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A modified smoothed particle hydrodynamics method considering residual stress for simulating failure and its application in layered rock mass

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Journal of Mountain Science 2024年第6期21卷 2091-2112页

作者： XIA Chengzhi shi zhenming KOU Huanjia Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai 200092China Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education Tongji UniversityShanghai 200092China

Residual strength is an indispensable factor in evaluating rock fracture,yet the current Smoothed Particle Hydrodynamics(SPH)framework rarely considers its influence when simulating *** improved cracking strategy considering residual stress in the base bond SPH method was proposed to simulate failures in layered rocks and slopes and verified by experimental results and other simulation methods(i.e.,the discrete element method).Modified Mohr–Coulomb failure criterion was applied to distinguish the mixed failure of tensile and *** fracture markψwas introduced to improve the kernel function after tensile damage,and the calculation of residual stress after the damage was derived after shear *** simulations were carried out to evaluate its performance under different stress and scale conditions and to verify its effectiveness in realistically reproducing crack initiation and propagation and coalescence,even fracture and *** results indicate that the improved cracking strategy precisely captures the fracture and failure pattern in layered rocks and rock *** residual stress of brittle tock is correctly captured by the improved SPH *** improved SPH method that considers residual strength shows an approximately 13%improvement in accuracy for the safety factor of anti-dip layered slopes compared to the method that does not consider residual strength,as validated against analytical *** infer that the improved SPH method is effective and shows promise for applications to continuous and discontinuous rock masses.

关键词： Smoothed particle hydrodynamics Cracking strategy Residual stress Layered rock Crack propagation

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A review of fracture mechanic behaviors of rocks containing various defects

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Underground Space 2023年第5期12卷 102-115页

作者： Fei Zhao zhenming shi Songbo Yu Hongchao Zheng Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai 200092China Key Laboratory of Geotechnical and Underground Engineering Ministry of EducationTongii UniversityShanghai 200092China

The existence of defects in a rock mass is a vital factor complicating the mechanical response of the rock mass under *** characteristics of defects control the rock mass’s mechanical *** report reviews the experimental studies on the influence of simulating the internal defects of rock mass’s mechanical *** effects of preexisting defects(shape,size,number,angle,and other factors)on the mechanical properties and failure modes of the rock are investigated from the perspectives of rock failure and fracture *** fracture propagation mechanisms of different defective rock masses are analyzed by studying the stress state of different defective rock masses under uniaxial *** the defective rock samples with varying inclination angles are destroyed,the relationship among the compressive strength,the fracture propagation,and the failure characteristics is *** primary findings are as *** increase in the size and number of defects rapidly damages the mechanical properties of the rock and intensifies defect penetration and *** rock mechanics characteristics of fissured rocks with different inclination angles show two primary variations:one is a continuous increase,and the other is a decrease followed by an *** result is strongly related to the failure pattern of rocks with preexisting *** investigation is crucial for further studying the failure modes of complex defective rock masses and the geotechnical engineering related to defective rocks.

关键词： Rock mechanics Preexisting defects Failure patterns Fracture characteristics

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Kernel broken smooth particle hydrodynamics method for crack propagation simulation applied in layered rock cells and tunnels

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Underground Space 2023年第3期10卷 55-75页

作者： Chengzhi Xia zhenming shi Hongchao Zheng Xiaohan Wu School of Civil Engineering Tongji UniversityShanghai 200092China College of Environmental Science and Engineering Tongji UniversityShanghai 200092China

Understanding the cracking process of layered tunnels requires a high-fidelity *** smooth particle hydrodynamics(SPH),termed kernel broken SPH(KBSPH),was implemented to simulate the crack propagation and deformation of layered rock cells and field layered tunnels with dip angles of 0°–90°,and the results were compared with those of the laboratory *** attempts,including the bedding angle,interlayer distance,and lateral pressure coefficient,were made to investigate the crack propagation and deformation of layered ***,the pros and cons of the KBSPH method applied in the rock field were compared with those of other *** results indicate that the KBSPH can explicitly reproduce crack propagation by improving the kernel function with a totally damaged symbol,and the deformation responses have been captured *** infer that this method is effective and rapid in crack propagation and large deformation simulation for other types of rock tunnels.

关键词： Smooth particle hydrodynamics Kernel broken Layered rock tunnel Crack propagation

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Sensitivity analyses of random cave groups on karst tunnel stability based on water–rock interaction using a novel contact dynamic method

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Underground Space 2024年第5期18卷 162-186页

作者： Chengzhi Xia zhenming shi Huanjia Kou Shaoqiang Meng Maomao Liu College of Civil Engineering Tongji UniversityShanghai 200092China Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education Tongji UniversityShanghai 200092China

This paper concentrates on the sensitivity and dynamic simulation of randomly distributed karst cave groups on tunnel stability and connectivity extended ratio based on water–rock interaction using a novel contact dynamic method(CDM).The concept of karst cave group connectivity extended ratio during tunneling and water inrush is *** effects of cave shape and spatial distribution on Qiyueshan tunnel are *** deformation and damage index,and connectivity extended ratio with uniform random karst cave groups are *** results demonstrate that the connectivity extended ratio is verified as a crucial judgment in predicting the safe distance and assessing the stability of the tunnel with the karst cave *** model captures the fracture propagation and contact behavior of rock mass,surface flow,as well as the bidirectional water–rock interaction during the water inrush of Qiyueshan tunnel with multiple caves.A larger cave radius and smaller minimum distance between the cave and tunnel increase the deformation and damage index of the surrounding *** the cave radius and cave area ratio increase,the failure pattern shifts from overall to local *** findings potentially have broad applications in various surface and subsurface scenarios involving water–rock interactions.

关键词： Karst tunnel stability Contact dynamic method Connectivity extended ratio Karst cave groups Qiyueshan tunnel Water-rock interaction

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Seismic behavior of breakwaters on complex ground by numerical tests:Liquefaction and post liquefaction ground settlements

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Earthquake Engineering and Engineering Vibration 2018年第2期17卷 325-342页

作者： Gu Linlin Zhang Feng Bao Xiaohua shi zhenming Ye Guanlin Ling Xianzhang Department of Civil Engineering Qingdao University of Technology Department of Civil Engineering Nagoya Institute of Technology Department of Civil Engineering Shenzhen University Department of Geotechnical Engineering Tongji University Department of Civil Engineering Shanghai Jiao Tong University

A large number of breakwaters have been constructed along coasts to protect humans and infrastructures from *** is a risk that foundation soils of these structures may liquefy,or partially liquefy during the earthquake preceding a tsunami,which would greatly reduce the structures’capacity to resist the *** is necessary to consider not only the soil’s liquefaction behavior due to earthquake motions but also its post-liquefaction behavior because this behavior will affect the breakwater’s capacity to resist an incoming *** this study,numerical tests based on a sophisticated constitutive model and a soil-water coupled finite element method are used to predict the mechanical behavior of breakwaters and the surrounding *** real breakwaters subjected to two different seismic excitations are examined through numerical *** simulation results show that,earthquakes affect not only the immediate behavior of breakwaters and the surrounding soils but also their long-term settlements due to post-earthquake consolidation.A soil profile with thick clayey layers beneath liquefied soil is more vulnerable to tsunami than a soil profile with only sandy ***,quantitatively evaluating the seismic behavior of breakwaters and surrounding soils is important for the design of breakwater structures to resist tsunamis.

关键词： breakwater settlement earthquake numerical test liquefaction

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Inverting the rock mass P-wave velocity field ahead of deep buried tunnel face while borehole drilling

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International Journal of Mining Science and Technology 2024年第5期34卷 681-697页

作者： Liu Liu Shaojun Li Minzong Zheng Dong Wang Minghao Chen Junbo Zhou Tingzhou Yan zhenming shi State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan 430071China China Railway Eryuan Engineering Group CO. LTD.Chengdu 610031China Department of Hydraulic and Hydropower Engineering Tsinghua UniversityBeijing 100084China Hubei Communications Planning and Design Institute CO. LTD.Wuhan 430051China Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education Tongji UniversityShanghai 200092China

Imaging the wave velocity field surrounding a borehole while drilling is a promising and urgently needed approach for extending the exploration range of the borehole *** paper develops a drilling process detection(DPD)system consisting of a multifunctional sensor and a pilot geophone installed at the top of the drilling rod,geophones at the tunnel face,a laser rangefinder,and an onsite computer.A weighted adjoint-state first arrival travel time tomography method is used to invert the P-wave velocity field of rock mass while borehole drilling.A field experiment in the ongoing construction of a deep buried tunnel in southwestern China demonstrated the DPD system and the tomography ***-frequency analysis of typical borehole drilling detection data shows that the impact drilling source is a pulse-like seismic exploration wavelet.A velocity field of the rock mass in a triangular area defined by the borehole trajectory and geophone receiving line can be *** the borehole core and optical image validate the inverted P-wave velocity field.A numerical simulation of a checkerboard benchmark model is used to test the tomography *** rapid convergence of the misfits and consistent agreement between the inverted and observed travel times validate the P-wave velocity imaging.

关键词： Deep buried tunnel Wave velocity field Borehole drilling Tomography Rock mass

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DEM investigation of weathered rocks using a novel bond contact model

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Journal of Rock Mechanics and Geotechnical Engineering 2015年第3期7卷 327-336页

作者： zhenming shi Tao Jiang Mingjing Jiang Fang Liu Ning Zhang Department of Geotechnical Engineering College of Civil Engineering Tongji University Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education Tongji University State Key Laboratory for Disaster Reduction in Civil Engineering Tongji University

The distinct element method（DEM） incorporated with a novel bond contact model was applied in this paper to shed light on the microscopic physical origin of macroscopic behaviors of weathered rock, and to achieve the changing laws of microscopic parameters from observed decaying properties of rocks during weathering. The changing laws of macroscopic mechanical properties of typical rocks were summarized based on the existing research achievements. Parametric simulations were then conducted to analyze the relationships between macroscopic and microscopic parameters, and to derive the changing laws of microscopic parameters for the DEM model. Equipped with the microscopic weathering laws, a series of DEM simulations of basic laboratory tests on weathered rock samples was performed in comparison with analytical solutions. The results reveal that the relationships between macroscopic and microscopic parameters of rocks against the weathering period can be successfully attained by parametric simulations. In addition, weathering has a significant impact on both stressestrain relationship and failure pattern of rocks.

关键词： Distinct element method(DEM) Bond contact model Rock weathering Weathering law Microscopic parameter

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A Surfactant-stable Bacillus pumilus K9 α-Keratinase and Its Potential Application in Detergent Industry

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Chemical Research in Chinese Universities 2015年第1期31卷 91-97页

作者： GONG Jinsong WANG Yue ZHANG Dandan LI Heng ZHANG Xiaomei ZHANG Rongxian LU zhenming XU Zhenghong shi Jinsong School of Pharmaceutical Science Jiangnan University Wuxi 214122 P. R. China

An a-keratinase producing strain was isolated with wool as the sole carbon and nitrogen source and identified as Bacilluspumilus K9. The major amino acids liberated from the keratin degradation of wool by B. pumilus K9 were glutamic acid and leucine. The a-keratinase was purified to electrophoretic homogeneity with a molecular weight of 32000. The purified enzyme exhibits an optimum activity at 60 ℃ and pH=9.0. It was stable at pH values between 8 and 11. Bacillas pumilus keratinase displays a high activity towards casein, keratin, wool and feather, which indicates its wide application range. The keratinase was completely inhibited by phenylmethyl-sulfonyl fluoride（PMSF） and β-mercaptoethanol, and moderately inhibited by ethylemediamine-tetraacetic acid（EDTA）, suggesting it is a metallo-cysteine keratinase. This enzyme could remain stable that could even be promoted in the presence of surfactants, including sodium dodecyl sulfate（SDS）, Tween and Triton. And Tween 40 and Triton X-100 could substantially enhance the activity of the enzyme by 54% and 35%, respectively. It may indicate the prominent feature of the keratinase to tolerate surfactants. The enzymatic properties distinguish this keratinase from others in the literature. Furthermore, this enzyme is extremely stable in the presence of a commercially available detergent with 1% concentration. Detergents ARIEL, Bluemoon and WhiteCat can enhance the activity of the keratinase by 43.56%, 15.22%, and 22.48%, respectively.

关键词： a-Keratinase Bacilluspumilus K9 Wool degradation Surfactant stability Detergent

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锦屏绿片岩分级加载流变试验研究

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同济大学学报（自然科学版） 2011年第3期39卷 320-326页

作者：石振明张力同济大学地下建筑与工程系上海200092 同济大学岩土及地下工程教育部重点实验室上海200092 上海广联建设发展有限公司上海200438

对锦屏二级水电站引水隧洞围岩进行了分级加载流变试验,分析了试验过程中出现的现象、试样轴向、侧向应力-应变关系,以及利用伯格斯模型求得的流变模型参数.分析结果表明,各试样总应变量轴向大于侧向,而各式样总流变量侧向大于轴向,流... 详细信息

对锦屏二级水电站引水隧洞围岩进行了分级加载流变试验,分析了试验过程中出现的现象、试样轴向、侧向应力-应变关系,以及利用伯格斯模型求得的流变模型参数.分析结果表明,各试样总应变量轴向大于侧向,而各式样总流变量侧向大于轴向,流变和应变表现出不一致性;各级流变的流变量随各级应力的增加在逐级增加,各级流变的轴向流变量和侧向流变量占轴向总流变量和侧向总流变量的百分比是相似的;各试样的各级瞬时变形的弹模不断增大,符合岩石流变试验的一般性规律;在轴向和侧向两个方向上存在明显的各向异性,侧向能更快速和灵敏的反映应力变化引起的流变特性的改变;各流变参数均能正常反映绿片岩流变规律,伯格斯模型能较好的模拟锦屏绿片岩单轴流变特性.

关键词：绿片岩流变试验伯格斯模型流变参数各向异性

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引桥地基沉降的三维有限元分析

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岩石力学与工程学报 2004年第1期23卷 144-148页

作者： LiuGuiyu ShenMingrong shizhenming DepartmentOfGeotechnicalEngineering TongjiUniversityShanghai200092China

FEM simulation is conducted for the foundation settlement of backfill slope of high bridge approach. On the basis of all kinds of stress contour sketches and data obtained from the site, a simple mechanical model is p... 详细信息

关键词：引桥地基沉降三维有限元 3D FEM

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