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学者姓名：郑路
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Abstract ：
Shield misalignment is a common problem in shield tunnels, which seriously affects the safety and durability of tunnels. However, at present, there is a lack of research on the influence of shield misalignment on the shear capacity of the circumferential joint structure, and the failure mechanism of the circumferential joint structure before and after reinforcement is not clear. Therefore, this paper simulates the influence of misalignment on the performance mechanism of segmented circumferential connection and the effect of channel reinforcement on the ABAQUS platform. The simulation results are compared with the full-scale test results, and the results show that the shear failure process of the circumferential joint can be divided into three stages under the condition of no reinforcement. In the first stage, the vertical load increases, but the misalignment between the shield tunneling sections is very small. In the second stage, the load almost does not increase, but the degree of misalignment increases. In the third stage, the load-displacement relationship is nonlinear, indicating that the bending bolt has been sheared. Under the condition of unreinforced, the bolt will form two plastic hinges when it fails. After reinforcing the channel, the removal of the bolt forms only one plastic hinge. After channel steel reinforcement, the boundary area between the channel steel web and the steel plate first reaches the ultimate tensile strength of the steel plate, and the failure mode becomes channel steel reinforcement failure. Under the same shear load, the misalignment of the circumferential joint reinforced with channel steel is reduced. In this paper, the misalignment relationship of shear load and the yield of the bending bolt obtained through numerical calculation is consistent with the conclusion of the full-scale test. However, the circumferential connection misalignment obtained via numerical calculation is relatively small. The yield position of the bending bolt is also in good agreement with the test results, and the bolt strain obtained through the test is relatively small.
Keyword ：
channel reinforcement channel reinforcement circumferential joints circumferential joints full-scale test full-scale test misalignment misalignment shield tunneling segments shield tunneling segments
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| GB/T 7714 | Su, Hang , Deng, Tao , Yang, Zengquan et al. Characterization of Shear Damage and Channel Reinforcement of Circumferential Joints between Shield Tunneling Segments Based on Numerical Simulation [J]. | BUILDINGS , 2024 , 14 (2) . |
| MLA | Su, Hang et al. "Characterization of Shear Damage and Channel Reinforcement of Circumferential Joints between Shield Tunneling Segments Based on Numerical Simulation" . | BUILDINGS 14 . 2 (2024) . |
| APA | Su, Hang , Deng, Tao , Yang, Zengquan , Qin, Jianpeng , Zheng, Lu . Characterization of Shear Damage and Channel Reinforcement of Circumferential Joints between Shield Tunneling Segments Based on Numerical Simulation . | BUILDINGS , 2024 , 14 (2) . |
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The unevenness of ring faces (or the local gaps due to gaskets) is inevitable during the assembling of lining segments, which could cause the cracking or damage of segments and might endanger the safety of lining structure in severe cases. Based on the shear resistance prototype test of lining segment, the refined numerical simulation for the P2-typed standard segment was established upon the ABAQUS numerical platform. The jacking plates were placed on the top of segment, the gaskets are placed at the bottom of segment, and the right gasket was left empty to form a local gap. The uniform load was gradually applied upon the top of segment through jacking plates. The mechanical responses of the segment with local void condition were analyzed under the gradual action of jacking force. The cracking process and the shearing capacity of segment with uneven ring face condition were well focused on. The simulation results show that the 1st crack appears on the upper part of segment inner surface with 2 mm under the jacking force of 850 kN. When the jacking force increases to 1 120 kN, the vertical displacement of the segment bottom reaches 6 mm. Another two new cracks appear on the segment inner surface, and the 1st crack further expands to the outer surface and develops into the penetrating cracks. The cracking process of the segment is described sequentially as inner surface → upper ring surface → outer surface. Considering the potential risk of leakage of water caused by penetrating cracks, the shear capacity (yield load) of P2-typed standard segment was determined to be approximately 1 120 kN. Comparing the numerical simulation results with the prototype test, the cracking expansion, the distribution pattern and the shearing capacity obtained from both two means were almost consistent, which implies the reliability of numerical simulation. These results can provide reference for the design and construction of shield tunnel. © 2024, Central South University Press. All rights reserved.
Keyword ：
Gaskets Gaskets Numerical models Numerical models Plates (structural components) Plates (structural components) Shearing Shearing Shielding Shielding Simulation platform Simulation platform Tunnel linings Tunnel linings
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| GB/T 7714 | Guan, Zhenchang , Yang, Zelong , Ning, Maoquan et al. On the shearing capacity characteristics of lining segment with uneven ring surface condition [J]. | Journal of Railway Science and Engineering , 2024 , 21 (4) : 1533-1543 . |
| MLA | Guan, Zhenchang et al. "On the shearing capacity characteristics of lining segment with uneven ring surface condition" . | Journal of Railway Science and Engineering 21 . 4 (2024) : 1533-1543 . |
| APA | Guan, Zhenchang , Yang, Zelong , Ning, Maoquan , Liu, Hao , Zheng, Lu . On the shearing capacity characteristics of lining segment with uneven ring surface condition . | Journal of Railway Science and Engineering , 2024 , 21 (4) , 1533-1543 . |
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The baffle effectively slowed down debris flow velocity, reduced its kinetic energy, and significantly shortened the distance of debris flow movement. Consequently, they are widely used for protection against natural hazards such as landslides and mudslides. This study, based on the three-dimensional DEM (Discrete Element Method), investigated the impact of different baffle positions on debris flow protection. Debris flow velocity and kinetic energy variations were studied through single-factor experiments. Suitable baffle positions were preliminarily selected by analyzing the influence of the first-row baffle position on the impact force and accumulation mass of debris flow. Subsequently, based on the selected baffle positions and four factors influencing the effectiveness of baffle protection (baffle position (P), baffle height (h), row spacing (Sr), and angle of transit area (α)), an orthogonal design was employed to further explore the optimal arrangement of baffles. The research results indicate that the use of a baffle structure could effectively slow down the motion velocity of debris flows and dissipate their energy. When the baffle is placed in the transit area, the impact force on the first-row baffle is greater than that when the baffle is placed in the deposition area. Similarly, when the baffle is placed in the transit area, the obstruction effect on debris flow mass is also greater than that when the baffle is placed in the deposition area. Through orthogonal experimental range analysis, when the impact on the first row of baffles is used as the evaluation criterion, the importance of each influencing factor is ranked as α > P > Sr > h. When the mass of debris flow behind the baffle is regarded as the evaluation criterion, the rank is changed to P > α > Sr > h. The experimental simulation results show that the optimal baffle arrangement is: P5, Sr=16, α=35°, h=9. © Science Press, Institute of Mountain Hazards and Environment, CAS and Springer-Verlag GmbH Germany, part of Springer Nature 2024.
Keyword ：
Baffle Baffle Debris flow Debris flow Discrete element Discrete element Protective effect Protective effect
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| GB/T 7714 | Sun, X. , Chen, M. , Bi, Y. et al. Protective effects of baffles with different positions, row spacings, heights on debris flow impact [J]. | Journal of Mountain Science , 2024 , 21 (7) : 2352-2367 . |
| MLA | Sun, X. et al. "Protective effects of baffles with different positions, row spacings, heights on debris flow impact" . | Journal of Mountain Science 21 . 7 (2024) : 2352-2367 . |
| APA | Sun, X. , Chen, M. , Bi, Y. , Zheng, L. , Che, C. , Xu, A. et al. Protective effects of baffles with different positions, row spacings, heights on debris flow impact . | Journal of Mountain Science , 2024 , 21 (7) , 2352-2367 . |
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When applying the three-dimensional discontinuous deformation analysis (3D-DDA) method to simulate the dynamic response of rock mass in an earthquake, appropriate artificial boundaries and input methods should be considered. In this study, the 3D-DDA method was modified by introducing the viscoelastic artificial boundary and the seismic motion input method based on the wave field decomposition method and with the consideration of the lateral free-field wave. Subsequently, the correctness of the boundary and the input method was verified through numerical examples. The results of the numerical examples were almost consistent with the theoretical solution. The introduced viscoelastic artificial boundary and seismic motion input method improved the applicability of the 3D-DDA method and can be further applied to simulate actual engineering cases. Viscoelastic artificial boundary is applied and validated in 3D-DDA.The differences between viscoelastic boundary and existing boundaries are compared.Modified 3D-DDA can consider wave field decomposition and lateral free-field wave for seismic motion input.Feasibility of modified 3D-DDA to study the dynamic response of rock mass in an earthquake is studied.
Keyword ：
Artificial boundary Artificial boundary Seismic motion input methods Seismic motion input methods Three-dimensional discontinuous deformation analysis method Three-dimensional discontinuous deformation analysis method Viscoelastic boundary Viscoelastic boundary
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| GB/T 7714 | Lin, Si-huang , Deng, Tao , Zheng, Lu et al. Implementation of Viscoelastic Artificial Boundary and Seismic Motion Input Method in Three-Dimensional Discontinuous Deformation Analysis Method [J]. | ROCK MECHANICS AND ROCK ENGINEERING , 2024 , 57 (7) : 4995-5015 . |
| MLA | Lin, Si-huang et al. "Implementation of Viscoelastic Artificial Boundary and Seismic Motion Input Method in Three-Dimensional Discontinuous Deformation Analysis Method" . | ROCK MECHANICS AND ROCK ENGINEERING 57 . 7 (2024) : 4995-5015 . |
| APA | Lin, Si-huang , Deng, Tao , Zheng, Lu , Zhang, Hong , Wu, Wei , Fu, Xiao-dong et al. Implementation of Viscoelastic Artificial Boundary and Seismic Motion Input Method in Three-Dimensional Discontinuous Deformation Analysis Method . | ROCK MECHANICS AND ROCK ENGINEERING , 2024 , 57 (7) , 4995-5015 . |
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Abstract ：
The baffle effectively slowed down debris flow velocity,reduced its kinetic energy,and significantly shortened the distance of debris flow movement.Consequently,they are widely used for protection against natural hazards such as landslides and mudslides.This study,based on the three-dimensional DEM(Discrete Element Method),investigated the impact of different baffle positions on debris flow protection.Debris flow velocity and kinetic energy variations were studied through single-factor experiments.Suitable baffle positions were preliminarily selected by analyzing the influence of the first-row baffle position on the impact force and accumulation mass of debris flow.Subsequently,based on the selected baffle positions and four factors influencing the effectiveness of baffle protection(baffle position(P),baffle height(h),row spacing(Sr),and angle of transit area(α)),an orthogonal design was employed to further explore the optimal arrangement of baffles.The research results indicate that the use of a baffle structure could effectively slow down the motion velocity of debris flows and dissipate their energy.When the baffle is placed in the transit area,the impact force on the first-row baffle is greater than that when the baffle is placed in the deposition area.Similarly,when the baffle is placed in the transit area,the obstruction effect on debris flow mass is also greater than that when the baffle is placed in the deposition area.Through orthogonal experimental range analysis,when the impact on the first row of baffles is used as the evaluation criterion,the importance of each influencing factor is ranked as α＞P＞Sr＞h.When the mass of debris flow behind the baffle is regarded as the evaluation criterion,the rank is changed to P＞α＞Sr＞h.The experimental simulation results show that the optimal baffle arrangement is:P5,Sr=16,α=35°,h=9.
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| GB/T 7714 | SUN Xinpo , CHEN Min , BI Yuzhang et al. Protective effects of baffles with different positions,row spacings,heights on debris flow impact [J]. | 山地科学学报（英文） , 2024 , 21 (7) : 2352-2367 . |
| MLA | SUN Xinpo et al. "Protective effects of baffles with different positions,row spacings,heights on debris flow impact" . | 山地科学学报（英文） 21 . 7 (2024) : 2352-2367 . |
| APA | SUN Xinpo , CHEN Min , BI Yuzhang , ZHENG Lu , CHE Chi , XU Ao et al. Protective effects of baffles with different positions,row spacings,heights on debris flow impact . | 山地科学学报（英文） , 2024 , 21 (7) , 2352-2367 . |
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Sudden freefall is very common in high-velocity and long-runout rockslides. The combination of freefall and joints (a rock mass structure) may cause a high degree of fragmentation of sliding rock mass. However, previous studies often simplified fragmentation of rock mass with initial joints to be caused by impact after sliding, ignoring the contribution of freefall to rockslide fragmentation and spreading. Several multi-stage slope models are created in this study referring to the topographic characteristics of rockslides, including impact after sliding, inter-slope freefall, once-end-slope freefall, and twice-end-slope freefall. The rock masses are simulated by setting different numbers of persistent joints in analog blocks. The joints are described by the unbonded particles. The results suggest that the fragmentation of analog blocks consists of the fracture caused by tensile cracks and the local fragmentation caused by impact. Fragmentation is an effective sink, which shortens the runout distance of the center of the mass. Freefall and initial joints limit the momentum transfer between the front and rear fragments, so the freefall cannot directly promote rockslide spreading. However, freefall and initial joints facilitate the fragmentation of the block, producing a high sphericity of fragments, which are easy to roll and bounce under the disturbance of the freefall. This might be an important reason for the long-runout spreading of rockslides. © The Author(s) 2024.
Keyword ：
Landslides Landslides Rock bursts Rock bursts Rock mechanics Rock mechanics Rocks Rocks
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| GB/T 7714 | Zhu, Zhiyuan , Wu, Yihan , Bi, Yuzhang et al. Contribution of freefall and rock mass structure to post-fragmentation spreading of rockslides [J]. | Bulletin of Engineering Geology and the Environment , 2024 , 83 (8) . |
| MLA | Zhu, Zhiyuan et al. "Contribution of freefall and rock mass structure to post-fragmentation spreading of rockslides" . | Bulletin of Engineering Geology and the Environment 83 . 8 (2024) . |
| APA | Zhu, Zhiyuan , Wu, Yihan , Bi, Yuzhang , Zheng, Lu , Chen, Fei , Wu, Wei et al. Contribution of freefall and rock mass structure to post-fragmentation spreading of rockslides . | Bulletin of Engineering Geology and the Environment , 2024 , 83 (8) . |
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在衬砌管片拼装过程中难免出现环端面不平整(或环缝间垫片局部脱空)的情形，进而在顶推力作用下管片容易产生局部开裂破损，严重时甚至危及衬砌结构安全。鉴于此，以衬砌管片抗剪原型试验为基础，在ABAQUS数值分析平台上建立P2型标准块管片的精细化模型，管片上部设置千斤顶靴板，底部设置垫片并使右侧垫片脱空。在靴板上逐级施加均布荷载，以分析局部脱空情况下衬砌管片在逐级顶推力作用下的力学响应，探讨环端面不平整条件下衬砌管片的裂缝发展过程及抗剪承载特性。数值模拟结果表明：顶推力加载至850 kN，管片脱空端竖向位移达到2 mm，管片内弧面上部出现第1道裂缝，内置钢筋仍处于弹性阶段；加载至1 120 kN，脱空端竖向位移达到6 mm，内弧面上出现2道新裂缝，同时第1道裂缝进一步扩展形成内外贯穿性裂缝，即管片裂缝发展过程大致为内弧面→上环端面→外弧面，且裂缝附近上层纵向钢筋达到屈服强度；考虑到内外贯穿裂缝给衬砌管片带来较大渗漏水隐患，认为P2型标准块管片的抗剪承载力(即屈服荷载)约为1 120 kN。将数值模拟结果与原型试验结果进行对比，二者所得管片裂缝分布与扩展规律大致一致，抗剪承载力基本相符，验证了数值模拟结果的可靠性。研究成果可为盾构隧道的衬砌设计与掘进施工提供参考依据。
Keyword ：
原型试验 原型试验 数值模拟 数值模拟 环端面不平整 环端面不平整 盾构隧道 盾构隧道 管片抗剪承载特性 管片抗剪承载特性
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| GB/T 7714 | 关振长 , 杨泽龙 , 宁茂权 et al. 环端面不平整条件下衬砌管片抗剪承载特性研究 [J]. | 铁道科学与工程学报 , 2024 , 21 (04) : 1533-1543 . |
| MLA | 关振长 et al. "环端面不平整条件下衬砌管片抗剪承载特性研究" . | 铁道科学与工程学报 21 . 04 (2024) : 1533-1543 . |
| APA | 关振长 , 杨泽龙 , 宁茂权 , 刘浩 , 郑路 . 环端面不平整条件下衬砌管片抗剪承载特性研究 . | 铁道科学与工程学报 , 2024 , 21 (04) , 1533-1543 . |
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Calculating disc cutter wear and predicting wear life are long-standing issues affecting the efficiency and cost of tunnel boring machines (TBMs). During the TBM excavation process, the wear of the disc cutter is a comprehensive outcome of the interaction between the tool and rock. Studying the mechanisms of tool rock breaking and wear can assist in developing a more precise model for predicting cutter wear. Therefore, based on the rock- breaking and wear mechanisms of a cutter, this study developed a model for predicting the cutter wear rate and life. The model is based on the theory of dense core-cavity expansion combined with the motion state of a cutter. First, the TBM excavation process and rock-breaking mechanism of a cutter were analyzed in detail. A cutting force model under the compression shear failure mode based on the dense core-cavity expansion theory was established. Based on the force model, a prediction model for the wear rate and life of the disc cutter was established, considering the working characteristics and wear mechanism. Furthermore, the impact of penetration on the prediction model was investigated. In addition, to demonstrate the practicality of the method, this study conducted a comprehensive examination using engineering examples. The results showed that the average difference in the cutter average wear rate using the developed model was less than 3% compared with the actual engineering result. In addition, the average difference in the wear life rate was less than 5%. Finally, the developed prediction method was compared with other models. The wear rate fitting accuracy was improved by 4.91-10.85% and the wear life fitting accuracy was improved by 5.11-12.19% by the developed method. This improvement confirms the reasonableness and reliability of the method. This method can estimate the wear rate and lifespan of a cutter more accurately and reliably than other methods, providing a practical tool to TBM engineers to make informed decisions and optimize tool replacement programs.
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| GB/T 7714 | Su, H. , Guan, Z. C. , Deng, T. et al. Force and wear prediction model of disc cutter under compression shear failure mode based on dense core-cavity expansion theory (U-713) [J]. | GEOSHANGHAI 2024 INTERNATIONAL CONFERENCE, VOL 4 , 2024 , 1333 . |
| MLA | Su, H. et al. "Force and wear prediction model of disc cutter under compression shear failure mode based on dense core-cavity expansion theory (U-713)" . | GEOSHANGHAI 2024 INTERNATIONAL CONFERENCE, VOL 4 1333 (2024) . |
| APA | Su, H. , Guan, Z. C. , Deng, T. , Yang, Z. Q. , Qin, J. P. , Zheng, L. . Force and wear prediction model of disc cutter under compression shear failure mode based on dense core-cavity expansion theory (U-713) . | GEOSHANGHAI 2024 INTERNATIONAL CONFERENCE, VOL 4 , 2024 , 1333 . |
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Soil desiccation is a common physical phenomenon, which causes many geotechnical problems to unsaturated clayey soils. In this paper, a proposed model was incorporated into the original Discontinuous Deformation Analysis (DDA) to simulate the full desiccation process of a clayey soil from volume shrinkage to desiccation cracking and then to desiccation curling by focusing on soil suction. In this model, evaporation-induced soil volume shrinkage and suction-induced tensile failure were separately considered, in particular, soil suction was reasonably treated as an equivalent attractive force rather than a strength parameter. Then, a constrained desiccation test was simulated using the extended DDA model, and obtained numerical results were compared with the experimental results. The comparison results show that this model can capture the main features of the full desiccation process of the clayey soil. Moreover, the influences of soil suction and sample thickness on the desiccation cracking and curling were investigated, which agrees with the laboratory observations. This work aims to propose a novel yet simple model to reproduce the key characteristics of the soil's full desiccation process, and the results demonstrate that the extended DDA model can be served as a promising approach to analyzing the full desiccation process of clayey soils.
Keyword ：
Cracking Cracking Curling Curling Extended DDA Extended DDA Full desiccation process Full desiccation process Soil suction Soil suction
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| GB/T 7714 | Guo, Longxiao , Chen, Guangqi , Ding, Luqiang et al. Numerical simulation of full desiccation process of clayey soils using an extended DDA model with soil suction consideration [J]. | COMPUTERS AND GEOTECHNICS , 2023 , 153 . |
| MLA | Guo, Longxiao et al. "Numerical simulation of full desiccation process of clayey soils using an extended DDA model with soil suction consideration" . | COMPUTERS AND GEOTECHNICS 153 (2023) . |
| APA | Guo, Longxiao , Chen, Guangqi , Ding, Luqiang , Zheng, Lu , Gao, Jingyao . Numerical simulation of full desiccation process of clayey soils using an extended DDA model with soil suction consideration . | COMPUTERS AND GEOTECHNICS , 2023 , 153 . |
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Joint structure and sudden free-fall are very common in rock avalanches. But their contributions to fragmen-tation and subsequent runout are not clear. Previous studies simplify joints as persistent structural planes with unbonded strength, weakening the contribution of passive disintegration. The rock avalanches are limited to impact after sliding, as rocks crush from a slope to a horizontal plane. This study establishes three-stage slope models and blocks with non-persistent joints to study the fragmentation and spreading under the impact after freefall by the discrete element method (DEM). The results suggest that (1) The spreading distance is determined by the competition between the energy consumed and the high-velocity fragments generated by fragmentation. It is inaccurate to estimate the runout trend only from the fragmentation degree. (2) The joint surface destroys the integrity of blocks and promoted fragmentation. The joint length, distribution form, and angle significantly affect spreading. (3) Free-fall increases the impact velocity and angle of blocks. The contact-damping and strain energy consumption increase significantly. Due to the lack of slope support, the rear fragments do not have a secondary acceleration effect. The momentum transfer between the front and rear fragments is hindered.
Keyword ：
DEM DEM Fragmentation Fragmentation Free-fall Free-fall Joint structure Joint structure Rock avalanche Rock avalanche
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| GB/T 7714 | Zhu, Zhiyuan , Wu, Yihan , Zheng, Lu et al. Contributions of joint structure and free-fall to the fragmentation of rock avalanche: Insights from 3D discrete element analyses [J]. | COMPUTERS AND GEOTECHNICS , 2023 , 160 . |
| MLA | Zhu, Zhiyuan et al. "Contributions of joint structure and free-fall to the fragmentation of rock avalanche: Insights from 3D discrete element analyses" . | COMPUTERS AND GEOTECHNICS 160 (2023) . |
| APA | Zhu, Zhiyuan , Wu, Yihan , Zheng, Lu , Chen, Fei , Wu, Wei , Zhang, Hong et al. Contributions of joint structure and free-fall to the fragmentation of rock avalanche: Insights from 3D discrete element analyses . | COMPUTERS AND GEOTECHNICS , 2023 , 160 . |
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