检索结果-南通市图书馆

A smoothed assumed enhanced strain method for frictional contact with constant strain elements

在线全文

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical engineering 2024年第11期16卷 4369-4385页

作者： Fushen Liu Wei Sun Minghui Li Xiaonan Shang Computing center for Geotechnical engineering Zhejiang UniversityHangzhou310058China research center of Coastal and urban Geotechnical engineering Zhejiang UniversityHangzhou310058China engineering research center of urban underground development of zhejiang province Hangzhou310058China School of Civil engineering Sun Yat-sen UniversityGuangzhou510275China School of Energy Resource China University of Geosciences(Beijing)Beijing100083China

This paper presents a finite element framework for imposing frictional contact conditions on embedded fracture faces,implemented by the constant-strain assumed enhanced strain(AES)method,where penalty method is used to impose both non-penetration constraint and Coulomb’s law of *** proposed constant-strain AES method for modeling embedded frictional contact can be cast into an integration algorithm similar to those used in the classical plasticity theory,where displacement jump is calculated from the local traction equilibrium at Gauss point,so the method does not introduce any additional global degrees of ***,constant-strain elements are often desirable in practice because they can be easily created automatically for large-scale engineering applications with complicated *** encountered in other enriched finite element methods for frictional contact,the problem of normal contact pressure oscillations is also observed in the constant-strain AES ***,we developed a strain-smoothing procedure to effectively mitigate the *** investigated and verified the proposed AES framework through several numerical examples,and illustrated the capability of this method in solving challenging nonlinear frictional contact problems.

关键词： Assumed enhanced strain(AES)method Frictional contact Strain-smoothing method Penalty method

Advancements and Challenges in Organic–Inorganic Composite Solid Electrolytes for All‑Solid‑State Lithium Batteries

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano-Micro Letters 2025年第1期17卷 46-97页

作者： Xueyan Zhang Shichao Cheng Chuankai Fu Geping Yin Liguang Wang Yongmin Wu Hua Huo State Key Laboratory of space Power‑Sources School of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin 150001People’s Republic of China College of Chemical and Biological engineering Zhejiang UniversityHangzhou 310058People’s Republic of China State Key Laboratory of space Power-Sources 2965 Dongchuan RoadMinhang DistrictShanghai 200240People’s Republic of China

To address the limitations of contemporary lithium-ion batteries,particularly their low energy density and safety concerns,all-solid-state lithium batteries equipped with solid-state electrolytes have been identified as an up-and-coming *** the various SEs,organic–inorganic composite solid electrolytes(OICSEs)that combine the advantages of both polymer and inorganic materials demonstrate promising potential for large-scale ***,OICSEs still face many challenges in practical applications,such as low ionic conductivity and poor interfacial stability,which severely limit their *** review provides a comprehensive overview of recent research advancements in ***,the influence of inorganic fillers on the main functional parameters of OICSEs,including ionic conductivity,Li+transfer number,mechanical strength,electrochemical stability,electronic conductivity,and thermal stability are systematically *** lithium-ion conduction mechanism of OICSE is thoroughly analyzed and concluded from the microscopic ***,the classic inorganic filler types,including both inert and active fillers,are categorized with special emphasis on the relationship between inorganic filler structure design and the electrochemical performance of ***,the advanced characterization techniques relevant to OICSEs are summarized,and the challenges and perspectives on the future development of OICSEs are also highlighted for constructing superior ASSLBs.

关键词： Composite solid electrolytes Inorganic filler Interfacial stability Li-ion conduction mechanism Characterization techniques

饱和软黏土不排水强度弱化模型及其在沉箱式防波堤的应用分析（英文）

在线全文

学校读者我要写书评

暂无评论

Journal of zhejiang University-Science A(Applied Physics & engineering) 2018年第8期19卷 650-662页

作者： Zhen YAN Yuan-zhan WANG Zhong-xuan YANG Zhong XIAO Kun PAN Tianjin research Institute for Water Transport engineering Ministry of Transport research center of Coastal and urban Geotechnical engineering Engineering Research Center of Urban Underground Development of Zhejiang Province Zhejiang University School of Civil engineering Tianjin University

目的:本文旨在建立简单实用的饱和软黏土不排水强度损伤弱化模型,应用于波浪循环荷载作用下沉箱式防波堤与软土地基相互作用的非线性数值计算,为解决防波堤软土强度弱化计算问题提供有效途径。创新点:1.基于不排水强度循环损伤弱化机理... 详细信息

目的:本文旨在建立简单实用的饱和软黏土不排水强度损伤弱化模型,应用于波浪循环荷载作用下沉箱式防波堤与软土地基相互作用的非线性数值计算,为解决防波堤软土强度弱化计算问题提供有效途径。创新点:1.基于不排水强度循环损伤弱化机理,得到软黏土不排水强度随循环荷载作用次数和应力水平的变化规律;2.结合Tresca屈服准则进行数值开发,应用于波浪循环荷载作用下沉箱式防波堤与软土地基相互作用的数值计算。方法:1.引入累积塑性变形相关的损伤变量表征土体结构性的损伤和重塑对软黏土不排水强度弱化的影响(公式(3)和(11));2.建立软黏土不排水强度随循环荷载作用次数和应力水平变化的损伤弱化模型(公式(14));3.结合Tresca屈服准则,实现软黏土不排水强度损伤弱化的数值计算过程(图9);4.针对烟台软黏土动三轴试验数据进行分析,对模型及其数值开发过程进行验证(图11和12);5.将模型应用到软土地基上沉箱式防波堤数值运算,分析软土地基响应,验证模型的有效性(图15~18)。结论:1.在临界循环应力比以下,损伤变量和归一化最大孔压比随循环荷载作用次数的增加逐渐增大,并趋于稳定;随循环应力比增大逐渐增大。循环后不排水强度折减系数随着循环荷载作用次数和循环应力比的增加而减小。2.有限元数值开发过程是正确的,不排水强度损伤弱化模型是合理的。3.该模型简单实用,可应用于波浪等循环荷载作用下沉箱式防波堤与软土地基相互作用的非线性数值计算,且能模拟循环荷载下软土地基的孔隙水压力增长以及不排水强度弱化等响应。软土地基的响应主要分布在基床两趾及正下方的软土层上部。

关键词：饱和软黏土不排水强度循环弱化模型损伤数值模拟

Behaviours of existing shield tunnels due to tunnelling underneath considering asymmetric ground settlements

在线全文

学校读者我要写书评

暂无评论

underground space 2022年第5期7卷 882-897页

作者： Xiaolu Gan Jianlin Yu Xiaonan Gong Nianwu Liu Dongzhu Zheng research Centre of Coastal and urban Geotechnical engineering Zhejiang UniversityHangzhou 310058China engineering research Centre of urban underground development Zhejiang UniversityHangzhou 310058China School of Civil engineering and Architecture Zhejiang Sci-Tech UniversityHangzhou 310018China Department of Civil engineering Ghent UniversityGhent 9052Belgium

New tunnelling underneath could influence existing shield tunnels in underground *** evaluation of the influences of tunnelling-induced ground movements on existing tunnels has been a major concern during urban *** paper presents a two-stage analytical method that considers the asymmetric ground settlement for investigating the longitudinal tunnel responses to new *** improved semi-analytical solution considering the horizontal movement of the new tunnel is established for evaluating the tunnelling-induced asymmetric greenfield *** proposed method is verified with field measurement data from a case study.A parametric analysis is conducted to study the influences of the input parameters on the tunnel *** indicate that the horizontal movement of the new tunnel due to bias loading or asymmetric construction may lead to asymmetric responses of the existing *** increasing tunnel horizontal movement,the asymmetry of the tunnel responses becomes more *** increase in the pillar depth and decreases in the tunnel horizontal movement and skew angle lower the internal forces induced by new tunnelling.

关键词： Analytical method Tunnelling undercrossing Asymmetric ground movement Longitudinal tunnel behaviours Tunnel horizontal movement

Numerical analysis of the influence of a river on tunnelling-induced ground deformation in soft soil

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of zhejiang University-Science A(Applied Physics & engineering) 2022年第7期23卷 564-578页

作者： Jia-xin LIANG Xiao-wu TANG Tian-qi WANG Yu-hang YE Ying-jing LIU research center of Coastal and urban Geotechnical engineering Department of Civil EngineeringZhejiang UniversityHangzhou310058China engineering research center of urban underground space development of zhejiang province Hangzhou310058China Zhongtian Construction Group Co. Ltd.Hangzhou310020China

When tunnels are constructed in coastal cities,they will inevitably undercross a *** the influence of rivers on tunnelling-induced deformation in costal soft soil is of great significance for controlling excessive settlement and protecting surrounding *** paper presents a case study of twin tunnels undercrossing a river in soft soil in Hangzhou,*** soft soil of Hangzhou refers to cohesive soil in a soft plastic or fluid plastic state with high natural water content,high compressibility,low bearing capacity,and low shear *** the influence of the river,the research region was divided into two parts,inside and outside the river-affected area,based on monitoring data of the Zizhi *** development law of surface settlement is divided into three *** the first and second stages,the surface settlement within and outside the river-affected area showed a similar trend:the settlement increased and the growth rate of settlement in the second stage was smaller within the river-affected *** the third stage,the surface settlement continued to increase within the river-affected area,while it converged outside the river-affected *** the river-affected area,there was an asynchronization of the sinking rate and stability of vault settlements and surface settlements.A numerical model was established by simulating different reinforcements of the *** numerical model revealed that the ground movement is influenced by the distribution and amount of the excess pore water *** excess pore pressure was concentrated mostly in the range of 1.0H_(t)-3.0H_(t)(H_(t) is the tunnel height)before the tunnel face,especially within the river-affected *** the river-affected area,the dissipation of excess pore water pressure needs more time,leading to slow stabilization of surface *** undercrossing a river,a cofferdam is necessary to reduce excessive ground deformation by dispersing the distribution o

关键词： Tunnelling Ground deformation Numerical analysis Reinforcement

Height of fractured zone inside overlying strata under high-intensity mining in China

在线全文

学校读者我要写书评

暂无评论

International Journal of Mining Science and Technology 2019年第1期29卷 45-49页

作者： Wenbing Guo Gaobo Zhao Gaozhong Lou Shuren Wang School of Energy Science and engineering Henan Polytechnic University Coal Production Safety Collaborative Innovation center in Henan province Henan Polytechnic University International Joint research Laboratory for underground space development and Disaster Prevention of Henan province Henan Polytechnic University

The height of fractured zone(HFZ) at the high-intensity longwall mining panel plays a vital role in the safety analysis of coal mining under bodies of water. This paper described definitions of the highintensity mining. The processes of overburden failure transfer(OFT) were analyzed, which were divided into the development stage and the termination stage. Through theoretical analysis, the limited suspension-distance and the limited overhanging distance were proposed to judge the damage of each stratum. Mechanical models of strata suspended integrity and overhanging stability were established.A theoretical method to predict the HFZ at the high-intensity longwall mining panel was put forward based on the processes of OFT. Taking a high-intensity longwall mining panel(No. 11915 panel) as an example, the theoretical method proposed, the engineering analogy and the empirical formulas in the Regulation were used to predict the HFZ. The results show that the theoretical result is consistent with the engineering analogies' result and empirical formulas' result. The rationality and reliability of the theoretical method proposed is verified.

关键词： High-intensity mining Overburden failure Height of fractured zone Overlying strata movement

Response of operating metro tunnels to compensation grouting of an underlying large-diameter shield tunnel:A case study in Hangzhou

在线全文

学校读者我要写书评

暂无评论

underground space 2022年第2期7卷 219-232页

作者： Xiaolu Gan Jianlin Yu Xiaonan Gong Yongmao Hou Nianwu Liu Min Zhu research center of Coastal and urban Geotechnical engineering Zhejiang UniversityHangzhou 310058China engineering research center of urban underground development Zhejiang UniversityHangzhou 310058China Shanghai Tunnel engineering Co. Ltd.118 Dalian RdShanghai 200082China School of Civil engineering and Architecture Zhejiang Sci-Tech UniversityHangzhou 310018China College of Civil and Transportation engineering Shenzhen UniversityShenzhen 518060China

Due to the shield tunneling underneath,long-term settlements may develop in the existing metro *** compensation grouting is applied worldwide to stabilize the settlement of ground and existing *** field studies concerning large-diameter shield pass-ing tunnel from below have analyzed the interaction between the compensation grouting and the existing *** paper presents a case study on the response of the operating metro tunnels to the compensation grouting of an underlying large-diameter tunnel in muddy clay *** tunnel deformations before,during,and after the compensation grouting were monitored and *** long-term tunnel settlements were mitigated and stabilized by the timely compensation *** settlement rates were observed during the grouting treatment,and the settlement was gradually stabilized three months after the *** grouting holes at the tunnel invert were used initially for better grouting *** horizontal displacement and convergence developed during the grouting construc-tion and remained stable after the grouting ***,some limitations of the grouting treatment were *** tunnel settlement in the section close to the center-line of the south-line tunnel cannot be prevented *** differential displacement cannot be reduced by this grouting program.

关键词： Grouting treatment Shield under-crossing Large-diameter shield tunnel Tunnel settlement

Robust Offline Actor-Critic With On-policy Regularized Policy Evaluation

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2024年第12期11卷 2497-2511页

作者： Shuo Cao Xuesong Wang Yuhu Cheng the engineering research center of Intelligent Control for underground space Ministry of Education and the School of Information and Control Engineering China University of Mining and Technology IEEE

To alleviate the extrapolation error and instability inherent in Q-function directly learned by off-policy Q-learning(QL-style) on static datasets, this article utilizes the on-policy state-action-reward-state-action(SARSA-style) to develop an offline reinforcement learning(RL) method termed robust offline Actor-Critic with on-policy regularized policy evaluation(OPRAC). With the help of SARSA-style bootstrap actions, a conservative on-policy Q-function and a penalty term for matching the on-policy and off-policy actions are jointly constructed to regularize the optimal Q-function of off-policy QL-style. This naturally equips the off-policy QL-style policy evaluation with the intrinsic pessimistic conservatism of on-policy SARSA-style, thus facilitating the acquisition of stable estimated Q-function. Even with limited data sampling errors, the convergence of Q-function learned by OPRAC and the controllability of bias upper bound between the learned Q-function and its true Q-value can be theoretically guaranteed. In addition, the sub-optimality of learned optimal policy merely stems from sampling errors. Experiments on the well-known D4RL Gym-MuJoCo benchmark demonstrate that OPRAC can rapidly learn robust and effective tasksolving policies owing to the stable estimate of Q-value, outperforming state-of-the-art offline RLs by at least 15%.

关键词： Offline reinforcement learning off-policy QL-style on-policy SARSA-style policy evaluation (PE) Q-value estimation

A practical constitutive theory based on egg-shaped function in elasto-plastic modeling for soft clay

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Central South University 2020年第8期27卷 2424-2439页

作者： JIANG Jia-qi XU Ri-qing YU Jian-lin QIU Zhi-jian QIN Jian-she ZHAN Xiao-bo research center of Coastal and urban Geotechnical engineering Zhejiang UniversityHangzhou 310058China engineering research center of urban underground space development of zhejiang province Hangzhou 310058China Hangzhou Metro Group Co. Ltd.Hangzhou 310020China Zhongtian Construction Group Limited Company Hangzhou 310008China

An exploratory discussion is presented on the application of egg-shaped function in elasto-plastic constitutive analysis for soft *** main tasks of the paper are:1)to propose a complete yield criterion based on egg-shaped function and supplement its definition in the deviatoric section,and then a yield criterion suitable for 3D stress conditions is obtained;2)to elaborate its numerical implementation based on the drained triaxial *** the above discussion,a non-associated flow rule is proposed,in which the stress-dilatancy relationship in most classical theory is replaced by a linear dependence between the stress state parameterηand the rotation angleγof the plastic potential ***,isotropic and kinematic hardening behavior is considered by employing the hardening parameter H,which can be expressed as the function of plastic work ***,comparisons between numerical results and test data on Taizhou soft clay are made to verify the effectiveness of the proposed model.

关键词： egg-shaped function elastoplasticity yield criterion non-associated flow