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Dynamic sub-structure method for longitudinal seismic response of large-diameter shield tunnel through the complex strata

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Tunnelling and Underground Space Technology 2025年 163卷

作者： Haiyang, Zhuang Xiaoxiong, Li Kai, Zhao Mingluqiu, Hu Key Laboratory of Traffic Infrastructure Safety of Jiangxi Province East China Jiaotong University Nanchang330013 China Institute of Geotechnical Engineering Nanjing Tech University Nanjing210009 China

Based on the deficiencies of the generalized response displacement method and the integral response displacement method for longitudinal seismic analysis of the shield tunnel, the dynamic sub-str1cture analysis method for longitudinal seismic response of a large-diameter shield tunnel crossing the complex soil layer is proposed. The feasibility and superiority of the dynamic sub-structure analysis method are explored by comparing it with the calculation results of the three-dimensional (3D) soil-underground structure interaction model. Then, a finite element refined 3D model of the 2.7 km Suai submarine shield tunnel is established by using the proposed method, and the longitudinal seismic response of the large-diameter shield tunnel crossing complex soil layers is simulated and analyzed. The research results indicate that the proposed dynamic sub-structure method has clear concepts, accurate calculation results and high efficiency to simulate the dynamic soil-tunnel interaction, which can avoid the error effect of the equivalent soil spring used in the generalized response displacement method. At the same time, this method can consider the seismic effect of the complex soil layers which has been avoided by the generalized response displacement method and the integral response displacement method. Also, the calculation results by the proposed method can comprehensively present the typical earthquake damages of shield tunnels crossing the wide river valley or the strait. It proves that it is not appropriate to simplify the longitudinally of the shield tunnel into a straight line, as doing so would neglect the influence of the longitudinal slope of complex river valleys or the straits. Also, the longitudinal seismic response of the shield tunnel is more sensitive to low-frequency seismic waves and the bolts are more susceptible to seismic damage compared to the segment opening. © 2025 Elsevier Ltd

关键词： Seismic response

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Experimental and Numerical Study of Stress Diffusion in Artificial Hard Shell Layer Double Foundation of Dredging Silt

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SSRN 2023年

作者： Gao, Shihu Cai, Faxin Zeng, Fangjin Yuan, Guohui Wang, Long College of Architecture and Civil Engineering Wenzhou Polytechnic Chashan University Town Wenzhou325035 China College of Architecture and Civil Engineering Wenzhou University Chashan University Town Wenzhou325035 China The Key Laboratory of Engineering and Technology for Soft Soil Foundation and Tideland Reclamation of Zhejiang Province Wenzhou325035 China Innovation Centre of Tideland Reclamation and Ecological Protection Wenzhou University Wenzhou325035 China School of Civil and Surveying&Mapping Engineering Jiangxi University of Science and Technology Jiangxi Ganzhou341000 China The Key Laboratory of Environmental Geotechnical and Engineering Disaster Control of Jiangxi Province Jiangxi Ganzhou341000 China

At present, the selection of stress diffusion Angle (SDA) for Artificial hard shell layer (AHSL) double foundation is controversial, but the stress diffusion theory of Natural hard shell layer (NHSL) double foundation is still used for reference. Based on this, the effects of AHSL thickness h, load width B, AHSL elastic modulus E1, elastic modulus E2 of soft soil layer (SSL) and thickness H on the SDA θ of AHSL double foundation were analyzed through laboratory tests and numerical simulation. The results show that the stress diffusion effect of increasing the thickness and elastic modulus of AHSL is better than that of increasing the load width. The increase of elastic modulus and thickness of SSL is not conducive to stress diffusion of AHSL. SDA decreases gradually with the increase of elastic modulus of SSL, but the thickness of SSL does not affect the change of SDA. The SDA gradually increases to about 30° with the increase of AHSL elastic modulus. The load width is increased so that the SDA is increased from 16.80° to 32.24° and then reduced to 9.85°. Finally, the SDA of AHS was determined to be about 30°. © 2023, The Authors. All rights reserved.

关键词： Elastic moduli

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Properties regulation and application of biomass carbon based composite phase change materials in thermal energy storage

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Solar Energy 2025年 298卷

作者： Chen, Liwen Li, Yuanlin Fei, Hua Tong, Jianmin Dai, Xi Jiangxi Province Key Laboratory of Environmental Geotechnical Engineering and Hazards Control Jiangxi University of Science and Technology Jiangxi Ganzhou341000 China College of Science Jiangxi University of Science and Technology Jiangxi Ganzhou341000 China

With the continuous growth of global energy consumption, significant attention is being directed toward the development of efficient energy storage materials. Phase change materials (PCMs) are known for their excellent thermal energy reservoir characteristics and their capability to keep relatively stable temperature during the phase transition process. It has received great attention in the realm of thermal energy storage. This is due to their excellent thermal storage capabilities and superior heat regulation. However, difficulties such as material leakage and poor thermal conductivity limit their application potential in diverse environments. In order to optimize the thermal properties of PCMs, biomass based porous media, which are cost-effective, sustainable, and commonly used, can be used as the support material to effectively prepare shape-stable biomass composite phase change materials. This paper reviews the synthesis and research progress of biomass carbon based CPCMs, discusses their impact on the thermal properties of the underlying PCMs and the challenges encountered in the realm of solar energy harvesting, electronics, thermal management in buildings and waste heat recovery, and supplies a reference for further research on biomass carbon based CPCMs. © 2025 International Solar Energy Society

关键词： Carbon carbon composites

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Experimental Study on Shear Strength Characteristics of Frozen Soil - Cast-in-Situ Concrete Interface

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SSRN 2022年

作者： Sun, Tiecheng Dong, Chuangqi Zhang, Jiao Zong, Zihang Wu, Kai State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China Key Laboratory of Roads and Railway Engineering Safety Control Ministry of Education Shijiazhuang050043 China Hebei Province Technology and Innovation Center on Intelligent Construction of Infrastructure Shijiazhuang050043 China School of Civil Engineering Shijiazhuang Tiedao University Shijiazhuang050043 China

The roughness of contact surface is closely related to the friction coefficient and shear strength characteristics of pile-soil interface. At present, there is no recognized and unified quantitative characterization method of contact surface roughness. In this paper, the roughness formula is corrected in combination with the proposed form factor, and the low temperature direct shear test of the frozen soil-cast-in-situ concrete interface is carried out. The influence of several test factors, such as contact surface roughness, normal pressure and moisture content of soil sample, on frozen shear strength of frozen soil-cast-in-situ concrete contact surface is analyzed. The test results show that: (a) The frozen shear strength at the contact surface is mainly determined by the cementation of ice cementation force, cohesion and the bite force between frozen soil and concrete. The roughness corrected by the form coefficient can accurately characterize the contribution of bite force to the frozen shear strength of the contact surface. (b) The primary and secondary order of the influence of test control factors on the frozen shear strength of contact surface is normal pressure > moisture content of soil sample > test temperature > roughness > dry density. The normal pressure and moisture content have a strong and significant influence on the test results, the influence of dry density is not significant, and the influence of test temperature and roughness is in the middle. (c) The frozen shear strength of the contact surface increases with the increase of roughness, but the increase of normal pressure can weaken the effect of roughness on the enhancement of shear strength. © 2022, The Authors. All rights reserved.

关键词： Temperature

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Effect of the Crosslinking Degree on the Microstructure and Thermomechanical Properties of a Polymer Grouting Material

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SSRN 2022年

作者： Yuan, Lingxiu Zhang, Chao Wang, Cuixia Wei, Ning Wan, Jing Zhu, Chunhua Fang, Hongyuan Shi, Mingsheng School of Water Conservancy Engineering Zhengzhou University Zhengzhou450001 China National Local Joint Engineering Laboratory of Major Infrastructure Testing and Rehabilitation Technology Zhengzhou450001 China Collaborative Innovation Center for Disaster Prevention and Control of Underground Engineering Jointly Built by Provinces and Ministries Henan Province Zhengzhou450001 China Jiangsu Key Laboratory of Advanced Food Manufacturing Equipment and Technology Jiangnan University Wuxi214122 China School of Mechanics and Safety Engineering Zhengzhou University Zhengzhou450001 China

Polymer grouting materials are widely used in the field of trenchless rehabilitation of infrastructure, and their properties are closely related to the crosslinking process and crosslinking degree between components. In this paper, polyurethane (PU) models with different crosslinking degrees were built based on the molecular dynamics (MD) simulations method and Python script. We investigated the crosslinking reaction process of PU grouting materials and the effect of their crosslinking degree on the glass transition temperature (Tg) and tensile properties. Also, the rationality of the model was verified by comparing the Tg obtained in the simulation and experiment. The results showed that the crosslinking reaction is a volume shrinkage process, and the PU model has a good network structure. The non-bonding energy is the main reason for the variation in the Tg, which increased with increasing crosslinking degree. Besides, the tensile properties of PU are greatly affected by the crosslinking degree, and the elastic modulus increased with increasing crosslinking degree. The results are of great significance for understanding the microstructure and thermomechanical properties of PU grouting materials at the molecular level. © 2022, The Authors. All rights reserved.

关键词： Microstructure

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Energy evolution and distribution patterns of sandstone and its microscopic mechanism under multistage cyclic loading

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Geomechanics for Energy and the Environment 2025年 43卷

作者： Hongying Tan Hejuan Liu Chunhe Yang Haijun Mao Yujia Song Debin Xia Shengnan Ban Weimin Wang State Key Laboratory of Coal Mine Disaster and Control Chongqing University Chongqing 400044 China School of Resources and Safety Engineering Chongqing University Chongqing 400044 China State Key Laboratory of Geomechanics and Geotechnical Engineering Safety Institute of Rock and Soil Mechanics Chinese Academy of Sciences Wuhan 430071 China University of Chinese Academy of Sciences Beijing 100049 China Wuhan Institute of Technology School of Resources and Safety Engineering Hubei Province Wuhan 430205 China

Sandstone, as a fundamental engineering material in depleted oil and gas reservoir gas storage systems, is susceptible to damage and failure under periodic stress disturbances. In this study, multi-level multi-cyclic loading tests were carried out on sandstone samples over the confining pressures range of 5–40 MPa, accompanied by real-time acoustic emission (AE) monitoring and periodic nuclear magnetic resonance (NMR) measurements. This study investigats the effects of confining pressure, stress level, and the number of cycles on energy evolution and energy distribution in rock, revealing the micromechanisms of energy evolution during cyclic loading. The results indicate that during the first cyclic loading, the input energy is primarily converted into dissipated energy through the compression of small pores and some medium pores. In subsequent loading cycles, the input energy is primarily converted into dissipated energy through the initiation and propagation of internal microcracks. Under high confining pressure, the rock transitions from brittle to ductile behavior, enabling it to withstand greater deformation. Additionally, at high confining pressure, rocks accumulate more strain energy, while energy dissipation is higher compared to lower confining pressures. Throughout the cyclic loading, dissipated energy consistently accounts for less than 30 % of the total input energy across all stress levels. The linear energy storage coefficient remains independence from stress level and cycle number, but exhibits an inverse relationship with confining pressure. There is an obvious linear relationship between rock dissipation energy and AE energy. Higher AE energy indicate that the rock dissipates more strain energy.

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Optimizing deep learning-driven computer vision for civil infrastructure defect Identification: Challenges and strategies

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engineering Applications of Artificial Intelligence 2025年 158卷

作者： Ronghua Fu Zhimeng Huang Maosen Cao Drahomír Novák Chunhui Xie Jinwen Huang College of Mechanics and Engineering Science Hohai University Nanjing China National Engineering Research Center of Visual Technology School of Computer Science Peking University Beijing China Institute of Structural Dynamics and Control Hohai University Nanjing China Jiangxi Province Key Laboratory of Environmental Geotechnical Engineering and Hazards Control Jiangxi University of Science and Technology Ganzhou China Institute of Structural Mechanics Faculty of Civil Engineering Brno University of Technology Brno Czech Republic

With advancements in Internet of Things (IoT) technologies and deep learning, Structural Health Monitoring (SHM) is progressing towards long-distance and intelligent applications. To promote the widespread adoption of deep learning in vision-based SHM, this survey compiles optimization strategies derived from deep learning models specifically designed for defect identification in civil infrastructure—an area that has not been comprehensively explored. First, a concise overview of fundamental deep learning models for vision-based defect identification is provided. Next, optimization methods are categorized into three main groups, each addressing a distinct challenge encountered in practical vision-based SHM: optimizing considering defect-specific characteristics, lightweight design for real-time identification, and enhance robustness under complex environmental conditions. These methods are further classified systematically based on their similar features. This survey offers researchers a deeper understanding of the challenges in vision-based defect identification and assists them in selecting appropriate optimization techniques to address these challenges. Ultimately, it aims to enhance the effective deployment of deep learning models in vision-based SHM by improving accuracy, enabling real-time operation, and facilitating automated defect identification.

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Effect of geomembrane defects on the degradable contaminant transport through composite geomembrane cutoff walls: A novel transient model

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Journal of Environmental Chemical engineering 2025年第5期13卷

作者： Chun-Hui Peng Xiang-Hong Ding Hong-Xin Chen Yong He Biao Luo School of Architecture and Civil Engineering Jinggangshan University Key Laboratory of Jiangxi Province for Agricultural Environmental Pollution Prevention and Control in red Soil Hilly Region Ji’an 343009 China School of Civil Engineering Central South University Changsha 410075 China Department of Geotechnical Engineering Tongji University Shanghai 200092 China Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring Central South University Ministry of Education Changsha 410083 China School of Civil Engineering Hunan University Changsha 410082 China

Composite geomembrane cutoff walls (CGCW) are among the most effective techniques for managing contaminated sites. Accurately predicting contaminant transport through CGCW is essential to the efficient remediation and management of contaminated sites. Previous prediction models have predominantly focused on contaminant diffusion in intact CGCW, with insufficient attention given to CGCW with geomembrane (GMB) defects. This study introduces fully transient models for contaminant transport in a CGCW-aquifer system, comprising an upstream slurry wall, a GMB with defects, a downstream slurry wall, and the adjacent aquifers. The model allows for three types of GMB defects, i.e., joint defects, bottom gaps, and GMB holes, and incorporates the contaminant advection-diffusion-adsorption-degradation process in the CGCW-aquifer system. Results indicate that existing CGCW models overlook the critical impact of GMB positioning on the containment performance of CGCW with GMB defects. The semi-infinite boundary assumption and the non-degradation assumption commonly adopted in previous models lead to, respectively, an underestimation and overestimation of contaminant plume concentrations in the downstream aquifer. Additionally, increasing the widths of joint defects, bottom gaps, and GMB holes significantly reduces the containment efficiency of CGCW, especially under conditions of high hydraulic head and low slurry wall permeability. To address this, an equivalent design curve for CGCW with GMB defects is proposed, offering engineers a practical reference for determining the required wall thickness.

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Degradation mechanism of coal pillars in an underground coal gasification environment: Bearing capacity, pyrolysis behaviour and pore structure

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International Journal of Mining Science and Technology 2025年

作者： Li, Jian Bai, Jinwen Feng, Guorui Yilmaz, Erol Han, Yanna Wang, Zhe Wang, Shanyong Wu, Guowei College of Mining Engineering Taiyuan University of Technology Taiyuan 030024 China Key Laboratory of Shanxi Province for Mine Rock Strata Control and Disaster Prevention Taiyuan University of Technology Taiyuan 030024 China Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering Taiyuan 030024 China Department of Civil Engineering Geotechnical Division Recep Tayyip Erdogan University Rize Fener TR53100 Turkey College of Safety and Emergency Management Engineering Taiyuan University of Technology Taiyuan 030024 China Priority Research Centre for Geotechnical Science and Engineering School of Engineering The University of Newcastle Callaghan 2308 NSW Australia

Coal pillars are critical supporting structures between underground coal gasification gasifiers. Its bearing capacity and structural stability are severely threatened by high-temperature environments. To elucidate the high-temperature deterioration mechanism of coal pillars at multiple scales, coal strength features as a function of temperature were investigated via uniaxial compression and acoustic emission equipment. The pyrolysis reaction process and microstructure evolution were characterized via X-ray diffractometer (XRD), scanning electron microscope (SEM), thermogravimetric (TG), Fourier transform infrared spectroscopy (FTIR), and computed tomography (CT) tests. Experimental results reveal a critical temperature threshold of 500 °C for severe degradation of the coal bearing capacity. Specifically, both the strength and elastic modulus exhibit accelerated degradation above this temperature, with maximum reductions of 45.53% and 61.34%, respectively. Above 500 °C, coal essentially undergoes a pyrolysis reaction under N2 and CO2 atmospheres. High temperatures decrease the quantity of O2-based functional groups, growing aromaticity and the degree of graphitization. These changes induce dislocation and slip inside the coal crystal nucleus and then lead to deformation of the coal molecular structural units and strain energy generation. This process results in a great increase in porosity. Consequently, the stress deformation of coal increases, transforming the type of failure from brittle to ductile failure. These findings are expected to provide scientific support for UCG rock strata control.

关键词： Bearing characteristics Coal pillar Pyrolysis Thermal damage Underground coal gasification

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Sludge-based carbon as an effective admixture in alkali-activated cementitious composites to shield electromagnetic radiation

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Construction and Building Materials 2025年 489卷

作者： Zhengfeng Cao Wenkui Dong Murat Öztürk Xinyan Yang Xiang Xi School of Integrated Circuits Chongqing University of Posts and Telecommunications Chongqing 400065 China Centre for Infrastructure Engineering and Safety School of Civil and Environmental Engineering The University of New South Wales NSW 2052 Australia Department of Civil Engineering Faculty of Engineering Bursa Uludag University Bursa Turkey Anhui Province Key Laboratory for Control and Applications of Optoelectronic Information Materials Department of Physics Anhui Normal University Wuhu 241000 China Anhui Conch Industrial Technology Research Institute Co. Ltd. Wuhu 241000 China

This study first utilizes pyrolyzed municipal sludge (PMS) to prepare waste-based alkali-activated cementitious composites (ACC) with enhanced electromagnetic interference (EMI) shielding properties. The effect of PMS content on the EMI shielding effectiveness of the ACC was systematically investigated. The PMS used in this study features an amorphous carbon structure and ion oxides, which contribute positively to the shielding performance. Both the real and imaginary components of permittivity increase with higher PMS content, indicating enhanced dielectric and conductive properties. When PMS content is below 12 wt%, absorption is the dominant shielding mechanism; however, reflection becomes dominant when the content exceeds 12 wt%. The skin depths of the ACC are smaller than the specimen thickness and decrease with increasing frequency, further enhancing EMI shielding effectiveness. The maximum total shielding effectiveness ( SE T ) achieved was 20.8–25.3 dB over the X-band, approximately five times higher than ACC without PMS. Across all PMS content levels, absorption loss ( SE A ) is the primary contributor to SE T . The shielding mechanisms include conduction loss and polarization loss, such as defect-induced interfacial polarization, dipolar polarization, and molecular currents. This study discovers a new approach to using municipal sludge as an EMI shielding admixture and contributes to global sustainability in the construction industry.

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