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Quick Search     Advanced Search MODERN TUNNELLING TECHNOLOGY   2014 Vol.51 Issue.6 Published 2014-12-25 Article 1 Study on Different Seismic Intensities and Earthquake Damage to Highway Tunnels in Wenchuan Area Affected by Earthquakes CUI Guang-Yao-1, LIU Wei-Dong-1, NI Song-Zhi-1, WANG Ming-Nian-2, LIN Guo-Jin-3 It is neccessary to study earthquake damage to highway tunnels in earthquake-affected areas with different seismic intensities for scientific design and earthquake fortification. Based on the earthquake-damage information regarding highway tunnels in Wenchuan, the above-mentioned study was carried out. The results show that: a tunnel was not destroyed in the area of 6-degree seismic intensity; the tunnel entrance and tunnel slope structure were smashed by rockfalls in the area of 7-degree seismic intensity; there was almost no lining damage to a hard-rock tunnel body in the area of 8～11-degree seismic intensity; slight cracks and water penetration occurred at the lining of a soft-rock tunnel body in the area of 8-degree seismic intensity; reticular cracks and large-area water penetration, concrete spalling, falling, and secondary lining collapse occurred at the lining of a soft-rock tunnel body in the area of 9-degree seismic intensity; a tunnel portal was blocked by sliding and collapse of the slope around the tunnel entrance in the area of 9-degree seismic intensity; increased secondary lining collapse occurred at the soft-rock tunnel body in the area of 10-degree seismic intensity; and surrounding rock collapse occurred at a soft-rock tunnel body in the area of 11-degree seismic intensity. These research results are significant to further study of the earthquake-damage mechanism and countermeasures for highway tunnels in earthquake-affected areas with high seismic intensity. Keywords Earthquake intensity region; Highway tunnel; Earthquake damage characteristics 2014 Vol. 51 (6): 1-6 [Abstract] ( 2122 ) [HTML 1KB] [ PDF 0KB] ( 568 ) 7 Formation Mode of Shallow Natural Gas in the Laoshishan Tunnel on the Kunming-Nanning Passenger Dedicated Line WANG Guang-Neng-1, SU Pei-Dong-2, DU Yu-Ben-1, CHEN Wan-Lin-2 Focused on the emission and burning of natural gas in the Laoshishan tunnel on the Kunming-Nanning passenger dedicated line, which passes through a non-coal stratum, the formation mode of natural gas was researched regarding the causes of tunnel hazards and natural gas sources. Based on the geological conditions of the emission area, the characteristics of the oil-gas generation layer, the reservoir layer, and the bearing layer were analyzed, proving that: 1) the anticline structure at the tunnel's exit is the affected area for oil and gas migration; 2) a series of underlying generation layers have the capacity to generate oil and gas; and 3) the shallow accumulation of oil and gas is possible via the fault structure. According to a comparison of gas concentrations before and after tunnel excavation, it is determined that shallow natural gas mainly comes from deep rock below the tunnel floor, and the rock around the tunnel body may have already been affected by accumulation at individual sections. The causes of shallow natural gas in the Laoshishan tunnel are obtained by analyzing gas distribution characteristics and the gas formation mode: namely, the gas comes from the shale of the Qiongzhusi formations of the deep Silurian system and the Cambrian system with migration along the Longquansi fault zone. 2014 Vol. 51 (6): 7-11 [Abstract] ( 1854 ) [HTML 1KB] [ PDF 0KB] ( 537 ) 12 Design Optimization of the Support Reinforcement at the Portal Section of a Highway Tunnel WU Jin-Gang-1, SONG Yan-Bin-1, CHEN Ren-Dong-1, CHEN Dao-Song-2 In light of the existing problems regarding the reinforcement design of support at the portal sections of highway tunnels, and based on the characteristics of surrounding rock and its loading at the portal and shallow-buried tunnel sections, this paper analyzes supporting features under different rock conditions by considering the action mechanisms of pipe-roof support, primary support, and secondary linings, and gives relevant suggestions for the above two sections. The results show that due to fractured surrounding rock and its poor self-stability at the portal section, the advance support plays an important role in enhancing the early stability of the rock, the primary support serves as the main bearing structure, and the secondary lining can be used to share part of load with a certain safety reserve. Thus, for the portal section it is better to strengthen the advance support and the primary support instead of the secondary lining, since the loads at the portal section are less than that at the shallow-buried section. Additionally, because of the intact surrounding rock and its certain self-stability at the shallow-buried section, the secondary lining serves as the main bearing structure and the primary support gives play to adhesion for better coordination between the surrounding rock and the support structure. Consequently, it is better to strengthen the secondary lining at the shallow-buried section and choose the best time for installation. 2014 Vol. 51 (6): 12-18 [Abstract] ( 1937 ) [HTML 1KB] [ PDF 0KB] ( 532 ) 19 Discussion of and Solutions for the Large Deformation Mechanism of a Tunnel in Carbonaceous Slate LIU Yang-1, 2 , WU Xiao-Jun-2, LIU Zhi-Qiang-2, LIU Yu-Yong-2, Shu-Bo-2 The Muzhailing tunnel of the Lanzhou-Chongqing railway, which is built under the complicated geological conditions of weak surrounding rocks, such as high ground stress, carbonaceous slate, and so on, exhibits obvious large deformation and partial failure in the carbonaceous slate section. Aiming at the large deformation of the Muzhailing tunnel, the influence factors regarding the occurrence of large deformation in carbonaceous slate are analyzed in this paper. The large deformation mechanism is studied, including the plastic deformation of carbonaceous slate, bending of the plate-girder, shear slip, and damage to the pressure bar. Thus, the construction measures, such as the surrounding rock stress, the reinforced support, and the advance control, are adjusted in order to control the large deformation of a tunnel, and this experience provides a reference for future tunnel construction in carbonaceous slate. 2014 Vol. 51 (6): 19-24 [Abstract] ( 2032 ) [HTML 1KB] [ PDF 0KB] ( 563 ) 25 On Monitoring Data for the Security of a Box-Type Subway Tunnel Structure Under the Influence of Surrounding Construction Activity ZHENG Zhang-Qing-1, Gao-Hai-Xiang-2 In this paper, the structural problems of a box-type subway tunnel and their impact on structure safety is analyzed considering such features as large integral rigidity, vulnerability against deformation, and likelihood of being affected by surrounding construction activity. The index and control values of safety monitoring for this type of structure are presented in accordance with a statistical analysis of cross section, space deformation, and internal force features of a box-type tunnel under the influence of surrounding construction activity. The results of this analysis and its application show that the proposed method for defining the index and control values for safety monitoring is safe and reliable and can provide a reference for structural safety monitoring in similar works. 2014 Vol. 51 (6): 25-28 [Abstract] ( 1896 ) [HTML 1KB] [ PDF 0KB] ( 525 ) 29 Analytical Solution for Elasto-Plastic Coupling of the Brittle Rock in an Circular Opening WANG Hong-Ying In this paper, aimed at the elasto-brittle-plastic circular opening under hydrostatic pressure, an elasto-plastic coupling model was adopted for an analytical study of stress and displacement of the surrounding rock. And based on the linear Mohr-Coulomb criterion and the non-associated flow rule, the analytical solution of the rock stress and deformation was deduced, thus determining theoretically the restrictive relationship between strength parameter and elasticity modulus in the post-failure region and giving the rules of rock stress and deformation in the post-failure region under different modulus deterioration conditions. The results show that the modulus deterioration may not result in variation of the plastic zone scope and the rock stress distribution, but it may contribute to the surge of rock deformation. 2014 Vol. 51 (6): 29-34 [Abstract] ( 1988 ) [HTML 1KB] [ PDF 0KB] ( 554 ) 35 Three-Dimensional Analytical Solution for Passive Limit Support Pressure During Shield Tunnelling SHEN Lin-Fang-1, 2 , WANG Zhi-Liang-1, 2 , WEI Gang-1, WU Zeng-2 Based on the Mohr-Coulomb yield criteria, the failure model of a wedge block + inverted truncated pyramid is improved by considering the influence of soil cohesion and optimizing the inclined angle of the wedge block, and a three-dimensional model is established to calculate limit support pressure when the excavation face is in the passive limit equilibrium state. Meanwhile, a corresponding formula is deduced to calculate the limit support pressure, and its solution is obtained by optimization analysis. Based on a calculation example, a comparison between the predicted results from the proposed model and the classic upper bound solution is made to verify its rationality. Finally, the relationship among the passive limit pressure, cohesion of the soil, friction angle of the soil, and thickness of the overburden is studied. Results show that there is a linear relationship between the cohesion of the soil and the passive limit support pressure, which means that the greater the cohesion of the soil, the greater the passive limit support pressure; the larger the friction angle of the soil, the greater the passive limit support pressure and the faster its rate of change is; and with an increase of the overburden of the tunnel, the passive limit support pressure increases gradually, and the rate of change becomes faster and faster, which presents an approximate exponential function relationship. 2014 Vol. 51 (6): 35-40 [Abstract] ( 2079 ) [HTML 1KB] [ PDF 0KB] ( 517 ) 41 Discussion of the Seismic Failure Mechanism of a Tunnel Based on the Improved Dynamic Strength Reduction Method SUN Chang-Xin-1, 2 , 吕Xiao-Chun-1 To explore the failure mechanism of tunnel structures in earthquakes, a static field was imposed to dynamic calculation by shifting the boundary between static and dynamic, which was taken as an initial stress condition for the improvement of the dynamic strength reduction method, the feasibility of which was proven by a computing application. The improved dynamic strength reduction method is used to calculate and analyze the failure mechanism of deep and shallow buried tunnels under seismic action, and the results show that failure processes are different for tunnels with different depths. For the shallow-buried tunnel, failure begins at the two sides above the tunnel and gradually forms a fracture plane cutting through the ground; for the deep tunnel, the plastic strain first occurs at four stress-concentrated corners with a smaller plastic strain on the crown and floor, and then a continuous plastic strain zone is formed gradually from the two sides until failure finally occurs. In light of seismic action, this paper analyzes the factors affecting tunnel failure, studies the failure mechanism of tunnel structures of different surrounding rock grades, spans, structure types, and buried depths, and finally carries on a comparative analysis for each influence factor. 2014 Vol. 51 (6): 41-49 [Abstract] ( 1894 ) [HTML 1KB] [ PDF 0KB] ( 516 ) 50 An Empirical-Theoretical Calculation Method and Full-Scale Verification Test for the Ultimate Bearing Capacity of an Expanded Pedestal Uplift Pile ZHANG Ji-Hong-1, 2 , Zhu-He-Hua-1 Considering the influences of such factors as soil mechanical characteristics, pile material properties, pile length and pile diameter (including the expanded pedestal diameter), depth of the pile top, and unloading and loading around the pile top and pile group effect, combined with engineering practices, an empirical-theoretical calculation method for the ultimate bearing capacity of an expanded pedestal uplift pile is proposed in this paper. Based on different positions of the failure surface of the expanded pedestal uplift pile, the failure mode of the expanded pedestal uplift pile is divided into three types: entire shearing failure from the failure surface extending to the ground surface, local shearing failure of the failure surface between the ground surface and borehole-expanded section, and punching shear failure of the failure surface near the borehole-expanded section. An ultimate equilibrium state equation under the entire shearing failure mode is derived. According to the axial symmetry conditions of the expanded pedestal uplift pile and the mechanical characteristics of the lower soil tensile strength, a differential cylinder numerical solution is given regarding the entire failure surface. By using the empirical method to estimate the end resistances under the local shearing failure mode or punching shear failure mode, the calculating procedure and method for the ultimate bearing capacity of the expanded pedestal uplift pile in any soil layer is put forward. Finally, the reliability and accuracy of the calculating method is verified through a comparison between the calculated ultimate bearing capacity and the measured one in a full-scale test. 2014 Vol. 51 (6): 50-57 [Abstract] ( 2034 ) [HTML 1KB] [ PDF 0KB] ( 526 ) 58 Fuzzy Clustering Theory Based Rock Mass Cuttability Classification Prediction Model for TBM Tunnelling WANG Pan, Guo-Wei, Zhu-Dian-Hua In this paper, systematic and quantitative studies are carried out regarding rock cuttability by a TBM under complex geological conditions. Based on the fuzzy clustering theory and construction sample analysis, a rock cuttability classification prediction model is established by using the rate of penetration (ROP) as a basic index. The ROP is related to four property indexes: rock uniaxial compressive strength, rock integrity coefficient, the angle between the rock structural plane and the tunnel axis, and water seepage. In the prediction model, the rock mass cuttability is classified into three levels: good, moderate, and poor. Furthermore the prediction model is refined to improve model precision and geological applicability. According to the prediction results for the West Qinling tunnel and the Dahuofang water conveyance tunnel projects, the ROP of the TBM basically agrees with that of the prediction model, proving the feasibility, scientific soundness, and availability of the rock cuttability classification prediction model and providing a basis for the selection, design, and construction of the TBM. 2014 Vol. 51 (6): 58-65 [Abstract] ( 1993 ) [HTML 1KB] [ PDF 0KB] ( 512 ) 66 Stability Analysis of Tunnels in Jointed Rock Masses WANG Wen, Zhu-Wei-Shen Joints and faults may cause discontinuity of rock mass deformation, and they significantly affect the mechanical behavior of rock mass deformation, stress, and so on. In this paper, two improvements are made to the existing discontinuous deformation analysis program, i.e., the adoption of an improved SSOR-PCG method and the addition of displacement convergence criterion. A stability analysis of a highway tunnel is carried out by the improved program, and the excavation procedures are optimized by monitoring displacement of the key points. The results show that one-time excavation of a left/right tunnel causes less disturbance to surrounding rocks than excavation by steps. Based on the monitoring of key displacement points, the anchoring effect is analyzed and support parameters are optimized. 2014 Vol. 51 (6): 66-72 [Abstract] ( 1869 ) [HTML 1KB] [ PDF 0KB] ( 525 ) 73 Effects of the Joint Dip Angle on the Collapsed Arch of Surrounding Rock Around a Highway Tunnel LIU Xue-Zeng-1, LIU Wen-Yi-2, 3 , SUO Chao-Feng-3 Based on an indoor gypsum model test, this paper discusses the span and height, as well as the area of collapsed arches of surrounding rock with joint spacings of 0.5 m; dip angles of 0°, 30°, 45°, 60°, 90°; and without support. Compared with the values of the Platts theory, there is a nonlinear relationship between the joint dip angle and the collapse height, width, and area, with the minimum values occurring with angles of 45°~60°. The test results are consistent with the calculated ones according to a 2D numerical analysis of the above conditions with UEDC software. Based on a comprehensive analysis of numerical calculations and indoor test results, a calculation method for collapsed arch heights under different joint dip angles is obtained. 2014 Vol. 51 (6): 73-77 [Abstract] ( 1811 ) [HTML 1KB] [ PDF 0KB] ( 565 ) 78 Normal Calculation Back Analysis of Dynamic Incremental Displacement and its Application in Tunnel Engineering ZHAO Cheng-Long-1, 2 , LI Shu-Cai-1, XU Bang-Shu-1, ZHANG Le-Wen-1 In order to optimize the inversion method for physical and mechanical parameters of tunnel surrounding rock and to improve the computational speed, normal calculation back analysis for dynamic incremental displacement in tunnel engineering is presented in this paper and applied in the Jiaozhou Bay subsea tunnel in Qingdao. With the establishment of an inversion prediction model of elastic-plastic dynamic incremental displacement, and the improvement of traditional elastic-plastic forward-optimized back analysis method, a construction process based inversion normal calculation back analysis of linear elastic dynamic incremental displacement is derived that is used for simplified analysis. A comparison is carried out regarding the calculated displacement and actual displacement in three construction sections of the Jiaozhou Bay subsea tunnel. Study results show that dynamic incremental displacement inversion normal calculation back analysis can reflect the increment measure information in any construction stage during dynamic construction, and guarantee the implementation of deformation control techniques; compared with the traditional elastic-plastic forward-optimized back analysis method, the proposed one increases efficiency and ensures calculation accuracy. 2014 Vol. 51 (6): 78-82 [Abstract] ( 2053 ) [HTML 1KB] [ PDF 0KB] ( 510 ) 83 Theoretical Research on the Inverse Analysis of the Internal Force of the Primary Support in a Horseshoe Tunnel WANG Xin-Yu, SHAO Zhu-Shan Internal force distribution of concrete support has dynamic variation characteristics during tunnel construction. Researching the distribution characteristics and pre-detecting weak parts is one of the most important means to guarantee construction security. This paper considers the primary supports at the arc and the sidewall sections as the curved beam and the straight beam of the elastic foundation respectively, and theoretically deduces an inversion formula for the internal force of the primary support in a horseshoe tunnel based on the initial parameter method and measured pressure of the surrounding rock. The comparison between the measured and analyzed results shows that the above inverse analysis is practicable and can provide a theoretical basis for primary support design and construction technology optimization. 2014 Vol. 51 (6): 83-87 [Abstract] ( 2072 ) [HTML 1KB] [ PDF 0KB] ( 494 ) 89 Numerical Research on Tunnel Deformation Under Two Sets of Coupling Joints SHI Yi-Dong-1, Li-Zhi-Zhong-2, Li-Jun-2, Sang-Yun-Long-3 Based on the rock joint characteristics of the Gaozhushan tunnel in Yushan county, a 2D calculation model is established using the discrete element software UDEC, and the effects of the joint dip angle and joint spacing on tunnel deformation under two sets of joint couplings is studied by calculating the vault collapse heights in different conditions. Results show that by increasing the joint dip angle, the collapse height decreases (30° to 45°) after initially increasing (0° to 30°), and then increases again (45° to 90°); the calculated collapse height is closest to PU's theoretical value when the dip angle is 60°; and with an increase in joint spacing, the collapse height decreases nonlinearly. When the joint spacing is 0.2~1.0 m, the collapse height can be calculated with equation (1) and the calculated value is closest to PU's theoretical value when spacing is no more than 0.2m. 2014 Vol. 51 (6): 89-93 [Abstract] ( 1908 ) [HTML 1KB] [ PDF 0KB] ( 506 ) 94 Settlement Prediction for a Metro Tunnel Adjacent to a Deep Large-Scale Foundation Pit CHEN Xi-Feng-1, LIU Ling-2, HUANG Teng-3 Due to the complex factors of and strict requirements for deformation control, it is difficult to accurately predict the settlement of a metro tunnel adjacent to a deep large-scale foundation pit. In this paper, the Support Vector Machine (SVM) theory is introduced for its excellent prediction capabilities regarding small sample, complex, and nonlinear data, and Ant Colony Optimization (ACO) was adopted to obtain an optimized SVM prediction model by selecting the most appropriate parameter combination. Based on the settlement prediction of a tunnel on Nanjing Metro Line 1, this model meets the requirements of settlement prediction for metro tunnels adjacent to deep large-scale foundation pits because of its sound prediction accuracy and accurate reflection of deformation trends. 2014 Vol. 51 (6): 94-100 [Abstract] ( 1858 ) [HTML 1KB] [ PDF 0KB] ( 500 ) 101 On Scheme Optimization of the PBA Subway Station Underneath a Bridge WEI Jing-1, Wang-Fang-2, Sun-Ming-Zhi-3 Based on the Huayuanqiao station of Beijing Metro Line 6, which passes under the Huayuan bridge, an optimal scheme for the subway station, which is constructed by the Pile-Beam-Arch (PBA) method, is determined by FLAC3D numerical simulation and the analytic hierarchy process (AHP). The impact of key construction stages on the stratum and pile foundation is analyzed in conjunction with the monitoring results. The research shows that: the effects of the four-heading method on control of the pile foundation displacement at the far and near sides is better than that of the five/six-heading method under the same grouting reinforcement conditions; the effects of the appropriate grouting reinforcement on the bridge-pile area at the near side is similar to that of wide-range grouting reinforcement if the construction methods and structures of the stations are the same; after comprehensive consideration, a five-heading method with appropriate grouting reinforcement is determined to be the optimal scheme; the ratio of surface subsidence of the heading excavation, buckle arch, and other construction procedures is 0.38∶0.32∶0.30; construction of the heading and buckle arch has a large impact on pile foundation displacement at the near side; and excavation of the platform has the most serious impact on pile foundation settlement at the far side, with heading excavation and the buckle arch taking second place (the latter greatly affects horizontal displacement). 2014 Vol. 51 (6): 101-107 [Abstract] ( 2100 ) [HTML 1KB] [ PDF 0KB] ( 552 ) 108 Research on the Dynamic Behavior of the Slurry Membrane of a Large-Section Slurry Shield in a Sandy Cobble Stratum WANG Jun, He-Chuan, Feng-Kun, Xia-Wei-Yang Taking a river-crossing tunnel on Nanjing Metro Line 10 as an example, a discrete element simulation and model test were carried out to study the formation-damage-reformation process of the slurry membrane, the penetration range of slurry in a sandy cobble stratum, and the influence of shield tunnelling on the ambient environment under different slurry pressures. The results show that: the discrete element simulation method can reproduce well the dynamic process of the slurry membrane during slurry shield tunnelling, the selection of slurry pressure plays an important role in controlling stratum deformation and working face stability, and a permeable slurry membrane can be formed in sandy cobble stratum using a pure-cone shape with an oval outline and a largest gyration radius of 0.3D. Its largest penetration distance can be 0.4D~0.5D in front of the shield, and the range of the slurry membrane develops with tunnelling. 2014 Vol. 51 (6): 108-115 [Abstract] ( 1885 ) [HTML 1KB] [ PDF 0KB] ( 515 ) 116 Experimental Study on the Deformation Law of a Cracked Lining Reinforced by a Superimposed Cover Arch YU Wen-Sheng-1, 2 , Sang-Yun-Long-3 A model plain concrete lining structure with longitudinal cracks in the vault (with a crack depth of one-third of the original lining thickness) was made of gypsum at a similarity ratio of 1∶10 and a superimposed concrete cover arch was adopted for reinforcement. After curing, loose earth pressure was applied in a graded manner on the crown by means of indoor peripheral radial loading appliances to study the bearing capability and failure law of the cracked lining reinforced by a superimposed cover arch by considering the effects of stratum resistance. Testing results show that the deforming process of the cracked lining under loading undergoes three stages after reinforcement of the superimposed cover arch: initial loading - cracking of the cover arch vault; cracking at the cover arch vault - cracking at the superimposed interface; and cracking at the superimposed interface of the vault - specimen failure. The sequence of key position failure is: cracking on the vault, ductile failure of the vault, and brittle fracture of the haunch; the failure mode is generally ductile in nature. 2014 Vol. 51 (6): 116-122 [Abstract] ( 1930 ) [HTML 1KB] [ PDF 0KB] ( 478 ) 123 The Design and Application of a Large-Scale Model Test for a Super-Long Immersed Tunnel HU Zhi-南, ZHANG Hong-Guang, XIE Yong-Li, YUE Xia-Bing, WANG Peng, LIU Yu-Yang In this paper, based on the immersed tunnel construction of the Hong Kong-Zhuhai-Macao bridge project, the mechanism of super-long immersed tunnel segment joints under actions of uneven settlement and uneven loads is researched by means of partial similarly assembling shear keys. The large-scale immersed tunnel segment model test with a ratio of 1∶4.69 is carried out by material proportioning and model fabricating, and the trial platform of the settlement model is technically transformed to possess such functions as model hauling, connecting, loading, and resetting in the process of the experiment. Uneven displacement in longitudinal and transversal directions of the immersed tunnel segment joints can be simulated through control of differential settlement of the jacks at the bottom of the trial platform. With reinforcement meters and pressure cells, the reinforcement stress of the immersed structure and the contact pressure between the model structure and the soil mass are tested, and by utilizing a resistance strain rosette and an FBG strain rosette, the external and internal strains of the shear keys are also tested. Furthermore, the distribution laws of segment joint shearing stresses along with differential settlement and immersed tunnel cross sections are obtained by a preliminary analysis of the test data. 2014 Vol. 51 (6): 123-129 [Abstract] ( 1800 ) [HTML 1KB] [ PDF 0KB] ( 481 ) 130 Model Test Study of the Anchor Bolt Arrangement in a Loess Subway Tunnel ZHENG Jia-Jia-1, Sa-Lei-2, Guo-Yong-Jian-3 In this paper, a three-axial loading device of plane strain is used for a laboratory model test. Contrast tests are carried out for three kinds of anchor bolt arrangements, i.e., an arrangement with no anchor bolts, a whole-section arrangement of anchor bolts, and an arrangement of anchor bolts on the sidewall. The role of the anchor bolt system in a loess subway tunnel is studied in reference to field test results. Data regarding anchor bolts applied to a loess subway tunnel are obtained by model testing, and "loading-before-excavation" and anchor-lining integration are realized. By contrast, the development of a plastic zone around the working face is well controlled by the anchor bolt system; after excavation and support of the tunnel cavern, the sidewall anchor bolt can comply quickly with surrounding rock stress and effectively improve the stress distribution of the lining. Considering the economic factors, the sidewall anchor support system is a good method for reinforcing surrounding rock in shallow-bored loess subway tunnels and should be adopted in actual construction. 2014 Vol. 51 (6): 130-135 [Abstract] ( 2052 ) [HTML 1KB] [ PDF 0KB] ( 479 ) 136 Impact of Shaft Types on the Ventilation Effect in Urban Road Tunnels CUI De-Zhen-1, Xing-Jin-Cheng-1, Ling-Ji-Hong-1, HAO Hai-Xian-2, LI Jian-Xing-3, Li-Chen-3 Based on a tunnel practice, the ventilation effect of the shaft during traffic clogging in a tunnel with ventilation shaft is studied through a model test. The research results show that ventilation shaft presents a character of cyclical transition between air intake and air exhaust with small air quantities when natural ventilation due to low speed movement of vehicles is used; and air exhaust rate of rectangular shaft increases with the increase of cross-section equivalent diameter while air exhaust rate increases with the decrease of slope angle of ventilation shaftwhen a combination of jet fan and traffic induced air is used to keep a constant state of air exhaust. 2014 Vol. 51 (6): 136-141 [Abstract] ( 1939 ) [HTML 1KB] [ PDF 0KB] ( 523 ) 142 Construction Techniques for a Single-Track Railway Tunnel in a Horizontal Stratum CHEN WANG In the South Luliangshan tunnel, the surrounding rock at the entrance of the #2 inclined shaft is mainly composed of horizontally layered mudstone, marlstone, and limestone with developed bedding and joint fissures, which are inclined to result in rock falls, chipping, and rock collapse at the arch after blasting, causing difficulties in terms of rapid excavation, cost control, and safety risks. In this paper, considering the excavation method, advance reinforcement, controlled blasting, primary support, monitoring, and measurement, major construction methods, measures, and techniques are presented for the single-track railway tunnel in horizontal stratum, such as the short bench method, advance condulet grouting, slight controlled blasting, hollow grouting anchor support for the arch, geological advance prediction, and strengthened construction monitoring. 2014 Vol. 51 (6): 142-147 [Abstract] ( 1980 ) [HTML 1KB] [ PDF 0KB] ( 457 ) 148 Key Techniques for EPB Shield Construction in a Waterless Sandy Stratum with Cobbles and Boulders GUO Cai-Xia-1, 2 , Zhang-Ding-Li-1, WANG Meng-Shu-1 Shield construction is was used for the Fengtai East Street Station-Fengtai North Road Station section of Beijing Subway Line 9, which is located in a waterless stratum with gravel, cobbles, and boulders. Based on the geological investigation and related data from an exploratory well, the spatial distribution and mechanical properties of the gravel, cobble, and boulder stratum are understood. Wear of the cutterhead and cutting tools is reduced by adaptability improvements to key parts of the EPB shield with a spoke-type cutterhead. By determining appropriate parameters for shield tunnelling, the long-distance full-face tunnel drive in waterless sandy stratum with cobbles and boulders was completed. 2014 Vol. 51 (6): 148-153 [Abstract] ( 1952 ) [HTML 1KB] [ PDF 0KB] ( 490 ) 154 Countermeasures and Construction Technologies for Clearance Intrusion of the Primary Support in the Sujiawan Tunnel DOU Ji-Ping-1, Chen-De-Jian-2 In light of the clearance intrusion of the primary support in the Sujiawan tunnel, this paper determines relevant parameters for controlling support deformation based on checking the support structure and secondary lining with MIDAS-GTS software and analyzing the geological conditions of the tunnel body. Reasonable countermeasures are proposed after the analysis of required construction technologies, including strengthening geological surveys of the top of the tunnel's central line, improving the drainage system, enhancing the support system with an increased reserved deformation allowance, and intensifying tunnel monitoring and measurements. 2014 Vol. 51 (6): 154-159 [Abstract] ( 2188 ) [HTML 1KB] [ PDF 0KB] ( 484 ) 160 Construction Techniques for a Shallow-Buried Long-Span Highway Tunnel in Soft Soil Passing Under the Subgrade of an Existing Railway Station ZHAO Li-Cai Considering that the safety coefficient is low when a shallow-buried long-span highway tunnel passes under an existing railway station (or within a short distance), the section of the Dongfu tunnel that passes under the existing Xiamen-Shenzhen railway station is taken as a project example in this paper. Through a theoretical analysis and technical comparison, an overall scheme of construction techniques is determined that is the combination of the following: reinforcing the tunnel's surrounding rock and soil mass in the excavation direction using the pipe-roofing method, setting the pile cap as provisional pier on the digging pile, structural selection and security checks for the digging pile, jacking up the existing railway track by erection of a 24m D-shaped beam, reinforcing the steel rail with a longitudinal and transverse lintel, reserving core soil in an arc-shaped heading, monitoring settlement, and analyzing the reinforcement effect. The results show that the reinforcement effect is remarkable, and can rapidly and effectively restrict stratum settling in the under-passing section; the pipe on the arc plays a load-bearing role while the D-shaped beam reduces the external load on the pipe-roofing system; thus, the safety coefficient of the under-passing tunnel and the existing railway operation is highly improved, and the expected effect is achieved. 2014 Vol. 51 (6): 160-166 [Abstract] ( 2007 ) [HTML 1KB] [ PDF 0KB] ( 478 ) 167 Application of Comprehensive Geological Prediction Technology for Water Burst in the Tongluoshan Tunnel WU De-Sheng, WU Feng-Shou, LI Fu-Ming, GU Ting Geological hazards like water inflow and mud bursts often occur during tunnel construction in water-rich geology, and these are detrimental to safe construction. Engineering practice indicates that single advance geological prediction may lead to erroneous judgment. Based on the geological conditions of the Tongluoshan tunnel, a comprehensive geological prediction technology was proposed concerning water bursts, namely, giving full play to the advantages of the TRT method, transient electromagnetic method, and advance horizontal drilling. The results show that this comprehensive technology provides an effective geological reference for construction decisions, to some extent preventing the tunnel from geological hazards. 2014 Vol. 51 (6): 167-172 [Abstract] ( 1840 ) [HTML 1KB] [ PDF 0KB] ( 515 ) 173 Experimental Study on Full-Face Concrete Cutting by a Rectangular Pipe-jacking Machine with a Planetary Cutterhead WEI Lin-Chun The mining method with soil reinforcement is now mainly adopted in the construction of cross passages of shield tunnels, which is characterized by high risk and complex working conditions. In this paper, based on the adoption of a specially developed rectangular pipe-jacking machine with a planetary cutterhead, full-face cutting tests are carried out on concrete samples of different strength grades. Research on cutting-tool selection and layout, as well as the machinability of pipe-jacking with a planetary cutterhead, are undertaken, providing a technical reference for future cross-passage construction in shield tunnels adopting pipe-jacking to cut concrete composite segments, thereby refraining from exposing the reinforced soil mass due to segment removal, and greatly reducing the construction risk. 2014 Vol. 51 (6): 173-178 [Abstract] ( 1850 ) [HTML 1KB] [ PDF 0KB] ( 471 ) 179 Improvement of the Shield Foam System and Relevant Field Tests WANG Zhan-1, WANG You-Yuan-1, SU Lin-Wang-1, HONG Cheng-Po-2 The foam system is a key factor affecting the safety, quality, and efficiency of EPBS during metro tunnelling. Using the shield tunnelling on Hangzhou Metro Line 1 as an example, and in light of the existing problems of the foam system-such as control difficulties, inconvenient maintenance, and complicated and dependent systems-relevant improvements are proposed in this paper aimed at achieving complete control and independence of the system. Excellent performance of the improved foam system were verified by comparing its operability, control precision, failure rate, and economic benefits before and after the improvement. Meanwhile, based on the improved foam system and a field test of its construction parameters during shield tunnelling in a silty soil stratum in Hangzhou, the influence of the foam output on cutter torque and advancing speed was analyzed, showing that the improved foam parameters are appropriate for tunnelling in a silty soil stratum. 2014 Vol. 51 (6): 179-185 [Abstract] ( 1802 ) [HTML 1KB] [ PDF 0KB] ( 515 ) 186 Technical Performance of the SWJ-V Convergence Gauge FAN Rong The SWJ-V convergence gauge, the first PDA-type convergence gauge developed based on the SWJ-IV convergence gauge, is an automatic measuring product developed using wireless PDA and photoelectric control techniques that features automatically controlled loading and automatic reading and recording. This convergence gauge overcomes the defects of inaccurate loading, the inconvenience of manual recording, and the lack of connection between data and the terminal of the existing convergence gauges, thereby achieving PDA recording and rapid measurement with accurate controlling devices. Accuracy assessments show that the certainty of the SWJ-V convergence gauge reaches a premium level regarding building deformation. 2014 Vol. 51 (6): 186-193 [Abstract] ( 1910 ) [HTML 1KB] [ PDF 0KB] ( 478 )

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