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Quick Search     Advanced Search MODERN TUNNELLING TECHNOLOGY   2019 Vol.56 Issue.5 Published 2019-10-25 1 Some Issues during TBM Trial Advance of Super-long Tunnel Group and Development Direction of Construction Technology DENG Mingjiang1 TAN Zhongsheng2 The total length of the water transfer project phase Ⅱ is 540 km in the northern area of Xinjiang Uygur Autonomous Region of China, of which the total length of tunnels is about 516 km. The tunnel boring machine (TBM) and drilling & blasting method were adopted for the tunnel construction, the main tunnels include 18 TBM tunnelling sections and 3 shield tunnelling sections, and the branch tunnels include 2 TBM tunnelling sections. The tunnelling length of single TBM is more than 15 km, and the maximum tunnelling distance is up to 26 km. It poses unprecedented challenges on the tunnel design and construction technique due to the group driving, adverse geology and extreme hard rock, long tunnelling distance by TBM and other construction risks and difficulties. Based on the summary and analysis of the TBM performance in the trial tunnelling, several aspects on the development directions of TBM construction of super-long tunnels were put forward to improve the technical level of safe and efficient TBM tunnelling. Namely, real-time advance geological prediction technique for rapid TBM excavation should be studied;developing of the TBM equipment with better geologic adaptability should be conducted; the intelligent TBM tunnelling technique should be studied; the real-time monitoring technique for TBM equipment state should be studied;the surrounding rock classification and corresponding supporting system should be studied; the auxiliary rock breaking technique should be developed; the one-end high-pressure ventilation technique for the super-long tunnel should be studied; the belt conveyor transportation technique should be developed for the super-long tunnel. By improving performance of TBM equipment and optimizing tunnel design and construction method, the adaptability of TBM equipment to various geological conditions is increased and safe and efficient TBM tunnelling for super-long tunnels is realized. 2019 Vol. 56 (5): 1-12 [Abstract] ( 884 ) [HTML 1KB] [ PDF 5208KB] ( 2499 ) 13 Experimental Study on Creep Characteristics of Anchored Rocks SONG Yongjun CHE Yongxin REN Jianxi ZHANG Kun Support with anchor bolts is one of the main supporting methods in underground engineering. In order to understand the long-term mechanical behavior of anchored rock mass, the standard sandstone specimens were drilled along radial direction and prestress was applied, and the mechanical behavior of rock creepage before and after anchoring was studied by indoor uniaxial compression creepage test. The results show that significant improvement of mechanical behavior of the anchored rock and restrain effect of radial deformation are obtained; after rock anchoring, the average axial transient deformation and radial transient deformation and creep deformation of the rock specimen reduce by 27%, 60% and 14% respectively; in light of the deformation characteristics of the rock specimen, it is to adopt Burgers model to describe the rheological behavior of the two kinds of rock specimen and to analyze the law of parameters changes of the rheological model. 2019 Vol. 56 (5): 13-18 [Abstract] ( 782 ) [HTML 1KB] [ PDF 2167KB] ( 1535 ) 19 Analysis on the Survey Techniques of Shield Tunnels in Sandy Pebble Stratum YAN Gengsheng1,2 HE Xiaoliang1,2 HAN Jinming3 ZHAO Shuang3 ZHAO Cheng1,2 The investigation and evaluation of water-rich and sandy pebble stratum is directly related to the suc? cess and failure of shield tunnel construction, but it is difficult to meet the technical requirements of shield construction in the sandy pebble with conventional survey and evaluation methods. In order to solve the problems of ground settlement due to over-excavation, tunnel collapse, blockage caused by large-size and high-strength pebbles and over-wear of cutterhead and so on, it studied the effect of grain size compositions of sandy pebbles, quantities of boulders, saturated uniaxial compressive strengths and quartz contents of pebbles on selection, design and construction of shield machine, summarized the survey techniques and methods for obtaining relative parameters of sandy pebble stratum, proposed a way of boulder grouping based on evaluation of the shield construction of Lanzhou rail transit in water-rich sandy pebble stratum. As for the shield tunnel passing through sandy pebble stratum, in-situ full particle size analysis should be carried out along the alignment during survey, and statistical analysis should be conducted regarding the contents, sizes and occurrence probabilities of pebbles and boulders at different depths. 2019 Vol. 56 (5): 19-25 [Abstract] ( 764 ) [HTML 1KB] [ PDF 1201KB] ( 1859 ) 26 Correlation Analysis of Q Value and Mechanical Parameters of Surrounding Rocks and Its Engineering Application ZHANG Heng ZHANG Gang SUN Jianchun ZHUYimo CHEN Shougen In order to verify the applicability of surrounding rock classification and support design method based on Q system in large underground caverns, taking Jinzhou large underground oil storage cavern project as an example, the mathematical function relationship among Q value, RMR value and BQ value was established in light of the statistical data of the Q value and geological sketch at the construction site as well as the empirical formula of Q value,furthermore the correlation between Q value and the main mechanical parameters of surrounding rocks was obtained, and the method of rapid obtaining Q value was put forward. The result shows that the Q value is in a logarithmic function with the RMR value with the coefficient of 0.99 and almost the same grade levels of surrounding rocks can be obtained by the two methods; the Q value is linearly related to the BQ value with the coefficient of 0.92; the surrounding rock classification obtained by BQ method is basically the same as that obtained by the two methods mentioned above if the Q value and the RMR value are smaller, while there is a difference of one level for the surrounding rock classification obtained by BQ method if the Q value and the RMR value are larger and the determined classification of surrounding rock is relatively high. The relatively accurate parameter values can be obtained by referencing the proposed corresponding table between common parameters and Q values when the measured values cannot be obtained. 2019 Vol. 56 (5): 26-34 [Abstract] ( 766 ) [HTML 1KB] [ PDF 3694KB] ( 1677 ) 35 A CBR-based Aided Decision Model for the Mountain Railway Tunnel Excavation Method LI Junda1,2 LI Yuanfu1,2 LI Shiqi1,3 LIU Kai1,3 WANG Guangkai1,2 In order to apply the experience of previous cases to decision making of the excavation methods in the Sichuan-Tibet railway tunnel to be built, an aided decision-making model for tunnel excavation method was established by the case-based reasoning (CBR) technology. It quantitatively expressed tunnel cases by several variables and determined the weight of each variable by OWA operator; then grey relational analysis was adopted for retrieval of similar cases and BP neural network was used to take train, furthermore the trained network was used for reasoning of the proposed tunnel schemes and a recommended scheme was obtained. This model was applied in the excavation scheme of Erlangshan tunnel on Sichuan-Tibet railway, which verified its effectiveness. The results show that the model can make full use of previous tunnel cases, a reasonable and feasible excavation scheme can be obtained by reasoning even if there is no detailed or definite information about topography, geology and so on. 2019 Vol. 56 (5): 35-41 [Abstract] ( 775 ) [HTML 1KB] [ PDF 1058KB] ( 1462 ) 42 Study on the Comprehensive Aseismic Measures for the Secondary Lining Structure of Highway Tunnels in Nine-degree Seismic Region WANG Qiuyi1 YANG Kui2 MAO Jinlong2 YANG Qingyuan3 ZHAO Boming3 To provide reference of the seismic countermeasures for the secondary lining structure of highway tunnels in the earthquake area with nine-degree seismic intensity, based on Hilber-Hughes-Taylor′s time integration method and dynamic boundary condition of equivalent viscous-spring element, the following four aseismic measures were proposed from the aspect of designed force, by taking the highway tunnel passing through the area with nine-degree seismic intensity as the background, specifically the four measures include increase of reinforcement of secondary lining,increase of the thickness of secondary lining, optimization of horseshoe section to the round section and addition of rubber absorption layer between the primary support and secondary lining. Through aseismic calculation and analysis, the actual aseismic effect, the advantages and disadvantages of the four countermeasures were understood. To maximize the advantages of the aseismic measures, a combining countermeasure of increase of reinforcement and addition of shock absorption layer between primary support and secondary lining was put forward. Based on the research achievements, the corresponding aseismic measures were proposed in light of the force on secondary lining under the effect of seismic wave with different peak accelerations (0.1g-0.9g）in the area with nine-degree seismic intensity. 2019 Vol. 56 (5): 42-49 [Abstract] ( 758 ) [HTML 1KB] [ PDF 1614KB] ( 1701 ) 50 Design Optimization for the Rapid Excavation of Inclined Shaft of the Long Tunnel and Construction Period Estimation ZHAO Licai1，2 YU Jianxing1 Based on the construction of the Aobaoliang Tunnel, this paper discussed the necessity of scheme opti? mization of inclined shaft before construction. In light of tight construction and low grade of surrounding rocks, the design schemes for the No. 1 and No. 3 inclined shaft were optimized from the following four aspects of designed alignment, section dimension, mucking equipment and support structure, e.g. 1) the single lane was changed to two lanes to solve the problem of vehicle passing in inclined shaft; 2) reinforcement mesh and cast-in place concrete lining were replaced by single-layer steel fiber reinforced concrete lining, and type I18 profile steel was optimized for type 150 lattice girder, so the cost of two-lane excavation and support structure was reduced. The results of toughness test show that the supporting performance of steel fiber reinforced shotcrete (40 kg/m3) is much better than that of reinforcement mesh, so the shotcrete and construction time is shortened. Due to the alignment adjustment, the lengths of main and auxiliary bore were balanced and the construction progress in auxiliary bore was speeded up. The mucking efficiency was improved and the gas emissions were decreased attributed to the design consisting of one electric hydraulic excavator and five dump trucks. Finally the construction period of main tunnel was shortened by 5.5 months and the labor cost of the Aobaoliang tunnel was reduced by RMB ￥15 million after optimization of the inclined shaft scheme. 2019 Vol. 56 (5): 50-57 [Abstract] ( 861 ) [HTML 1KB] [ PDF 2004KB] ( 1720 ) 58 On Influencing Factors of the Tunnel Geological Prediction Results Obtained by Multi-source Seismic Interferometry WANG Xu1 MENG Lu1 YANG Gang2 LU Song1 Multi-source seismic interferometry is a newly developed geophysical prediction method in recent years. The future of this method is promising in the field of tunnel geological prediction since it can directly use seismic waves excited by blasting excavation and TBM cutters to predict the geological conditions in front of tunnel face,the construction won′t be affected and the prediction cost decrease thereof. However it is more difficult for the imaging of geological prediction due to the complexity of actual seismic source and tunnel construction environment. By means of numerical simulation, the theoretical results of multi-source seismic interferometry method for tunnel geological prediction were simulated in condition of TBM and drill-and-blast construction, and the effects of acquisition time, source excitation delay time, distribution of seismic source and receiving points on imaging results were studied. 2019 Vol. 56 (5): 58-66 [Abstract] ( 827 ) [HTML 1KB] [ PDF 5613KB] ( 1647 ) 67 Discussion and Suggestions for Explosion-proof Based Modification of Construction Machinery and Vehicles in the Gas Tunnel TANG Bin XU Wenping As for the explosion-proof purpose, modification of construction machineries and vehicles is one of the key measures to prevent gas explosion in the gas tunnels, but in current codes and specifications the corresponding patterns and technical terms are absent regarding the explosion-proof construction machineries and vehicles in the gas tunnel. Based on the explosion-proof requirements for the vehicle and machinery specified in“Technical Code for Railway Tunnel with Gas”, it analyzed the requirements of explosion-proof grades and technical conditions for the construction equipment and machinery used in coal mine. In light of the modification and application cases of explosion-proof construction machinery and vehicles used in the gas tunnel, a contrastive analysis was conducted in terms of the advantages, disadvantages and adaptability of various explosion-proof modification forms, and the suggestions on explosion-proof modification of construction machinery and vehicles were proposed for the gas tunnel with different gas levels. 2019 Vol. 56 (5): 67-71 [Abstract] ( 812 ) [HTML 1KB] [ PDF 589KB] ( 1926 ) 72 Brief Introduction to Revision of the Segment Section of“Code for Construction and Acceptance of Shield Tunnelling Method” CAI Yaning ZHANG Jinxun WU Fumei This paper introduces the background of the revision of segment section of“Code for Construction and Acceptance of Shield Tunnelling Method: GB50446-2017”，analyzes its hierarchy, presents the main contents and reasons of the revision, summarizes the results of special research on breakthrough the specifications in 2008 edition regarding mould, main reinforcement connection and concrete slump closely related to the manufacturing quality and technique of steel concrete segment, guaranteeing the operability, practicability and advancement of the contents of segment section of the 2017 edition in order to provide guidance for the green, qualified and efficient manufacturing of segment and improve the quality of shield tunnels. 2019 Vol. 56 (5): 72-76 [Abstract] ( 802 ) [HTML 1KB] [ PDF 625KB] ( 1068 ) 77 Effect of Rock Mechanical Parameters on Stability of Tunnel Surrounding Rocks CHEN Xi1 ZHAO Yong2 YANG Yushun3 The effects of mechanical parameters of rock mass on horizontal convergence, crown settlement and fac? tor of plastic zone were studied by an orthogonal numerical simulation test. The 6 factors (elastic modulus, poisson ratio, internal friction angle, tensile strength, cohesion and density) and the orthogonal test program of three level were selected, and the test results were analyzed by ANOVA. The results show that the horizontal convergence is affected by the following factors in a sequence of cohesioin, elastic modulus, internal friction angle, tensile strength and Poisson ratio; the crown settlement is affected by the following factors in a sequence of cohesion, internal friction, elastic modulus, tensile strength and Poisson ratio; the plastic zone is affected by the following factors in a sequence of internal friction angle and cohesion, while the density has little effect on stability of tunnel surrounding rocks; the test results agree with the results from orthogonal test in condition of change of any mechanical parameter of tock mass; a comprehensive consideration should be given to the horizontal convergence, crown settlement and plastic zone after tunnel excavation in view of stability of tunnel surrounding rocks. Reasonable support method was proposed regarding the construction of Sanquan tunnel with the surrounding rock of grade V, and it proves that the surrounding rocks are stable by numerical analysis and site monitoring and measurement. 2019 Vol. 56 (5): 77-84 [Abstract] ( 806 ) [HTML 1KB] [ PDF 3539KB] ( 1601 ) 85 Research on Stratified Thickness Inversion of Roadway Composite Roof LIU Siwei1 YANG Hongyun1,2 PAN Ruikai1 In order to understand the thickness of each layer of the composite roof and to determine the position of hard delamination in the case of only obtaining the monitoring data of roof delamination, a method for inversion of each layer thickness of composite roof was proposed based on the support failure section of N3702 transport lane of the Yuyang coal mine. In light of the monitoring data of roof delamination, the position of delamination void and the amount of delamination were analyzed; the composite roof was simplified as a simply supported beam and its deflection equation was deduced, and the first stratified mudstone layer was inverted combined with the maximum roof subsidence; the remaining delamination thicknesses were reasonably assumed, and each delamination thickness was inversed by combining compound stratification and the actual roof delamination. The field test results show that the hard stratified position determined by each stratification thickness of composite roof inversed by the proposed method can effectively optimize the parameters of roadway support, and the roof subsidence of test section is reduced by 127mm and continuous roof deformation is shortened by nearly 25 days compared with that of original support. 2019 Vol. 56 (5): 85-91 [Abstract] ( 812 ) [HTML 1KB] [ PDF 2139KB] ( 1431 ) 92 The Influential Factors on Instability of Slope during Excavation of a Metro Station Based on Upper Limit Analysis Method LI Fengyun It is liable to cause tensile cracking and settlement at slope during excavation of metro station under the influence of various factors, resulting in adverse effect on slope stability. A calculation equation for safety factor of cracking slope under the effect of overloaded slope top and earthquake was deduced by logarithmic spiral failure mode based on upper limit method, the optimal solutions for safety factors under different parameter combinations were obtained by using MATLAB numerical solution software, and the effect of overloaded slope top on slope stability in condition of different parameters was analyzed. The results show that the safety factors decrease with an increase of overload and the decrease rate of safety factor is relatively large when overload is small; the effect of slope angle, horizontal seismic factor, internal friction angle and cohesion factor on slope stability is significant under certain overload. 2019 Vol. 56 (5): 92-97 [Abstract] ( 866 ) [HTML 1KB] [ PDF 1398KB] ( 1413 ) 98 Study on Rigid and Flexible Compound Disaster Reduction Technology for the Tunnel with High Rock Temperature in Meizoseismal Area CUI Guangyao1 WANG Xuelai1 ZUO Kuixian1 WANG Mingnian2,3 JING Hongfei4 In order to improve seismic safety of the tunnel with high rock temperature in meizoseismal area, this paper studied the rigid and flexible compound disaster reduction technology by finite difference software based on a research of Jiwoxiga tunnel on the Lasa-Rikase railway. And the results show that the damping effect and thermal insulation effect of tunnel structure are 40.91% and 1.4% respectively if only shock absorption layer is laid; the antiseismic effect and heat resistance effect of tunnel structure are 46.39% and 1.9% respectively if only interval injection of surrounding rock is taken and the pressure of surrounding rocks on secondary lining structure is reduced; the anti-seismic and damping effect, heat resistance or isolation effect of tunnel structure are 63.38% and 2.7% respectively if full-ring interval injection of surrounding rock is conducted and shock absorption layer is laid. The disaster reduction effect of the rigid and flexible compound technology is the best. 2019 Vol. 56 (5): 98-103 [Abstract] ( 805 ) [HTML 1KB] [ PDF 2274KB] ( 1323 ) 104 Study on Local Structural Resistance of Ventilation System in Highway Tunnels WANG Xing1 QIN Wei2 MA Jia3 WANG Lei1 In the ventilation system of highway tunnels, there are a large number of structures of local three-way, variable diameter and bending. In order to study the movement pattern of air flow and loss coefficient of local resistance in this context, the software named Fluent was adopted to analyze the cases of three-way structure (oblique confluence, straight and oblique confluence, oblique shunting, straight and oblique shunting), variable diameter structure (sudden enlargement, sudden downsizing, gradual enlargement and gradual downsizing) and curved air duct and so on. The results show that: for the oblique confluence structure, the area ratio of branch and trunk duct A3/A1 and angle θ between the branch and trunk duct have significant influence on loss coefficient ζ of local resistance, but the section form and flow ratio Q1/Q3 of branch and trunk duct have little influence on ζ; for the oblique shunting structure, the angel θ between branch and trunk duct, the area ratio A3/A1 and flow ratio Q1/Q3 have significant influence on loss coefficient ζ of local resistance while the section form has little influence on loss coefficient ζ of local resistance; for the sudden enlargement and downsizing of ventilation duct, the ratio of two different sections has obvious influence on loss coefficient ζ of local resistance, and all the section should be designed as round form; for the curved duct, the loss coefficient ζ of local resistance will decrease with an increase of bending radius r which should not be smaller than the bending diameter D, and the loss coefficient ζ of local resistance will increase with an increase of bending angle γ and the section should be designed as round form. 2019 Vol. 56 (5): 104-113 [Abstract] ( 766 ) [HTML 1KB] [ PDF 4184KB] ( 1570 ) 114 Influence of Air Duct Arrangement on Gas Concentration in the Large-section Gas Tunnel LIU Chun1 DU Junsheng1 GUO Chenye1,2,3 LIU Shang1 In order to optimize the air duct arrangement for the large-section gas tunnel to improve ventilation con? dition at tunnel face, a calculation of required air volume and selection of fan type were conducted by taking the Liangfengya tunnel as an example, then a hydrodynamic analysis model was established by FLUENT software to study the variation laws of gas concentration and air velocity of the large-section tunnel and the effect of air duct arrangement on airflow field and gas distribution in condition of forced ventilation, in consequence the optimal arrangement of air duct was determined. The results show that for the large-section gas tunnel the distributions of gas concentration and air velocity are very uneven in the same section; the influence range of recirculation zone in the large-section gas tunnel is positively related to the distance between air duct and tunnel face; the distance between the place where gas concentration is stable and tunnel face increases with an increase of the distance between air duct and tunnel face; for this tunnel the optimum distance from the outlet of air duct to the tunnel face is about 2.5 S（30 m） and it is 15-20 m longer compared with that of the small-section tunnel, the place where gas concentration is the lowest is around 2 m away from the tunnel face; The gas concentration at the tunnel section shows a tendency of‘decrease-increase-balance?? with an increasing of Ly. 2019 Vol. 56 (5): 114-121 [Abstract] ( 651 ) [HTML 1KB] [ PDF 3478KB] ( 1399 ) 122 Study on the Influence of Approaching Construction of the Trailing Shielddriven Tunnel on the Large-section Mined Tunnel in Argillaceous Siltstone Stratum ZHANG Junru YE Lun YAN Congwen LIU Dingding CUI Yao FENG Jimeng Adjacent construction of more than two tunnels will cause force changes of both existing and new tun? nels, and it′ s necessary to consider optimization issues of construction method, procedure, countermeasures and so on. Based on the construction of the shield-driven tunnel approaching the large-section mined tunnel of Changsha metro line 3, the numerical simulation and model test methods were adopted to study the effect of shield-driven tunnelling on adjacent mined tunnel in argillaceous siltstone stratum, and a concept of influence zoning was proposed in light of the criterion of ground surface settlement. Research results show that increase of corresponding surface settlement and additional displacement of existing mined tunnel are mainly caused during the process of shield driving which starts from 1 time tunnel diameter away from the studied section and finishes at completion of segment erection at the studied section ; in terms of the effect on the mined tunnel, vertical additional deformation is of the main form and it presents as overall tunnel heaving, the closer the existing tunnel structure to the shield-driven tunnel, the greater the influence; regarding the influence on internal force, it is manifested in uneven change of internal force of the existing mined tunnel structure, the existing tunnel structure near the shield-driven tunnel is more compressed and it is liable to occur tensile failure at the side far away from the shield-driven tunnel. 2019 Vol. 56 (5): 122-132 [Abstract] ( 710 ) [HTML 1KB] [ PDF 5227KB] ( 1690 ) 133 Research on Pile Foundation Underpinning Technology for the Shield Tunnel Passing through Bridge Pile Foundation Group CHEN Ziquan WANG Bo WU Di YANG Yi In order to study the stress transfer mechanism of pile foundation during underpinning and the influence of tunnel excavation on pile foundation group, a numerical simulation of pile foundation underpinning and metro tunnel construction was conducted by FLAC3D based on the shield tunnel of Shenzhen metro line 10 passing through the bridge pile foundation of Guangzhou-Shenzhen motorway. The results show that the bridge load system changes from the order of bridge deck→pile foundation-soil to the order of bridge deck→existing pile foundation→underpinning pile→subsoil after underpinning of pile foundation, and the overlying load on underpinned pile is effectively transferred to the new pile; the settlement deformation induced by underpinning and excavation can increase the resistance at pile end and pile friction, so the maximum principal stress of pile foundation is reduced; the settlement of bridge pile foundation is mainly the deformation induced by ground loss and excavation disturbance in the process of shield tunnelling, and the proportion of settlement caused by underpinning of pile foundation is 20%-30% of total settlement; the reduction effects of settlement deformation, lateral displacement and principal stress of pile founda? tion occur at the underpinned pile while there is little change for the non-underpinned pile; deformation of lining structure of shield tunnel mostly occurs at the area near the underpinned area and it is mainly of settlement with small lateral deformation. 2019 Vol. 56 (5): 133-142 [Abstract] ( 665 ) [HTML 1KB] [ PDF 3704KB] ( 1475 ) 142 Study on the Effect of Leakage Water on Chloride Erosion Degradation in the Segment Joint SUN Qi1,2,3 LIU Sijin1,4 Water leakage is more likely to occur at the segment joint of subsea shield tunnel and consequently it will accelerate the erosion and deterioration rate of the lining structure. A numerical model for the seepage erosion of segment joint of the subsea tunnel was established considering the penetration of sea water, erosion of chloride ion and water leakage. The migration law and effect of chloride ion erosion were analyzed under different external water pressures and volumes of water seepage. The results show that water leakage results in change of distribution pattern of seepage field in the adjacent area and increase of pore water pressure; water seepage aggravates the erosion of concrete at the inner side of segment, the larger the external water pressure, the more obvious the increase of deterioration, while the effect of water seepage volume can be ignored; the increase of external water pressure will increase the ion content on the surface of steel bar, reduce the inhomogeneity of ion distribution, and shorten the time to reach the critical ion concentration of steel bar, and the ion content of the steel bar surface increases with an in? crease of water seepage at the same time under small external water pressure; in the case of water seepage, the icon migration moves toward joint surface, the larger the water seepage, the more concentrating of moving track of icon. 2019 Vol. 56 (5): 142-149 [Abstract] ( 613 ) [HTML 1KB] [ PDF 5523KB] ( 1518 ) 150 Numerical Analysis of Controlled Blasting Effect of the Spheroidal Weathered Granite Body in Shield Tunnelling ZHU Siran1 SUN Li2 It is challenging for shield tunnel construction when spheroidal weathered granite body is encountered, and controlled blasting could be adopted as a pretreatment measure. In this paper a numerical simulation calculation was conducted by FEM ANSYS regarding controlled blasting of the spheroidal granite weathered body, the blast vibration and rock breaking effect were analyzed. The results show that the vibration velocity of the ground right above explosive is 0.35 cm/s after blast treatment, meeting the requirement of the specification of blast construction;good rock breaking effect is obtained for the spheroidal weathered granite body under the effect of blasting, and the max. size of the broken rock is 6.71 cm, meeting the mucking requirement for shield driving. 2019 Vol. 56 (5): 150-156 [Abstract] ( 632 ) [HTML 1KB] [ PDF 3611KB] ( 1333 ) 157 Study on the Design and Construction Method for the Large-span Highway Tunnel with Small Interval LI Jianlin WU Jingang BI Qiang In order to determine the design parameters and corresponding construction method of the small-inter? val tunnel, the deformation and mechanical behaviors were obtained by a simulation analysis of construction of the small-interval section excavated by bench method, CD method and CRD method in the surrounding rock of grade Ⅳ by FEM software based on the construction of the small-interval section at north side of the Baiyanggou tunnel on the Xingyan expressway. The monitoring results show that it is reasonable for this section of small-interval tunnel to be constructed by bench method in the surrounding rock of grade Ⅳ and it is effective for the safe and smooth construction of the small-interval section by reinforcement of the rock pillar between the two tunnel tubes with a combination of pre-stressed long anchor bolts and advance ductule injection. 2019 Vol. 56 (5): 157-162 [Abstract] ( 587 ) [HTML 1KB] [ PDF 4599KB] ( 1495 ) 163 Mechanism and Application of Tunnel Full-face Pre-reinforcement Technology with Glass Fiber Anchor Bolts XIAO Hongwu Stress redistribution of surrounding rocks is a 3D process during tunnel excavation, the deformation re? sponse of the“advance core”in front of working face is closely related to cavern convergence, and the possibility of natural arching of surrounding rock after excavation is very much dependent on the lithology of“advance core”. So as the full-face pre-reinforcement measure, the glass fiber anchor bolts are commonly installed at tunnel working face for the fractured and soft rock mass in which natural arching is impossible. Through simulation analysis of fullface pre-reinforcement by glass fiber anchor bolts in different cases, the deformation law of working face varying with excavation process and the displacement index showing the effect of full-face pre-reinforcement were obtained. Based on the railway tunnel project in typical soft surrounding rocks and various kinds of cases, the optimized design parameters and construction schemes were proposed. 2019 Vol. 56 (5): 163-169 [Abstract] ( 702 ) [HTML 1KB] [ PDF 3458KB] ( 1775 ) 170 Field Monitoring and Analysis of In-situ Tunnel Extension by Three-bench Method ZHONG Yuanqing In order to study the effect law of three-bench construction method on extended tunnel structure and ad? jacent existing tunnel, site monitoring of stress of surrounding rocks and support structure, loosening circle and stress field as well as blast vibration of existing tunnel was conducted based on the extension project of the Houci tunnel on Xiamen-Chengdu expressway in Fujian province. The results show that stress of the rock mass and support structure increases gradually with the time and tends to be stable at last, each bench excavation will cause disturbance and it is represented as sudden increase of stress; after tunnel extension the loosening circle of surrounding rocks at the vault is 6-9 m deep, the loosening circle at the left and right sidewall is 0-6m deep, and the crown settlement is larger than the convergence at the two shoulders, the stress of surrounding rocks of the left sidewall is larger than that of the right sidewall, the stress of surrounding rocks at the depth of 3 m around tunnel is smaller than that at the depth of 6 m, and the excavation induced plastic zone is around 3 m; the actual blast vibration velocity is mostly smaller than the one specified by the designed standard, blasting didn′t cause serious damage to the support structure system of existing tunnel, the max. blast vibration velocity occurs at the place 10 m ahead of the monitoring section and it increases by 2.9%-4.5% compared with that at working face, the better the quality of rock mass, the larger the peak vibration velocity, the attenuation rate of vibration velocity in front of the section with the max. peak vibration velocity is far less smaller than that at the rear. 2019 Vol. 56 (5): 170-179 [Abstract] ( 635 ) [HTML 1KB] [ PDF 4909KB] ( 1560 ) 180 Analysis on the Characteristics of Ground Surface Settlement Caused by EPB Shield Tunnelling in Fuzhou Soft Ground ZHONG Junhui1,2 YIN Peilin1,2 LIU Jun1,2 Based on a EPB shield running tunnel of Fuzhou metro line 2 in soft ground, it summarized the charac? teristics of ground settlement by analyzing the monitoring data and driving parameters during shield construction,and proposed the parameters of modified hyperbolic model for predicting ground settlement with consideration of the measured settlements. The analysis results indicate that the settlements caused by ground loss and consolidation during EPB shield construction in soft ground as well as the long-term horizontal settlements in transverse direction conform to the results by Peck equation; the affected scope during shield driving is 3D-5D ahead of the cutterhead and it results in small amount of heaving(settlement); the ground settlements are mainly the ground loss induced settlement and consolidation settlement of disturbed soil mass within 3-5 d after passing shield tail, with the percentages of 65% and 32% of the total settlement respectively in the course of measuring, and actually the percentage of final consolidation settlement is larger; the modified hyperbolic model can be used to predict ground settlements at central axis caused by EPB shield driving in soft ground of Fuzhou, and the ranges of parameter values of a, b, c are -0.14~0.67 mm/d, -0.028~0.042 mm-1 and -0.89~7.67 mm respectively. 2019 Vol. 56 (5): 180-186 [Abstract] ( 684 ) [HTML 1KB] [ PDF 2666KB] ( 1563 ) 187 Characteristics of Roof Caving and Rock Falling of the Dege Tunnel and Corresponding Treatment Measures YAN Jian1,2 HE Chuan1 LU Daiyue1 LEI Deming2 Roof caving and rock falling occurred during the construction of Dege tunnel on the Sichuan-Tibet high? way. The characteristics of displacement and stress of surrounding rock and support were studied by numerical simulation and site test, a thorough analysis was carried out regarding the features and mechanism of roof caving and rock falling occurred at the same tunnel, and some corresponding treatment measures were proposed. The research results show that roof caving was represented by debris flow and rock falling was represented by cracked deformation; plastic zone of crushed stone occurs at tunnel crown in the course of roof caving and dilatancy occurs due to the difference of vertical stress and horizontal stress in the course of rock falling; roof caving is caused by construction disturbance due to poor self-stability of shallow-buried crushed rock mass and rock falling is induced by dead load of rock mass and blasting construction attributed to developed fissure of deep-buried sericite quartz schist. The main corresponding measures include restriction of plastic deformation and cracking development, installation of anchoring and injection support system, implementation of forced composite support and strengthening of the support parameters. 2019 Vol. 56 (5): 187-194 [Abstract] ( 608 ) [HTML 1KB] [ PDF 3457KB] ( 1533 ) 195 An Intelligent Device for Coring at Tunnel Vault and Corresponding Coring Hole Repairing Technology TAN Wen1 GONG Chengming2 SHE Hailong3 GENG Chunlei3 Because of the special position of tunnel vault, conventional water drill can′ t safely and effectively carry out coring. An intelligent device for coring at tunnel vault was developed, which eliminates the risks of motor burning and electric leakage caused by cooling water reflux. The device can intelligently identify the position of waterproof board to avoid the risk of breaking of waterproof board; in the process of coring, the compactness, strength and homogeneity of lining concrete are predicted based on the changes of coring speed and electric current of drilling rig;through coring, the thickness and void depth of lining at tunnel vault can be detected. Finally a kind of core hole repairing technology was proposed. 2019 Vol. 56 (5): 195-200 [Abstract] ( 578 ) [HTML 1KB] [ PDF 3057KB] ( 1445 ) 201 Application of Non-Curing Rubber Asphalt Coating in Waterproofing of Shield Tunnel Segment Joints in Water-rich Stratum ZHU Kaofei1,2 HE Xiangdong1,2 QUAN Yonghua3 ZHONG Wenjing3 ZHANG Keneng1,2 The waterproof effect of shield tunnel segment joints affects the construction and operation quality and safety of tunnels in the water-rich stratum, and it can′ t meet the waterproof requirements of segment joints by the conventional measures. Based on an investigation and analysis of the composition, non-curing performance and waterproof mechanism of the non-curing rubber asphalt coating, a composite waterproofing technology combining noncuring rubber asphalt coating with rubber gasket for the joints of shield tunnel segments was proposed and applied in a test section of the shield tunnel of Changsha metro underneath the Liuyang River. A statistic was conducted regarding the water leakage of both the left and right tunnel tube after shield driving beneath the Liuyang River. The test results show that this composite waterproof technology for the joints of shield tunnel segments can effectively reduce the rate of water leakage. 2019 Vol. 56 (5): 201-205 [Abstract] ( 535 ) [HTML 1KB] [ PDF 1320KB] ( 1644 ) 206 Study on Key Technology of Embedded-channel for the Segment of Shield Tunnels LI Jihong1 JIN Shihe1 LIANG Qingguo2 YAN Songhong2 In order to determine the key parameters of optimal section dimension, channel material, material of ero? sion-resistant coating and insulation layer and etc., the performance indexes of anti-fatigue, fire-resistance, insulation and erosion-resistance were proposed based on the theoretical research and engineering application of the embedded channel for the shield tunnel segment of Lanzhou metro, and the key techniques of section dimension of the segment embedded channel, main channel body and erosion-resistance coating were studied. The results show that it is optimal to have the embedded channel with the section dimensions of 30 mm×20 mm both in terms of mechanical behavior and cost; it is scientific and reasonable regarding the parameters of material for main channel body and erosion resistance of the embedded channel for the segment of shield tunnel of Lanzhou metro; this research provides a foundation of establishing relative national standards and technical basis for the design, production and installation of embedded channel of similar projects. 2019 Vol. 56 (5): 206-210 [Abstract] ( 655 ) [HTML 1KB] [ PDF 1505KB] ( 1651 ) 211 Study on Material Performance of Steel Fiber Reinforced Concrete Segments for Subway Shield Tunnels in Marine Stratum ZHENG Aiyuan1 XU Bin2 CHEN Xiangsheng1 The structural performance will be improved if certain amount of short steel fibers are added into the or? dinary concrete. The steel fiber reinforced concrete has been applied in the above-ground structure but there is no application case in metro shield tunnels in marine stratum by the sea, so the relevant technical indexes and design parameters should be further studied and perfected. Based on the Xilihu-Xili running tunnel of Shenzhen metro, a study on steel fiber reinforced concrete segment of metro shield tunnel in marine stratum was conducted by laboratory test, and the results show that: 1) various kinds of strengths of concrete are improved attributed to steel fibers; 2)it is significant to have reasonable steel fiber length and reasonable proportion of course aggregates with maximum grain size to improve the flexural strength of concrete segment; 3) sand ratio change has significant effect on workability of mixture; 4) the proportion of steel fibers should be reasonable; 5) the micro-crack of fiber reinforced concrete is reduced, the pore structure is improved and the permeability of segment is improved thanks to steel fibers. 2019 Vol. 56 (5): 211-217 [Abstract] ( 602 ) [HTML 1KB] [ PDF 1387KB] ( 1583 ) 218 Experimental Study on Red Clay Conditioning for EPB Shield Tunnelling CAI Binghua1 LI Zhongchao1 YU Shoulong1 LV Bingquan2 WANG Fangyan2 Red clay is a kind of special soil which has the characteristics of high liquid plastic limit, high cohesive force, high clay mineral content, complex microstructure and so on. Mud cake at cutterhead, blocking in earth chamber and poor soil mucking are often encountered during the shield construction in red clay. Based on the EPB shield adopted in a newly built high-voltage cable tunnel on the Xiongchu avenue passing through red clay, a modified additive compounded with anionic surfactant A, nonionic surfactant B and bond-resistance additive C was developed,and the effect of soil mass conditioning was evaluated by performance test, mixing test, slump test, consistency test and liquid-plastic limit combination test, the ideal parameters for conditioning of soil mass are water content of 40%and 30% of additive injection rate. Contrast test indicates that good effect of red clay conditioning was obtained with this modified additive. The mechanism of red clay conditioning by additive was analyzed, and it is found that radical reasons for mud cake generated during shield construction are the red clay which is liable to have argillization and expansion upon meeting water and has strong glutinousness. 2019 Vol. 56 (5): 218-227 [Abstract] ( 715 ) [HTML 1KB] [ PDF 2954KB] ( 1410 )

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