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Investigation of mechanical failure performance of a large-diameter shield tunnel segmental ring

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第5期25卷 411-428页

作者： Binyong GAO renpeng chen Huaina WU chengcheng ZHANG Meng FAN Chao XIAO Research Center of Underground Space Advanced Technology Hunan UniversityChangsha 410082China Key Laboratory of Building Safety and Energy Efficiency of the Ministry of Education Hunan UniversityChangsha 410082China Department of Civil Engineering Hunan UniversityChangsha 410082China China Construction No.5 Civil Engineering Co. Ltd.Changsha 410004China

The control criteria for structural deformation and the evaluation of operational safety performance for large-diameter shield tunnel segments are not yet clearly *** address this issue,a refined 3D finite element model was established to analyze the transverse deformation response of a large-diameter segmental *** analyzing the stress,deformation,and crack distribution of large-diameter segments under overload conditions,the transverse deformation of the segmental ring could be divided into four *** main reasons for the decrease in segmental ring stiffness were found to be the extensive development of cracks and the complete formation of four plastic *** deformation control value for the large-diameter shield tunnel segment is chosen as 8%o of the segment's outer diameter,representing the transverse deformation during the formation of the first semi-plastic hinge(i.e.,the first yield point)in the *** control value can serve as a reinforcement standard for preventing the failure of large-diameter shield tunnel *** flexural bearing capacity characteristic curve of segments was used to evaluate the structural strength of a large-diameter segmental *** was discovered that the maximum internal force combination of the segment did not exceed the segment ultimate bearing capacity curve(SUBC).However,the combination of internal force at 9°,85°,and 161°of the joints,and their symmetrical locations about the 0°-180°axis exceeded the joint ultimate bearing capacity curve(JUBC).The results indicate that the failure of the large-diameter segment lining was mainly due to insufficient joint strength,leading to an instability *** findings from this study can be used to develop more effective maintenance strategies for large-diameter shield tunnel segments to ensure their long-term performance.

关键词： Finite element model Transverse deformation response Upper overload Plastic hinges Flexural bearing capacity

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基于深度学习的盾构机土舱压力场预测方法

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岩土工程学报 2024年第2期46卷 307-315页

作者：张超朱闽湘郎志雄陈仁朋程红战湖南大学土木工程学院湖南长沙410082 湖南大学地下空间开发先进技术研究中心湖南长沙410082 建筑安全与节能教育部重点实验室湖南长沙410082

土舱压力是盾构机受力状态和掌子面稳定等核心问题中的关键因素。土舱压力具有显著的空间变异性,其形成演化机制源于装备与岩土之间的复杂耦合作用,与地质特征、掘进参数等多源参数相关。然而,现有土舱压力预测方法一般未考虑空间分布... 详细信息

土舱压力是盾构机受力状态和掌子面稳定等核心问题中的关键因素。土舱压力具有显著的空间变异性,其形成演化机制源于装备与岩土之间的复杂耦合作用,与地质特征、掘进参数等多源参数相关。然而,现有土舱压力预测方法一般未考虑空间分布特征或地质参数影响。针对该问题,提出了一种基于空间分布物理特征函数导引深度学习的盾构机土舱压力场预测方法。该方法构建物理特征函数用于解耦土舱压力空间分布特征,采用卷积神经网络和门控循环单元分别提取多源参数历史信息的空间特征和特征系数的时序特征,结合多源参数实时信息对特征系数进行预测,从而实现土舱压力场的预测。以长沙地铁四号线某区段为案例,利用该方法准确预测了土舱压力空间分布实测数据,准确率高达0.98,验证了所提方法的有效性。敏感性分析表明,不同地层中土舱压力空间分布特征系数的主要敏感参数基本一致,但其敏感度随地层地质条件的变化规律差异显著,可为复杂地层盾构机土舱压力精细化调控提供参考。

关键词：土舱压力场卷积神经网络门控循环单元物理特征函数土压平衡盾构机盾构隧道

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SOC对锂离子电池存储性能影响及K值筛选工艺

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电池 2024年第4期54卷 519-524页

作者：许汉良陈仁鹏伍斌南俊民珠海鹏辉能源有限公司广东珠海519199 华南师范大学化学学院广东广州510006

锂离子电池荷电状态(SOC)和老化工艺对电池的存储性能以及模组电池的制备和性能具有重要影响。研究SOC对磷酸铁锂锂离子电池存储性能的影响。高温(60℃)长时间存储时,随着SOC降低,电池的产气变严重,负极上发生的副反应是产气的主要来源... 详细信息

锂离子电池荷电状态(SOC)和老化工艺对电池的存储性能以及模组电池的制备和性能具有重要影响。研究SOC对磷酸铁锂锂离子电池存储性能的影响。高温(60℃)长时间存储时,随着SOC降低,电池的产气变严重,负极上发生的副反应是产气的主要来源。在30%SOC下,电池处于产气较少的理想存储状态。在30%SOC下,通过调整45℃高温和常温老化时间对K值筛选工艺进行优化。高温老化有利于区分不同自放电速率的电池。模组充放电一致性测试表明,随高温老化时间的延长,模组充放电压差减小,电池一致性提高。实验结果为磷酸铁锂锂离子电池长期储存、运输和制备提供参考。

关键词：磷酸铁锂锂离子电池荷电状态(SOC) 高温老化模组

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Experimental study on applicability of using time-domain reflectometry to detect NAPLs contaminated sands

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Science China(Technological Sciences) 2013年第8期56卷 1534-1543页

作者： ZHAN LiangTong MU QingYi chen YunMin chen renpeng MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering Zhejiang University

Underground contamination by non-aqueous phase liquids (NAPLs) becomes increasingly serious. Rapid and reliable detection of contaminated zone and degree is the first step to site remediation. In this paper, diesel and fine sand are used as experiment materials to investigate the applicability of using time-domain reflectometry (TDR) to detect LNAPLs contamination. The major work includes: measurement of dielectric constant and electrical conductivity for the diesel-water-air-sand mixtures; measurement of reflection waveform and dielectric constant for specimens with a diesel contaminated layer being sandwiched in sand. The experimental results show the followings: A significant decrease in both dielectric constant and electrical conductivity is observed for the diesel-water-air-sand mixtures when diesel displaces the pore water, and the content of diesel can be calculated by the model; insignificant change in dielectric properties is measured when diesel only displaces the pore gas; when the diesel contaminated sand is sandwiched between two saturated sand layers, the interfaces of the diesel contaminated layer can be identified by analyzing the reflection waveform; for field application, TDR method is valid for the case that LNAPLs seep into saturated sand layer, and the applicability of TDR method in vadose zone depends on the initial saturation of the sand layer. The findings obtained in this paper provide a guidance for the use of TDR for the field investigation of NAPLs contaminated site.

关键词： LNAPLs sand time domain reflectometry dielectric constant electrical conductivity

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门式抗浮框架作用下上方开挖既有盾构隧道响应解析解

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岩土工程学报 2024年第8期46卷 1675-1684页

作者：刘源陈仁朋程红战吴怀娜张凯湖南大学土木工程学院湖南长沙410082 湖南大学地下空间开发先进技术研究中心湖南长沙410082 建筑安全与节能教育部重点实验室湖南长沙410082

上方开挖卸载导致既有盾构隧道结构产生上浮,易引发结构渗漏水、开裂等病害。竖井开挖联合门式框架技术是限制上方开挖引起既有隧道上浮的一种有效控制措施,但是目前仍缺少相应的理论方法用于指导门式抗浮框架的设计。为此,提出了既有... 详细信息

上方开挖卸载导致既有盾构隧道结构产生上浮,易引发结构渗漏水、开裂等病害。竖井开挖联合门式框架技术是限制上方开挖引起既有隧道上浮的一种有效控制措施,但是目前仍缺少相应的理论方法用于指导门式抗浮框架的设计。为此,提出了既有隧道结构响应的解析解,可以实现竖井和基坑开挖阶段既有隧道结构纵向和横截面变形计算,并给出了相关的计算流程。通过与工程实例和三维数值模拟结果进行对比,验证了解析解的可靠性。通过典型算例计算和参数敏感性分析讨论了门式抗浮框架的作用机理以及既有隧道埋深和竖井开挖尺寸等因素的影响规律。结果表明:门式抗浮框架在基坑开挖阶段可以有效控制上方开挖引起的既有隧道变形,控制效果与既有隧道上方剩余覆土厚度密切相关,剩余覆土越小控制效果越明显;门式抗浮框架的作用效果主要取决于抗浮板与土体之间的作用力,抗拔桩与土体的作用力对既有隧道变形影响较小。

关键词：既有隧道门式抗浮框架解析解竖井开挖 Timoshenko梁

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双道密封垫分布形式对大直径盾构隧道接缝力学性能影响研究

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隧道建设（中英文） 2024年第4期44卷 750-761页

作者：杨思齐吴怀娜陈仁朋崔庆龙杨林松湖南大学湖南长沙410082 中交第二公路勘察设计研究院有限公司湖北武汉430056

为探究大直径盾构隧道双道防水密封垫的合理分布方式,采用考虑接缝细部构造及混凝土塑性损伤的精细化数值模拟方法,通过纵缝抗弯足尺试验验证该方法的有效性,并进一步利用精细化数值模拟对比分析密封垫双道内外分布及密封垫双道外侧分... 详细信息

为探究大直径盾构隧道双道防水密封垫的合理分布方式,采用考虑接缝细部构造及混凝土塑性损伤的精细化数值模拟方法,通过纵缝抗弯足尺试验验证该方法的有效性,并进一步利用精细化数值模拟对比分析密封垫双道内外分布及密封垫双道外侧分布下接缝的力学性能及防水性能。研究结果表明:1)精细化数值模拟在反映接缝抗弯性能方面具有良好的可靠性;2)接缝受压区高度、张开量及螺栓应力随弯矩增大呈现4阶段的发展模式,受压侧外缘接触一定程度提升了抗弯性能;3)轴力显著影响接缝初始抗弯刚度的保持,且轴力与初始抗弯刚度并非完全正相关,高轴力下初始抗弯刚度有一定下降;4)密封垫双道内外分布的负弯性能略优于正弯性能,密封垫双道外侧分布的负弯性能远超正弯性能;5)密封垫分布从轴力附加弯矩和核心区混凝土高度2方面影响了接缝的抗弯刚度;6)正弯矩下双道外侧防水性能优于双道内外的防水性能,而负弯矩下双道外侧防水性能较双道内外的防水性能差。由于具有更好的正弯性能以及至少有一侧密封垫受压的防水性能,密封垫双道内外分布的纵缝形式具有更好的适用性。

关键词：大直径盾构隧道管片接头双道防水密封垫力学分析数值模拟

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Seismic stability and permanent displacement of landfill along liners

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Science China(Technological Sciences) 2008年第4期51卷 407-423页

作者： chen YunMin GAO Deng ZHU Bin chen renpeng MOE Key Laboratory of Soft Solis and Geoenvironmental Engineering Zhejiang UniversityHangzhou 310027China

The three-part wedge limit equilibrium method for seismic stability analysis of the landfill along liners is presented. The approximate solutions of the factor of safety and the yield acceleration coefficient are obtained. Parametric studies show that the interface strength of liners, the shear strength of waste and the height of retaining wall can influence the seismic stability of landfill along liners. The density and the shear wave velocity of the field waste are obtained by the borehole investigation and the spectral analysis of surface wave (SASW), respectively. The strain-dependent shear modulus and damping ratio of the artifical waste are obtained by the moderate-scale dynamic triaxial tests. The onedimensional (1D) equivalent linear dynamic response analysis is used to calculate the horizontal equivalent seismic coefficient-time history of the sliding landfill during earthquake. The seismic permanent displacement of the landfill along liners with different site conditons and heights is evaluated by the Newmark method. The catculated results show that ratio of ky /kmax, site conditions, the amplitude and frequency content of the bedrock motion can affect the seismic permanent displacement of the landfill along liners in some degree. Finally, the seismic stability and permanent displacements of three expanded configurations of a certain landfill case are analyzed.

关键词： landfill liner seismic stability permanent displacement Newmark method

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Shear wave velocity-based evaluation and design of stone column improved ground for liquefaction mitigation

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Earthquake Engineering and Engineering Vibration 2017年第2期16卷 247-261页

作者： Zhou Yanguo Sun Zhengbo chen Jie chen Yunmin chen renpeng MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering Institute of Geotechnical Engineering Zhejiang University Hangzhou 310058 China

The evaluation and design of stone column improvement ground for liquefaction mitigation is a challenging issue for the state of practice. In this paper, a shear wave velocity-based approach is proposed based on the well-defined correlations of liquefaction resistance （CRR）-shear wave velocity （V）-void ratio （e） of sandy soils, and the values of parameters in this approach are recommended for preliminary design purpose when site specific values are not available. The detailed procedures of pre- and post-improvement liquefaction evaluations and stone column design are given. According to this approach, the required level of ground improvement will be met once the target V of soil is raised high enough （i.e., no less than the critical velocity） to resist the given earthquake loading according to the CRR-V relationship, and then this requirement is transferred to the control of target void ratio （i.e., the critical e） according to the V-e relationship. As this approach relies on the densification of the surrounding soil instead of the whole improved ground and is conservative by nature, specific considerations of the densification mechanism and effect are given, and the effects of drainage and reinforcement of stone columns are also discussed. A case study of a thermal power plant in Indonesia is introduced, where the effectiveness of stone column improved ground was evaluated by the proposed V-based method and compared with the SPT-based evaluation. This improved ground performed well and experienced no liquefaction during subsequent strong earthquakes.

关键词： Liquefaction mitigation Stone column Shear wave velocity Void ratio Densification Ageing effect

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基坑开挖坑底土拱效应离心模型试验及数值分析

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岩土工程学报 2024年第9期46卷 1936-1944页

作者：吴楷陈仁朋孟凡衍王瀚霖程红战湖南大学地下空间先进技术研究中心湖南长沙410082 湖南大学土木工程学院湖南长沙410082 湖南大学建筑安全与节能教育部重点实验室湖南长沙410082

基坑开挖会导致坑底产生土拱效应。与活动门上方土拱效应相比,基坑底土拱效应发展方向与土体自重应力方向相同且具有不同的力-位移边界条件。为探究土拱效应影响下基坑底土体竖向应力和回弹变形等力学响应,开展了干砂地层基坑开挖离心... 详细信息

基坑开挖会导致坑底产生土拱效应。与活动门上方土拱效应相比,基坑底土拱效应发展方向与土体自重应力方向相同且具有不同的力-位移边界条件。为探究土拱效应影响下基坑底土体竖向应力和回弹变形等力学响应,开展了干砂地层基坑开挖离心模型试验,并同时进行了不同开挖深度和宽度的多工况下数值分析。研究表明,基坑底地层存在差异变形和应力转移现象,证明了坑底土拱效应的存在;基坑底存在松动区和土拱区,松动区内土体相对密实度明显下降,土拱区以下地层回弹量仅占坑底总回弹量的20%;开挖深度和宽度是影响坑底土拱效应形成-演化的关键因素,二者与松动区和土拱区高度呈正相关。研究结论可为预测基坑开挖导致的地层响应和下方既有地下结构变形控制提供支撑。

关键词：基坑开挖土拱效应离心模型试验数值分析

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Prediction of shield tunneling-induced ground settlement using machine learning techniques

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Frontiers of Structural and Civil Engineering 2019年第6期13卷 1363-1378页

作者： renpeng chen Pin ZHANG Huaina WU Zhiteng WANG Zhiquan ZHONG Key Laboratory of Building Safety and Energy Efficiency Hunan UniversityChangsha 410082China National Joint Research Center for Building Safety and Environment Hunan UniversityChangsha 410082China College of Civil Engineering Hunan UniversityChangsha 410082China China Construction Fifth Engineering Division Co. LtdChangsha 410082China

Predicting the tunneling-induced maximum ground surface settlement is a complex problem since the settlement depends on plenty of intrinsic and extrinsic *** study investigates the efficiency and feasibility of six machine learning(ML)algorithms,namely,back-propagation neural network,wavelet neural network,general regression neural network(GRNN),extreme learning machine,support vector machine and random forest(RF),to predict tunneling?induced *** data sets including geological conditions,shield operational parameters,and tunnel geometry collected from four sections of tunnel with a total of 3.93 km are used to build *** indicators,mean absolute error,root mean absolute error,and coefficient of determination the(7?2)are used to demonstrate the performance of each computational *** results indicated that ML algorithms have great potential to predict tunneling-induced settlement,compared with the traditional multivariate linear regression *** and RF algorithms show the best performance among six ML algorithms,which accurately recognize the evolution of tunneling-induced *** correlation between the input variables and settlement is also investigated by Pearson correlation coefficient.

关键词： EPB shield shield tunneling settlement prediction machine learning

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