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Study on disc cutter chipping of TBM based on field data and particle flow code simulation

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Underground Space 2023年第2期9卷 122-139页

作者： Yadong Xue Yongqiang Fan Xing Li Kai Shen Jiaxuan Wang Key Laboratory of Geotechnical and Underground Engineering of Education Ministry Tongji UniversityShanghai 200092China Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai 200092China China State Construction Silkroad Construction Investment Group Co. LTDXi’an 710075China School of Civil Engineering Central South UniversityChangsha 410075China

Using tunnel boring machines to excavate high-strength intact rock masses is becoming more *** to the interactions between disc cutters and rocks,abnormal wear of disc cutters,especially cutter chipping,has become a common *** research has mainly focused on normal wear of disc cutters without addressing abnormal wear *** study used the disc cutter consumption data of a tunnel project in China to investigate the abovementioned problem based on field *** to the fail-ure patterns and fracture surface characteristics,the cutter chipping patterns were mainly categorized into four types:granule chipping,patch chipping,primary collapse,and secondary *** further simulate the evolution of disc cutter chipping,based on the linear plastic bond model,a new contact model called the modified plastic bond(MPB)model was proposed to solve the metal simulation prob-lem in particle flow code *** this end,a set of uniaxial tensile and compressive tests were initially conducted to verify the applicability of the MPB ***,a series of three-dimensional rock-cutting simulation tests were conducted to reflect the evolu-tionary processes involved in each type of cutter *** cutter chipping mechanism and morphological characteristics were clas-sified and summarized in *** results revealed that the cutting speed and penetration growth led to a rising trend in the probability and intensity of the cutter *** presence of initial defects also induced an adverse effect on the service life of the *** results indicated suitable working conditions for the cutter and suggested ways to control tunneling parameters and avoid frequent cutter chipping cases.

关键词： Tunnel boring machine Disc cutter Cutter chipping particle flow code Modified plastic bond model

Microdamage study of granite under thermomechanical coupling based on the particle flow code

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Frontiers of Structural and Civil Engineering 2023年第9期17卷 1413-1427页

作者： Chong SHI Yiping ZHANG Yulong ZHANG Xiao CHEN Junxiong YANG Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering Hohai UniversityNanjing 210098China College of Civil and Transportation Engineering Hohai UniversityNanjing 210098China Key Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines College of Resources and Civil EngineeringNortheastern UniversityShenyang 110819China Department of Civil and Mineral Engineering University of TorontoToronto M5S1A1Canada

The thermomechanical coupling of rocks refers to the interaction between the mechanical and thermodynamic behaviors of rocks induced by temperature *** study of this coupling interaction is essential for understanding the mechanical and thermodynamic properties of the surrounding rocks in underground *** this study,an improved temperature-dependent linear parallel bond model is introduced under the framework of a particle flow simulation.A series of numerical thermomechanical coupling tests are then conducted to calibrate the micro-parameters of the proposed model by considering the mechanical behavior of the rock under different thermomechanical *** agreement between the numerical results and experimental data are obtained,particularly in terms of the compression,tension,and elastic responses of *** this improved model,the thermodynamic response and underlying cracking behavior of a deep-buried tunnel under different thermal loading conditions are investigated and discussed in detail.

关键词： thermomechanical coupling effect granite improved linear parallel bond model thermal property particle flow code

Mechanical Behavior of Polyurethane Polymer Materials under Triaxial Cyclic Loading:A particle flow code Approach

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Journal of Wuhan University of Technology(Materials Science) 2018年第4期33卷 980-986页

作者：刘恒 WANG Fuming 石明生 TIAN Wenling School of Water Conservancy and Environment Zhengzhou University School of Civil and Transportation Engineering Henan University of Urban Construction State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining & TechnologyXuzhou

Polyurethane polymer grouting materials were studied with conventional triaxial tests via the particle flow code in two dimensions（PFC^（2D）） method, and the simulation results agreed with the experimental data. The particle flow code method can simulate the mechanical properties of the polymer. The triaxial cyclic loading tests of the polymer material under different confining pressures were carried out via PFC^（2D） to analyze its mechanical performance. The PFC^（2D） simulation results show that the value of the elastic modulus of the polymer decreases slowly at first and fluctuated within a narrow range near the value of the peak strength; the cumulative plastic strain increases slowly at first and then increases rapidly; the peak strength and elastic modulus of polymer increase with the confining pressure; the PFC^（2D） method can be used to quantitatively evaluate the damage behavior of the polymer material and estimate the fatigue life of the materials under fatigue load based on the number and the location of micro-cracks. Thus, the PFC^（2D） method is an effective tool to study polymers.

关键词： polymer particle flow code cyclic loading elastic modulus micro-cracks axial strain

Failure mechanism and stability analysis of the Zhenggang landslide in Yunnan Province of China using 3D particle flow code simulation

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Journal of Mountain Science 2016年第5期13卷 891-905页

作者： SHI Chong LI De-jie CHEN Kal-hua ZHOU Jia-wen Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering Hohai UniversityNanjing 210098China Institute ofC eotechnical ResearchHohai UniversityNanjing 210098China State Key Laboratory of Hydraulics and Mountain River Engineering $iehuan UniversityChengdu 610065China

Based on the principle of 3D particle flow code,a numerical landslide run-out model is presented to simulate the failure process of the Zhenggang landslide(in southwestern China) under the effect of water after a *** relationship between the micro-mechanical parameters and the macro-shear strength of the grain material is determined through numerical *** the rainfall effect is considered in numerical simulations and rain-induced sliding processes are performed,which help us to discuss the mechanism of deformation and failure of this landslide together with field *** shows the Zhenggang landslide would most likely be activated in Zone I and would gain momentum in Zone *** order to prevent the potential disaster,a tailing dam is advised to be designed about 175 m downstream from the current landslide boundary of Zone *** by field observations,the presented landslide model can reflect the failure mechanism after *** can also provide a method to predict the potential disaster and draft disaster prevention measures.

关键词： Back analysis Deposit avalanche Dynamic process Landslide particle flow code

Study of seismic response of colluvium accumulation slope by particle flow code

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Study of seismic response of colluvium accumulation slope by...

Calibration method of mesoscopic parameter in sandy cobble soil triaxial test based on PFC3D

中国科学院地质与地球物理研究所第十届(2010年度)学术年会

作者： Jianming He·Xiao Li·Shouding Li·Yueping Yin·Haitao Qian Key Laboratory of Engineering Geomechanics,Institute of Geology and Geophysics,Chinese Academy of Sciences, Beijing 100029,People’s Republic of China China Geological Survey,Beijing 100037, People’s Republic of China Institute of Crustal Dynamics,China Earthquake Administration, Beijing 100085,People’s Republic of China

Colluvium accumulation slopes(CAS)are widely distributed in Sichuan Province of China,especially in the regions with intense earthquake *** kinds of accumulations show obvious discontinuous and heterogeneous characteristics,to which the discrete element method (DEM)for discontinuous material is more suitably applied. Wenchuan earthquake with a magnitude of 8.0,caused a large number of debris flows or landslides in the colluvium formations, which are densely distributed in the quake-hit region in Sichuan *** dynamic response of CAS is a key problem for study of stability of these kinds of *** this paper,PFC(particle flow code)from Itasca based on DEM is used for modeling the dynamic response of the colluvium accumulations and some typical models were built according to the geological investigations carried out in the epicentral *** shearing waveforms of WenChuan earthquake were input into the model for the study of the dynamic response of overlying colluvium accumulation and bedrock. The modeling results of different models under the same seismic conditions are described and analyzed at the end of the paper.

关键词： Colluvium accumulation slope(CAS) Dynamic response particle flow code Discontinuous characteristics

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Frontiers of Structural and Civil Engineering 2023年第12期17卷 1924-1933页

作者： Pengfei LI Xiaopu CUI Yingjie WEI Junwei XIA Xinyu WANG Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education Beijing University of TechnologyBeijing 100124China China Railway 14th Bureau Group Co. Ltd.Jinan 250014China China Railway 19 Bureau Group Rail Traffic Engineering Co. Ltd.Beijing 101399China School of Civil Engineering Henan Polytechnic UniversityJiaozuo 454000China

This paper presents a rapid and effective calibration method of mesoscopic parameters of a threedimensional particle flow code(PFC3D)model for sandy cobble *** method is based on a series of numerical tests and takes into account the significant influence of mesoscopic parameters on macroscopic ***,numerical simulations are conducted,with five implementation ***,the multi-factor analysis of variance method is used to analyze the experimental results,the mesoscopic parameters with significant influence on the macroscopic response are singled out,and their linear relations to macroscopic responses are estimated by multiple linear ***,the parameter calibration problem is transformed into a multi-objective function optimization *** simulation results are in good agreement with laboratory results both qualitatively and *** results of this study can provide a basis for the calibration of microscopic parameters for the investigation of sandy cobble soil mechanical behavior.

关键词： sandy cobble soil particle flow code orthogonal experiment regression analysis multi-objective optimization calibration

Discrete element simulation of crushable rockfill materials

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Water Science and Engineering 2013年第2期6卷 215-229页

作者： Lei SHAO Shi-chun CHI Liang-jing ZHOU Yu-zan WANG Faculty of Infrastructure Engineering Dalian University of Technology Hydrochina Chengdu Engineering Corporation Changjiang Institute of Survey Planning Design and Research Changjiang Water Resources Commission

A discrete element method was used to study the evolution of particle crushing in a rockfill sample subjected to triaxial shear. A simple procedure was developed to generate clusters with arbitrary shapes, which resembled real rockfill particles. A theoretical method was developed to define the failure criterion for an individual particle subjected to an arbitrary set of contact forces. Then, a series of numerical tests of large-scale drained triaxial tests were conducted to simulate the behaviors of the rockfill sample. Finally, we examined the development of micro-characteristics such as particle crushing, contact characteristics, porosity, deformation, movement, and energy dissipation. The simulation results were partially compared with the laboratory experiments, and good agreement was achieved, demonstrating that the particle crushing model proposed can be used to simulate the drained triaxial test ofrockfill materials. Based on a comparison of macro behaviors of the roekfill sample and micro structures of the particles, the microscopic mechanism of the rockfill materials subjected to triaxial shear was determined qualitatively. It is shown that the crushing rate, rather than the number of crushed particles, can be used to reflect the relationship between macro- and micro-mechanical characteristics of rockfill materials. These research results further develop our understanding of the deformation mechanism of rockfill materials.

关键词： discrete element simulation triaxial shear test," roclcfill material geometric construction of particles particle flow code microscopic mechanism

Crack mechanism of ground fissures in loess layer of Fenwei Basin, China

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Journal of Mountain Science 2024年第5期21卷 1683-1696页

作者： LI Cong LU Quanzhong WANG Feiyong LUO Wenchao XU Qiang School of Geological Engineering and Geomatics Chang’an UniversityXi’an 710054China Key Laboratory of Western Mineral Resources and Geological Engineering Ministry of EducationXi’an 710054China Observation and Research Station of Ground Fissure and Land Subsidence Ministry of Natural ResourcesXi’an 710054China School of Engineering and Technology China University of GeosciencesBeijing 100083China

The Fenwei Basin, covered by loess, experiences severe ground fissure disasters. These disasters disrupt the continuity of the loess and pose significant threats to engineering construction safety along transportation routes. Nevertheless, the crack characteristics and the influence zone of ground fissures in the loess layer remain inadequately investigated. To effectively prevent and control ground fissure disasters, physical model tests and the PFC(particle flow code) numerical simulation method are used to investigate the crack mechanism of buried ground fissures in the loess layer. The results show that there are two main cracks in the layer profile, which have a Y-shape morphology. As the dip angle of the preset cracks increased from 60° to 90°, the main deformation zone at the surface gradually shifted towards the footwall. The process of crack propagation from depth to surface is divided into five stages. Additionally, the results confirm the accuracy of the width of the rupture zone d2in the footwall calculated by the cantilever beam theory. These findings can offer theoretical guidance for determining the avoidance distance of ground fissures in loess regions, as well as for implementing disaster prevention and corresponding control measures for various stages of buried ground fissure propagation.

关键词： Ground fissure Fenwei Basin Physical model test particle flow code Crack propagation

An elasto-plastic constitutive model incorporating strain softening and dilatancy for interface thin-layer element and its verification

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Journal of Central South University 2012年第7期19卷 1988-1998页

作者：彭凯朱俊高冯树荣王荣刘汉龙 Hydrochina Zhongnan Engineering Corporation Key Laboratory of Geo-mechanics and Embankment Engineering of Ministry of Education(Hohai University) Geotechnical Research Institute Hohai University

The mechanical behaviors of the interface between coarse-grained soil and concrete were investigated by simple shear tests under condition of mixed soil slurry (bentonite mixed with cement grout).For comparison,the interfaces both without slurry and with bentonite slurry were *** experimental results show that different slurries exert much influence on the strength and deformation of soil/structure *** mixed soil slurry,strain softening and shear dilatation are observed,while shear dilatation appears under the small normal stress of the interface without slurry,and shear contraction is significant under the condition of the bentonite *** thickness of the interface was determined by analyzing the disturbed height of the sample with both simple shear test and particle flow code (PFC).An elasto-plastic constitutive model incorporating strain softening and dilatancy for thin layer element of interface was formulated in the framework of generalized potential *** relation curves of shear stress and shear strain,as well as the relation curves of normal strain and shear strain,were fitted by a piecewise function composed by hyperbolic functions and resembling normal *** entire model parameters can be identified by *** new model is verified by comparing the measured data of indoor cut-off wall model tests with the predictions from finite element method (FEM).The FEM results indicate that the stress of wall calculated by using Goodman element is too large,and the maximum deviation between the test data and prediction is about 45%.While the prediction from the proposed model is close to the measured data,and the error is generally less than 10%.

关键词： simple shear test mixed soil slurry dilatancy particle flow code generalized potential theory constitutive model FEM