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Quick Search     Advanced Search MODERN TUNNELLING TECHNOLOGY   2025 Vol.62 Issue.2 Published 2025-04-25 1 Review and Prospect of the Mining Construction Methods for Subway Stations in China SONG Zhanping1,2,3 LI Xueli1 ZHANG Yuwei1,2,3 ZHONG Shiming1 SHI Wei4 In order to understand the development of mining construction methods for subway stations in China, a literature database on mining construction of subway stations was established, and VOS viewer software was used to visually analyze literatures from 2000 to 2023, summarizing research topics and evolution trends. The current research and application status of various mining construction methods were summarized, with a focus on key construction processes that may lead to "surface settlement." The targeted construction measures adopted were also sorted out. Finally, a prospect for the minging construction methods of subway stations was provided, suggesting that refined design, green construction, and intelligent construction will be the key research focus and development direction in the future. 2025 Vol. 62 (2): 1-15 [Abstract] ( 63 ) [HTML 1KB] [ PDF 9161KB] ( 204 ) 16 A Review of Researches on the Multi-disaster Scenarios and Structural Responses in Metro Shield Tunnels YU Tongsheng1,2 GUAN Linxing3 YAN Zhiguo1,2 Metro shield tunnels face complex multi-disaster scenarios throughout their life cycle, mainly including the interaction of structural damage (such as material degradation and cracking) with sudden disasters (such as earthquakes, fires, and explosions). Currently, research on the structural response and failure mechanisms under these influences is still in its infancy. In this context, this paper provides a systematic review of the current researches on key issues involved in the structural response analysis of tunnels under multi-disaster scenarios. First, the definition and classification of multi-disaster scenarios are clarified based on the literature review, distinguishing between short-term sudden disasters and the broader concept of multi-disasters over the entire life cycle. Secondly, the structural response characteristics and current research status under multi-disaster scenarios are detailed at three levels: materials, components, and systems. This includes the development of concrete elasto-plastic damage constitutive models, the mechanical performance of segment joints under multi-disaster loads, and disaster response analysis at the system scale. Finally, based on the above researches, the paper proposes the following suggestions for tunnel structural research under multi-disaster scenarios: (1) further development of joint probability models for disaster chain load characteristics and determination of load values; (2) optimization of the concrete elasto-plastic damage constitutive model under multi-disaster paths; (3) study of joint response characteristics under multi-disaster scenarios through scaled and full-scale tests, and optimization of numerical simulation methods based on experimental data; (4) integration of research results from materials and components to conduct system-level random disaster response analysis and establish a framework for the quantitative risk assessment of tunnel structures under under multi-disaster scenarios. 2025 Vol. 62 (2): 16-26 [Abstract] ( 101 ) [HTML 1KB] [ PDF 2677KB] ( 173 ) 27 Hotspot Identification and Development Trend Analysis of Tunnel Intelligent Construction Technology Based on Patent Data YIN Jing YI Yongqiang DU Youde WANG Wei LUO Gan In order to explore the current research and development status of tunnel intelligent construction technology and accelerate its innovation, this paper adopts a multi-dimensional patent technology hotspot identification method based on the BERTopic topic model to analyze the research and development trends of global patents related to tunnel intelligent construction technology. An innovative two-dimensional technical topic analysis of "professional technology-information technology" is applied. The study analyzes the research hotspots of tunnel intelligent construction technology based on patents in the field, and analyzes the overall technology-effectiveness layout of global tunnel intelligent construction-related patents in conjunction with the patent technology-effectiveness matrix. The research identifies current technical hotspots and gaps in the field of tunnel intelligent construction, clarifying the future de? velopment trends of tunnel intelligent construction technology. It also provides suggestions for the development of tunnel intelligent construction technology in China. The results indicate that there is still significant room for development in areas such as surrounding rock determination, auxiliary equipment, anchor bolt drilling, operational management, and tunnel blasting in China. There is a need to accelerate the research and development of related key technologies and optimize the corresponding patent layout. 2025 Vol. 62 (2): 27-38 [Abstract] ( 63 ) [HTML 1KB] [ PDF 6569KB] ( 149 ) 39 Analysis of the Correlation between the Slip Line Net and the Shear Strength Reduction Path of Surrounding Rocks in Circular Tunnels XIE Yongli1 LU Zhejin1 YANG Feng2 PENG Qi1 LIU Shifa2 When the shear strength (c0, tan?0) of tunnel surrounding rock is reduced non-proportionally to the limit, there are countless possible critical instability failure states. Therefore, the strength reduction shortest path theory is introduced, and the upper bound method with rigid translatory moving elements (UB-RTME) is applied. Using mesh updating, inheritance strategy, and nonlinear programming computation, the critical unit weight γcr is solved incrementally to approach the actual unit weight γ0. This enables the non-proportional strength reduction analysis of circular tunnel surrounding rock. The results indicate: (1) The proportional reduction results from the UB-RTME match well with those calculated by the Optum G2 software, confirming the reasonableness of the surrounding rock slip line net failure mode; (2) Different strength reduction ratios ξ and reduction paths L can invert the ultimate state strength parameters (cs, tan?s), the comprehensive safety factor Fs, and their corresponding surrounding rock slip line net. As the reduction ratio ξ increases, the safety factor Fs and reduction path L first decrease and then increase,and the corresponding slip line net′s main failure surface shrinks inward, intensifying the dislocation effect between the rigid blocks representing failure characteristics; (3) The slip line net corresponding to different ultimate state points（cs/c0, tan?s/tan?0) has the same internal dissipated energy and resistance to failure effects. The ultimate line can distinguish the failure domain from the safety domain, but cannot identify the most unfavorable instability failure state of the surrounding rock according to the upper bound theorem; (4) The strength reduction shortest path theory shows that there is always a shortest reduction path Lmin in the limit state lines, corresponding to the minimum comprehensive safety factor Fs, min and the most unfavorable instability fai. 2025 Vol. 62 (2): 39-48 [Abstract] ( 56 ) [HTML 1KB] [ PDF 7239KB] ( 155 ) 49 Study on the Distribution Law of Geotress Field and Classification of Disaster Prediction in Super Long and Deep-buried Highway Tunnels YUAN Quanyou1 CHEN Ziquan1 YUAN Song1,2 WANG Xibao2 JIANG Changwei1 To investigate the characteristics of the geostress field along the axis of the Longmenshan super-long deep-buried tunnel, a 3D geological model was established using ABAQUS based on engineering geological survey and hydraulic fracturing test data. The nonlinear inversion of the geostress field was performed using the Bayesian regularized neural network, analyzing the impact of active fault zones on the geostress field, and comparing the results with traditional multiple linear regression methods. The results indicate: (1) The principal stress increases approximately linearly with the buried depth, with horizontal tectonic stress dominating( ), and the principal stress along the tunnel route exceeds 20 MPa, with local peaks reaching 64.5 MPa; (2) The geostress value in hard rock sections is very high, indicating a moderate risk of rock bursts; in soft rock sections, the risk of large deformation is significant, and local stress differences lead to the instability of surrounding rock; (3) In the fault zone, the variation rane of geostress is large, the azimuth angle shows deviation, and the surrounding strata exhibit stress relaxation and stress concentration in valleys. 2025 Vol. 62 (2): 49-59 [Abstract] ( 53 ) [HTML 1KB] [ PDF 5615KB] ( 174 ) 60 Analysis of the Load Bearing Mechanism and Mechanical Properties of the Advanced Pipe Roof and Discussion on Its Engineering Application YAO Zhixiong1，2 HE Jiawei1 ZHENG Guowen3 ZHOU Qichuang1 SHI Linxin1 GAO Xiaoming4 YANG Yawei4 To understand the load bearing and deformation characteristics of the pipe roof and optimize the support scheme, ensuring the safe construction of tunnels in poor geological conditions, this paper discusses the role of advanced pipe roof in terms of support mechanisms, environmental influence, and spatial constraint effects. The segmented load bearing characteristics of the pipe roof are revealed. Based on the Pasternak elastic foundation beam theory, a mechanical analysis model for the entire construction process of the pipe roof is established. An analysis of the mechanical characteristics and parameter influences of the pipe roof is conducted using a large-span tunnel project in Fujian as a case study. The results show that grouting to improve the foundation reaction coefficient of rock and soil mass can reduce the deformation of the pipe roof. Increasing excavation round length will cause the pipe roof deformation to increase non-linearly. The pipe roof's diameter, wall thickness, and spacing are significant factors affecting its deformation. The influence of each parameter on pipe roof deformation, from smallest to largest,is as follows: excavation round length, foundation reaction coefficient, pipe roof diameter, spacing, and wall thickness. The optimized design of the pipe roof should consider the compatibility of different parameters, their couplling effects on deformation control, and environmental impact effects. 2025 Vol. 62 (2): 60-70 [Abstract] ( 53 ) [HTML 1KB] [ PDF 3963KB] ( 164 ) 71 Theoretical Innovation, Method Implementation, and Engineering Verification of Shield Machine with Thrust Vector Intelligent Control ZHU Yeting1,2 ZHU Yanfei1 WANG Zhihua1,3 WANG Shuaifeng4 WANG Hao1 MA Zhigang1 In order to address the practical issue of unstable tunnel axis quality caused by manual control of the shield machine, the motion mechanism of the shield machine under the dual vector effects of load and thrust is analyzed.A method for autonomous control of the shield machine's posture based on thrust vector technology is proposed, and schemes for autonomous planning of shield motion path and intelligent control of thrust vector are presented. This method is applied to large-diameter shield tunnelling. The practice demonstrates that the target thrust of the shield machine maintains a fixed deviation from the actual value, and the shield machine's excavation speed remains stable. The effective execution of the target thrust torque enables accurate steering control in both the horizontal and elevation directions, and the shield machine's actual posture gradually approaches the set target. 2025 Vol. 62 (2): 71-78 [Abstract] ( 102 ) [HTML 1KB] [ PDF 5746KB] ( 130 ) 79 Force Analysis and Numerical Calculation Platform for Anti Back-sliding Device of TBM in Inclined Shafts JIA Lianhui1 ZHENG Wentao2 LU Yiqiang1 HE Fei1 SHANGGUAN Linjian2 ZHANG Yuxiang1 The inclined shaft section of a pumped-storage hydropower station has a relatively large slope, and the risk of sliding for Tunnel Boring Machines (TBM) during construction is high. Based on this, a double anti backsliding (ABS) device is taken as the research object. First, the mutual cooperation of various devices under different working modes of the inclined shaft TBM is analyzed, and the mathematical model for the pressing force required for the ABS gripper is established. Second, based on mechanical theory and ADAMS simulation, the structural force analysis of the ABS device is conducted, leading to the conclusion that the hydraulic cylinder's required thrust is highly sensitive to the piston rod extension length. Finally, a numerical calculation platform for the ABS device is developed based on the MATLAB App module, aiming to assist researchers in understanding the pressing force required for the ABS gripper and the thrust that the hydraulic cylinder needs to provide. 2025 Vol. 62 (2): 79-86 [Abstract] ( 43 ) [HTML 1KB] [ PDF 5021KB] ( 135 ) 87 Research on Construction and Application of a Rapid Tunnel Surrounding Rock Classification Model Based on Real-time Images and Advanced Geological Information ZHANG Meining1,2 SONG Zhanping1,2,3 YUE Bo4 LI Xu1,2,3 ZHAO Yirui2 TAO Lei5 To accurately determine the surrounding rock grade of a tunnel, it is essential to conduct real-time, rapid, and objective evaluations of the tunnel excavation face and perform proactive rock mass risk assessments. Based on the Jianhe-Liping Expressway project in Guizhou, a rapid classification system for surrounding rock is established using basic rock mass quality indicators. During construction, image recognition, target detection, and image threshold segmentation technologies are used to quickly capture the joint information and weathering degree of the tunnel excavation face. Combined with seismic wave velocity and waveform diagrams from advanced geological prediction,surrounding rock parameters, rock integrity, and the development of joints and fractures are obtained. A Mamdani fuzzy inference system (FIS) is introduced, with both qualitative descriptions and quantitative parameters of surrounding rock as inputs to the evaluation information. This system is used to build a rapid real-time dynamic classification model for surrounding rock during the construction phase. The study shows that the model can integrate realtime tunnel excavation face images and advanced geological prediction data to monitor the surrounding rock condition at the tunnel excavation face in real-time, quickly responding to geological changes. The model classification results can provide a basis for adjusting construction strategies in a timely manner. 2025 Vol. 62 (2): 87-97 [Abstract] ( 104 ) [HTML 1KB] [ PDF 7033KB] ( 139 ) 98 GAPSO-LightGBM-based Intelligent Prediction Method of Surrounding Rock Grade in TBM Tunnelling ZHANG Huan1, 2 ZHANG Shishu3 LI Tianbin1, 2 YANG Gang1, 2 LI Shisen1, 2 XIAO Huabo3 CHEN Weidong3 The tunnel boring machine (TBM) excavation parameters are sensitive to changes in geological condi? tions. Accurately and real-time identifying the quality grade of tunnel surrounding rocks is crucial for efficient tunnelling and geological hazard prevention. To address this, pre-processing is performed on TBM excavation parameter data to obtain a high-quality database. Selected the LightGBM as the basic model, a surrounding rock grade prediction model based on GAPSO-LightGBM is constructed by introducing the GAPSO optimization algorithm for hyperparameter tuning. The model's performance is compared with PSO-LightGBM, GA-LightGBM, LightGBM, XGBoost, and Random Forest models. The results show that the GAPSO-LightGBM-based surrounding rock grade prediction model outperforms the traditional models. For the prediction of grades Ⅱ, Ⅲ, and Ⅳ surrounding rocks, the F1 scores are 0.849, 0.871, and 0.893, with an accuracy of 87.5%. The field validation demonstrate that this method can effectively predict the changes in surrounding rock quality grades and provide reference for practical engineering. 2025 Vol. 62 (2): 98-109 [Abstract] ( 62 ) [HTML 1KB] [ PDF 7516KB] ( 143 ) 110 Research on the Inversion Model of the Ground Load on Ultra-large Diameter Shield Tunnels Based on TL-GA-BP Algorithm ZENG Shiqi1,2 CHEN Xiangsheng1,2,3,4 TAN Yijun1,2 LIU Pingwei2 SU Dong1,2,3,4 The ground load acting on the structure is crucial for the design of ultra-large diameter shield tunnels. Taking the Zhuhai Mangzhou Tunnel project as the basis, a load inversion model is established using the GA-BP algorithm based on accurate measured values of lining axial force and bending moment for the shore crossing section.The model uses measured segment internal forces as input and vertical soil pressure on the segment as output. For the underwater crossing section, the GA-BP inversion model is optimized using transfer learning to realize the inversion analysis of vertical soil pressure and lateral pressure coefficient. The results show that for the uniform stratum of the shore crossing section, the relative error between the inverted vertical soil pressure from the GA-BP neural network model and the field measurement is small, indicating that the GA-BP neural network is feasible for the inversion of vertical load on ultra-large diameter shield tunnels. For the complex strata in the underwater crossing section, the GA-BP inversion model optimized by transfer learning can reasonably invert the values of vertical soil pressure and lateral pressure coefficient, demonstrating that the improved TL-GA-BP algorithm is reliable and practical. 2025 Vol. 62 (2): 110-120 [Abstract] ( 70 ) [HTML 1KB] [ PDF 6750KB] ( 135 ) 121 Interval Prediction of TBM Parameters in Stable Excavation Sections Based on Bootstrap-COA-BiGRU Model ZHANG Guang1 GONG Qiuming1 XIE Xingfei1 PEI Chengyuan2 SHANG Ceng2 Existing TBM parameter point prediction models for stable excavation sections ignore the uncertainty errors during the prediction process and fail to describe the confidence level of the prediction results. This paper proposes a TBM parameter interval prediction model for stable excavation sections based on the Bootstrap-COA-BiGRU algorithm. First, the COA algorithm is used to optimize the hyperparameters of the BiGRU neural network, allowing the model to better autonomously learn the complex nonlinear relationship of the rock-machine interaction in the time and feature dimensions of the TBM data in ascending phase , effectively improving the model's prediction accuracy.Secondly, by analyzing the results of point prediction models, the interval prediction method is introduced to quantify the uncertainty of the model and random uncertainty in the data, obtaining high-quality parameter prediction intervals in TBM stable excavation phase. Finally, the proposed model is applied to the Xinjiang YEGS project for interval prediction of TBM parameters under class Ⅱ~Ⅳ surrounding rock conditions, and the results are compared with BP, GRU, BiGRU, and COA-GRU models to verify the superiority and practicality of the proposed model, promoting the development of TBM intelligent construction. 2025 Vol. 62 (2): 121-131 [Abstract] ( 60 ) [HTML 1KB] [ PDF 6563KB] ( 152 ) 132 Study on Grouped Prediction of Shield Posture Based on EMD-GRU Model with Fixed Component Number WANG Heng1 HU Jinjian2 SUN Chengguo1 ZHANG Jian2 LIANG Yu3,4 FENG Tugen2 Excessive shield posture deviations can severely compromise the safety of shield construction and project quality. To accurately predict shield posture deviations and provide decision support for early correction, a machine learning algorithm combining Empirical Mode Decomposition (EMD) with fixed component number and Gate Recurrent Unit (GRU) is proposed for grouped prediction of shield posture deviations in different directions. The results show that EMD can decompose irregular shield posture deviation signals into several regular components, and GRU can extract temporal dependencies in the input data, enabling precise prediction of shield posture deviations in different directions. Using a fixed number of EMD decomposition components and grouped prediction method ensures the independence of the prediction and training sets. After comparison with other models, the EMD-GRU model proved to be the optimal model. The analysis of the effects of different input parameter combinations on prediction results verifies the interdependence of posture deviations in the same direction (horizontal or vertical). 2025 Vol. 62 (2): 132-140 [Abstract] ( 59 ) [HTML 1KB] [ PDF 5379KB] ( 127 ) 141 Study on the Influence Factors of Additional Earth Pressure Caused by Shield Attitude Deviation in Soft Soil Strata XIAO Mingqing1 FENG Kun2 XUE Guangqiao1 WANG Yunchao2 LU Zhipeng1 CHEN Long2 During shield tunnel construction, the shield attitude often deviates from the designed axis, leading to changes in tunnel loads. In view of this, a parametric analysis is conducted to study the variation law of additional earth pressure in tunnels under different geological conditions, tunnel burial depths, attitude deviations, and tunnel diameters. And it investigates the influence of various factors on the variation of additional earth pressure. The results indicate that any angle of shield deviation will cause an increase in earth pressure on the side of the deviation and a decrease in the earth pressure on the opposite side. The variation of additional earth pressure caused by shield attitude deviation is more significant in sandy soil layers than in clay soil layers. When the shield body deviation angle is -90°, 0°, and 90°, the impact on additional earth pressure in sandy soil is 199.47%, 636.08%, and 162.04%,respectively, compared to clay soil layers. As the parameter values increase, the influence of tunnel burial depth and diameter on additional earth pressure decreases, while the influence of shield attitude deviation on additional earth pressure increases. The sensitivity of additional earth pressure to changes in tunnel burial depth and diameter gradually decreases, while the sensitivity to attitude deviation remains essentially unchanged. 2025 Vol. 62 (2): 141-150 [Abstract] ( 107 ) [HTML 1KB] [ PDF 7543KB] ( 153 ) 151 Study on TBM Jamming Problems in Jurassic and Cretaceous Argillaceous Sandstone Strata in Northern Xinjiang DONG Weijie1 ZHANG Siyang1 LI Bochang2 JIANG Yao1 CHEN Xu1 ZHENG Xiangle2 CHEN Sipan2 WU Di1 In order to study the TBM jamming issues in the Jurassic and Cretaceous argillaceous sandstone strata in northern Xinjiang, rock mechanical and rheological tests were conducted to obtain relevant physical and mechanical parameters, followed by numerical calculations regarding TBM construction. The results show that the strength, elastic modulus, and internal friction angle of Jurassic argillaceous sandstone are significantly higher than those of Cretaceous argillaceous sandstone, while their Poisson's ratio and cohesion values are similar. Under sustained loading,the strength of Jurassic argillaceous sandstone decreases significantly over time, and the deformation gradually increases. After TBM shutdown, the frictional resistance on the shield shell will experience a process of slow growth,rapid growth, and eventual stabilization. Compared to Jurassic argillaceous sandstone, TBM shutdown in Cretaceous argillaceous sandstone occurs earlier, with the shield-rock contact time and jamming accidents happening sooner.The creep characteristics of Cretaceous argillaceous sandstone are more pronounced than those of Jurassic argillaceous sandstone. After TBM shutdown, the longer the shield shell, the greater the frictional resistance, and the greater the over-excavation, the smaller the frictional resistance. Based on numerical results, the minimum design values for the rated thrust of TBM to prevent jamming and the safe shutdown time under different working conditions are derived. 2025 Vol. 62 (2): 151-161 [Abstract] ( 63 ) [HTML 1KB] [ PDF 5231KB] ( 145 ) 162 Numerical Simulation Study on the Load Bearing Performance of Segment-steel-concrete Composite Beams under Prestress CHEN Weijie1 FU Zeng2 ZHU Taifeng1 YU Changyi2 SU Dong1,3 WANG Quansheng2 This study addresses the synergistic force issue of segment-steel-concrete composite beams (SSC com? posite beams) in metro station structures built by the large-section mechanical construction method. A three-dimensional refined numerical model of the SSC composite beam is established to investigate the effect of prestress on the load-bearing performance of the SSC composite beam. The accuracy of the numerical model is verified through experimental tests on SSC composite beams, followed by an analysis of the influence of prestress magnitude, steel strand cross-sectional area, and steel strand position on the load-bearing performance. The results indicate that the contribution of the steel strand connected between the segments to the ultimate load-bearing capacity of the SSC composite beam varies significantly under different loading conditions. Under negative bending moment conditions(where segments are in the tension zone), the ultimate load-bearing capacity increases by 47.2%, while under positive bending moment conditions (where segments are in the compression zone), it only increases by 3.3%. Under positive bending moment conditions, the effects of prestress magnitude, steel strand cross-sectional area, and steel strand position on the load-bearing performance of the SSC composite beam are relatively small. However, under negative bending moment conditions, adjusting the prestress magnitude, steel strand cross-sectional area, and steel strand position can optimize the load-bearing performance of the SSC composite beam, effectively enhancing its stiffness against deformation and load-bearing capacity. 2025 Vol. 62 (2): 162-171 [Abstract] ( 55 ) [HTML 1KB] [ PDF 7550KB] ( 148 ) 172 Influence of Shield Cutter Layered Configuration and Cutting Parameters on the Fracture Mechanism of Hollow Pipe Piles WU Weisong1 LIANG Tianyi2 CAI Zhe2 FANG Yingran3 YAN Tao4 LIU Xiaohai4 LI Xinggao3 To explore the dynamic damage and fracture process of hollow reinforced concrete pipe piles under the cutting action of shield cutters, a dynamic model for shield cutter groups cutting reinforced concrete pipe piles is established with the Ningbo Metro Line 7 tunnel project as the engineering background. The effect of cutter layered configuration and cutting parameters on cutting performance is investigated. The research results show: (1) When cutters are arranged in layers, the first layer rippers locally fracture the concrete and effectively cut the reinforcement cage. When cutters are arranged with uniform high difference configuration, a penetrating crack appears at the middle of the hollow pipe pile, and the cracking expands into a large-scale fracture, causing the reinforcement cage to lose its constraint and deform, which cannot be effectively cut. (2) When the cutter cuts the first main reinforcement, the reinforcement cage is constrained by the relatively intact concrete, and the instantaneous impact load is the largest, which represents the most unfavorable condition. The impact load peak for the layered cutter configura? tion is much smaller than that for the uniform high difference configuration. (3) As the cutting speed increases, the peak impact load increases significantly due to the strain rate effect of the concrete. The increase in penetration leads to an overall higher cutting load, but the impact on the peak impact load is relatively small, as the rebar diameter is small and breaks completely in a single cut. (4) Engineering practice shows that when the cutter head rotation speed is maintained at 0.9 r/min and the penetration is maintained between 20~40 mm/r, the thrust during the cutting process fluctuates around 15 500 kN, with a peak value of only 18 000 kN, and the torque remains around 800 kN·m. 2025 Vol. 62 (2): 172-182 [Abstract] ( 51 ) [HTML 1KB] [ PDF 9456KB] ( 134 ) 183 Design of Pre-set Energy Absorbing Anchor Bolt and Numerical Analysis of Its Impact Resistance Mechanical Performance YU Mingqiu1,2 TANG Zhi1,2 WU Zhiwei2 LV Jinguo2 ZHANG Shengrui2 In order to improve the impact resistance mechanical performance of anchor bolts, a pre-set energy ab? sorbing anchor bolt composed of a rod body, energy absorber, plate, and nut is designed, and its working principle is introduced. ABAQUS finite element analysis software is used to analyze the mechanical performance of the pre-set energy absorbing anchor bolt under static and impact loads based on key indicators such as elongation rate, impact resistance time, and energy absorption. The results show that under static load, the elongation rate and energy absorption of the pre-set energy absorbing anchor bolt are 1.94 times and 1.8 times that of a conventional anchor bolt,respectively. Under 80 kJ impact energy, the impact resistance time, energy absorption, and elongation rate of the pre-set energy absorbing anchor bolt are 2.68 times, 1.83 times, and 2.16 times that of the conventional anchor bolt,respectively. Under different impact velocities, the elongation rate, impact resistance time, and energy absorption of the pre-set energy absorbing anchor bolt are 2.2 times, 2.63 times, and 1.88 times that of the conventional anchor bolt, respectively. The pre-set energy absorbing anchor bolt has longer impact resistance time, higher energy absorption, and good elongation performance. Changes in the loading form have little effect on its energy absorption, elongation rate, yield load, and breaking load. 2025 Vol. 62 (2): 183-190 [Abstract] ( 53 ) [HTML 1KB] [ PDF 3110KB] ( 127 ) 191 Study on Ventilation and Cooling Effect in Shield Assembly Caverns under Concrete Hydration Heat and Multi-tunnel Coditions JIANG Wei Based on the Yangtze River Tunnel on Chongqing-Qianjiang High-Speed Railway, a study is conducted on the distribution characteristics of high-temperature gases caused by the hydration heat of mass concrete in the shield assembly cavern under multi-tunnel condition, as well as the effects of ventilation and cooling. A 3D fluidthermal coupled model is established based on field testing and numerical simulation methods to study the influence of hydration heat temperature, air supply position, and air supply speed on the transient temperature and wind speed variation in the tunnel during various excavation stages. The results show that in complex space conditions, the aggregation of concrete hydration heat leads to higher air temperatures inside the tunnel. During the upper excavation stage, the airflow is relatively simple and flows from bottom to top. In the lower excavation stage, under low wind speeds, the airflow mainly moves upwards, while under high wind speeds, the airflow spreads out in all directions.Ventilation can effectively reduce the air temperature inside the tunnel, but its effect is limited at specific wind speeds. The cooling amplitude increases proportionally with the wind speed, but the cooling rate decreases inversely with the wind speed. During upper excavation stage, the air temperature drop increases with the air supply position's depth; under 40 °C, 50 °C, and 70 °C, the cooling efficiency can be improved by 9.3% to 14.6%. During the lower excavation stage, setting the air supply outlet at the intersection of the assembly cavern and the main tunnel is more conducive to heat removal and can increase the cooling efficiency by 2.2% to 15.5%. When the hydration heat is 40 °C, the air temperature can be reduced to 28 °C through mechanical ventilation and optimized air supply outlet positions. The required wind speed and air supply outlet position for the upper excavation are 1.8 m/s (Position B),and for the lower excavation, they are 4.4 m/s (Position C) and 9.8 m/s (Position D). 2025 Vol. 62 (2): 191-200 [Abstract] ( 119 ) [HTML 1KB] [ PDF 7404KB] ( 118 ) 201 Study on Gas Migration and Accumulation Patterns in Tunnels after Sealing Auxiliary Tunnels LI Jing1 LUO Lusen1 ZHANG Bailin2 HU Haoran2 To ensure the safe operation of railway tunnels and prevent gas disasters in auxiliary tunnels, a study is conducted based on the closure of a gas-containing auxiliary tunnel (inclined shaft) in a certain railway tunnel. Using computational fluid dynamics (CFD) software for numerical simulation, this study reveals the gas concentration distribution characteristics as well as migration and accumulation patterns under different closure conditions. The results show that the highest gas concentration occurs near the coal seam. Due to the slope and the gas′s own properties, after the gas escapes from the coal seam, it first accumulates at the top and then diffuses downward under the influence of the concentration gradient. Gas concentration is higher in the uphill section than in the downhill section.When only the lower end is sealed, or both ends are open, the gas concentration remains low but eventually reaches0.05-0.16, close to the explosive limit. In other sealing conditions, the final gas concentration is generally higher than 0.16, exceeding the explosive limit. Sealing the upper end and setting a pressure relief hole at the upper end has limited effects, resulting in generally higher final gas concentrations. It is recommended to strengthen monitoring and ventilation in areas with excessively high gas concentrations in the uphill section and seal the lower end of the inclined shaft to prevent gas from leaking into the main railway tunnel. 2025 Vol. 62 (2): 201-211 [Abstract] ( 101 ) [HTML 1KB] [ PDF 6271KB] ( 135 ) 212 Experimental Study on Crack Propagation Characteristics and Mechanical Behavior of Plain Concrete Lining in Highway Tunnels CHEN Xiang1,2 LIN Zhi1,2 FENG Wanlin1,2 YANG Hongyun1,2 To ensure the structural safety of operating tunnels, accurately assessing the bearing capacity state of the lining structure is crucial. Due to the concealed nature of tunnel structures, while surface cracks are easy to observe,spatial parameters such as crack depth and propagation patterns are difficult to measure precisely. To address this,full-scale loading failure tests were conducted on plain concrete components, and combined with Digital Image Correlation (DIC) technology, the crack propagation evolution characteristics and bearing capacity evolution of the lining were systematically revealed. The results show that: (1) The crack propagation of plain concrete linings exhibits an evolution pattern of no crack stage, I-type crack stage, and Γ-type crack stage; (2) The initiation of cracks significantly changes the stress state of the structure, leading to stress redistribution and the formation of distinct zoning features; (3) In the region surrounding the cracks, crack propagation has the most significant effect on the stress distribution within a 150 mm range, with less influence on further regions; (4) By comprehensively analyzing the evolu? tion characteristics of bending moment, deflection, load, crack morphology, and bearing capacity, it is proposed to establish the development stage of the Γ-type crack as a control standard for assessing the safety of the lining structure. 2025 Vol. 62 (2): 212-220 [Abstract] ( 64 ) [HTML 1KB] [ PDF 5526KB] ( 130 ) 221 Design and Experimental Research on Segment Sealing Gasket of Vertical Shaft Using Upward Pipe Jacking Technology BAI Zhongkun1,2 WANG Yawei1,2 BI Chengcheng1,2 ZHAO Xiuwang1,2 ZHU Qiang3 In order to study the waterproof and assembly performance of prefabricated vertical shaft segments in up? ward pipe jacking construction, finite element simulations of sealing gaskets with three different cross-sectional forms were performed using ABAQUS/ Explicit. After comparison and analysis, a sealing gasket with high water pressure resistance and strong compressibility was specifically developed. Compression assembly tests, water-tightness tests, and radial assembly tests were conducted sequentially to analyze the physical and mechanical properties of the sealing gasket under different joint opening and misalignment conditions. The results show that the joint opening and misalignment are negatively correlated with the waterproof performance of the sealing gasket. To achieve the designed waterproof pressure value of 0.8 MPa, the joint opening should be kept within 6 mm, and the misalignment should be controlled within 10 mm. During radial assembly, the longitudinal deformation of the sealing gasket is approximately in arc-shape, with the maximum deformation at the center and gradually decreasing at the sides. Attention should be paid to misalignment caused by squeezing deformation during assembly. The radial assembly thrust is negatively correlated with joint opening. To meet the waterproof performance and assembly deformation control requirements, an expanding diameter assembly method can be considered, with the pre-set joint opening between the segments greater than 9 mm. 2025 Vol. 62 (2): 221-229 [Abstract] ( 122 ) [HTML 1KB] [ PDF 6178KB] ( 160 ) 230 Calculation Method and Validation of Equivalent Length for Traffic Tunnel Ventilation Model Test GUO Ying PENG Wenqing CHEN Shiqiang ZHANG Qiong WANG Jiawei The method for adjusting the equivalent length in the ventilation and smoke extraction model test for long traffic tunnels is still immature. Based on the running tunnel section between Wawuzhuang Station and Guizhou Road Station of Qingdao Metro Line 1, a tunnel model test platform was built. A throttle ring was installed to control the tunnel air outlet area and change the pressure drop, achieving active adjustment of the model’s equivalent length. Thirty-one sets of variable parameter tests were conducted using numerical simulation methods to reveal the impact of area ratio on the model's equivalent length. On this basis, the air outlet shapes were changed, and simulations for multiple sets of area ratio conditions were completed. The research results show that when the area ratio is between 0.133 and 0.735, the calculated equivalent length of the traffic tunnel ventilation model is between 21.86 m and 362.53 m. Inverse verification through numerical simulation shows that the tunnel model's equivalent length only depends on the area ratio and is independent of the air outlet shape and the model's original length. The air outlet area ratio is the core parameter for adjusting the equivalent length. 2025 Vol. 62 (2): 230-240 [Abstract] ( 88 ) [HTML 1KB] [ PDF 7139KB] ( 128 ) 241 Study on Gas Occurrence Characteristics and Prevention Technology for Tunnels in Natural Gas-bearing Sandstone Formation HAO Junsuo1 ZHANG Xiangbing1 WANG Shiguang1 CHU Xiaojin1 SU Peidong2 In order to solve the technical problems that gas emission and gas pressure is difficult to be predicted quantitatively, and the spark induced by cutting surrounding rock may ignite gas during the milling excavation of horizontal natural gas-bearing sandstone formation in hydraulic tunnels, based on the analysis of geological identification and the characteristics of occurrence and migration of natural gas-bearing sandstone formations in Muzhuzhai tunnel of Tingzikou water diversion project, comprehensive prevention and control technologies such as comprehensive detection, directional drilling and discharge, and gas risk control, etc.are proposed. The research shows that: (1)the gas concentration in the borehole is as high as 80%, the gas pressure is 0.62 MPa, and the gas emission in the borehole is about 30 L/min. It shows that there is pressurized gas in the natural gas-bearing sandstone formation,and abnormal emission is easy to occur after the fracture is connected. (2) Within the discharge range of 35 m in front of the tunnel face and 15 m on the side wall of the tunnel, Ф89 mm gas discharge boreholes shall be arranged in the natural gas-bearing sandstone formation according to the effective emission radius of 3.2 m and the spacing between the holes at the bottom of 4.5 m. After discharge, the residual gas pressure is less than 0.15 MPa, the gas emission at the working face is 0.24 m3/min, with the gas emission reaching the expected goal. (3) During the gas discharge operation, through the environmental safety monitoring at the working face, the review and determination of ventilation capacity, and the grouting and sealing of the discharge holes after the completion of gas discharge, the safety operation of drilling and gas discharge is realized. 2025 Vol. 62 (2): 241-253 [Abstract] ( 90 ) [HTML 1KB] [ PDF 5261KB] ( 117 ) 254 Study on the Water Leakage and Emergency Treatment in the Foundation Pit Retaining Structure in Sandy Composite Strata CHEN Xiafei1,2 LI Bingwei1,2 ZHANG Xuemin3,5 WANG Lichuan2,3 LUO Zhiyang3 LIU Rui1,2 FU Lei4 This study focuses on the issue of water leakage in the retaining structures of foundation pits in sandy composite strata and the corresponding control measures. Based on the excavation of the foundation pit for the Yanghu Block Post on Guangzhou-Huadu Intercity Railway, numerical simulations and field testing were conducted to analyze the effects of water leakage on soil, structural deformation, and flow field distribution. The effectiveness of three treatment measures against water leakage—back-filling soil, grouting reinforcement outside the pit, and dewatering outside the pit—was compared. The results indicate: (1) When the structure experiences slight water seepage, the horizontal displacement and deformation of the soil and structure is significant, while the vertical displacement is relatively small. (2) Near the water seepage point, sand particles in the soil are lost, reducing strength and increasing horizontal deformation. The water seepage area of the diaphragm wall experiences significant water-soil pressure, resulting in a "bulging" curvature, with the maximum horizontal displacement increasing to 15.13 mm. The pore water pressure at the defect area significantly increases, which exacerbates the wall deformation. (3) The three treatment measures can effectively control both water seepage and structural deformation. The dewatering treatment outside the pit shows the best effect in controlling structural deformation, while grouting reinforcement outside the pit is more effective in controlling deformation in the depth direction. (4) The above treatment measures have shown good control effects on-site, significantly reducing the wall deformation rate and gradually restoring it. 2025 Vol. 62 (2): 254-264 [Abstract] ( 69 ) [HTML 1KB] [ PDF 7305KB] ( 160 ) 265 Study and Application of Dual-component Synchronous Grouting Technology in Shield Tunnelling YAO Zhanhu1 YANG Qin2 LI Hui2 WEI Daiwei2 MENG Jia2 The dual-component synchronous grouting technology for shield tunnels is still immature and faces many challenges during construction. Therefore, experiments on dual-component grout mix proportions were conducted,recommended performance index values for grouting materials were proposed, new grouting equipment was developed, key construction technical points were summarized, and the technical effectiveness was verified through engineering practice. The results show that sodium silicate mainly provides early strength, while the water-cement ratio mainly affects the later strength. The dual-component grout exhibits good stability and concretion rate. The selection of dual-component grout parameters should be based on factors such as hydrogeological conditions, deformation control requirements, and equipment structure, with the mix ratio adjusted accordingly. Synchronous grouts preparation and storage trolley can avoid the degradation of Component A, and the automatic cleaning function of the grouting system effectively reduces the risk of pipe blockage. The flow monitoring method can reduce mix ratio deviations. The filling coefficient of the dual-component grout can be between 1.2 and 1.3, and the grouting pressure should be greater than the water-soil pressure at the grouting point by 0.05~0.1 MPa. The dual-compnent grout can control the segment uplifting within 5 mm, and the axis deviation within ±50 mm. Ground penetrating radar tests showed that the grout density exceeded 99.93%. 2025 Vol. 62 (2): 265-273 [Abstract] ( 117 ) [HTML 1KB] [ PDF 5556KB] ( 159 ) 274 Active-controlled Prefabricated and Mechanized Open-caisson Construction Technology WU Wenfei1,2 ZHU Yanfei1 ZHU Yeting1,2 ZHAI Yixin1,2 TU Lei1,2 PAN Weiqiang1,2 To address the issues in traditional open-caisson construction methods, such as large land occupation, high environmental disturbance, low work efficiency, difficulty in controlling the sinking process, and posture control in soft soil urban areas, an active-controlled prefabricated and mechanized open-caisson construction method is proposed. This method integrates technologies such as underwater robot excavation, ground-propulsion system penetration, synchronous grouting, and prefabricated segment assembly, etc. and has developed a complete set of construction equipment. Based on indoor tests and on-site field tests, the automation and controllability of underwater excavation robots were verified. The technology was applied to an escape shaft project on Shanghai Metro Line 13.The measured verticality of the shaft wall was about 0.65‰, and the overall structural average ovality was 1.2‰,both of which exceeded acceptance standards. 2025 Vol. 62 (2): 274-282 [Abstract] ( 116 ) [HTML 1KB] [ PDF 5851KB] ( 153 ) 283 Study on the Control Law of Surface Deformation in Shield Tunnels in Mudstone Strata with the Clay Shock Construction Method ZHANG Xinyang1,2 SHEN Yusheng1,2 CHANG Mingyu1,2 LIU Tong1,2 SUN Tianshe3, 4 HU Shuai3, 4 Ground settlement and deformation caused by shield tunnelling is a critical issue that needs to be ad? dressed during construction. The clay shock construction method is an important measure to control surface settlement and deformation during shield tunnelling. To explore the effect law of the clay shock method on surface settlement and deformation in mudstone strata during shield tunnel construction and its control effect, this study uses Sichuan Normal University station to Jiaozili Flyover station running tunnel section of the Chengdu Metro Line 13 as a case study. The research investigates the impact of the clay shock method on surface deformation when tunnelling through mudstone strata, and indoor tests are conducted to reveal the viscosity variation of clay shock samples with different material ratios. Finally, the clay shock method is applied in the field construction, verifying and analyzing its effectiveness. The results indicate: (1) Filling the shield excavation gap with clay shock slurry has a significant impact on surface settlement, reducing the maximum surface settlement by approximately 23.48%; (2) The soil-towater ratio significantly affects the viscosity of the clay shock slurry. The smaller the soil-to-water ratio, the higher the slurry viscosity, and the additives can regulate the slurry viscosity within a certain range; (3) The field measurement data and research results are consistent (with an error of approximately 10%), and the surface settlement value is within the engineering requirement of -20 mm. 2025 Vol. 62 (2): 283-290 [Abstract] ( 51 ) [HTML 1KB] [ PDF 4998KB] ( 145 ) 291 Research on Prediction and Treatment of Screw Conveyor Fault in Long-distance Large-diameter EPB Shield Tunnelling in Composite Strata ZHANG Hairong In long-distance large-diameter EPB shield tunnelling in composite strata, screw conveyor shaft fracture accidents can lead to severe safety and construction schedule risks. To quantitatively predict the spatial distribution characteristics of screw conveyor shaft fractures, a combined numerical simulation and statistical modeling approach was used, combining nonlinear regression algorithms and BP neural networks. A prediction model for screw conveyor shaft fracture risk was developed and tested based on actual engineering projects. The results show that: (1) The screw conveyor fault prediction model achieves high accuracy in predicting shaft fracture risks and demonstrates reliability in risk probability predictions, providing non-parametric interval estimates for risk ring numbers; (2) Measures such as using fully solid shafts or double-head solid shafts, controlling the welding quality of stressed components like cutter heads and screws, regulating the cutter head opening size, and setting reasonable torque limits for screw conveyors can reduce the risk of screw conveyor shaft fractures. 2025 Vol. 62 (2): 291-297 [Abstract] ( 131 ) [HTML 1KB] [ PDF 3909KB] ( 139 )

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