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Quick Search     Advanced Search MODERN TUNNELLING TECHNOLOGY   2014 Vol.51 Issue.5 Published 2014-10-25 Article 1 Statistical Empirical Relationship of Coseismic Surface Rupture and Aseismic Tunnel Design WANG Cheng-Hu-1, 2 , CHOU Wen-Ge-1, CHEN Yong-Qian-2, HU , HUI 1 Coseismic surface rupture displacement is the key influential factor for shear failure and collapse in tunnels. This paper systematically summarizes the statistical empirical relationships of the characteristic parameters of coseismic surface ruptures, and compares and analyzes the seismic damages inflicted upon a tunnel by the Wenchuan Earthquake. The results show that: (1) the surface rupture length and the maximum and average coseismic rupture displacements are the main parameters directly related to the aseismic design of a tunnel, of which surface rupture length mainly reflects the influence range of shear displacement; (2) in seismic tunnel design, the average coseismic rupture displacement can be used to estimate the degree of damage to an underground structure considering the relative position of the tunnel, the main deep-and-large faults, and the affiliated faults; (3) the subsurface rupture length, downdip rupture width, and rupture area can be used to estimate the influence range of an earthquake and the possible losses due to tunnel damage; and (4) coseismic displacement may also occur at an affiliated fault near a seismogenic fault, resulting in damages to the underground structure and tunnel. 2014 Vol. 51 (5): 1-8 [Abstract] ( 2240 ) [HTML 1KB] [ PDF 0KB] ( 622 ) 9 Epigenetic Reformation of the Rock Mass in the Chijiahe Tunnel and its Relationship with the Surrounding Rock Grade MENG Lu-Bo-1, Li-Tian-Bin-1, Fang-Xing-1, He-Yong-2 In order to investigate the surrounding rock quality in the Chijiahe tunnel, the strength grade of epigenetic reformation is preliminarily classified, and the surrounding rock classification proposal is applied to the geological conditions of the Chijiahe tunnel. A construction period is established, and the relationship between epigenetic reformation and surrounding rock grades is discussed on the basis of epigenetic reformation characteristics and the spatial development law at the tunnel site. The results show that the rock mass at the Chijiahe tunnel site has suffered strong epigenetic reformation, being mainly characterized by developed low-angle structural planes and steeply dipping fractures. The rock mass structure and grade at the Chijiahe tunnel site are governed by an epigenetic reformation with strengths that can be classified into three levels: strong, medium, and slight. The surrounding rock at the strongly reformed zone is commonly Grade V; at the medially reformed zone, most of the rocks are Grade IV and a few are Grade V; and at the slightly reformed zone, most of the rocks are Grade III and a few are Grade IV. The epigenetic reformation zones at the Chijiahe tunnel site, which control of the grades of the surrounding rock, are mostly of the medium level. 2014 Vol. 51 (5): 9-14 [Abstract] ( 2081 ) [HTML 1KB] [ PDF 0KB] ( 618 ) 15 Auxiliary Tunnel Lighting Technology Based on the Light Reflection and Energy Storage Concept LIANG Bo-1, CUI Lu-Lu-1, PAN Guo-Bing-1, LUO Hong-2 Based on the analysis of domestic and foreign lighting quality standards and evaluation methods, an investigation of the existing illumination sources, interior decoration materials, and illumination situations of mountain tunnels in southwest China was carried out. This paper presents a series of tests based on the light reflection and storage concept, such as the indoor simulation test, the physical model test, and the field test, to explore the energy-saving illumination law. The results show that: (1) the tunnel pavement illumination can be improved by using reflective and light-storing materials on the sidewall: its luminance can increase by at least 10% with the wall reflectivity reaching up to 70%; (2) the illumination load can be reduced by a light reflection function based on the equivalent illumination theory. By introducing the visual effect concept, the traffic safety in a tunnel can be evaluated, providing a basis for improving the lighting evaluation method; (3) the matching of reflective materials and commonly-used lighting sources is studied, and the performance of reflective materials used in tunnels is evaluated, which provides a basis for further promoting reflective and light-storing materials in tunnel. 2014 Vol. 51 (5): 15-22 [Abstract] ( 2239 ) [HTML 1KB] [ PDF 0KB] ( 611 ) 23 Cause Analysis and Countermeasures for "Hindered" Mucking in Shield Construction ')" href="#"> ZHU Wei-Bin-1, ZHONG Chang-Ping-2, 3 , HUANG Wei-Ran-2, ZHOU Cui-Ying-3, LUO Shu-Yi-2 Based on the shield construction practices in mixed ground at home and abroad, this paper determines the definition of "hindered mucking" for the first time. In addition to the classification, causes, and risks, it proposes systematic solutions, including reducing large-particle mucks, improving muck workability, and adjusting construction parameters, and presents countermeasures in terms of design, manufacture, and construction of the shield. This paper also provides a reference for countermeasures against hindered mucking regarding new theory, equipment, approach, material, etc. 2014 Vol. 51 (5): 23-32 [Abstract] ( 2057 ) [HTML 1KB] [ PDF 0KB] ( 578 ) 33 Acoustic Emission Characteristics of Granite in a Triaxial Compression Test at Different Temperatures ZHANG Hang, LI Tian-Bin, CHEN Guo-Qing, CHEN Zi-Quan, WANG Min-Jie In order to study the failure law of granite under thermal action, a triaxial compression test of biotitegranite under different confining pressures and different temperatures was carried out using the rock mechanics testing system MTS815 Flex Test GT and the PCI-II acoustic emission (AE) detector. The results show that: (1) when the temperature is 20℃, 40℃, or 60℃, the intensive degree of acoustic emission events, AE accumulative ringing counts, and the maximum AE energy rate increase with a rising temperature, and the macroscopic rupture angle decreases with an increase of the brittle failure characteristics of the rock; (2) when the temperature is 60℃, 90℃, or 130℃, the intensive degree of acoustic emission events, AE accumulative ringing counts, as well as the maximum AE energy rate decrease with a rising temperature, and the macroscopic rupture angle increases with the increase of the shear failure characteristics of the rock; meanwhile, (3) as the temperature increases, the large number of acoustic emissions with low energy release rates emerges with the local shear failure, and the concentrated acoustic emission area is characterized by a few acoustic emissions with a high-energy rate and a high number of acoustic emissions with a low-energy rate. 2014 Vol. 51 (5): 33-40 [Abstract] ( 2118 ) [HTML 1KB] [ PDF 0KB] ( 573 ) 41 Analysis of the Influence of Spatial Variability of Surrounding Rock on the Reliability of a Tunnel Structure FANG Chao-1, 2 , Xue-Ya-Dong-1 A random field model can be used to effectively simulate the spatial variability of surrounding rock. In this paper, the local average random field theory, finite difference method, and Monte-Carlo simulation are combined, and the Monte-Carlo random finite difference method is developed. Based on this method, a calculation program for the structural reliability of a tunnel considering the spatial variability of surrounding rock is worked out, and the influence of the rock's vertical and horizontal correlation distance on the tunnel's structural reliability is also researched by regarding the rock density, elastic module, and internal friction angle as 3D normal random fields. The results show that: to obtain a more economical and reasonable support scheme, it is necessary to take the spatial variability of surrounding rock into account in the design, since it has a significant effect on the tunnel's structural reliability; the tunnel failure probability increases with the increase of the vertical or horizontal correlation distance, but there is a greater effect from the vertical spatial variability. So once the geotechnical investigation fee is limited, the majority of the cost can be focused on a survey of the vertical correlation distance. 2014 Vol. 51 (5): 41-47 [Abstract] ( 2025 ) [HTML 1KB] [ PDF 0KB] ( 564 ) 48 Research on the Sequential Fractal Characteristics of the Deformation Monitoring Data for an Underground Cavern Group ZOU Jing-1, 2 , Li-Zhong-Kui-1 Based on a large underground cavern group, the R/S analysis method is introduced to process convergence monitoring data. Using the Hurst exponent and mechanical principles, it is inferred that the convergence velocity of the section is represented by the fractal dimension, and the degree of loosening of the surrounding rock after excavation can be measured by the Hurst exponent itself. Both the Hurst exponent and fractal dimension of the actual deformation data are computed, the dynamic characteristic of deformation is established in a time-history curve, and the differences of each measurement line at the same section are compared. Furthermore, the Hurst exponent values of the monitoring data of different sections at the same axis are calculated, and the evolution of surrounding rock deformation behavior in this project area is deduced. Finally, the influential factors of the Hurst exponent and improvements related to the algorithm are summarized. 2014 Vol. 51 (5): 48-54 [Abstract] ( 1991 ) [HTML 1KB] [ PDF 0KB] ( 594 ) 55 Distribution of an Explosive Stress Wave in Surrounding Rock and the Relevant Stability of an Underground Cavern SHEN Jun, ZHANG Xiang-Yang, CHEN An-Min, XU Jing-Mao, KONG Fu-Li Combined with model testing and numerical calculations, the propagation of an explosive stress wave in the surrounding rock of a proposed tunnel and the stability of an existing underground cavern were researched, and the relevant wave distribution law and displacement curve of the vault were obtained. The results show that: (1) the pressure peak decreases with an increase of distance from the explosion point; (2) the vertical pressure peak on the vertical measuring line through the explosion center is greater than the horizontal pressure peak in the same position through the centroid of the cavern, and the vertical pressure peak on the horizontal measuring line is greater than that of the horizontal pressure peak; (3) the pressure peak on the vault is less than the compressive strength of the lining, and moreover, the cavern is safe and stable without the unrecoverable displacement of the vault; and (4) attention should be focused on the dynamic response of the lining at the intersection of the cavern vault, arch foot, and sidewall crown during the blasting of a transportation tunnel. 2014 Vol. 51 (5): 55-60 [Abstract] ( 1973 ) [HTML 1KB] [ PDF 0KB] ( 610 ) 61 Analysis of the Stability Control Measures for a Ground-Penetrating Shield Tunnel WU Hui-Ming-1, 2 , Teng-Li-3, YU Ya-Lei-4, Ye-Guan-Lin-4 Based on the Nanjing ground-penetrating shield tunnel project, the finite-element simulation method is adopted to simulate the whole construction process of the ground-penetrating shield. An internal counterweight and surface loading are imposed on the model to analyze their effectiveness at controlling floating and improving stability of the tunnel. The results show that the internal counterweight can significantly improve the stability of the tunnel, while surface loading can reduce tunnel floating to some extent without obvious effects. According to in-situ conditions, the best way to realize the optimum stability of the tunnel is the combination of an internal counterweight and surface loading. 2014 Vol. 51 (5): 61-65 [Abstract] ( 2058 ) [HTML 1KB] [ PDF 0KB] ( 590 ) 66 Study of the Mechanical Properties of Bench Length Based on the Hoek-Brown Criterion ZHAO Jing-Bo Based on the Hoek-Brown criterion, the tunnel construction process under different bench lengths was simulated with finite-element simulation, and the displacement response laws of the tunnel section and ground surface were analyzed. The results show that: the horizontal convergence and vault settlement increase with an increase of the bench length; compared with a bench length of 2m, the vault settlements increase by 9%, 25%, 29%, and 36%, and the horizontal convergences increase by 9%, 12.5%, 15.6%, and 25% with the bench lengths of 4m, 6m, 8m and 10m; and bench length has little effect on the principal stress and plastic zone after excavation. 2014 Vol. 51 (5): 66-70 [Abstract] ( 2069 ) [HTML 1KB] [ PDF 0KB] ( 538 ) 71 Influence of Lining Section Type on a Tunnel Structure Under Active Fault Movement LIU Xue-Zeng-1, GU Xue-Ying-2, DAI Zhi-Ping-2, LI Xue-Feng-3 Using the finite-element method, this paper compares and studies the influence of lining section type on the stress and plastic strain of tunnels with chain-structures under active fault movement based on five three-centered circular sections of different invert radii from the Qipanshi tunnel project. The results show that: (1) the secondary lining is subjected to the combined action of tensioning, shearing, and squeezing due to fault movement; (2) high stress is mainly distributed at the arch spring with the peak stress on the hanging wall, and tensile force will be effectively absorbed by the shear crack; (3) with the tunnel section constantly tending toward a perfect circle, the maximum and minimum principal stresses and shear stress of the secondary lining decrease while the equivalent plastic stain increases. 2014 Vol. 51 (5): 71-77 [Abstract] ( 2074 ) [HTML 1KB] [ PDF 0KB] ( 585 ) 78 A Macroscopic Analysis Model for the Mechanical Behaviors of a Shield Tunnel Segment Lining Reinforced with a Composite Cavity LIU Xian-1, ZHANG Le-Le-1, LI , GANG 2, WU Hui-Ming-2, ZHU Yan-3 Based on a full-scale test to verify the ultimate bearing capacity of a shield tunnel reinforced with a composite cavity, a non-linear additive model that can be used to simulate the structural reinforcement of the shield tunnel is presented, in which the composite cavity and segment are defined by various materials, and the bi-directional spring unit is adopted to simulate the bonding between a non-reinforced tunnel and the composite cavity. Additionally, the effectiveness of the model is verified by means of a comparison with the results of full-scale test. Furthermore, the values of some key parameters are described and the stress on the tunnel structure and failure mechanism are presented based on the simulated results, thereby providing a reference for the reinforcement optimization of operated shield tunnels. 2014 Vol. 51 (5): 78-84 [Abstract] ( 2382 ) [HTML 1KB] [ PDF 0KB] ( 576 ) 85 Model Test on the Stability of the Surrounding Rock of a Tunnel Constructed by the Arch-Cover Method YANG Zhong-Nian-1, Ji-Zhao-Qi-1, Liu-Quan-Wei-2, 3 In this paper, surface deformation law and the force applied on surrounding rock during the arch-cover method of tunnel construction are studied by a large-scale model test. The results show that surface subsidence undergoes three settlement phases in the process of tunnel excavation: slow settlement, fast settlement, and slow settlement again. The fast development of surface subsidence occurred during middle pilot tunnel excavation and vertical bracing dismantlement. Excavation of the bottom surrounding rock had little impact on surface deformation when the secondary lining at the crown was completed. The load-releasing process of the surrounding rock at each part of the monitoring section was quite different while the working face was advancing, and the load-releasing speed at the tunnel crown was greater than that at the arch springing and sidewall. Excavation of the middle pilot tunnel at the tunnel crown and dismantlement of the temporary support resulted in a secondary pressure release of the stable surrounding rock. Radial convergence of the surrounding rock was well controlled, which is attributed to its self-supporting capacity and immediate support. Is it is suggested that crown settlement be considered a main criterion for judging the stabilization of the surrounding rock in tunnels characterized by the arch-cover method. 2014 Vol. 51 (5): 85-91 [Abstract] ( 1972 ) [HTML 1KB] [ PDF 0KB] ( 585 ) 92 Model Test Study of the Active Freezing Scheme for the Combined Pipe-Roof and Freezing Method HU Xiang-Dong-1, 2 , REN Hui-1, 2 , CHEN Jin-1, 2 , CHENG Yong-3, ZHANG Jun-3 The pre-supporting system of the Gongbei tunnel situated at the Zhuhai Link of the Hong Kong-Zhuhai-Macao Bridge, was constructed by a new construction method, the Freeze-Sealing Pipe-Roof (FSPR) method, which combines pipe-roof reinforcement with artificial freezing technology. According to practical conditions, this paper proposes for the first time a freezing scheme composed of three special types of pipes arranged inside the steel tubes of the pipe-roof system, i.e. the circular main freezing pipe, the specially shaped intensive freezing pipe, and the heat brine pipe for limiting the over-growth of the frozen body. A large-scale physical model test was carried out to study the validity and controllability of this freezing scheme. This paper briefly introduces the model test, focusing on the experimental study of the freezing effects at an active freezing stage before excavation. The test results show that the development of a frozen curtain is of expected regularity, the freezing effect is remarkable, and the frozen curtain is formed between pipe roofs, which guarantees a good sealing effect. 2014 Vol. 51 (5): 92-98 [Abstract] ( 2368 ) [HTML 1KB] [ PDF 0KB] ( 591 ) 99 Model-Testing Technology for an Extra-Large Span Tunnel in Soft Rock JIN Wei-1, 2 , DING Wen-Qi-1, 2 , XU Qian-Wei-3, YE Liang-1, 2 Based on a geo-mechanical model test stand, the model-testing technology for an extra-large span tunnel within soft rock is studied. Included in this study are the preparation of similar materials, model test stands, loading systems, and stress and displacement measurement systems. Regarding stress measurement, the single-point thin film pressure sensor is used because of its characteristics of high precision, sound sensitivity, and little disturbance. For the rock displacement distribution, the grating scale and PIV-based displacement measurement technique is used. The model test results verify the excellent operating performance and advanced measuring level of the model test system, which satisfy the requirements of a large-scale geo-mechanical model test. 2014 Vol. 51 (5): 99-107 [Abstract] ( 1860 ) [HTML 1KB] [ PDF 0KB] ( 534 ) 108 A Study of the Trapdoor Test of the Bolt-Support Effects in a Soft Rock Tunnel XU Qian-Wei-1, ZHU He-Hua-2, DING Wen-Qi-2, LI Zhi-Hou-3, LUO Yun-4, ZHU Dao-Jian-5 Instability and even failure of surrounding rock are often caused by excessive rock deformation or local stress concentration when tunneling in soft surrounding rocks, and the anchor bolt is mainly used in practical engineering for initial support. Based on soft surrounding rock of grade IV, tunnel construction with bolt support was simulated by a similarity model test, and the progressive failure feature, failure mode of the surrounding rock, and supporting effects of an anchor bolt were studied. The results show that a stress disturbance area will be formed around the tunnel by excavation, but only a part of the disturbance area really will be damaged. Because of the support of the anchor bolt, rock damage on the crown presents a partitional failure mode, and the failure area of the rock is mainly concentrated in the sector formed by two tunnel sides with an angle of 45°+φ/2 to the horizontal plane. After excavation, a pressure-bearing arch, which is mainly located approximately 1.0-1.25B (B= tunnel span) away from the crown, is formed with increasing tangential stress of the rock mass above the crown. 2014 Vol. 51 (5): 108-113 [Abstract] ( 2188 ) [HTML 1KB] [ PDF 0KB] ( 582 ) 114 Numerical Analysis and Experimental Study of the Influence of Spandrel Cracks on Tunnel Stability LI Yuan-Xin, Zhu-Zhe-Ming Using the software Abaqus, the influence of spandrel cracks on the overall stability and strength of an arched tunnel with straight walls is analyzed and a failure law is established based on a model test. The Tresca criterion at various points along the tunnel periphery and the stress intensity factors YI and YII at the crack tips are calculated by numerical simulation and the simulated results are verified by a model test. The results indicate that: the overall stability and strength of an arched tunnel with straight walls could be reduced by cracks at the spandrel depending on the variation of the included angle θ between the crack and side wall; and when θ=130°, tunnel strength is minimized, the dimensionless stress intensity factor YII at the crack tip is maximized, and the stress concentration is more significant. 2014 Vol. 51 (5): 114-120 [Abstract] ( 1908 ) [HTML 1KB] [ PDF 0KB] ( 545 ) 121 Measurements and Analysis of Settlement Caused by the Construction of an Undersea Immersed Tunnel WEI Gang-1, QIU Hui-Jie-2, DING Zhi-1, WEI Xin-Jiang-1, XING Jian-Jian-2 In this paper, a settlement development law is analyzed based on settlement monitoring data obtained during the construction of an undersea immersed tunnel in the Zhejiang Province of China. Single-element settlement and differential settlement of multiple elements are studied, and the settlement mechanism of an undersea immersed tunnel is discussed from the perspective of soil compression in order to present that construction time differences and accumulative settlement differences of a single element are the main causes for differential settlement. Additionally, the influence of grouting and backfilling is analyzed and it is determined that grouting differences are internal causes for subsequent differential settlements and that compression of the foundation layer and soil layer induced by backfilling is the external cause of settlement during construction. Using the layerwise summation method, the foundation layer compression modulus of 1.89MPa is obtained by back-analysis, which shows a poor compression characteristic of the foundation layer caused by a high degree of siltation. 2014 Vol. 51 (5): 121-128 [Abstract] ( 1861 ) [HTML 1KB] [ PDF 0KB] ( 571 ) 129 Stress-Monitoring Analysis of the Intermediate Rock Pillar in a Double-Arched Tunnel DING Zhi-1, 2 , HE Jia-Wei-1, CHEN Chun-Lai-1, WEI Gang-1, Zhang-Meng-Ya-2 As an important load-bearing member of a double-arched tunnel, the law of stress variation for an intermediate rock pillar in the process of construction is complex. In this paper, based on a highway tunnel on provincial road 13, a three-axial stress test is carried out at the tunnel section K2+163. Testing results show that the three-axial stresses on different parts of the intermediate rock pillar are inconsistent with each other, in which the top and bottom parts of the rock pillar are loaded by vertical stress and the middle part is loaded by horizontal stress along the direction of excavation. As for the advanced excavation of a single tunnel, the tri-axial stresses inside the rock pillar approach their peak value when the working face is advanced to the monitoring section. On two vertical orthogonal planes parallel to the excavation direction and tunnel portal, an equivalent bending moment exists that is caused by stress action at the opposite direction. In addition, combined with engineering practices, the existing analysis formula is further developed to predict the tri-axial stresses of an intermediate rock pillar under of Class IV rock. 2014 Vol. 51 (5): 129-133 [Abstract] ( 1944 ) [HTML 1KB] [ PDF 0KB] ( 560 ) 134 The Judgment Method and Field Research Regarding Safety for an Extra-Large Diameter Shield Passing Under High-Risk Pipelines LI Lin In this paper, a computation formula is deduced that can be used to judge the safety status of a hazardous buried pipeline when a super-large diameter shield is crossing under it. The relationship between the pipeline′s stress status and the ground deformation above the pipeline is established. Using the measured ground settlement data, the equation for a deflection curve of the buried pipeline is fitted. The stress status of the pipeline is then deduced from the curvature functions, which can be established using a differential calculation for the deflection curve. Finally, the pipeline safety factor is determined by comparing the actual stress to the allowable stress, and this factor can be used as a reference parameter for shield construction. Using an example of large-diameter shield construction from Shanghai, and based on measured data from rings 950 to 1040, the safety factor for pipelines is calculated. The results show that the safety factor varied from 5~15, resulting in a reduction of the pipeline safety. Controlling the shield construction parameters could ensure the pipeline's safety. 2014 Vol. 51 (5): 134-138 [Abstract] ( 1756 ) [HTML 1KB] [ PDF 0KB] ( 575 ) 139 On the Mechanism and Influence of the Delayed Effect of Longitudinal Ventilation in Urban Tunnels WU Ke, Zhu-Kai, Tan-Zhen, Fang-Fei-Long, Huang-Zhi-Yi, WANG Li-Zhong Field measurements regarding the dynamic process of longitudinal ventilation in tunnels show that more time is needed for wind-speed to reach a steady state in a tunnel when the running status of a jet fan is changed, which indicates a delayed effect of longitudinal ventilation in the tunnel. A dynamic response formula deduced by a theoretical equation for tunnel flow under the control of ventilators can be used to predict the strength of this delayed effect, and the theoretical results are consistent with measured data. This parametric study finds that under the same initial velocity: the more jet fans started, the shorter the amount of time for wind velocity to reach a steady state; the more jet fans that are shut, the longer it takes for wind velocity to reach a steady state; with certain numbers of jet fans being started and shut, the slower the initial velocity, and the longer it takes for wind velocity to reach a steady state; the longer the tunnel, the larger the section, and the smoother the tunnel wall, the longer it takes for wind velocity to reach a stable state and the more obvious the delayed ventilation effect. 2014 Vol. 51 (5): 139-144 [Abstract] ( 2011 ) [HTML 1KB] [ PDF 0KB] ( 549 ) 145 On the Deformation Law of Longitudinal Joints of Shield Tunnel Segment Rings GAO Bo-1, WU Ting-2, PENG Hong-Xia-1, LI Xue-2 By analyzing the segment erection process and the force applied on the segment, a finite-element method was adopted to study the variation law of the opening angles of longitudinal joints under different erection ovalities and different positions of the key segments. Additionally, the maximum internal and external openings at the sealing gasket were calculated for when the key segment is at the most unfavorable position. Research results indicate that: there is a linear relationship between the erection ovality and the segment opening angle, the position of the key segment affects the magnitude of the opening angle under the same erection ovality, the opening angle is at a maximum when the key segment is positioned at an angle of ±32.7276°, and the maximum opening at the sealing gasket is 5.1mm under the ovality of ±5‰D at this position. 2014 Vol. 51 (5): 145-149 [Abstract] ( 2008 ) [HTML 1KB] [ PDF 0KB] ( 579 ) 150 Simulation and Analysis of the Glare Effects of Highway Tunnel Lighting FU Yi, YANG Bo, CHEN Yun-Qing In order to reduce the impact of glare on the safety of highway tunnels, the area in a highway tunnel affected by lighting glare was studied by combining analog simulation and quantitative analysis. Using a calculation method introducing the glare constant G and relative threshold increment T1, the glare-affected areas generated by three kinds of glare arrangements, i.e., symmetrical, staggered, and centralized, were obtained by a simulative analysis of tunnel lighting glare. The results show that the glare-affected area for the symmetrical arrangement is 75.73°, 76.22° for the centralized one, and 79.58° for the staggered one. Based on the calculation analysis of glare constant G, the following conclusion was drawn: no matter which kind of luminaire arrangement is applied in tunnel lighting, once glare impact occurs, the drivers in the tunnel will be endangered. 2014 Vol. 51 (5): 150-154 [Abstract] ( 1993 ) [HTML 1KB] [ PDF 0KB] ( 579 ) 155 The Mechanism and Effects of AFRP Reinforcement for a Shield Tunnel in Soft Soil LIU Zi-Sheng-1, Zhang-Dong-Mei-1, 2 Since the horizontal convergence of a shield tunnel is directly related to tunnel safety, AFRP (Aramid Fiber Reinforced Polymer) reinforcement is one of the commonly used treatment methods for deformation. In this paper, its mechanism and effects are discussed using a numerical simulation based on the horizontal convergence and joint opening, and the influence of AFRP pasting time and number of layers on the effects of reinforcement are analyzed in light of related parameters. The results show that: AFRP reinforcement can effectively restrict horizontal convergence and joint deformation, but the reinforcement effect is affected by the extent of tunnel deformation, i.e., the smaller the deformation, the better the reinforcement; and the reinforcement effect may increase significantly with an increase in the AFRP layers, with 2~3 being the best choice for layer numbers. 2014 Vol. 51 (5): 155-160 [Abstract] ( 2141 ) [HTML 1KB] [ PDF 0KB] ( 519 ) 161 Numerical Analysis of Shield Tunneling Under an Electric Power Tunnel in Sandy Strata of Zhengzhou ZHANG Lu-Gen Based on a shield tunnel of the Zhengzhou metro that passes under an electric power tunnel, a numerical simulation analysis was carried out by ABAQUS software and the settlement laws of the ground surface and the electric power tunnel were researched, as well as shield tunnel construction in sandy strata. The results show that: the maximum ground surface settlement that occurred at the middle of the two tunnels is about 12mm, while the maximum ground settlement of the electric power tunnel, occurring at the intersection of the two tunnels, is about 15mm, all of which are within an allowable range. Thus, it is concluded that the settlements are both controlled by targeted construction measures, which ensure the security of electric power tunnel. 2014 Vol. 51 (5): 161-173 [Abstract] ( 2241 ) [HTML 1KB] [ PDF 0KB] ( 572 ) 168 Analysis of the Disturbance to Surrounding Soils During Shield Driving for the Hangzhou Metro Line 1 Project YU Xing-Fu-1, Ren-Hui-2, Hu-Xiang-Dong-2 Using the right tube tunnel of the Hongpu Station - Jiubao Station section of the Hangzhou Metro Line 1 as a background, experimental monitoring was carried out to study the variation of surrounding soils during the process of shield driving. The monitoring items included ground surface settlement, layered settlement, horizontal displacement, and pore water pressure. Monitoring data analysis indicates that: (1) ground surface settlement mainly occurs when the shield cutterhead approaches the monitoring section and the shield tail leaves the monitoring section; (2) while the shield is passing through the monitoring section, the settlement of the soil mass around the shield is obvious with different degrees of heaving before and after the shield passes through. The lateral horizontal displacement of the soil mass is larger, indicating that the soil mass is distinctly squeezed; and (3) when the shield cutterhead is arriving at and the shield tail is leaving the monitoring section, the pore water pressure always presents a regular variation of abruptly increasing and afterwards sharply decreasing, reflecting the states of disturbance of the soil mass being squeezed, restored, and loosened. 2014 Vol. 51 (5): 168-173 [Abstract] ( 2067 ) [HTML 1KB] [ PDF 0KB] ( 523 ) 174 Design for a Super-Shallow Large-Section Double-Level Tunnel in Complex Conditions Underneath Sensitive Buildings LIU Ji-Guo-1, CHENG Yong-1, GUO Xiao-Hong-1, Wang-Wen-Zhou-2 In light of the Gongbei tunnel in the Hong Kong-Zhuhai-Macao Bridge, which is a current world-class project in China, this paper introduces a new construction method: shallow mined excavation with a combination pipe roof and supporting structure system for the construction of a super-shallow large-section tunnel with six lanes and two levels underneath sensitive buildings in water-rich soft ground. In this method, the pipe-roof advance support and the supporting structure as the primary support are combined and connected to form an integrated circumferential and longitudinal load system with great stiffness, which can effectively control surface deformation during tunnel construction and operation and significantly reduce construction risks. Using this method, a waterproof curtain is formed by freezing soil between the pipes to avoid the surface deformation caused by loss of groundwater and the water- and mud-bursting that occurs during excavation, as well as to ensure excavation in a water-tight underground space. Pipe-jacking and ground freezing, which are rarely used in tunnel construction, have been combined reasonably with the supporting structure, successfully solving the technical problems of constructing a super-shallow large-section tunnel underneath sensitive buildings in complex geological and environmental conditions. A new concept and method for tunnel construction has been developed. 2014 Vol. 51 (5): 174-179 [Abstract] ( 2234 ) [HTML 1KB] [ PDF 0KB] ( 569 ) 180 Research on Construction Techniques for an SMW Retaining Structure for a Deep Foundation Pit in Soft Muddy Soil LI Ai-Di, LI Cheng-Xun, DONG Ying Along the Yangtze River, it is challenging to construct a deep foundation pit due to widely distributed and thick muddy soil, a high confined water level, and complex geological conditions. In this paper, based on the Meizizhou river-crossing passage of the Nanjing YOG transportation axis project, a tri-axial soil-mixing pile retaining structure constructed using the SMW method is studied systematically. By combining data from the field piling test and the laboratory experiment, main construction technology parameters, like water cement ratio, cement content, drilling speed, and lifting speed, are determined and the displacement law of the SMW retaining structure is analyzed in light of field test results. Engineering practices show that the SMW retaining structure has a good supporting effect under the above geological conditions, and this paper provides a reference for the construction of retaining structures for large-scale, deep foundation pits. 2014 Vol. 51 (5): 180-186 [Abstract] ( 2156 ) [HTML 1KB] [ PDF 0KB] ( 591 ) 186 Optimization and Improvement of Shield Construction Measures in a Silty Soil Stratum WANG Zhan-1, 吕Xue-Jin-2 , WANG Jin-Chang-3, HONG Cheng-Po-4 Based on the excavation of Hangzhou Metro Line 1, the commonly encountered problems for advancing EPB shields in silty soil strata are analyzed, and a corresponding improvement proposal is put forward in this paper. According to the wear regularity of the cutterhead and screw conveyor impeller in practical driving, the effective wear-resisting reinforcement measures are presented by way of an experimental comparison, which achieved good results. Meanwhile, the defects of the original foaming system are optimized and improved for system simplification and cost saving purposes, and the optimal thrust force for this type of stratum is obtained by specific tests of thrust force at all levels. Ultimately, the project is completed safely and efficiently with a series of optimized measures, which can be used as a reference for similar engineering endeavors. 2014 Vol. 51 (5): 186-194 [Abstract] ( 2083 ) [HTML 1KB] [ PDF 0KB] ( 560 ) 195 Research on the Technology for Monitoring and Controlling Blasting Vibration During Shallow Tunnel Excavation CHEN Gui-1, GAO Wen-Xue-1, LIU Dong-1, 2 , SHI Lian-Song-1 Based on the blasting excavation of the Xisiduhe tunnel of the Huaichang Road reconstruction project, the technology for monitoring and controlling blasting-induced vibration during tunnel construction is addressed in this paper. By monitoring the particle vibration velocities on the ground surface and in the structure, the transmission law of the blasting vibration wave is studied and a spectral analysis is conducted. Finally, a rational controlling technology is presented. The results of monitoring analysis show that: (1) the magnitude of the particle blasting vibration velocity is closely related to the maximum explosive charge of each blasting and the distance between the monitoring points and the blasting center; (2) for left- and right-part blasting excavations on the lower bench, the larger the clamping force of the first blasting on the rocks, the bigger the blasting vibration response and the higher the vibration velocity. Because the first blasting offers a new free face to the second blasting, it can mitigate the blasting vibration effects and decrease the vibration velocity; (3) since the high-frequency components of the particle vibration velocity are not abundant, the dominant frequency of the vibration velocity is mainly distributed in low-frequency band; (4) because the air vents laid on the covered arch at the cut-and-cover section generate the reflecting action of a stress wave, the blasting vibration has a significant influence on the reinforced concrete covered-arch structure. 2014 Vol. 51 (5): 195-198 [Abstract] ( 1913 ) [HTML 1KB] [ PDF 0KB] ( 551 ) 199 3D Point Cloud Monitoring Technology and its Application in Tunnels DENG Hong-Liang-1, FU Si-Yuan-1, GAO Wen-Xue-1, ZHOU Shi-Sheng-2, DENG Qi-Hua-３ Underground engineering is full of difficulties and risks during tunnel construction, and observational monitoring is becoming more and more important in the course of tunneling construction. Using 3D laser scanning measurement technology, and based on 3D point cloud monitoring, a comparative analysis is carried out in terms of the tunnel excavation process, deformation, and clearance intrusions, the purposes of which are: (1) to trace tunnel settlement, convergence, stress and deformation; (2) to provide a dependable basis for adjusting the support parameters, installing the secondary lining at an optimum time, and modifying the design scheme; and (3) to provide early warning and alarms and risk management based on monitoring results. Engineering practices indicate that the 3D laser scanning system is characterized by high speed and high precision, and its measurement precision meets the specified requirements with the data being very close to that of the Leica TPS1200 total station. 2014 Vol. 51 (5): 199-204 [Abstract] ( 2065 ) [HTML 1KB] [ PDF 0KB] ( 579 ) 205 Field Test on the Impacts of Foundation Pit Construction on Ground Settlement and Underground Utilities in the Yangtze River Floodplain Area GE Zhao-Guo Dewatering during deep foundation pit construction causes ground settlement around the pit. As for foundation pits in areas with rich groundwater, dewatering would largely result in worse ground settlement and have negative impacts on nearby underground utilities. This paper, based on the Meizizhou river-crossing passage of the Nanjing YOG transportation axis project, gives a profile of the foundation pit construction and a layout of measuring points and monitoring results for the Yangtze River floodplain area. Through an analysis of the monitoring data, it presents the causes and law of ground settlement and impacts to underground utilities around the foundation pit and addresses the countermeasures against these problems. 2014 Vol. 51 (5): 205-209 [Abstract] ( 1867 ) [HTML 1KB] [ PDF 0KB] ( 565 )

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