sandy soil deposit." Soils and Rocks 44, no. 2 (2021): 1–13. http://dx.doi.org/10.28927/sr.2021.059520.
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Earthquakes of large magnitudes cause fault ruptures propagation in soil layers and lead to interactions with subsurface and surface structures. The emergence of fault ruptures on or adjacent to the position of existing tunnels cause significant damage to the tunnels. The objective of this paper is to study the interaction of an embedded tunnel within a soil layer and the soil deformations imposed upon by normal faulting. A centrifuge modeling under 80-g acceleration was conducted to investigate the rupture propagation pattern for different relative tunnel positions. Compared with the free field condition, due to tunnel and normal fault rupture interactions, focused on soil relative density and tunnel rigidity in this research, found that they can dramatically modify the rupture path depending on the tunnel position relative to the fault tip. The tunnel diverts the rupture path to its sides. This study presents the normal fault-tunnel interaction with the tunnel axis parallel to the normal fault line, to examine the changes that take place in fault rupture plane locations, the vertical displacement of the ground surface with tunnel presence and the effect of tunnel rigidity and soil density on fault tunnel interaction.
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Sun, Lan Ning, and Zhong Hu Zhao. "The Study on Movement of Underground Water and its Effect on the Stability of Surrounding Rocks." Advanced Materials Research 838-841 (November 2013): 726–32. http://dx.doi.org/10.4028/www.scientific.net/amr.838-841.726.
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Because of the special geological structure, folds are the main place where underground water gathers and moves. When we build roads or tunnels in folds of the western mountain areas, we should consider the effect of underground water on surrounding rocks and on stability of lining of a tunnel. The author explains in system the movement of underground water in anticlines, limbs and synclines, analyzes the physical, chemical and mechanic effects on rocks during its movement, then puts forward the reasonable advices in choosing the location where a tunnel should be built and specifies the stability of a tunnel. Also, in order to solve the water-gushing problem which may occur during the construction, the author brings forward some control measures for reference when selecting tunnel line and constructing.
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Xu, Hua, Tianbin Li, Jingsong Xu, and Yingjun Wang. "Dynamic Response of Underground Circular Lining Tunnels Subjected to Incident P Waves." Mathematical Problems in Engineering 2014 (2014): 1–11. http://dx.doi.org/10.1155/2014/297424.
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Dynamic stress concentration in tunnels and underground structures during earthquakes often leads to serious structural damage. A series solution of wave equation for dynamic response of underground circular lining tunnels subjected to incident plane P waves is presented by Fourier-Bessel series expansion method in this paper. The deformation and stress fields of the whole medium of surrounding rock and tunnel were obtained by solving the equations of seismic wave propagation in an elastic half space. Based on the assumption of a large circular arc, a series of solutions for dynamic stress were deduced by using a wave function expansion approach for a circular lining tunnel in an elastic half space rock medium subjected to incident plane P waves. Then, the dynamic response of the circular lining tunnel was obtained by solving a series of algebraic equations after imposing its boundary conditions for displacement and stress of the circular lining tunnel. The effects of different factors on circular lining rock tunnels, including incident frequency, incident angle, buried depth, rock conditions, and lining stiffness, were derived and several application examples are presented. The results may provide a good reference for studies on the dynamic response and aseismic design of tunnels and underground structures.
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Zhang, Pei, Jianhua Cai, Feng Zong, Yanpeng He, and Qiong Wang. "Dynamic Response Analysis of Underground Double-Line Tunnel under Surface Blasting." Shock and Vibration 2021 (July 29, 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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Voudouris, K. S., C. Tsatsanifos, S. Yannopoulos, V. Marinos, and A. N. Angelakis. "Evolution of underground aqueducts in the Hellenic world." Water Supply 16, no. 5 (2016): 1159–77. http://dx.doi.org/10.2166/ws.2016.054.
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Historical and archaeological evidence shows that ancient Hellenes had developed underground aqueducts since the prehistoric times. However, innovative methods of underground aqueducts were developed in Hellas mainly during the Archaic, Classical, Hellenistic, and Roman periods. Since the well-known tunnel at the island of Samos, Hellas, was designed and begun its construction (ca. 550 bc) by Eupalinos of Megara (the first civil engineer in history), several underground tunnels (with and without well-like vertical shafts) were implemented in the country. The goal of Eupalinos tunnel was to transfer water into the town from a spring. This tunnel, representing the peak of ancient hydraulic technology, was dug through limestone by two separate teams advancing in a straight line from both sides of the mountain. Delivering fresh water to growing populations has been an ongoing problem since ancient times. Several underground aqueduct paradigms (e.g. Peisistration in Athens, Polyrrhenia in Crete), some of which are in use even today, are presented and discussed. After late Roman times and the Adrianic aqueduct a gap of about 1,700 years in construction of such hydraulic works is noted. However, a remarkable development of tunneling in Hellas appeared during the last 50 years due to the ‘cosmogony’ of the construction of infrastructure projects using modern technology, e.g. Evinos-Mornos aqueduct with 15 tunnels of 71 km total length and the diversion tunnels in Sykia to the Thessaly plain and Messochora of the Acheloos River of 17.5 and 7.5 km length, respectively. Also, very recently three small conventional tunnels and one tunnel boring machine (TBM) were constructed in Aposelemis aqueducts used for water supply of Iraklion and Agios Nikolaos cities in Crete. As a consequence, significant design and construction experiences were gained. Overall, it seems that underground aqueducts of modern societies are not very different in principle from those during antiquity.
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Li, Peixian, Lili Yan, and Dehua Yao. "Study of Tunnel Damage Caused by Underground Mining Deformation: Calculation, Analysis, and Reinforcement." Advances in Civil Engineering 2019 (February 18, 2019): 1–18. http://dx.doi.org/10.1155/2019/4865161.
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Bayueshan tunnel (BYS) is an important construction crossing over coal mine goaf. The underground mining subsidence has led the tunnel cracked seriously in three years after it was built. In order to evaluate the coal mine influence and future stability of the tunnels, probability integral method (PIM) was used to calculate the tunnel deformation. PIM is an experience function method based on random medium theory which is used widely in China. With the parameters analyzed, the tunnels’ subsidence was calculated. The results show that it can interpret the tunnel damage well, and the maximum normal strain positions fit the damaged tunnel positions well. It proved that PIM can be used to evaluate the tunnel’s radial deformation caused by underground coal excavation. In order to maintain tunnels to keep a long-term stability, the future deformation was calculated in case the coal excavation continues. It shows that the tunnel would be cracked again if the excavation continued. Other reasons such as the old goaf deformation and water and vehicle dynamic load are also important reasons for the tunnels’ deformation. In order to keep traffic safety, it needs to reinforce the cracked foundation under the tunnel. Then, grouting injection was proposed to reduce the old goaf deformation under the tunnels. If the fracture zone under the tunnels disturbed by the dynamic traffic load, the old goaf will face a risk of sudden collapse. So, to ensure the grouting effect, the grouting depth should be deeper than the sum of traffic load influence depth and height of coal mine caved fissure zone. The grouting scope should keep all the crack rock area under the tunnel from being disturbed by the dynamic traffic load. This design can reduce the sudden collapse risk of the goaf and reduces the vehicles’ load disturbance on the cracked rock. The researched technology provides an engineering guidance to tunnel subsidence calculation, stability evaluation, and maintenance in complex geological and engineering situations.
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Galieva, Anna B., Vladimir N. Alekhin, and Liliya G. Pastukhova. "Monitoring of underground subsurface structures in Ekaterinburg." MATEC Web of Conferences 146 (2018): 02010. http://dx.doi.org/10.1051/matecconf/201814602010.
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This paper presents the issues of technical state of subsurface structures in operation and the erection of buildings under available development. It is stated that detailed monitoring of technical state of underground tunnels is essential, since the structure is unique and technologically complex. The aspects of geotechnical monitoring of underground tunnels are considered. The principles of geodesic monitoring of underground rings, tension increase in tube lining and pressure from the building under construction on the ground are described. Recommendations for underground tunnel monitoring are presented.
11
Zong, Wei Kai. "The Influence of Underpass on Surface Subsidence Caused by Double-Tube Shield Tunneling." Advanced Materials Research 915-916 (April 2014): 108–13. http://dx.doi.org/10.4028/www.scientific.net/amr.915-916.108.
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Shield construction will cause surface subsidence, and the presence of underground structures above the tunnel has an impact on surface subsidence. Based on this, with the engineering of undercross shield tunnel construction on railway station as background, used numerical simulation method to analyze the effect of surface subsidence of underground passage, and studied the influence of depth and width of underpasses on ground movement induced. The results show that: The impact of the underground passage to the wire surface subsidence caused by the shield cannot be ignored. Surface subsidence caused by double shield will be decreased because of the existence of the underground passage, and that related to the channel depth and width. The greater the depth of underground channel, the greater the surface subsidence; greater the underground channel width, the smaller surface subsidence. Meanwhile, the surface subsidence trough width and the largest settlement scope unrelated to the depth of underground tunnels but the underground channel width, and increases with the increasing of the underpass width.
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Yang, Run Lin, Jie Kong, and Juan Hua Zhou. "Study on Influencing Factors of Tunnel in Seismic Performance of Adjacent Underground Pipeline." Advanced Materials Research 807-809 (September 2013): 1823–28. http://dx.doi.org/10.4028/www.scientific.net/amr.807-809.1823.
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The existing tunnels may have an influence on seismic performance of adjacent underground pipelines. However, most of previous relevant studies are separately focused on seismic performance of the pipeline or the tunnel. In this paper, the major influencing factors of the existing tunnel in the seismic performance of adjacent underground pipelines, including joint types of the pipeline, the different angles and the distances between the pipeline and tunnel, were discussed. Numerical results show that flexible joint is the important factor which is helpful to decrease the settlement difference and the axial stress of the pipeline. Meanwhile, the relative position between the pipeline and the tunnel may also have a significant influence on seismic performance of pipelines.
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Kumar, Parvesh, and Amit Kumar Shrivastava. "Physical Investigation of Deformation Behaviour of Single and Twin Tunnel under Static Loading Condition." Applied Sciences 11, no. 23 (2021): 11506. http://dx.doi.org/10.3390/app112311506.
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This paper presents a new testing method for the problems encountered in field testing. To this end, single-tunnel and twin-tunnel small-scale rock models are prepared in the laboratory. A new methodology is proposed to encounter problems that are faced during field testing. The test results show that rock strength characteristics, overburden pressure, and tunnel spacing have important effects on the stability of underground structures. For rocks with poor strength properties, the damage degree is greater. When the strength property of rock changes, the deformation value of unlined tunnels changes from 21.05% to 27.58%, while that of lined tunnels changes from 11% to 21.42%. Also, in the twin tunnel, the deformation value reduces from 20% to 15.78% when the spacing between the tunnels is increased. For the measurement of stress and deformation in tunnels, the results obtained from experiments are analyzed. The method adopted in this study helps determine the tunnel’s design parameters to make it safe under overlying static loads. Finally, the key factors affecting the stability of underground structures are determined by simulating the field conditions through experimental research.
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Liamasov, A. K., M. A. Biriulin, and K. E. Denisov. "Underground tunnel type PSPP." IOP Conference Series: Earth and Environmental Science 808, no. 1 (2021): 012007. http://dx.doi.org/10.1088/1755-1315/808/1/012007.
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Nguyen, Khai Cao, and Khuong Van Ngo. "Application of mobile hydraulic anti - rigging complex in tunnels excavation and mining at the Mong Duong Coal Joint Stock Company - Vinacomin." Journal of Mining and Earth Sciences 62, no. 5a (2021): 1–10. http://dx.doi.org/10.46326/jmes.2021.62(5a).01.
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The strategy for Vietnam's coal industry in the period to 2030 is to continuously increase the mining output. In particular, the structure of shifting to coal mining by underground method will be essential. However, the increase in underground mining output is affected by many factors. Currently and in the future, almost all underground coal mines in Vietnam must expand their mining areas, apply advanced technology, to meet the increase in mining output. However, a long - standing problem that the underground coal mines in Quang Ninh have not improved much is speeding up the digging. This is one of the problems causing congestion in production when it is necessary to increase production. The article has studied the design and application of a mobile hydraulic anti - rigid complex for tunnel excavation and mining at Mong Duong Coal Company - Vinacom. This is a type of advanced technology in tunnel excavation and mining, which has been researched and applied in the world in recent years, in order to speed up the speed and ensure very effective safety. The application of a mobile anti - rigs in tunnel excavation will solve the current urgent requirement of speeding up the excavation progress by 30÷50% and ensuring labor safety. The article has researched and designed the excavation of a underground tunel through the seam at the in level - 400 m at Mong Duong Coal Joint Stock Company - Vinacomin. The underground tunnel the seam at the in level - 400 m is excavated underground tunnel with relatively typical conditions of underground coal mines in Quang Ninh region. The experimental design and application will be universal and increase the reliability of this type of advanced technology in the orientation of the underground coal mining industry in our country.
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Zhang, Peixing, Zhen Huang, Shuai Liu, and Tiesheng Xu. "Study on the Control of Underground Rivers by Reverse Faults in Tunnel Site and Selection of Tunnel Elevation." Water 11, no. 5 (2019): 889. http://dx.doi.org/10.3390/w11050889.
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Along with the need for western economic development, the number of long tunnel projects which go through mountains is constantly on the rise. In the process of construction, various disaster-causing structures are frequently exposed, which leads to many geological disasters. The traditional idea is that the reverse fault is not easily developed for an underground river, which means that the tunnel elevation design is not considered adequately. When some tunnels cross the bottom of the river, the fractures near the fault between the underground river and the excavation space may be activated and then evolve into channels, causing serious water inrush accidents during construction and operation processes. Taking the Qiyueshan Tunnel site as an example, on the premise of the anatomy of the control mechanism of the reverse fault on the development of the underground river, based on the multiperiod typical structural traces of the tunnel and surface outcrop, it was found that stratifications, dip joints, transverse joints, and tension joints of good aperture grade are important control factors. The cut block easily loses its stability and provides space for karst development, while intermittent uplifting of regional structures provides hydrodynamic conditions for the development of the underground river, causing the hydraulic gradient to be inconsistent in the overall underground river. Finally, the rainwater dynamic monitoring and tracer connectivity are data that can be fully utilized to demonstrate that a reverse fracture can control the development of the underground river. The authors further considered the effect of the vertical zoning of the fault structure and the excavation disturbance, and, drawing on the experience of the relative location of the same site in the same field, put forward the suggestion that the construction of the follow-up tunnel in the study area should be slightly higher than the elevation of the underground river. The research results can provide useful reference for similar engineering problems in the future.
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Xu, Hua, Tian Bin Li, and Long Qi Li. "Research on Dynamic Response of Underground Circular Lining Tunnel under the Action of P Waves." Applied Mechanics and Materials 99-100 (September 2011): 181–89. http://dx.doi.org/10.4028/www.scientific.net/amm.99-100.181.
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Dynamic stress concentration of tunnels and underground engineers under the action of earthquake waves is a fundamental problem. Selecting circular lining tunnel in semi-infinite space under the action of P waves as prototype, based on the assumption of large circular arc, a set of dynamic stress series solution in semi-infinite space and lining is deduced by wave function expansion method. With specific examples, the influences on shallow-buried depth rock tunnels of different factors which include incident frequency, incident angle, buried depth, rock conditions and lining rigidity are studied. The results show that low-frequency P waves are more dangerous to tunnel lining than high-frequency P waves; When P waves is incident from the bottom of the vertical tunnel or small angle (θα = 0° ~ 30°), the damage of tunnel lining is more seriously; Under the hard rock conditions, when the tunnel buried depth reaches more than 100m, the thickness of overlying rock is not a major factor effecting the dynamic stress and earthquake damages of tunnel structure lining; Under the soft surrounding rock condition, the value of dynamic stress concentration coefficient of lining is still up to 6.5 when the buried depth of tunnels is more than 100m, and what’s more the tunnel lining may still be caused seriously earthquake damage; With the increasing of lining stiffness, the dynamic stress concentration of lining is more uneven, and the value span is greater; so under the premise of meeting bearing capacity and deformation of lining, soft lining is recommended to adapt in the tunnel structure to decrease earthquake damage of tunnels.
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Svoboda, Pavel, and Alexander N. Kravtsov. "Mathematical Model of Seismoexplosion in Tunnel Surrounding." Applied Mechanics and Materials 744-746 (March 2015): 1021–26. http://dx.doi.org/10.4028/www.scientific.net/amm.744-746.1021.
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The construction of objects of critical infrastructures such as a new roads, utility tunnels, communication networks, underground parks and other structures is associated by the way with generation of vibrations in the vicinity of the underground structures, and not only human lives can be lost but also extensive material damage can be expected due to technological and natural hazards based on vibrations. This paper presents the general governing equations for coupled thermo-hydromechanical process in the tunnel surrounds. Modeling and analysis of laminated composite cylinder applied for the objective analysis of shock wave propagation in the soils and possibilities to estimates of the tunnel structure damage.
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Rostami, Arash, Abdolreza S. Moghadam, Mahmood Hosseini, and Nima Asghari. "Evaluation of Formation of Plastic Hinge and Seismic Behavior of Steel Structures Due to Soil–Structure–Tunnel Interaction." Journal of Earthquake and Tsunami 14, no. 03 (2020): 2050014. http://dx.doi.org/10.1142/s1793431120500141.
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The seismic design of the structures is carried out by technical regulations and codes in free-field conditions (regardless of underground cavities). With the availability of tunnels and the complex interaction between the tunnel and the aboveground structures, which may be contemplated wrongly, it could be dangerous for over ground buildings and structures. Consequently, the examination of the underground tunnels and their impact on the land surface and adjacent buildings seismic response seems to be significant. The present research focuses on formation of the plastic hinges in steel structures due to underground cavities and the soil–tunnel–structure interaction of underground structures. First, an existing model was verified by finite element method and the results were compared with a sample specimen. Thus, several effective parameters were considered and studied such as soil type, multi-story structures (4, 8 and 12 stories) and dynamic load type. Then the models were evaluated under real earthquake records. As a result, the seismic response of the structures and plastic conditions of plastic hinge conditions were obtained. The results indicate that the underground cavities have affected the formation of plastic hinges in the structure. They increased the input energy to the structure and had an impact on the total behavior of the structures. Also, the high-rise structures were much more vulnerable to underground tunnels. Therefore, the structures which are located above the underground cavities should be retrofitted and rehabilitated.
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Shi, Cun Peng, Xia Ting Feng, and Quan Jiang. "Calculation of Underground Tunnels' Safety Factor Based on the Strength Reduction Technique." Advanced Materials Research 594-597 (November 2012): 1206–9. http://dx.doi.org/10.4028/www.scientific.net/amr.594-597.1206.
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The safety of underground tunnels is a key problem of large substructure engineering during excavation and design. A new method to calculate the general safety factor of underground multi-tunnel is put forwarded based on the strength reduction theory. By the way of reducing rock material strength parameters (cohesion strength C and friction angle φ) step by step, the general safety of tunnels is got when the calculated result of excavation simulation shows that the equivalent plastic strain of rock wall becomes connection exactly. Engineering application indicates that the method of underground tunnels strength reduction is very useful for analysis quantitatively the general stability of tunnels and design of substructure.
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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 (2021): 10343. http://dx.doi.org/10.3390/app112110343.
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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.
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Zhang, Hongtao, and Yufei Zhao. "Study on Underground Utility Tunnel Fire Characteristics under Sealing and Ventilation Conditions." Advances in Civil Engineering 2020 (January 9, 2020): 1–11. http://dx.doi.org/10.1155/2020/9128704.
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With the development of the underground utility tunnel in China, the safety evaluation during facility operation inside tunnels is increasingly important after construction. In contrast to fixed fire source in the traffic tunnel, the fire characteristics of the electric cable compartment of the utility tunnel with different ventilation modes are studied. Firstly, the thermal physical parameters of cable material are determined by experiment and numerical simulation. Different fire sealing and ventilation conditions are established according to the practical utility tunnel engineering in FDS. The maximum temperature and smoke gas concentrations are obtained, as well as the heat release rate. The results show that the utility tunnel fire has obvious differences compared with road tunnel fire, where the maximum ceiling temperature and the distributions of smoke is related to fire sealing and ventilation mode. Some suggestions related to evaluation and firefighting are provided for practical purposes.
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Lin, Trains Qinhua, and Victor V. Krylov. "Effect of Tunnel Diameter on Ground Vibrations Generated by Underground." Journal of Low Frequency Noise, Vibration and Active Control 19, no. 1 (2000): 17–25. http://dx.doi.org/10.1260/0263092001492769.
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A theoretical model has been developed of generating ground vibrations by underground trains travelling in idealised circular tunnels of finite diameter. By means of the reciprocity principle, the displacement field radiated by a point force applied to the bottom of the tunnel, i.e., the Green's function of the problem, has been derived in zero and first approximations versus tunnel diameter. This more precise Green's function has been applied to carry out calculations of railway-generated ground vibrations using earlier developed methods. The results show that the velocities of generated low-frequency ground vibrations increase with the increase in tunnel diameter. It is also shown that zero approximation is accurate only at very low frequencies.
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Cao, Shiding, Shusen Huo, Aipeng Guo, Ke Qin, Yongli Xie, and Zhigang Meng. "Numerical Simulation Research on the Stability of Urban Underground Interchange Tunnel Group." Mathematical Problems in Engineering 2021 (April 29, 2021): 1–13. http://dx.doi.org/10.1155/2021/9913509.
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Highway tunnel group has the characteristics of large span and small spacing, and the load distribution characteristics of surrounding rock between each tunnel section are complex. Based on geological prospecting data and numerical analysis software, the stress distribution characteristics along the characteristic section and the profile of the tunnel group were obtained. Taking Shenzhen Nanlong complex interchange tunnel group project as an example, the results show that (1) the excavation area of Qiaocheng main tunnel gradient section is large, and the grade of surrounding rock is poor, which leads to the phenomenon of large-area stress concentration on the right wall of this section. (2) The tunnels in the joint construction section of the tunnel group belong to the stress concentration area, and the influence of the right line excavation of Qiaocheng on the stability of the main tunnel of the right line of Baopeng is greater than that of the main tunnel of the left line of Baopeng. (3) The stress concentration of surrounding rock in the intersection section between the main tunnel and the ramp is caused by the too small distance between the main tunnel and the ramp of Baopeng. (4) The distance between the partitions in the K3 + 240 multiarch section of Qiaocheng is an important factor affecting the stability of the surrounding rock of the cave.
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Yang, Run Lin, and Tian Yuan Zhang. "Study on Influence of Tunnel Excavation on Seismic Performance of Underground Pipeline." Applied Mechanics and Materials 90-93 (September 2011): 1801–6. http://dx.doi.org/10.4028/www.scientific.net/amm.90-93.1801.
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It is often necessary to study on the seismic performance of the buried pipelines subjected to tunnel excavation, because the ground motion will inevitably endanger the nearby underground pipelines. In this paper, modeling and analysis of earthquake-resistant performance of tunnel excavation to the upper underground pipeline have been carried out. The changes of stress and displacement of the upper underground pipeline under action of the same seismic wave before and after tunnel excavation was compared. It is showed that there’s a greater impact on the stress and displacement of upper underground pipeline under seismic action, and a tunnel with reasonable supporting would support the underground pipeline to some extent.
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Zhang, Zhiqiang, Mingming He, Fangfang Chen, and Ning Li. "Excavation Sequence and Surrounding Rock Mass Stability of Large-Scale Underground Engineering with 8 Tunnels." Advances in Civil Engineering 2020 (September 4, 2020): 1–11. http://dx.doi.org/10.1155/2020/3207072.
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In some large-scale hydroelectric power projects, there are more than 3 tunnels that are too close to each other to eliminate the mutual influence during the excavation period, especially for large-scale tunnel groups. In this paper, aimed at analyzing the Bukun hydropower station consisting of 8 tunnels in Malaysia, the displacement, stress, and plastic zone of the surrounding rock mass are analyzed to study the effect of the excavation sequence on the stability of the surrounding rock mass for large-scale tunnel groups. On the one hand, the in situ monitoring of the surface displacement of the rock mass surrounding the tunnel using extensometers is performed to obtain the deformation characteristics on the excavation limit under the typical excavation sequence. On the other hand, a series of elastic-plastic 3D numerical experiments are carried out to explore the displacement characteristics, stability of the large-scale tunnel groups, and safety of the initial supporting system. The results show that the tendencies of the displacement increase corresponding to the tunnel face movement are similar for the three excavation sequences. The displacement under initial excavation sequence 2 (IES2) is the smallest among the three sequences; the area of the plastic zone under IES2 is the smallest among them; and the stresses in the shotcrete layer and axial forces in the rock bolt under the three excavation sequences are within the safety limitation. Initial excavation sequence 2 is an optimized excavation sequence, in which tunnels #1 and #5 are excavated first; after an advance of 3 times the diameter of the tunnel, tunnels #3 and #7 are excavated; tunnels #2 and #6 are excavated after an advance of 3 times diameters; and tunnels #4 and #8 are excavated after an advance of 3 times diameters.
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Zhu, Gen Qiao, and Zhi Lin. "The Study on the Construction Technology of Large-Scale Underground Interchange Tunnels under the Rivers." Applied Mechanics and Materials 170-173 (May 2012): 1583–94. http://dx.doi.org/10.4028/www.scientific.net/amm.170-173.1583.
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A Large-scale underground interchange tunnels will be applied in the Chongqing Two Rivers Tunnel project with six crossings and four interchanges adopting NATM. The paper analyzes and discusses the whole-process construction mechanical behavior of the underground interchange by the numerical analysis method, at the same time considering the similar project established, and then suggests some important design parameters about crossings and close overlap interchanges between NATM tunnels, such as proper space of crossings and interchanges. Through the analyses, the paper suggests the design and construction method and construction organization project, especially for the crossings and close overlap interchanges between the NATM tunnels. The paper discusses the key problems of an underground interchange tunnels, and first suggests a mode how to construct an underground interchange tunnels. So, it is important in theory and practical engineering.
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Tu, Xiao Ming, Yu You Yang, and Gui He Wang. "Face Stability Analysis of Rectangular Tunnels Driven by a Pressurized Shield." Advanced Materials Research 378-379 (October 2011): 461–65. http://dx.doi.org/10.4028/www.scientific.net/amr.378-379.461.
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With the development and utilization of underground space, some new tunnel forms are emerging, such as the rectangular tunnel, double tunnels, treble tunnels and so on. The aim of this paper is to determine the collapse face pressure of a rectangular tunnel driven by a pressurized shield. The calculation is based on the upper-bound method of the limit analysis theory. A translational kinematically admissible failure mechanism consists a sequence of truncated rigid cones are considered for the calculation schemes. The numerical results obtained by the calculation are presented.
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Soheyli, Mohamad Reza, A. H. Akhaveissy, and 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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El Omari, Abdelhay, Mimoun Chourak, Carlos Navvaro Ugena, et al. "Seismic analysis of the zaouiat ait mellal twin tunnels of Agadir motorway (Morocco)." E3S Web of Conferences 150 (2020): 03001. http://dx.doi.org/10.1051/e3sconf/202015003001.
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Underground structures, such as tunnels, are vital for ensuring all kinds of transportation; and being buried under the surface makes them exposed to soil dynamics. Added to the moderate seismic activity in Morocco, the stability of tunnels is put to the test. This paper examines the interaction between the ZAM (Zaouit Ait Mellal) twin tunnels between the cities of Marrakesh and Agadir, using the Difference Element Method provided by FLAC 2D software. The acceleration is introduced as the one related to the historic event of El centro 1940 with free-field boundary conditions in the numerical model, with three configurations: tunnel 1 without tunnel 2, tunnel 2 without tunnel 1 and tunnel 1 with tunnel 2. The results of the simulations indicate that the differences values of the maximum displacement, axial force and bending moment on structural elements are very noteworthy from the configuration of the tunnel (single) to the twin tunnels in order to prove the interaction between these latter under seismic loading.
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Li, Zili, Kenichi Soga, and Peter Wright. "Three-dimensional finite element analysis of the behaviour of cross passage between cast-iron tunnels." Canadian Geotechnical Journal 53, no. 6 (2016): 930–45. http://dx.doi.org/10.1139/cgj-2015-0273.
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The behaviour of cast-iron cross passages in the London Underground was investigated using three-dimensional finite element models. Unlike the behaviour of a full tunnel ring, the structural integrity of a tunnel cross-passage opening relies on support from adjacent linings. In clayey soils, the opening may deform further as the soil stiffness changes from undrained to drained conditions. Degradation of the circumferential bolts and trackbed may also lead to further tunnel movement. A parametric study was conducted to examine the influence of soil stiffness and structural components (e.g., bolts and lintel) on the structural integrity of a tunnel opening. Results show that a lintel effectively transfers the load above the opening to the adjacent linings, and its distortion affects tunnel deformation significantly. If a lintel is not present, both bolts and friction between tunnel segments provide shear resistance to the lining deformation at the tunnel opening against soil loading. Results are compared with field observations made at a critical cross passage in one of the London Underground tunnels. The findings contributed to identifying the critical deformation mechanisms of cast-iron tunnel cross passages, which can be useful during inspection of such structures.
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Gao, Quan Chen, Cheng Xiang Lei, Ming Liang, and Hua Shuai Zhao. "Experimental Study on Mutual Effects of Rock Tunneling Positions with High Underground Pressures." Applied Mechanics and Materials 405-408 (September 2013): 1367–70. http://dx.doi.org/10.4028/www.scientific.net/amm.405-408.1367.
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Using the mould pattern contrasting experiments the carrying capacities and deformation effects of underground tunnels within soft bed and top or floor strata are studied under high ground pressures in this paper. Through measuring mould strengths and deformation with different stratum and space position the relations of tunneling positions in different strata with carrying capacity and strains are obtained. It is shown that the soft seam tunneling under high ground pressure can bring about higher secondary stresses and have more acting effects than top or floor tunnels. In the same pressure conditions the carrying capacity of having top tunneling above soft tunnel decreases near 30% with that of having floor tunnel. The mutual effects with double horizontal spaces of tunnels decrease 25%. The experiment conclusions are important significance of conducting and applying for reasonable designing underground tunneling engineering.
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He, Bin, and Yonggang Li. "Big Data Reduction and Optimization in Sensor Monitoring Network." Journal of Applied Mathematics 2014 (2014): 1–8. http://dx.doi.org/10.1155/2014/294591.
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Wireless sensor networks (WSNs) are increasingly being utilized to monitor the structural health of the underground subway tunnels, showing many promising advantages over traditional monitoring schemes. Meanwhile, with the increase of the network size, the system is incapable of dealing with big data to ensure efficient data communication, transmission, and storage. Being considered as a feasible solution to these issues, data compression can reduce the volume of data travelling between sensor nodes. In this paper, an optimization algorithm based on the spatial and temporal data compression is proposed to cope with these issues appearing in WSNs in the underground tunnel environment. The spatial and temporal correlation functions are introduced for the data compression and data recovery. It is verified that the proposed algorithm is applicable to WSNs in the underground tunnel.
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Haiko, Hennadiy, Іllia Savchenko, and Nataliya Pankratova. "IDENTIFYING DEVELOPMENT PRIORITIES OF UNDERGROUND INFRASTRUCTURE IN METROPOLISES USING SYSTEM METHODOLOGY." Geoengineering, no. 6 (November 30, 2021): 17–27. http://dx.doi.org/10.20535/2707-2096.6.2021.241820.
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Purpose: Determining construction priorities of underground transport infrastructure objects by evaluating morphological models of car tunnels considering the impact on the ecological and technogenic safety of urbanized territories.
 Methodology: modified morphological analysis of geological environment, urbanized territories and transport infrastructure of sites in a metropolis, expert estimation method.
 Findings: a morphological model was tested as a tool set for determining construction priorities of underground transport infrastructure objects; inter-related morphological tables for geological environment and structural-functional factors of urbanized territories in a tunnel area were constructed; an estimation of models regarding development of underground infrastructure was conducted using the planned car tunnels in Kyiv as an example; the impact of tunnels on reducing the ecological and technogenic risks of urbanized space was justified, and the priority construction object was chosen according to these criteria.
 Originality: for the first time the reduction of ecological and technogenic risks of urbanized space was chosen as a goal function in morphological models for the development of underground transport infrastructure in metropolises; the systemic characteristics of urban territories were obtained that describe the favorability of the geological environment and structural-functional factors for car tunnel construction in center metropolis areas; an impact ratio was proposed for synthesizing morphological analysis results and determining the priorities of underground transport infrastructure objects by influence on the ecological and technogenic risks.
 Practical implications: the created methodology and tool set for determining priorities of underground object construction at the pre-project stage, the opportunity to consider the ecological and technogenic risks of urban space development by consecutive construction of underground transport infrastructure objects and identifying an order for this sequence.
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Méndez, Fidencio. "Aguamilpa underground penstocks — excavation phase." Canadian Journal of Civil Engineering 21, no. 4 (1994): 585–95. http://dx.doi.org/10.1139/l94-060.
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The Aguamilpa hydroelectric project is one of a number of hydroelectric schemes currently being constructed along the course of the Santiago River in western Mexico. Aguamilpa, with a total cost of $750 million U.S., is a 960 MW installation scheduled for operation by October 1993. As the most important plant in the complex, Aguamilpa qualifies as one of the more spectacular engineering construction jobs of the decade in Mexico. The facility is composed of a complex set of tunnels, including the underground penstocks, the powerhouse and surge chamber caverns, the tailrace tunnel, and temporary tunnels. In the initial design, most of the tunnelling work was to have been of a permanent nature. However, as the date of completion was brought forward, it became necessary to open up more working faces and as such a number of temporary tunnels were started. This paper presents the sequences of underground penstocks excavation, the construction methods developed, and the equipment employed. Also, the complex patterns of tunnels that were drilled initially for access and to facilitate later excavation of the underground penstocks are described. Key words: tunnels, underground penstocks, powerhouse, construction methods.
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Colombo, Matteo, Paolo Martinelli, and Marco di Prisco. "Underground Tunnels Exposed to Internal Blast: Effect of the Explosive Source Position." Key Engineering Materials 711 (September 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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Rehman, Zahid Ur, Sajjad Hussain, Muhammad Tahir, Noor Muhammad, Saira Sherin, and Nasrullah Dasti. "Prevention and Mitigation Management of Tunnel Collapse and Failure during ConstructionA ReviewPrevention and Mitigation Management of Tunnel Collapse and Failure during ConstructionA Review." International Journal of Economic and Environmental Geology 12, no. 2 (2021): 72–79. http://dx.doi.org/10.46660/ijeeg.vol12.iss2.2021.590.
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Empirical and numerical methods of design play a vital role in assessing rock mass behaviour quantitativelyand qualitatively for the design of underground structures and support systems. The purpose of this research is to reviewthe techniques used for the management and prevention of failures that occur in rock mass for safe, stable, efficient, andeconomical design of support system for underground structures especially tunnels in diverse rock mass conditions.Failure of tunnels in rocks can occur during construction as well as during service; however, the former is very common.The most challenging task in tunnel construction is the rehabilitation and remedial process of the failed tunnel section.Unfortunately, due to differences in nature, shape, and type of failure, each case needs to be treated discretely andindependently. The risk of failure can be minimized by implementing prior preventive measures, while the success ofrehabilitation is based on better management of rehabilitation work. However, both prevention and rehabilitation needample investigative knowledge that can be learned from case histories. The current work is related to the prevention andmitigation methods of tunnel failure and collapses that occur during the early stages of tunnel designing.
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Kamel, Taous, Ali Limam, and Claire Silvani. "Residual strength of underground structures in service." Canadian Geotechnical Journal 53, no. 6 (2016): 988–99. http://dx.doi.org/10.1139/cgj-2014-0554.
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Old tunnels suffer from deterioration and it is necessary to assess their residual strength to properly organize their repair and strengthen them. The stress state of underground structures evolves over time, firstly because of the advancement of the working face during construction, then due to gradual changes in soil properties and mechanical properties of materials composing the infrastructures, such as reduction of cohesion, loss of strength and (or) stiffness, etc. These changes are caused by combined actions such as creep and (or) weathering processes as well as the appearance of cracks that induce redistribution of stresses and therefore strains. This study investigates tunnels and galleries of the Paris underground. Macromodeling based on the finite element method allows consideration of different scenarios of tunnel-lining deterioration, specifically at the extrados of the galleries or tunnels. To understand changes in the stress state, and also damage occurrence and associated redistributions (stress and strain), it is necessary to model the delayed deformations. To model the infrastructure behavior, a time-dependency approach has been chosen. This approach can quantify the damage and predict the residual strength of this type of underground structure. An elastic–viscoplastic constitutive model with strain-softening is used to reproduce the appearance of the degraded zones and their behavior. The results obtained with the numerical approach reproduce Paris metro tunnel behavior, corroborate geoendoscopy results, clarify their interpretation, and improve the management of infrastructure repairs.
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Yu, Zi-Tian, Heng-Yu Wang, Wenjun Wang, et al. "Experimental and Numerical Investigation on the Effects of Foundation Pit Excavation on Adjacent Tunnels in Soft Soil." Mathematical Problems in Engineering 2021 (April 22, 2021): 1–11. http://dx.doi.org/10.1155/2021/5587857.
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Excavations near an existing tunnel are often encountered in underground construction. The influence of the excavation on the adjacent tunnels is not yet fully understood. This study presented a centrifugal model test about excavation next to existing tunnels in soft soil foundation. The bending moment of diaphragm wall, surface settlement, tunnel deformation, and earth pressure around the tunnel were mainly studied. The influence of tunnel location is further studied by numerical simulation. During the stabilization stage of foundation pit, the diaphragm walls present convex deformation towards foundation pit, and the surface settlement outside the diaphragm wall appears to be the concave groove type. During the overexcavation stage, the diaphragm walls are almost damaged, and the shear bands are nearly tangent to the tunnels. The displacement of the tunnels and the surface settlement rapidly increase. The deformation of the diaphragm wall and the surface settlement are limited by the existing tunnel. The numerical results indicate that the change of tunnel location has little effect on the retaining wall but an obvious effect on the tunnel itself.
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Wang, Zhen, and Chun Han. "Study on Influence Factors of Underground Joint Rock Cavern Displacement." Applied Mechanics and Materials 353-356 (August 2013): 1515–18. http://dx.doi.org/10.4028/www.scientific.net/amm.353-356.1515.
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The safety response of joint rock underground tunnels is one of the many problems that draw the attention of geology specialists and scholars. Adopting two dimensional discrete element method, a numerical model of joint rock underground cavern is established to study its stability. The buried depth and the lateral pressure coefficient are considered respectively. The result shows: when the lateral pressure coefficient is identical, the depth is bigger the displacement is more bigger, and the displacement is strong influenced by the buried depth when the lateral pressure coefficient is big; In the same depth the tunnel is buried, the tunnel rocks displacement is slightly influenced by the lateral pressure coefficient when it is small, but the influence is seriously as the lateral pressure coefficient is big. The simulation in the context can be used to provide guide for joint rock tunnel excavation and supporting.
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Hung, Yin-Chun, Yu-Xiang Zhao, and Wei-Chen Hung. "Development of an Underground Tunnels Detection Algorithm for Electrical Resistivity Tomography Based on Deep Learning." Applied Sciences 12, no. 2 (2022): 639. http://dx.doi.org/10.3390/app12020639.
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Kinmen Island was in a state of combat readiness during the 1950s–1980s. It opened for tourism in 1992, when all troops withdrew from the island. Most military installations, such as bunkers, anti airborne piles, and underground tunnels, became deserted and disordered. The entries to numerous underground bunkers are closed or covered with weeds, creating dangerous spaces on the island. This study evaluates the feasibility of using Electrical Resistivity Tomography (ERT) to detect and discuss the location, size, and depth of underground tunnels. In order to discuss the reliability of the 2D-ERT result, this study built a numerical model to validate the correctness of in situ measured data. In addition, this study employed the artificial intelligence deep learning technique for reprocessing and predicting the ERT image and discussed using an artificial intelligence deep learning algorithm to enhance the image resolution and interpretation. A total of three 2D-ERT survey lines were implemented in this study. The results indicate that the three survey lines clearly show the tunnel location and shape. The numerical simulation results also indicate that using 2D-ERT to survey underground tunnels is highly feasible. Moreover, according to a series of studies in Multilayer Perceptron of deep learning, using deep learning can clearly show the tunnel location and path and effectively enhance the interpretation ability and resolution for 2D-ERT measurement results.
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Dang, Van Kien, Ngoc Anh Do, Tai Tien Nguyen, Anh Duy Huynh Nguyen, and Van Vi Pham. "An overview of research on metro tunnel lining in the sub-rectangular shape." Journal of Mining and Earth Sciences 62, no. 4 (2021): 68–78. http://dx.doi.org/10.46326/jmes.2021.62(4).08.
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Circular tunnels are the most popular shapes used in urban underground transportation systems when mechanized tunneling is used for tunnel excavation. However, circular tunnels have a small space utilization ratio. With the material development, non - circular tunnels such as sub - rectangular, U - shaped lining, etc. are now common, and their cross - section helps to improve the underground space utilization. However, there have been not many studies on the structure and the calculation method of the metro tunnels with the above cross - sections. The paper uses the analytical synthesis method to find out the advantages and disadvantages, the application conditions of the sub - rectangular shape, as well as the development direction for the complete calculation methods for this cross - section in Vietnamese conditions.
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Liu, Wanrong, Chao Peng, and Baoliang Zhang. "Study on Influence of Joint Distribution on Surrounding Rock Failure of an Underground Tunnel." Geofluids 2021 (October 12, 2021): 1–12. http://dx.doi.org/10.1155/2021/3621040.
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Due to geological structure and artificial disturbance, a large number of joints and fissures are formed in the surrounding rock of an underground tunnel. In order to study the influence of joints on the failure characteristics of tunnels, three test schemes with different joint lengths, joint spacing, and joint positions are designed. The results show that the bearing capacity of the tunnel decreases with the increase in the joint length. With the increase in joint spacing, the bearing capacity of the tunnel decreases first and then increases. The crack propagation law of the three test schemes has experienced four stages: no crack, crack initiation, crack rapid development, and crack gradual reduction. The location of joints has the greatest influence on the failure mode of the tunnel. The crack is most likely to appear at the top of the tunnel and expand along the joint, mainly because it is easy to form tensile stress at the top of the tunnel and compressive stress concentration at the joint tip. Therefore, when excavating the tunnel in the underground space, the influence of joints on the tunnel should be considered. Analyzing the relationship between the tunnel and joints has important practical guiding significance for the control of the surrounding rock of the tunnel. Finally, the failure results of the indoor physical model and numerical model are compared and analyzed. They are in good agreement, which also reflects the rationality of numerical simulation.
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Liu, Jin Long, and Jie Qun Liu. "Influence of Tunnel Excavation on Adjacent Underground Pipeline." Advanced Materials Research 150-151 (October 2010): 1777–81. http://dx.doi.org/10.4028/www.scientific.net/amr.150-151.1777.
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Based on nonlinear finite element method, the influence of tunnel construction on adjacent underground pipeline is studied. It is shown that remarkable settlements occurred above tunnel working surface due to tunnel excavation, and soil bulged below tunnel working surface due to load-off. The inhomogeneous deformation of pipeline become more serious when the distance between tunnel working surface and pipeline become shorter. So it is important to keep enough distance between tunnel working surface and pipeline. The deformation of pipeline become less when the radius of tunnel decreased. It is also find that there is no obvious influence on settlement of pipeline with different materials of pipeline. The settlement of pipeline can be reduced and stability of tunnel can be enhanced evidently by local excavation above tunnel working surface. Therefore, local excavation above tunnel working surface can be prior used to protect underground pipeline if allowable.
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Pelli, F., P. K. Kaiser, and N. R. Morgenstern. "The influence of near face behaviour on monitoring of deep tunnels." Canadian Geotechnical Journal 28, no. 2 (1991): 226–38. http://dx.doi.org/10.1139/t91-029.
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Convergence, radial displacements, and stress changes are often recorded during the advance of a tunnel for the observational tunnel design approach. In deep tunnels, instruments must be installed from underground and can seldom be placed in undisturbed ground. Consequently, observations are only partial records of the total change induced by an excavation and the influence of the three-dimensional state near the face must be considered. This paper presents results from numerical simulations to assess face effects on monitoring data. The influence of such aspects as in situ state of stress, anisotropy, nonlinearity, and plasticity (yielding ground) are evaluated. Guidelines for underground monitoring of deformations are given. Key words: tunnelling, monitoring, back-analysis, convergence, extensometers, numerical modelling.
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Mirghasempour, M., and A. Y. Jafari. "THE ROLE OF ASTRO-GEODETIC IN PRECISE GUIDANCE OF LONG TUNNELS." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-1-W5 (December 11, 2015): 453–57. http://dx.doi.org/10.5194/isprsarchives-xl-1-w5-453-2015.
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One of prime aspects of surveying projects is guidance of paths of a long tunnel from different directions and finally ending all paths in a specific place. This kind of underground surveying, because of particular condition, has some different points in relation to the ground surveying, including Improper geometry in underground transverse, low precise measurement in direction and length due to condition such as refraction, distinct gravity between underground point and corresponding point on the ground (both value and direction of gravity) and etc. To solve this problems, astro-geodetic that is part of geodesy science, can help surveying engineers. In this article, the role of astronomy is defined in two subjects: <br><br> 1- Azimuth determination of directions from entrance and exit nets of tunnel and also calibration of gyro-theodolite to use them in Underground transvers: By astronomical methods, azimuth of directions can be determine with an accuracy of 0.5 arcsecond, whereas, nowadays, no gyroscope can measure the azimuth in this accuracy; For instance, accuracy of the most precise gyroscope (Gyromat 5000) is 1.2 cm over a distance of one kilometre (2.4 arcsecond). Furthermore, the calibration methods that will be mention in this article, have significance effects on underground transverse. <br><br> 2- Height relation between entrance point and exit point is problematic and time consuming; For example, in a 3 km long tunnel ( in Arak- Khoram Abad freeway), to relate entrance point to exit point, it is necessary to perform levelling about 90 km. Other example of this boring and time consuming levelling is in Kerman tunnel. This tunnel is 36 km length, but to transfer the entrance point height to exit point, 150 km levelling is needed. According to this paper, The solution for this difficulty is application of astro-geodetic and determination of vertical deflection by digital zenith camera system TZK2-D. These two elements make possible to define geoid profile in terms of tunnel azimuth in entrance and exit of tunnel; So by doing this, surveying engineers are able to transfer entrance point height to exit point of tunnels in easiest way.
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Li, J. C., H. B. Li, G. W. Ma, and Y. X. Zhou. "Assessment of underground tunnel stability to adjacent tunnel explosion." Tunnelling and Underground Space Technology 35 (April 2013): 227–34. http://dx.doi.org/10.1016/j.tust.2012.07.005.
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Kim, Jaeyoung, and Sehong Min. "Study on Securing Safety Based on Emergency Power Dualization inside Road Tunnel." Journal of the Korean Society of Hazard Mitigation 20, no. 1 (2020): 217–21. http://dx.doi.org/10.9798/kosham.2020.20.1.217.
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With continued economic development, movement and logistics to various parts of the country are increasing. Consequently, long tunnels in the mountains and the large city underground road tunnels under construction have become increasingly important. Further, the escalating number of road tunnels has resulted in the deepening of tunnels and an increase in the number of long tunnels. Because it is highly possible fora traffic accident inside a tunnel to cause further accidents, various safety improvement measures should be prepared. To resolve the problem, dualizing the emergency power of CCTVs (which perform the major functions of tunnel safety) is proposed for application in a plan to improve safety. This plan improves safety control inside the tunnel and contributes to its maintenance. This study was prompted by the expressway tunnel accidents that occurred in the Central Region Expressway in October 2015 and February 2016. The safety security system based on the dualization of the emergency power inside the road tunnel is being monitored, with its application in some tunnels as the pilot project of an actual lab concept. Moreover, measures on safety control inside the road tunnel can be prepared through the monitoring.
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Kim, Seungwon, Jaewon Shim, Ji Young Rhee, Daegyun Jung, and Cheolwoo Park. "Temperature Distribution Characteristics of Concrete during Fire Occurrence in a Tunnel." Applied Sciences 9, no. 22 (2019): 4740. http://dx.doi.org/10.3390/app9224740.
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Fire in a tunnel or an underground structure is characterized by a rise in temperature above 1000 °C in 5–10 min, which is due to the characteristics of the closed space. The Permanent International Association of Road Congresses has reported that serious damage can occur in an underground structure as a consequence of high temperatures of up to 1400 °C when a fire accident involving a tank lorry occurs in an underground space. In these circumstances, it is difficult to approach the scene and extinguish the fire, and the result is often casualties and damage to facilities. When a concrete structure is exposed to a high temperature, spalling or dehydration occurs. As a result, the cross section of the structure is lost, and the structural stability declines to a great extent. Furthermore, the mechanical and thermal properties of concrete are degraded by the temperature hysteresis that occurs at high temperatures. Consequently, interest in the fire safety of underground structures, including tunnels, has steadily increased. This study conducted a fire simulation to analyze the effects of a fire caused by dangerous-goods vehicles on the tunnel structure. In addition, a fire exposure test of reinforced-concrete members was conducted using the Richtlinien für die Ausstattung und den Betrieb von Straßentunneln (RABT) fire curve, which is used to simulate a tunnel fire.
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Timchenko, R. A., D. A. Krishko, and S. О. Macyshin. "CONSTRUCTIVE SOLUTION OF A TUNNEL UNDER THE EXISTING HIGHWAY." ACADEMIC JOURNAL Series: Industrial Machine Building, Civil Engineering 2, no. 49 (2017): 214–20. http://dx.doi.org/10.26906/znp.2017.49.845.
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Urban underground structures (shallow tunnels), which are usually built in conditions of urban area with heavy traffic, are considered. It was clarified that the reinforced concrete lining are performed of concrete, reinforced concrete, natural and artificial stones in most cases. The types of tunnels road cutting are given. The geometrical dimensions and characteristics of using materials in the construction of tunnels are given. It was established that the existing methods of tunnel construction do not allow to solve the problem in cramped conditions and intense traffic. The new constructive solution of the transverse tunnel under the existing highway was proposed. It is found that the proposed design of the transverse tunnel may be performed in cramped urban environments with the use of modern technological equipment and the proposed method of tunnel meets the requirements of strength, reliability, durability.