检索结果-内蒙古大学图书馆

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

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

来源：评论

学校读者我要写书评

暂无评论

Influence of random joints on mechanical and fracture behavior of rocks under uniaxial compression: experimental study and particle flow code simulation

引用

COMPUTATIONAL particle MECHANICS 2025年 1-16页

作者： Ma, Wenqiang Zong, Mengting Xinyang Normal Univ Coll Architecture & Civil Engn 237Nanhu Rd Xinyang 464000 Henan Peoples R China

Random joints are the most common defects in rock mass. Joint size or number seriously affects the stability of rock mass. To study the effects of random joints on the mechanical properties and failure characteristics of rock mass, rock-like specimens and numerical models containing random joints were prepared and constructed, and laboratory and numerical uniaxial compression tests were both carried out. The experimental and simulation results show that as the joint size or number increases, the compressive strength of specimen or model decreases in a cubic polynomial curve, the elastic modulus decreases slightly in a straight line, and the fracture growth degree increases linearly. Joint size or number has significant effect on crack initiation and growth. Cracks initiate at the place of joint intersection and concentration and expand into macro-fracture surface. Tensile cracks are the main crack type during the compression process, the number of tensile cracks account for more than 80%, and this proportion increases with increasing joint size or number, while shear cracks only increase significantly after peak stress. Increasing joint size or number reduces the CI stress, and advances the initiation, propagation and intersection of cracks. The influence of joint size or number on mechanical properties and crack propagation is similar, but the influence of joint size is greater. The failure mode is tension-shear coupling failure, but tensile failure is the main one. The results can provide reference for stability analysis and safety assessment of jointed rock mass.

关键词： Random joints Rock specimen Fracture behavior particle flow code

来源：评论

学校读者我要写书评

暂无评论

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

引用

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

来源：评论

学校读者我要写书评

暂无评论

Influence of defect hole location on acoustic emission characteristics and damage evolution of rocks: a numerical study based on particle flow code

引用

COMPUTATIONAL particle MECHANICS 2023年第6期10卷 1943-1954页

作者： Rong, Lifan Hu, Jinlin Li, Haoran Shijiazhuang Tiedao Univ Collaborat Innovat Ctr Performance & Secur Large S Shijiazhuang 050043 Peoples R China Shijiazhuang Tiedao Univ Sch Safety Engn & Emergency Management Shijiazhuang 050043 Peoples R China

In this paper, the mechanical properties, acoustic emission characteristics and damage evolution laws of rocks with different defect holes are explored by considering the influence of the location of defect holes. The rock models with different defect hole locations are constructed based on particle flow code. The influence of different defect hole positions on the mechanical characteristics, acoustic emission (AE) characteristics, damage evolution process, and failure modes of rock models are discussed. The research result shows that the elastic modulus (E) of numerical models with different defect hole locations has little change;the uniaxial compressive strength (UCS) of the model with defect hole at the center of the model is larger than the UCS of the defect hole at the boundary of the model;the evolution law of acoustic emission can be roughly divided into three stages: the silent emission stage, the slow development stage and the rapid development stage. The position of defect holes has little influence on the first two stages, but has obvious influence on the third stage, such as the intensity of acoustic emission (maximum AE counts) and strain range. The position of different defect holes has little influence on the first two stages of damage evolution of rock models, but mainly affects the rapid damage stage. The position of the defect hole has little effect on the crack initiation position of the rock, both in the upper and lower directions of the circular hole. However, the location of the defect hole will affect the failure process of the rock.

关键词： Hole defective rocks Acoustic emission Damage evolution particle flow code Failure

来源：评论

学校读者我要写书评

暂无评论

Study on the Mechanism of Squeezing Silt by Riprap of Rubble Mound Breakwater Based on the particle flow code

引用

ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING 2023年第10期48卷 13679-13694页

作者： Liu, Xin Shi, Yunqiang Leng, Xinliang Zhang, Siqing Shao, Zhiwei Hohai Univ Inst Tunnel & Underground Engn Key Lab Minist Educ Geomech & Embankment Engn Nanjing 210098 Peoples R China Planning & Design Inst Anhui Prov Hefei 230088 Peoples R China

Rubble mound breakwater (RMB) is a kind of sloping breakwater built by squeezing silt by riprap, and the effect of squeezing silt by riprap has a significant influence on the stability of RMB. This paper simulated the dynamic process of squeezing silt by riprap based on the particle flow code and studied the influences of the silt mixed sand layer's thickness, the riprap height, and the riprap radius on the depth of squeezing silt. In the squeezing silt test by single riprap, the depth of squeezing silt increases exponentially as the thickness of silt mixed sand layer increases and increases linearly as the riprap height and the riprap radius increase. In the process of squeezing silt by complete ripraps, the depth of squeezing silt increases linearly as the thickness of silt mixed sand layer increases, increases exponentially as the breakwater height increases, and increases quadratically as the maximum riprap radius increases. Besides, through analyzing the vertical displacement curve of the characteristic particles, the process of squeezing silt by riprap is divided into three parts: instantaneously squeezing silt, squeezing silt by kinetic energy transfer, and squeezing silt by the gravity of riprap heap. The mechanism of squeezing silt by riprap is revealed. This study can well guide the riprap construction of RMB and estimate the amount of riprap, which has greatly practical significance.

关键词： Rubble mound breakwater particle flow code Process of squeezes silt by riprap Depth law of squeezing silt by riprap Mechanism of squeezing silt by riprap

来源：评论

学校读者我要写书评

暂无评论

The numerical investigation of tensile strength of coal model on the performance of coal plow using particle flow code

引用

STRUCTURAL ENGINEERING AND MECHANICS 2022年第6期82卷 713-724页

作者： Fu, Jinwei Haeri, Hadi Sarfarazi, Vahab Marji, Mohammad Fatehi Li, Tong North China Univ Water Resources & Elect Power Sch Civil Engn & Transportat Zhengzhou 450046 Peoples R China Hamedan Univ Technol Dept Min Engn Hamadan Hamadan Iran Yazd Univ Inst Engn Fac Min & Met Mine Exploitat Engn Dept Yazd Iran

Effects of coal tensile strength and plow configuration on the coal fragmentation process was modeled by twodimensional particles flow code (PFC2D). Three tensile strength values, 0.5, 1,5 and 3.5 MPa were considered in this numerical study. The cutters of plow penetrated in the coal for 4 mm at a rate of 0.016 m/s. According to the PFC manual, the local damping factor was 0.7. Three failure mechanism of coal during the fragmentation process by plow were modelled. The coal material beneath the cutters showed the elastic, plastic and fracturing behaviors in this analysis. In all the models, the plastic zone was fractured and some micro-cracks were induced but the elastic zone remained undamaged. It was observed that the tensile strength affected the failure mechanism of coal significantly and as it increased the extent of the fractured zone underneath the plow cutter decreased during the fragmentation process.

关键词： coal plow particle flow code tensile strength

来源：评论

学校读者我要写书评

暂无评论

The rock fragmentation and crack propagation under TBM tunneling based on particle flow code

引用

JOURNAL OF GEOPHYSICS AND ENGINEERING 2022年第6期19卷 1355-1366页

作者： Lan, Donghao Deng, Hongjian Gao, Yanan Wang, Yunlong Zhang, Guangkai Shandong Univ Sci & Technol Key Lab Min Disaster Prevent & Control Qingdao 266590 Shandong Peoples R China China Univ Min & Technol State Key Lab Geomech & Underground Engn Xuzhou 221116 Jiangsu Peoples R China China Univ Min & Technol Sch Mech & Civil Engn Xuzhou 221116 Jiangsu Peoples R China Beijing Inst Technol State Key Lab Explos Sci & Technol Beijing 100081 Peoples R China

The rock fragmentation and crack propagation of anisotropic rock induced by tunnel boring machine (TBM) tunneling is studied in this paper. First, a numerical model based on the 2D particle flow code (PFC2D) is established and calibrated to reveal the four stages of rock fragmentation. In Stage I (indentation depth 0-0.4 mm), the indentation force beneath the cutterhead increases and decreases dramatically with the accumulation and release of mechanical energy. Such a phenomenon indicates that a hydrostatic core (crushed zone) can be observed. In Stage II (indentation depth 0.4-1.1 mm), many median cracks propagate dramatically with the indentation force. Meanwhile, the hydrostatic core is pushed because the mechanical energy of the cutterhead is reaccumulated in the specimen. In Stage III (indentation depth 1.1-2.6 mm), lateral cracks begin to develop due to the further increase in indentation depth. In Stage IV (indentation depth 2.6-5 mm), the lateral cracks and median cracks continue to propagate, and rock chips can be found on the sides of the cutterhead. Then, with increasing confining pressure, lateral cracks begin to gradually develop and the maximum angle of lateral cracks is 70.5 degrees. Furthermore, the magnitude of the intrusion velocity can seriously influence the evolution of the indentation force during Stages III and IV because of the accumulation and release of mechanical energy. The accumulation and release of mechanical energy are more obvious with a higher intrusion velocity of the cutterhead.

关键词： TBM indentation particle flow code rock fragmentation crack propagation

来源：评论

学校读者我要写书评

暂无评论

particle flow code simulation of intact and fissured granitic rock samples

引用

Journal of Rock Mechanics and Geotechnical Engineering 2020年第5期12卷 960-974页

作者： Uxía Castro-Filgueira Leandro R.Alejano Diego Mas Ivars Department of Natural Resources and Environmental Engineering University of VigoVigoSpain Department of Geology and Geological Engineering Colorado School of MinesGoldenCOUSA Swedish Nuclear Fuel and Waste Management Company(SKB) StockholmSweden Division of Soil and Rock Mechanics Royal Institute of Technology(KTH)StockholmSweden

This study presents a calibration process of three-dimensional particle flow code(PFC3D)simulation of intact and fissured granite ***,laboratory stressestrain response from triaxial testing of intact and fissured granite samples is ***,PFC3D is introduced,with focus on the bonded particle models(BPM).After that,we present previous studies where intact rock is simulated by means of flatjoint approaches,and how improved accuracy was gained with the help of parametric ***,models of the pre-fissured rock specimens were generated,including modeled fissures in the form of“smooth joint”type ***,triaxial testing simulations of 1 t 2 and 2 t 3 jointed rock specimens were *** show that both elastic behavior and the peak strength levels are closely matched,without any additional fine tuning of micro-mechanical *** the postfailure behavior,models reproduce the trends of decreasing dilation with increasing confinement and ***,the dilation values simulated are larger than those observed in *** is attributed to the difficulty in modeling some phenomena of fissured rock behaviors,such as rock piece corner crushing with dust production and interactions between newly formed shear bands or axial splitting cracks with pre-existing joints.

关键词： Numerical methods Artificially fissured samples Rock mass behavior particle flow code Parallel bond Flat-joint Smooth-joint

来源：评论

学校读者我要写书评

暂无评论

Deformation Monitoring and Dynamic Analysis of Long-Runout Bedding Landslide Based on InSAR and particle flow code

引用

REMOTE SENSING 2023年第21期15卷 5105-5105页

作者： Gao, Yang Li, Jun Liu, Xiaojie Wu, Weile Zhang, Han Liu, Pengfei Chinese Acad Geol Sci Inst Geomech Beijing 100081 Peoples R China Minist Nat Resources Key Lab Act Tecton & Geol Safety Beijing 100081 Peoples R China China Geol Survey Res Ctr Neotectonism & Crustal Stabil Beijing 100081 Peoples R China Lanzhou Univ Technol Sch Civil Engn Lanzhou 730050 Peoples R China Changan Univ Sch Geol Engn & Geomat Xian 710054 Peoples R China Chongqing Inst Geol Environm Monitoring Chongqing 401122 Peoples R China

Long-runout landslides occur frequently in the sandstone and mudstone mountainous areas in southwestern China under heavy rainfall conditions. This has been a key issue in the field of disaster prevention and reduction. Considering the Niuerwan landslide in Wulong, Chongqing, on 13 July 2020, as an example, we employed technical methodologies, including unmanned aerial vehicle (UAV) images, field investigation, geological condition analysis (including geomorphology and topography, stratigraphic structure and formation lithology, etc.), interferometric synthetic aperture radar (InSAR) monitoring and particle flow code 3D (PFC3D) simulations to study failure mechanism and a long-runout motion model of flow-like landslides induced by the heavy rainfall. The results showed that (1) the large differences between the upper and lower strata are the root cause of the instability and long-runout fluidization movement;(2) heavy rainfall is the key driving factor of slope instability and deep-seated landslides, leading to long-distance movement of the upper saturated residual soil;(3) the long-runout fluidization model of bedding landslides is mainly divided into the overall sliding in the lower layer, the mixing of coarse and fine particles in the middle layer, and saturation fluidization in the upper layer;and (4) the long-runout fluidization process of bedding landslides is composed of three stages: overall instability, mixed acceleration, and fluidization accumulation. In view of these findings, in the risk evaluation and prediction of long-runout fluidization landslides in sandstone and mudstone mountainous areas, this particular disaster model can be used to provide quantitative references for disaster prevention and mitigation.

关键词： long-runout landslide slope instability fluidization Interferometric synthetic aperture radar (InSAR) particle flow code

来源：评论

学校读者我要写书评

暂无评论

Mechanical and Microcrack Evolution Characteristics of Roof Rock of Coal Seam with Different Angle of Defects Based on particle flow code

引用

MATERIALS 2023年第4期16卷 1401-1401页

作者： Deng, Qinghai Liu, Jiaqi Wang, Junchao Lyu, Xianzhou Shandong Univ Sci & Technol Coll Earth Sci & Engn Qingdao Peoples R China Longshou Mine Jinchuan Grp Co Ltd Jinchuan 737100 Peoples R China

The creation of the natural ceiling rock of the coal seam is rife with fractures, holes, and other flaws. The angle of the defects has a significant influence on the mechanical characteristics and crack evolution of coal seam roof rock. Multi-scale numerical simulation software PFC2D gets adapted to realize the crack propagation and coalescence process in the roof rock of a coal seam with different angles of defects under uniaxial compression. The effect of flaw angles on the micro and macro mechanical characteristics of rock is also discovered. The results show that: (1) the defect angle has influence on the stress-strain, elastic modulus, peak strength, peak strain, acoustic emission (AE) and strain energy of roof rock of coal seam. When the defect angles are different, the starting position of the roof rock in a coal seam fracture is different. The quantity of microcracks firstly reduces with an increase in defect angles before gradually increasing. At the same fault angle, the cracks are mostly tensile ones and only a few shear ones. (2) When the defect angle is less than 90 degrees, tensile and shear fractures are mostly localized at the defect's two tips and propagate along the loading direction. When the defect angle is 90 degrees, the tensile and shear cracks are not concentrated at the tip of the defect. (3) As the defect angles increase, the elastic strain energy rises initially and then falls, and the dissipated energy and total input energy both increase continuously. The elastic strain energy is greatest at the highest strength. The study provides a certain reference for the use of various analysis methods in practical engineering to evaluate the safety and stability of rock samples with pre-existing defects.

关键词： rock mechanics microcrack evolution defects angles failure modes multi-scale characterization particle flow code

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：