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Quick Search     Advanced Search MODERN TUNNELLING TECHNOLOGY   2025 Vol.62 Issue.4 Published 2025-08-25 1 A Review of Spray-applied Waterproofing Membrane Technology for Drill-and-Blast Tunnels YANG Shaoyu1 WANG Xiaotian2 ZHANG Peiyuan1 LIU Shengchen1 LI Shuchen2 LI Luoning2 To address the issues of poor adhesion, water leakage, and difficult repairs associated with traditional wa? terproofing sheets, this paper reviews the types, performance, structural design, and construction applications of spray-applied waterproofing membranes in composite linings, and analyzes the current status and development trends of this technology. Firstly, the development history of spray-applied waterproofing membrane materials is summarized, comparing the waterproofing performance, durability, adhesion, and mechanical properties of different materials, while analyzing the influence of interfacial behavior and failure mechanisms on structural performance.Secondly, through numerical simulations and engineering case studies, the advantages of spray-applied waterproofing membrane linings in terms of load-bearing capacity and construction efficiency are verified, with key technical requirementsfor construction processes elaborated. Finally, the challengesin occupational health and safety,standardization, and adaptability to complex conditions are identified, suggesting future improvements through material optimization, development of environmentally friendly products, refinement of design theories, and standardization of construction techniques to promote wider application in tunnel waterproofing engineering. 2025 Vol. 62 (4): 1-14 [Abstract] ( 27 ) [HTML 1KB] [ PDF 4091KB] ( 209 ) 15 Catastrophic Mechanisms and Research Development Trends of Water and Mud Inrushes in Tunnels WANG Sheng1,2,3,4 WEI Qin1,2 LI Liping3 This study systematically investigates the formation mechanisms of water-mud inrushes in tunnel and un? derground engineering through comprehensive analysis of geological development characteristics, disaster-causing structure classification, failure modes, minimum safe thickness calculations, and multi-field information evolution patterns. The research summarizes the geological development characteristics and geological precursor information of water and mud inrush, establishes a computational method for determining the minimum safe thickness of inrushresistan rock masses under combined water pressure and blasting loads, while critically examining current research methodologies including numerical simulations and physical model tests along with their limitations. Key findings reveal that disaster-causing structures can be categorized into karst-type, fault-type, and special geological types.Distinct precursor signals are identified during tunnel construction near these structures, including rust-colored or wetted rock masses, increased spalling, and muddy seepage flows with sediment content. The onset of water-mud inrushes is characterized by abrupt decreases in rock temperature, seepage pressure and resistivity, coupled with sudden increases in microseismic activity and displacement monitoring data. The study highlights three emerging research directions for catastrophic evolution mechanism: continuum-discontinuum multiscale fluid-solid coupling analysis methods, true triaxial geomechanical visualization physical model testing techniques, and artificial intelligence interpretation-based fusion analysis of multi-source heterogeneous precursor information. 2025 Vol. 62 (4): 15-25 [Abstract] ( 22 ) [HTML 1KB] [ PDF 3094KB] ( 183 ) 26 Study on Fracture Characteristics of Different Types of Sandstone Based on Acoustic Emission Characteristic Parameters LI Kexi1,2 DANG Jiandong3 ZHANG Jian3 YE Guangxiang4 WANG Xiaojun1,2 CHEN Qinglin1,2 The fracture modes of rock masses with different pore structures and varying proportions of high-strength minerals exhibit significant differences under the influence of engineering activities, which increases the complexity of underground support management. To investigate the crack evolution characteristics during the fracture process of three types of sandstone, a dual-gradient classification method was adopted based on sandstone porosity and quartz content. Uniaxial loading tests and real-time monitoring of acoustic emission throughout the failure process were conducted to analyze the evolution patterns of acoustic emission ringing counts, RA-AF values, and b-values for the three sandstone types. The experimental results indicate that: (1) With decreasing initial porosity, shear failure becomes more dominant, the fracture mode gradually changes from tensile to shear failure, and the degree of damage increases; (2) Pore structure and high-strength mineral content influence acoustic emission signals, under the combined effect of a porous medium and low elastic modulus, the transmission of elastic waves in sandstone is weakened,leading to reduced acoustic emission frequency and amplitude; (3) When the albite content exceeds that of quartz,the dislocation pile-up phenomenon generates high-frequency and dense acoustic emission signals during the compaction stage. 2025 Vol. 62 (4): 26-36 [Abstract] ( 19 ) [HTML 1KB] [ PDF 6807KB] ( 127 ) 37 Influence of Permeability Characteristics of Vertical Zonation in Water-rich Karst on External Water Pressure of Tunnels LI Zhensong1 GUO Qinghua2 ZHANG Ning1 HE rongjian2 ZHANG Xiaoping1 ZHANG Haoran1 To investigate the influence of vertical zonation permeability characteristics of water-rich karst on external water pressure in deep-buried long-distance water conveyance tunnels, the Fenjie river valley section of the Yunkai Mountain Tunnel in the Beibu Gulf Guangdong Water Resources Allocation Project was selected as the study site. A novel borehole water pressure testing device was developed to conduct stratified hydraulic connection measurements, revealing the permeability characteristics between upper and lower rock layers above the tunnel and enabling vertical zoning of the overlying rock mass. Results indicate that the overlying rock mass of the valley section can be vertically divided into a modern karst layer, a middle enhanced karst layer, and a deep isolated karst void layer. The lower boundary of the modern karst layer is approximately 100 m, the middle enhanced karst layer extends down to about 160 m, and the tunnel is located within the deep isolated karst void layer, approximately 30 m away from the bottom of the middle enhanced karst layer. Based on this, numerical simulations were conducted to compare the effects of vertical zonation permeability and homogeneous permeability on external water pressure.Compared with the homogeneous seepage model, the seepage modele considering karst vertical zonging eliminates the funnel-shaped pore pressure contour distribution due to variations in permeability within rock layers. The maximum and minimum external water pressures occur at the tunnel crown (7.13 × 10? Pa) and invert arch(7.07 × 10?Pa), respectively. The maximum external water pressure in the vertically zoned seepage model reaches 231.5% of that predicted by the homogeneous seepage model. 2025 Vol. 62 (4): 37-49 [Abstract] ( 20 ) [HTML 1KB] [ PDF 6808KB] ( 141 ) 50 Load-bearing Behavior and Reinforcement Schemes of High-performance Fiber-reinforced Concrete Jacking Pipes under Three-point Loading ZHOU Cairong1 YI Liming1 MA Shanqing2 ZHOU Li3 YU Jinhong4, 5 High-performance fiber-reinforced concrete (HPFRC) exhibits significant potential for use in electricpower pipe-jacking engineering due to its superior strength, ductility, and durability. However, research on the mechanical properties of HPFRC jacking pipes remains scarce. This study investigates the load-bearing characteristics of C150 HPFRC jacking pipes under three-point loading and evaluates the influence of different reinforcement schemes through model tests, analytical calculations, and numerical simulations. The results indicate that the loaddisplacement relationship of HPFRC jacking pipes initially follows a linear elastic trend. When the load exceeds200 kN/m, the displacement accelerates, and cracks develop in the pipe segment. Structural failure occurs at a peak load of 437 kN/m. Compared to conventional concrete jacking pipes, HPFRC pipes demonstrate significantly improved load-bearing capacity, crack resistance, and post-damage residual strength while requiring less steel reinforcement and reduced wall thickness. The three analytical methods yield consistent results regarding structural stress behavior and failure progression. However, the analytical calculation method exhibits notable errors in predicting crack widths. Furthermore, different reinforcement schemes significantly influence structural damage and load capacity, with double-sided and inner-layer reinforcement configurations demonstrating superior damage resistance. 2025 Vol. 62 (4): 50-60 [Abstract] ( 22 ) [HTML 1KB] [ PDF 6233KB] ( 124 ) 61 Influence of Ground Surcharge on Existing Shield Tunnel Segments in Xi′an Loess Strata GUO Yongjun1 LI Chao2 ZHENG Jianguo3 YU Yongtang4 ZHU Caihui5 Sudden ground surcharge may impose additional loads on existing metro shield tunnel segments, poten? tially leading to deformation or structural damage. Investigating the mechanical response of existing segments under surcharge conditions is crucial for optimizing segment design. This study focuses on a running tunnel section of Xi′an Metro Line 9, employing a similarity model test with a geometric scaling ratio CL = 40. Based on 3D printing technology and artificial preparation method of collapsible loess, this study investigates the surrounding rock pres? sure and segment deformation patterns under surface surcharge conditions, with comprehensive consideration of in? fluencing factors including surcharge magnitude, tunnel burial depth, and loading position. A modified calculation method for surrounding rock pressure based on the surrounding rock pressure amplification coefficient β and trans? fer coefficient η was proposed. Additionally, a four-zone influence classification system is established under surface surcharge conditions, along with segment displacement control criteria for different surcharge magnitudes and positions. The results demonstrate that the surrounding rock pressure of the tunnel increases linearly with the surcharge magnitude, while the increment of surrounding rock pressure generally exhibits a decreasing trend with increasing eccentric distance. When the surcharge is positioned at 0.5D and 1.0D, the reduction in surrounding rock pressure on the eccentric side is significantly smaller than that on the non-eccentric side. At a surcharge position of 1.5D, the variations in surrounding rock pressure on both sides of the tunnel become nearly identical. Furthermore, the influence of surface surcharge on tunnel surrounding rock pressure relatively diminishes with increasing tunnel burial depth. 2025 Vol. 62 (4): 61-72 [Abstract] ( 20 ) [HTML 1KB] [ PDF 5360KB] ( 133 ) 73 Comparative Analysis of Disc Cutter Forces and Wear under Different Wear Modes WANG Yonggang1 CUI Yikun1 WU Jiuqi2, 3 HUANG Jun4 SHEN Xiang2, 3 YANG Kui4 SU Dong2, 3 Based on a self-developed shield rock-breaking simulation device, rotary cutting and rock-breaking tests of disc cutters were carried out. Compared with conventional linear cutting tests, this method more realistically reproduces the actual motion pattern and loading state of disc cutters. By combining laboratory tests with the discrete element method (DEM), a numerical model for disc cutter circular cutting was established to systematically investigate the force characteristics, wear mechanisms, and specific energy variations of normally worn and eccentrically worn disc cutters during the rock-breaking process. The results show that: (1) the fluctuation ranges of vertical force and torque of disc cutters obtained from the numerical simulations are generally consistent with those mea? sured in laboratory tests, verifying the capability of the numerical model to represent the dynamic mechanical behavior of disc cutters in rock cutting in laboratory tests ; (2) eccentric wear of disc cutters leads to a 29.9% reduction invertical force and a 48.6% increase in tangential force; (3) engineering case data analysis indicates that when a large number of disc cutters undergo uniform wear, the shield thrust increases while the torque remains essentially stable.In contrast, when eccentric wear becomes prevalent, both shield thrust and torque increase, which is consistent with the numerical simulation results. 2025 Vol. 62 (4): 73-81 [Abstract] ( 18 ) [HTML 1KB] [ PDF 5842KB] ( 133 ) 82 Mechanical Response Analysis of Subway Shield Tunnel Structure under Pile Foundation Load ZHANG Xiaolong To investigate the influence of pile foundation loading on metro shield tunnel structures, a differential equilibrium equation for the circumferential shear angle of the ring structure was established based on the geometric equation of circular arc microelements, physical equations, and static equilibrium equations. This reveals the differential relationship between the shear angle and circumferential/radial deformations. By incorporating the modified routine method to account for joint damage reduction, analytical solutions for stress, shear force, axial force, and bending moment of the ring structure under concentrated loading were derived. The accuracy of the theoretical model was validated using field measurement data from a metro engineering case. Furthermore, parametric analysis was conducted to explore the variation patterns of structural responses under different loading conditions. The results indicate that axial force, bending moment, and shear force all increase significantly with external load. The shear force exhibits positive and negative peaks at the crown and invert of the ring, while reaching a positive peak at the waist.Additionally, bending moment, axial force, and shear force all approach zero at positions of ±135° and ±45°. The research provides a theoretical basis for load response analysis and design optimization of shield tunnel structures. 2025 Vol. 62 (4): 82-89 [Abstract] ( 20 ) [HTML 1KB] [ PDF 3448KB] ( 128 ) 90 Digital Twin and Risk Decision-making for Water-richess of Surrounding Rock Ahead of Tunnel Face XU Caijian1 CHEN Xingyu1 LEI Minglin1 ZHANG Xinglong2 SUN Huaiyuan2 LI Xiaojun2 To address the challenges of acquiring water-richness information in surrounding rock during tunnel construction and the lack of timely early warning for water-inrush risks, this study proposes a digital twin and risk decision-making framework for evaluating the water-richness of surrouding rock ahead of tunnel face. The framework achieves virtual mapping of rock water-richness through point cloud modeling and introduces a fuzzy cloud probability model for refined risk assessment of water-inrush per meter. The framework comprises three key steps: (1) Acquisition of rock resistivity data via transient electromagnetic method (TEM) with 3D spatial registration to construct a water-richness database; (2) Generation of forward point cloud models based on tunnel face geometry, where Knearest neighbors (KNN) algorithm assigns water-richness attributes to establish a digital twin of water-richness of surrounding rock; (3) Uncertainty quantification of the digital twin using the fuzzy cloud probability model for intelligent water-inrush risk assessment. Application in Yanjiazhai Tunnel demonstrates that the framework enables rapid extraction of water-richness information and virtual mapping through digital twins. Comparative analysis with actual water-inrush conditions during excavation verifies the accuracy of the proposed fuzzy cloud probability model in risk evaluation of water inrush ahead of tunnel face. 2025 Vol. 62 (4): 90-99 [Abstract] ( 19 ) [HTML 1KB] [ PDF 7378KB] ( 123 ) 100 Improved UNet Model-based Image Segmentation for Tunnel Seepage Defects under Low-light Conditions YANG Ying1 NI Kai1 GE Lin2 ZHANG Mingfei3 WANG Xiaorui4 Computer vision technology offers an intelligent solution for tunnel seepage area detection, yet its feature extraction and segmentation accuracy remains constrained by low-light conditions and pipeline obstructions. This study proposes a Light-UNet model based on the Unet model, an enhanced tunnel seepage zone segmentation network with three key contributions: (1) To enhance the extraction accuracy of the seepage area, a light-shadow transformation boot item is introduced, and a parallel attention module is designed to extract internal information of the boot item. Subsequently, channel attention mechanisms are employed to aggregate the boot item with deep network information. (2) To overcome the scarcity of tunnel seepage datasets, the data was manually collected from a tunnel under construction. Perspective transformation was used to alter camera angles and expand the dataset. (3) To address insufficient lighting in tunnels, Gaussian noise and salt-and-pepper noise were randomly added to the dataset images to simulate images captured in dim environments, thereby enhancing the network’s generalization ability. Ultimately, the Light-Unet network was trained using the constructed training set, achieving a mean Intersection over Union (mIoU) of 88.84% and a mean Dice coefficient (mDice) of 88.04%, both significantly higher than the Unet baseline model. Visualization comparisons between the improved and baseline networks demonstrate that the improved network better adapts to the segmentation of seepage areas in complex environments, including poor lighting and pipeline obstructions. 2025 Vol. 62 (4): 100-110 [Abstract] ( 15 ) [HTML 1KB] [ PDF 6761KB] ( 119 ) 111 Short-term Multi-step Traffic Volume Prediction for Highway Tunnels Based on DBO-A-LSTM SU Kaichun1 FU Rui2,3 ZENG Hongrui2,3 LENG Xiqiao4 GUO Chun2,3 With the proposal of the“dual carbon”goal and the increasing demand for energy conservation and emis?sion reduction, the need for energy-efficient ventilation in highway tunnels has grown substantially, placing higher requirements on the accuracy of traffic volume forecasting. To enable low-carbon regulation of tunnel ventilation systems, this study utilizes traffic volume data recorded at 5-minute intervals from a highway tunnel and compares the performance of several common forecasting models in short-term multi-step prediction tasks. An improved prediction framework is proposed by integrating the dung beetle optimization (DBO) algorithm and the self-attention mechanism into the LSTM neural network, yielding the DBO-A-LSTM model with significantly enhanced predictive performance. To address the issue of high prediction errors during holiday peak periods, the DBO-A-LSTM model is further refined through dataset optimization. Confidence interval analysis, t-tests, and Wilcoxon tests demonstrate that the optimized DBO-A-LSTM model achieves a stable R2 exceeding 0.75 under all scenarios, with accurate trend prediction; the mean absolute percentage error (MAPE) is reduced to below 22.2%, and the mean percentage error remains small. Visual analysis further confirms that the predicted values closely follow the fluctuation patterns of traffic peaks. The proposed model can be applied to real-time tunnel ventilation demand estimation, enabling proactive control of ventilation systems up to 20 minutes in advance based on 5-minute dynamic predictions. This approach significantly improves the accuracy and timeliness of intelligent energy-saving ventilation control in highway tunnels, offering practical implications for advancing low-carbon operation oftransportation infrastructure. 2025 Vol. 62 (4): 111-121 [Abstract] ( 18 ) [HTML 1KB] [ PDF 4507KB] ( 103 ) 122 Propagation and Attenuation Characteristics of Blast-induced Stress Waves in Layered Soft Rock XIONG Ying1,2 ZHANG Junru1,2 FAN Ziyan1,2 CHEN Jiahao1,2 MA Jianchi1,2 CHEN Pengtao1,2 To investigate the influence of joints in horizontally stratified soft rock formations on the propagation and attenuation characteristics of blast-induced stress waves, this study employs LS-DYNA numerical simulations based on the Changzheng Tunnel on the Chengdu-Zigong high-speed railway. The research systematically analyzes the propagation patterns, vibration attenuation, and energy dissipation characteristics of stress waves in jointed rock masses under varying joint thicknesses and spacings, elucidating the impact of joint geometric characteristics on vibration attenuation zoning. Field monitoring data further validate the reliability of the numerical approach. Key findings reveal that joint thickness and spacing significantly govern stress wave energy dissipation and attenuation. When the joint thickness exceeds 0.4 times the charge radius, the amplitude of vibration velocity attenuation stabilizes. Increased joint thickness enhances stress wave reflection energy while markedly reducing transmitted energy,with both trends reaching equilibrium beyond critical thresholds. Under multi-joint conditions, the peak resultant vibration velocity decreases with larger joint spacings, exhibiting predictable decay rates. Based on vibration attenuation zoning, a new classification standard for blast control in jointed rock masses is proposed. Field-measured surface particle vibration velocities demonstrate strong agreement with numerical results. 2025 Vol. 62 (4): 122-131 [Abstract] ( 20 ) [HTML 1KB] [ PDF 4821KB] ( 89 ) 132 Damage Mechanisms of Coal Pillars Induced by Blasting Construction in Highway Tunnels Underlying Room-and-Pillar Mine Goafs LIU Yang1 SHAO Zekai2 TIAN Haofan2 ZHANG Ruxi1 ZHENG Bo3 WANG Zhengzheng2 To investigate damage patterns of coal pillars during blasting construction of highway tunnels underlying room-and-pillar mine goafs, this study establishes a stress wave transmission model for inclined goaf areas based on stress wave energy distribution theory, analyzing spatial distribution characteristics and evolution trends of blast-induced stress wave energy transmitted to overlying coal pillars. Comparative analysis demonstrates strong consistency in damage spatial distribution patterns among theoretical calculations, numerical simulations, and field borehole inspection results. Through 20 sets of numerical simulations under different working conditions for the Changliangzi Tunnel on the Benxi-Huanren Expressway crossing under goafs, the results indicate: (1) Coal pillar damage modes are predominantly controlled by geostress rather than goaf dip angle. Without considering geostress, pillars exhibit shear failure with tensile failure at crowns; with increasing geostress, damage mode transitions sequentially to splitting failure and then compressive-shear failure. (2) Under constant goaf dip angles, damage extents first decrease rapidly, then stabilize, and finally increase sharply with rising geostress. At identical geostress levels, damage extents progressively reduce with increasing dip angles. (3) Dual-index analysis (internal energy evolution and damage rate) reveals that geostress inhibits pillar damage in room-and-pillar mine goafs above the tunnel, with suppression effects intensifying at steeper dip angles. When geostress reaches 8 MPa, all pillars except No.5 demonstrate inverse growth characteristics of the damage rate. 2025 Vol. 62 (4): 132-144 [Abstract] ( 23 ) [HTML 1KB] [ PDF 8149KB] ( 66 ) 145 Research on Water Inrush Mechanisms and Grouting Sealing Techniques for TBM Tunnels in Fractured Rock Masses LUO Zhiyang1 ZHANG Chunyu2,3 WANG Lichuan1,2,4,5 XU Shuo1 LI Liping4 WANG Qianqian5 LIU Zhiqiang6 To address water inrush control in water-rich fractured rock tunnels, this study is focused on the Chaor River to the Western Liaohe River Water Diversion Tunnel Project. Statistical analysis of rock mass fracture characteristics was conducted, and an equivalent fractured rock numerical model was developed based on field observations of water inrush to assess full-face grouting and sealing performance. The results reveal that interconnected fractures penetrating the tunnel serve as dominant pathways for water inrush, with single-point polyurethane grouting showing limited effectiveness in sealing continuous fracture flow paths. The established 3D equivalent numerical model accurately simulates actual water inrush conditions, demonstrating that increasing the grouting ring thickness to 2.5-4.0 m while reducing permeability to 2.07×10??-4.14×10?? cm/s can reduce water inrush by 83.27-93.25%.Field application of full-face cement-sodium silicate double-liquid grouting proved highly effective, achieving 96.9-98.3% sealing efficiency and transforming gushing water and large-area linear flow into localized dripping and a small linear flow. 2025 Vol. 62 (4): 145-154 [Abstract] ( 22 ) [HTML 1KB] [ PDF 7058KB] ( 66 ) 155 Study on the Deformation Control Effectiveness of Extra-long Pipe Roofs in Large-section Tunnels in Reclamation Strata FENG Jimeng1,2 SONG Jiadai1,2 WANG Shengtao3 LI Yifei1,2 ZHANG Junru1,2 WANG Haoming4 WANG Bo1,2 To address the deformation control challenges in the construction of large-section mined metro tunnels in upper-soft and lower-hard strata, this study employs numerical simulations and field monitoring to investigate the structural mechanical behavior and deformation patterns of extra-long pipe roof as advanced support. The deformation control efficacy is systematically analyzed. The results demonstrate that extra-long pipe roof effectively mitigates deformation, eliminates risks associated with construction method transition, and exhibits high structural stability. The implementation of extra-long pipe roof reduces crown settlement by 16.9 mm, keeping deformations with?in allowable limits. Additionally, structural stress states are improved, with the arch stress decreasing by 11%-25%, and stress concentration in the vault structure is effectively alleviated. 2025 Vol. 62 (4): 155-162 [Abstract] ( 20 ) [HTML 1KB] [ PDF 4990KB] ( 69 ) 163 Study on the Bending Behavior and Damage Characteristics of Longitudinal Segment Joints in Super-large Diameter Shield Tunnels ZHOU Yili1 FENG Kun1 GUO Wenqi1 ZHANG Liangliang2 LI Chunlin3 To investigate the bending behavior and damage characteristics of longitudinal segment joints in superlarge diameter shield tunnels, this study develops a three-dimensional refined numerical model based on the concrete damage plasticity (CDP) constitutive model, using the Jinan Yellow River Tunnel as a case study. Key findings include: (1) The bending behavior and damage characteristics of longitudinal joint under the bending moment exhibited obvious nonlinearity and stages. Owing to the asymmetric waterproofing structures, the deformation and failure process of segments comprised four distinct phases under positive bending moment compared to three phases under negative bending moment. (2) Pre-yield bolt stress shows non-uniform distribution, peaking at sleeve ends. There are obvious differences in the magnitude and distribution pattern of stress in the inner and outer regions of the segments. Bolt yielding under negative bending moment is delayed by 31.14% compared to positive bending moment.(3) Concrete damage propagates at 45° from the joint surface. The damage phenomenon of concrete on the surface of the sleeve side and the hand hole side was basically the same, but the damage phenomenon of concrete on the sleeve side was more serious at the bolt area, while the concrete on the hand hole side was damaged at the hand hole area.(4) Under positive moment, outer main rebars and joint-surface reinforcement experience peak stresses coinciding with concrete failure zones. The outer main rebars yield after the concrete in the compression zone was seriously damaged. 2025 Vol. 62 (4): 163-173 [Abstract] ( 19 ) [HTML 1KB] [ PDF 6273KB] ( 52 ) 174 Analysis of the Influence of Bolt Failure of Shield Tunnel Segment Structure on Transverse Seismic Response YI Dan1 XUE Haoyun2 YANG Shaoyi2 YU Bo1 FENG Kun2 LIN Gang1 The segment joints of shield tunnels represent critical weak points in the overall tunnel structure, with the failure of connecting bolts directly compromising the service performance. To investigate the influence of circumferential bolt failure of shield tunnel segments on the transverse seismic behavior of the sgment structure, this study establishes three-dimensional finite element models of both single- and double-lining configurations for a large crosssection shield tunnel project, employing implicit dynamic time-history analysis for seismic performance evaluation. Results demonstrate that circumferential bolt failure leads to increased transverse deformation and peak damage levels. While the application of a secondary lining enhances transverse deformation resistance and reduces peak damage, it concurrently expands the damage distribution zone. Under bolt failure conditions, the secondary lining improves the mechanical performance utilization of the segment reinforcement cages. For tunnel sections with potential bolt failure risks, the implementation of secondary linings is recommended to enhance seismic resilience. 2025 Vol. 62 (4): 174-181 [Abstract] ( 18 ) [HTML 1KB] [ PDF 4177KB] ( 54 ) 182 Mechanical Behavior of Steel Fiber Reinforced Concrete Segments with Different Joint Configurations JIA Yonggang1 HAO Zihan1 LU Weidong1 WU Fan1 YANG Weiwei2 This study investigates the mechanical behavior of steel fiber-reinforced concrete (SFRC) segments with different joint configurations (bent bolts, inclined bolts, and double-layer bolts) through numerical simulation method verified by laboratory tests, focusing on bending stiffness, ultimate bearing capacity, and failure modes. The results demonstrate that SFRC joints exhibit superior ultimate bearing capacity compared to plain concrete (PC) and reinforced concrete (RC) joints, particularly under positive bending moments, while their stiffness remains comparable to PC joints but lower than RC joints during the moment-increasing phase, indicating limited influence of steel fibers on joint rigidity. Compared with single-bolt designs, the double-layer bolt configuration significantly improves both ultimate bearing capacity and joint stiffness, demonstrating 398% (bent bolts) and 225% (inclined bolts) stiffness enhancement under positive bending, along with 12%-14% ultimate capacity improvement under negative bending. While inclined-bolt joints exhibit intermediate mechanical performance appropriate for conventional applications, double-layer bolt joints provide superior ultimate bearing capacity under negative bending conditions, making them ideal for projects demanding high negative moment resistance. 2025 Vol. 62 (4): 182-196 [Abstract] ( 17 ) [HTML 1KB] [ PDF 12932KB] ( 63 ) 197 Research on Wind Resistance and Optimization Design of Steel Corrugated Plate Support for Tunnel Shafts ZHONG Wulin1 HAN Xingbo1 YE Fei1 WANG Han1 CAO Xiaoyong2 XI Weizheng2 Due to the high structural strength and rapid assembly construction advantages, corrugated steel plates have been increasingly applied in tunnel shaft support structures. As shafts serve as ventilation channels during the operational period of tunnels, the wall surface resistance directly affects operational energy consumption. To investigate the ventilation resistance characteristics when corrugated steel plates are used as shaft linings, numerical simu? lations were employed to analyze the influence patterns of key design parameters (such as corrugation depth and pitch) on ventilation resistance. An optimal parameter combination and a calculation formula for the frictional resis? tance of steel corrugated plates along the shaft length were proposed. Regarding the influence of the initial installation position of the inlet corrugated steel plate on local ventilation resistance, comparative analyses of the pressure loss patterns for three starting positions—corrugation trough, crest, and mid-wave—were conducted. Furthermore,by establishing local resistance analysis models for different corrugation profiles, the effects of varying corrugation radii on local resistance were revealed. Results indicate that the corrugated plate with a profile of 68×13 exhibits the lowest frictional resistance along the shaft length. However, considering structural performance, construction convenience, and long-term stability, the 230×64 corrugated plate—having slightly higher resistance—is recommended.For inlet corrugation starting position, the crest is preferred, resulting in only 54% of the ventilation resistance compared to starting at the trough. For the 230×64 corrugated plate, it is recommended to optimize its radius to 52 mm,which can reduce the frictional resistance coefficient to 48% of that obtained using the code-specified radius (57 mm). 2025 Vol. 62 (4): 197-207 [Abstract] ( 19 ) [HTML 1KB] [ PDF 5103KB] ( 72 ) 208 Development of a Scaled Multifunctional TBM Rock-breaking Test Platform GENG Qi XIE Weifeng YANG Mulin WANG Xuebin HUANG Yufeng LI Lei LI Xiaobin LI Zhibiao To meet the experimental requirements for studying rock-breaking mechanisms, excavation performance, and cutter wear characteristics during the research and construction of full-face TBM, an innovative modular cutterhead design was proposed, and a scaled-down multifunctional TBM rock-breaking test platform was developed. The platform integrates disc cutter rotary rock-breaking, continuous cutterhead excavation, disc cutter wear testing, and tunnel face image reconstruction. The dimensions of the test platform are 1,180 mm × 960 mm × 1,600 mm, accommodating rock specimens up to 540 mm × 540 mm × 120 mm in size. The maximum thrust capacity is 200 kN, and the maximum torque capacity is 2,000 N?m. After construction of the test platform, a series of experiments were conducted by replacing the cutterhead cutting tools, including disc cutter rock-breaking tests, disc cutter group excavation tests, disc cutter wear tests, and tunnel face surrounding rock reconstruction tests. The results demonstrated desirable experimental outcomes and reliable test data, verifying the comprehensiveness and reliability of the test platform's functions. 2025 Vol. 62 (4): 208-218 [Abstract] ( 14 ) [HTML 1KB] [ PDF 6723KB] ( 53 ) 219 Experimental Test and Mechanism Study on Soil Adhesion Reduction Techniques for Mud Cake Formation on Shield Cutterheads TAN Xinyu1 WEI Meng1,2 LAN Lingshen1 SHANG Qiang1 ZHANG Haitao1 The mud cake formation on shield cutterhead in clay strata severely impacts tunnelling efficiency. Traditional single-component soil conditioner faces limitations in adhesion inhibition effectiveness and unclear mechanisms. To resolve these limitations, this study develops a synergistic soil conditioning approach integrating foam agents and dispersants. Comprehensive experiments were conducted to assess adhesion reduction performance, supported by quantitative analyses of liquid-plastic limits, zeta potential, and interparticle repulsion energy to clarify the fundamental mechanisms. Results reveal that under optimal synergistic parameters (20% foam injection ratio with 0.1%-0.2% dispersant dosage), the combined additives achieve superior adhesion mitigation. The conditioners reduce the liquid-plastic limits and increase the negative charge of the soil, causing the Zeta potential to decrease with increasing conditioner dosage. Moreover, dispersants synergize with foam lubrication to intensify interparticle electrostatic repulsion energy, thereby effectively suppressing clay particle agglomeration and adhesion on cutterhead surface. 2025 Vol. 62 (4): 219-229 [Abstract] ( 18 ) [HTML 1KB] [ PDF 8120KB] ( 63 ) 230 Experimental Evaluation and Application Study on the Shield Muck Cake Decomposition Agents LIU Pengfei1,2 ZENG Dexing2 WANG Xiao3 YANG Zhao2 LI Yu2 In response to the challenges in evaluating the performance of decomposition agents in the treatment of muck cakes in shield air bubble chamber, and the difficulty in accurately determining the optimal agent parameters,this study, based on a shield tunnel project, developed a muck cake compaction device and a decomposition effect evaluation device. Muck cake specimens were fabricated by compacting muck cake-prone formation soils using the compaction device, and their decomposition behavior under different types and concentrations of decomposition agents was investigated. The optimal decomposition agent was identified and subsequently applied in the shield air bubble chamber treatment. The results indicate that: (1) The decomposition process of muck cakes in water can be divided into three stages: initial water absorption, rapid decomposition, and stabilization. In the initial stage, muck cakes first absorb water and then start decomposing; during the rapid decomposition stage, the decomposition rate is high and decomposition mass increases rapidly; in the stabilization stage, the decomposition mass no longer significantly increases. (2) The best decomposition performance for muck cake specimens was achieved using decomposition agent A with 6% concentraion. (3) After injecting the decomposition agent solution into the shield chamber, the muck cake on the cutterhead was effectively removed, resulting in noticeable reductions in shield thrust and cutterhead torque, as well as a significant increase in advance rate, confirming the excellent practical effectiveness of the selected decomposition agent in muck cake treatment. 2025 Vol. 62 (4): 230-237 [Abstract] ( 18 ) [HTML 1KB] [ PDF 2970KB] ( 71 ) 238 Experimental Study on the Road Performance of Geopolymer-based Solidifiable Fluid Shield Waste Slurry ZHANG Ming1, 2, 3 HOU Hao4 CHEN Changqing2, 3 HAN Zhihao5, 6, 7 CHEN Foci2, 3 HE Junpei5 The disposal of waste slurry generated during urban tunnel construction is challenging, while road construction often faces a shortage of fill materials. To achieve the resource utilization of shield slurry, this study explores and verifies the feasibility of the geocell-reinforced geopolymer solidification technology for the disposal of shield slurry. By comparing the solidification effects of geopolymer and cement on waste slurry, the study comprehensively evaluates the static and dynamic properties of the solidified materials, and analyzes their suitability as subgrade fill materials based on road performance criteria. The results indicate that: (1) Geopolymer solidification exhibits a faster strength development rate compared to cement solidification, with a strength increase of 42% to 238%,making it more likely to meet road strength requirements. (2) The introduction of geocells not only significantly enhances the strength of the solidified soil but also shifts the failure mode from plastic failure to elastic failure. It reduces both plastic and elastic strain under cyclic loading, and under 10,000 cycles of the load with 400 kPa, the geopolymer-solidified sample accumulates less than 0.6% plastic strain, demonstrating superior dynamic performance.(3) When dynamic stress exceeds 600 kPa, the deformation between the embossed surface of the geocell and the solidified soil becomes non-coordinated, leading to cyclic shear damage at the contact interface, though no significant adverse effects on normal road use are observed. 2025 Vol. 62 (4): 238-247 [Abstract] ( 16 ) [HTML 1KB] [ PDF 4678KB] ( 60 ) 248 The Reuse and Performance Testing of Shield Tunnel Mucks in Synchronous Grouting Materials CHEN Ming1 ZHAO Dapeng2 ZHANG Jingxiang1 GAO Hui1 WANG Xing1 HAO Jianshuai3 FANG Kuizhen3 The utilization of tunnel shield muck for the preparation of backfill grouting materials presents a viable strategy for enhancing resource recycling and achieving carbon reduction goals in shield tunnelling. This study employs waste sands and mucks generated during shield construction in the NanchangTianxiang Avenue Tunnel along with locally sourced steel slag (SS), as primary raw materials. An orthogonal experimental design is applied to optimize the mix proportions of the grouts, examining the effects of SS substitution rate, superplasticizer dosage, and muck content on key performance parameters such as grout fluidity and 28-day compressive strength. Micro-structural analyses, including X-ray diffraction and scanning electron microscopy, are conducted to investigate the phase composition, morphology, and hydration characteristics of hardened grouts at various curing ages. Experimental results indicate that a mix with 20% SS replacement rate, 5% superplasticizer dosage, and 30% muck content yields an initial fluidity of 215 mm and a 28-day compressive strength of 4.6 MPa. The determined optimal mix ratio is cement : fly ash : SS : shield waste sand : muck : bentonite : superplasticizer : water = 130 : 200 : 50 : 630 : 270 : 100 :6.4 : 600. The grout prepared with this formulation demonstrates low bleeding and shrinkage rates, meeting the engineering requirements for backfill grouting applications. Hydration analysis reveals that the synergistic effect of SS hydration and the pozzolanic reaction of fly ash promotes the formation of more ettringite and C-S-H gel, which effectively fills internal voids and enhances the bonding strength of the interfacial transition zone. Consequently, a significant improvement in compressive strength at 28 days is achieved. 2025 Vol. 62 (4): 248-258 [Abstract] ( 18 ) [HTML 1KB] [ PDF 6140KB] ( 73 ) 259 Key Construction Technologies for the Ruyifang Immersed Tunnel LIU Liying1 WEI Lixin1 YU Zhiyuan2 YANG Xudong3 YE Tingting1 The construction of the Ruyifang Immersed Tunnel in Guangzhou faces challenges, such as deep soft soil,dense buildings and structures, limited space for alignment layout, spatial intersection between the tunnel and subway, difficulties in retaining deep soft soil, full- ection concrete pouring of tunnel segments within a limited space,and the vibration response of the adjacent shield tunnel induced by rock excavation in the foundation trench. To solve spatial conflicts with subway space, the design concept of close-range parallel-construction and local integral co-construction was proposed. The wall anchor and lattice wall support scheme enabled vertical excavation of the adjacent dry dock. This overcame difficulties in dry dock site selection and deep soft soil support in sensitive areas.The development of a fully automated hydraulic walking combined steel formwork system for full-section element without counter-pulling within the confined space of a dry dock, as well as pouring, cooling, and insulation technologies, has significantly enhanced prefabrication efficiency and pouring quality. A double-row steel sheet pile cofferdam retaining system addressed issuses of limited working areas and insufficient bearing capacity in deep silty soil.The vibration response characteristics of adjacent shield tunnel induced by foundation trench excavation were revealed, and the environmental impact control schemes including drilling rod weight and drilling safety distance were determined. These research results support Ruyifang Immersed Tunnel construction and provide valuable references for similar projects. 2025 Vol. 62 (4): 259-272 [Abstract] ( 22 ) [HTML 1KB] [ PDF 14213KB] ( 58 ) 273 Research on Optimization of Construction Methods for Ultra-large Cross-section Tunnels: A Case Study of the Lihuashan Tunnel on the Tianfu New Area-Qionglai Expressway LUO Long1 ZHU Kaicheng2 HAN Yuxuan3 CAI Dong4 LIU Zheqi5 WANG Jun6 With the rapid development of infrastructure projects in western China, the demand for expressway tunnelling has been increasing. Among them, ultra-large cross-section tunnels present considerable challenges for construction due to their low flatness ratio, large span, and complex excavation procedures. This study takes the Lihuashan Tunnel, a key control project on the Tianfu New Area-Qionglai Expressway, as the research object, and systematically investigates construction methods suitable for ultra-large cross-section tunnels. Numerical simulations were conducted to compare the differences between the double side drift method and the six-step steel frame rock wall method in terms of surrounding rock stability and structural stress characteristics, thereby verifying the safety and reliability of the latter. Further optimization of construction sequences for different steel frame rock wall method construction schemes was carried out to determine the most effective sequence. Based on field monitoring data, the deformation characteristics of surrounding rock and the stress characteristics of primary support structures during actual construction were analyzed, further validating the engineering applicability of the six-step steel frame rock wall method. The results indicate that this method can ensure construction safety while significantly improving progress. 2025 Vol. 62 (4): 273-282 [Abstract] ( 16 ) [HTML 1KB] [ PDF 7612KB] ( 76 ) 283 Mechanical Behaviors and Control Techniques of Karst Tunnel Support Structures in Dolomitic Limestone Strta BA Jin1 TANG Gang2 To investigate the mechanical behavior of karst tunnel support structures in dolomitic limestone formations, this study combines laboratory tests and numerical simulations based on the Lanhua Railway Tunnel project,analyzing the effects of permeability, porosity, and hydraulic head of karst water channels on tunnel structural stress.The results show that the dolomitic limestone formation in the study area is Grade IV? surrounding rock with uniaxial compressive strength of 26.3 MPa. The forces on both primary support and secondary lining structures increase with the permeability and porosity of water channels, showing faster initial growth rates that gradually slow down, while exhibiting linear growth with increasing water head height. Structural forces are most sensitive to water head height,followed by porosity, and least sensitive to permeability. Based on field conditions, a stability control technology of"advanced prediction + on-site treatment + post-construction monitoring" was proposed for tunnel karst sections,with application results demonstrating its effectiveness in ensuring construction safety of karst tunnels. 2025 Vol. 62 (4): 283-290 [Abstract] ( 18 ) [HTML 1KB] [ PDF 4278KB] ( 57 ) 291 Safety Evaluation of Tunnel Lining Reinforced with Steel Strips under Coupled Multiple Defects WEN Jingzhou1 LI Youhe1 YANG Xinze1 WU Gang1 YU Yangshou2 WANG Zhiliang2 To clarify the reinforcement effect of steel strips on tunnel linings under coupled multiple defects, three typical defect types—insufficient lining thickness, concrete degradation, and voids behind the lining—were investigated. Based on the load-structure method, a numerical model of the lining was established to analyze the variation of sectional safety factors under different coupled defect conditions, and the safety performance of linings reinforced with steel strips of varying thicknesses was further evaluated. The results indicate that: when a single defect occurs,such as insufficient local lining thickness reduced to 60% of its initial value, concrete performance degraded to 60% of its initial value, or the presence of voids alone, the sectional safety factors of the lining still meet the code requirements. However, when insufficient thickness and concrete degradation occur simultaneously at the arch crown, arch waist, or arch foot, the safety factor of the defective section all falls below the code limit of 2.4. When insufficient thickness and voids couple at the arch waist, stress redistribution reduces the safety factor of the arch crown to 2.3.When all three defects act simultaneously at the arch crown, arch waist, or arch foot, the safety factors drop to 2.1, 2.0, and 2.0, respectively. For coupled insufficient thickness and concrete degradation at the arch crown, reinforcement with a 6 mm steel strip restores the safety performance to meet the code requirements. For coupled insufficient thickness and voids at the arch waist, reinforcement with a 4 mm steel strip increases the arch crown safety factor to 3.0. Moreover, 4 mm steel strip reinforcement ensures that the sectional safety factors meet the code requirements even under the coupling of all three defects. 2025 Vol. 62 (4): 291-300 [Abstract] ( 14 ) [HTML 1KB] [ PDF 5715KB] ( 72 ) 301 Multi-source Data Fusion-based Diagnosis and Treatment Strategies for Tructural Defects in Liangjiashan Tunnel on Heavy-haul Railway LI Ruijun1 SONG Zongying2 LI Chen1 WANG Wenbin2 REN Yuzhen3,4 CAI Jianhua3,4 ZHANG Jiaxu3,4 This study addresses typical defects observed during long-term operation of the Liangjiashan heavy-haul railway tunnel, including lining cracks, water leakage, and subgrade mud pumping, by proposing an integrated tunnel defect diagnosis method based on multi-source data fusion from geological and structural perspectives. The methodology systematically combines geological survey analysis, historical seismic data, 3D laser scanning of surface defects, ground-penetrating radar detection of lining quality, concrete strength testing, permeable groundwater analysis, core drilling verification, historical maintenance records, and manual inspections to perform comprehensive correlation analysis of defect characteristics, development patterns, and causative factors, thereby providing a scientific basis for systematic tunnel rehabilitation. Diagnostic results classify the tunnel's deterioration level as Grade AA, with proposed countermeasures including valley drainage, radial grouting reinforcement, crack repair,drainage system optimization, and implementation of an intelligent monitoring system. 2025 Vol. 62 (4): 301-308 [Abstract] ( 16 ) [HTML 1KB] [ PDF 4508KB] ( 74 )

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