检索结果-内蒙古大学图书馆

Anisotropic shearing mechanism of Kangding slate:Experimental investigation and numerical analysis

Journal of Rock Mechanics and geotechnical engineering 2024年第5期16卷 1487-1504页

作者： Ping Liu Quansheng Liu Penghai Deng Yucong Pan Yiming Lei Chenglei Du Xianqi Xie The Key Laboratory of Geotechnical and Structural Engineering Safety of Hubei Province School of Civil EngineeringWuhan UniversityWuhan430072China State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan430072China

The shear mechanical behavior is regarded as an essential factor affecting the stability of the surrounding rocks in underground *** shear strength and failure mechanisms of layered rock are significantly affected by the foliation *** shear tests were conducted on cubic slate samples with foliation angles of 0°,30°,45°,60°,and 90°.The effect of foliation angles on failure patterns,acoustic emission(AE)characteristics,and shear strength parameters was *** on AE characteristics,the slate failure process could be divided into four stages:quiet period,step-like increasing period,dramatic increasing period,and remission period.A new empirical expression of cohesion for layered rock was proposed,which was compared with linear and sinusoidal cohesion expressions based on the results made by this paper and previous *** comparative analysis demonstrated that the new expression has better prediction ability than other *** proposed empirical equation was used for direct shear simulations with the combined finite-discrete element method(FDEM),and it was found to align well with the experimental *** both computational efficiency and accuracy,it was recommended to use a shear rate of 0.01 m/s for FDEM to carry out direct shear *** balance the relationship between the number of elements and the simulation results in the direct shear simulations,the recommended element size is 1 mm.

关键词： Anisotropy Empirical expression of cohesion foliation angles Combined finite-discrete element method(FDEM) Shear rate Element size

来源：评论

学校读者我要写书评

暂无评论

Experimental study on the influences of cutter geometry and material on scraper wear during shield TBM tunnelling in abrasive sandy ground

引用

Journal of Rock Mechanics and geotechnical engineering 2024年第2期16卷 410-425页

作者： Shaohui Tang Xiaoping Zhang Quansheng Liu Qi Zhang Xinfang Li Haojie Wang Key Laboratory of Safety for Geotechnical and Structural Engineering of Hubei Province School of Civil EngineeringWuhan UniversityWuhan430072China State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan430072China

When shield TBM tunnelling in abrasive sandy ground,the rational design of cutter parameters is critical to reduce tool wear and improve tunnelling ***,the influence mechanism of cutter parameters on scraper wear remains unclear due to the lack of a reliable test *** and material optimisation are often based on subjective experience,which is unfavourable for improving scraper geological *** the present study,the newly developed WHU-SAT soil abrasion test was used to evaluate the variation in scraper wear with cutter geometry,material and *** influence mechanism of cutter parameters on scraper wear has been revealed according to the scratch characteristics of the scraper *** geometry and material parameters have been optimised to reduce scraper *** results indicate that the variation in scraper wear with cutter geometry is related to the cutting resistance,frictional resistance and stress *** appropriate increase in the front angle(or back angle)reduces the cutting resistance(or frictional resistance),while an excessive increase in the front angle(or back angle)reduces the edge angle and causes stress *** optimal front angle,back angle and edge angle for quartz sand samples areα=25°,β=10°andγ=55°,*** wear resistance of the modelled scrapers made of different metal materials is related to the chemical elements and *** wear resistances of the modelled scrapers made of 45#,06Cr19Ni10,42CrMo4 and 40CrNiMoA are 0.569,0.661,0.691 and 0.728 times those made of WC-Co,*** the alloy hardness is less than 47 HRC(or greater than 58 HRC),scraper wear decreases slowly with increasing alloy hardness as the scratch depth of the particle asperity on the metal surface stabilizes at a high(or low)***,when the alloy hardness is between 47 HRC and 58 HRC,scraper wear decreases rapidly with increasing alloy hardness as the scratch depth transitions

关键词： Shield TBM Scraper wear Cutter shape Metal material Alloy hardness

来源：评论

学校读者我要写书评

暂无评论

A review of test methods for uniaxial compressive strength of rocks:Theory,apparatus and data processing

引用

Journal of Rock Mechanics and geotechnical engineering 2025年第3期17卷 1889-1905页

作者： Wei-Qiang Xie Xiao-Li Liu Xiao-Ping Zhang Quan-Sheng Liu En-ZhiWang State Key Laboratory of Hydroscience and Engineering Tsinghua UniversityBeijing100084China Yunlong Lake Laboratory of Deep Underground Science and Engineering Xuzhou221000China The Key Laboratory of Safety for Geotechnical and Structural Engineering of Hubei Province School of Civil EngineeringWuhan UniversityWuhan430072China

The uniaxial compressive strength(UCS)of rocks is a vital geomechanical parameter widely used for rock mass classification,stability analysis,and engineering design in rock *** UCS testing methods and apparatuses have been proposed over the past few *** objective of the present study is to summarize the status and development in theories,test apparatuses,data processing of the existing testing methods for UCS *** starts with elaborating the theories of these test *** the test apparatus and development trends for UCS measurement are summarized,followed by a discussion on rock specimens for test apparatus,and data processing ***,the method selection for UCS measurement is *** reveals that the rock failure mechanism in the UCS testing methods can be divided into compression-shear,compression-tension,composite failure mode,and no obvious failure *** trends of these apparatuses are towards automation,digitization,precision,and multi-modal *** size correction methods are commonly *** is to develop empirical correlation between the measured indices and the specimen *** other is to use a standard specimen to calculate the size correction *** to five input parameters are commonly utilized in soft computation models to predict the UCS of *** selection of the test methods for the UCS measurement can be carried out according to the testing scenario and the specimen *** engineers can gain a comprehensive understanding of the UCS testing methods and its potential developments in various rock engineering endeavors.

关键词： Uniaxial compressive strength(UCS) UCS testing methods Test apparatus Data processing

来源：评论

学校读者我要写书评

暂无评论

Robust model for tunnel squeezing using Bayesian optimized classifiers with partially missing database

引用

Underground Space 2023年第3期10卷 91-117页

作者： Yin Bo Xing Huang Yucong Pan Yanfang Feng Penghai Deng Feng Gao Ping Liu Quansheng Liu Key Laboratory of Geotechnical and Structural Engineering Safety of Hubei Province School of Civil EngineeringWuhan UniversityWuhanHubei 430072China State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhanHubei 430072China State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhanHubei 430071China

Accurately predicting and estimating the squeezing and ground response to tunneling remains ***,tunnel-squeezing hazards are much more likely to occur in deeply buried long tunnels with complex engineering-geological ***-fore,a high-performance predictive model for tunnel squeezing is necessary.A superior ensemble classifier is put forward in this study,which is composed of four individual classifiers(gradient boosting classifier,extra-trees classifier,AdaBoost classifier,and Logistic regression classifier)and two optimization algorithms(Bayesian optimization(BO)and sparrow search algorithm(SSA)).The training database covers five parameters:tunnel depth(H),rock tunneling quality index(Q),tunnel diameter(D),support stiffness(K),and strength stress ratio(SSR),about which the basic information is accessible at the early design ***,the dataset compiled from the literature is ***,the ten proposed methods are used to replace the missing *** the model training pro-cess,BO shows its strong ability to optimize seventeen *** applied to tune the classifiers’weights,SSA achieves a fast and efficient *** novel Shapley Additive Explanations–LightGBM method indicates that the K is the most important input feature,followed by SSR,Q,H,and D,*** ensemble classifier is then validated using the test set and additional his-torical case *** validation shows that the model can achieve an accuracy of 98%(i.e.,the error rate is 2%)on the test set,higher than those achieved by previous prediction ***,the predicted probability could provide warning information for timely support ***,the application results are illustrated through tests on the tunnel sections that have not yet been excavated in the line of the Sichuan–Tibet railway *** applied predictive tendencies and laws are in line with the practical *** sum-mary,the proposed model

关键词： Tunnel squeezing hazard Bayesian optimization Machine learning techniques Sparrow search algorithm Ensemble classifier Incomplete database

来源：评论

学校读者我要写书评

暂无评论

Acoustic emission characteristics of damage evolution of multi-scale fiber reinforced rubberized concrete under uniaxial compression and tension after being subjected to high temperatures

引用

Frontiers of structural and Civil engineering 2024年第8期18卷 1237-1266页

作者： Shaoqi ZHANG Yao ZHANG Qianru LEI Yumeng YANG Yichao WANG Fei XU Zhiguo YAN Hehua ZHU Laboratory of Fire Safety School of Safety Engineering and Emergency ManagementShijiazhuang Tiedao UniversityShijiazhuang 050043China Structural Health Monitoring and Control Key Laboratory of Hebei Province Shijiazhuang Tiedao UniversityShijiazhuang 050043China Department of Geotechnical Engineering Tongji UniversityShanghai 200092China

Recently developed multi-scale fiber(i.e.,CaCO3 whisker,polyvinyl alcohol(PVA)fiber,and steel fiber)reinforced rubberized concrete exhibits excellent mechanical properties and spalling resistance at high *** of macro properties such as strength and Young’s modulus cannot reveal and characterize damage mechanisms,particularly those relating to the multi-scale fiber strengthening *** this study,acoustic emission(AE)technology is applied to investigate the impact of multi-scale fiber on the damage evolution of rubberized concrete exposed to high temperatures,under the uniaxial compression and tension loading *** mechanical properties,AE event location,peak frequency,b-value,the ratio of rise time to amplitude(RA),average frequency(AF)values,and AE energy of specimens are *** results show that the number of events observed using AE gradually increases as the loading *** crumb rubber and fibers inhibit the generation and development of the *** is concluded that both the peak frequency and b-value reflect the extension process of *** the cracks develop from the micro scale to the macro scale,the peak frequency tends to be distributed in a lower frequency range,and the b-value decreases *** the peak stress point,the AE energy increases rapidly and the b-value *** specimens without multi-scale fibers exhibit brittle failure,while the specimens with fibers exhibit ductile *** addition,adding multi-scale fibers and crumb rubber increases the peak frequency in the medium and high frequency ranges,indicating a positive effect on inhibiting crack *** being subjected to high temperatures,the maximum and minimum b-values decrease,reflecting an increase in the number of initial cracks due to thermal ***,the RA and AF values are used to classify tensile and shear *** specimens fracture with more shear cracks under compression,and there are more tensile

关键词： multi-scale fibers acoustic emission fracture damage evolution rubberized concrete

来源：评论

学校读者我要写书评

暂无评论

Numerical investigation of geostress influence on the grouting reinforcement effectiveness of tunnel surrounding rock mass in fault fracture zones

引用

Journal of Rock Mechanics and geotechnical engineering 2024年第1期16卷 81-101页

作者： Xiangyu Xu Zhijun Wu Lei Weng Zhaofei Chu Quansheng Liu Yuan Zhou The Key Laboratory of Safety for Geotechnical and Structural Engineering of Hubei Province School of Civil EngineeringWuhan UniversityWuhan430072China Wuhan University Shenzhen Research Institute Shenzhen518057China State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan430072China Institute of Rock and Soil Mechanics Chinese Academy of SciencesWuhan430071China

Grouting is a widely used approach to reinforce broken surrounding rock mass during the construction of underground tunnels in fault fracture zones,and its reinforcement effectiveness is highly affected by *** this study,a numerical manifold method(NMM)based simulator has been developed to examine the impact of geostress conditions on grouting reinforcement during tunnel *** develop this simulator,a detection technique for identifying slurry migration channels and an improved fluid-solid coupling(FeS)framework,which considers the influence of fracture properties and geostress states,is developed and incorporated into a zero-thickness cohesive element(ZE)based NMM(Co-NMM)for simulating tunnel ***,to simulate coagulation of injected slurry,a bonding repair algorithm is further proposed based on the ZE *** verify the accuracy of the proposed simulator,a series of simulations about slurry migration in single fractures and fracture networks are numerically reproduced,and the results align well with analytical and laboratory test ***,these numerical results show that neglecting the influence of geostress condition can lead to a serious over-estimation of slurry migration range and reinforcement *** validations,a series of simulations about tunnel grouting reinforcement and tunnel excavation in fault fracture zones with varying fracture densities under different geostress conditions are *** on these simula-tions,the influence of geostress conditions and the optimization of grouting schemes are discussed.

关键词： Numerical manifold method(NMM) Grouting reinforcement Geostress condition Fault fracture zone Tunnel excavation

来源：评论

学校读者我要写书评

暂无评论

Development of a Three-Dimensional Multiscale Octree SBFEM for Viscoelastic Problems of Heterogeneous Materials

引用

Computer Modeling in engineering & Sciences 2024年第8期140卷 1831-1861页

作者： Xu Xu Xiaoteng Wang Haitian Yang Zhenjun Yang Yiqian He State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentDepartment of Engineering MechanicsDalian University of TechnologyDalian116024China Hubei Key Laboratory of Geotechnical and Structural Safety School of Civil EngineeringWuhan UniversityWuhan430072China Mechanik–Materialtheorie Ruhr-Universität BochumBochum44801Germany

The multiscale method provides an effective approach for the numerical analysis of heterogeneous viscoelastic materials by reducing the degree of freedoms(DOFs).A basic framework of the Multiscale Scaled Boundary Finite Element Method(MsSBFEM)was presented in our previous works,but those works only addressed two-dimensional *** order to solve more realistic problems,a three-dimensional MsSBFEM is further developed in this *** the proposed method,the octree SBFEM is used to deal with the three-dimensional calculation for numerical base functions to bridge small and large scales,the three-dimensional image-based analysis can be conveniently conducted in small-scale and coarse nodes can be flexibly adjusted to improve the computational ***,the Temporally Piecewise Adaptive Algorithm(TPAA)is used to maintain the computational accuracy of multiscale analysis by adaptive calculation in time *** results of numerical examples show that the proposed method can significantly reduce the DOFs for three-dimensional viscoelastic analysis with good *** instance,the DOFs can be reduced by 9021 times compared with Direct Numerical Simulation(DNS)with an average error of 1.87%in the third example,and it is very effective in dealing with three-dimensional complex microstructures directly based on images without any geometric modelling process.

关键词： Three-dimensionalmultiscale viscoelastic analysis numerical base functions octree SBFEM image-based analysis temporally piecewise adaptive algorithm

来源：评论

学校读者我要写书评

暂无评论

Numerical Study of Hydraulic Fracturing Assisted Rock Breaking Based on Discrete Element Method 18th

Numerical Study of Hydraulic Fracturing Assisted Rock Breaki...

引用

18th Conference of the Associated Research Centers for the Urban Underground Space, ACUUS 2023

作者： Zhang, Xiao-Ping Ji, Pei-Qi Zhang, Han Zhang, Qi Key Laboratory of Safety for Geotechnical and Structural Engineering of Hubei Province School of Civil Engineering Wuhan University Wuhan430072 China Changjiang Survey Planning Design and Research Co. Ltd Wuhan430014 China

ISBN: (纸本)9789819712564

To improve the rock breaking efficiency of TBMs in hard rock, this research attempts to apply hydraulic fracturing technology to assist rock breaking and conduct numerical simulation of multi-step injection fracturing near the tunnel face to find suitable hydraulic fracturing scheme. The simulation results demonstrate that the initiation and propagation directions of hydraulic fracturing cracks are influenced by two key factors: the distance between the fluid injection hole and the tunnel face, as well as the injection sequence. As the initial fluid injection position becomes far ahead from the tunnel face, the propagation direction of hydraulic fracturing cracks gradually changes from vertical to horizontal. The second injection position in the vertical section should not be too close to the initial injection position to prevent the newly initiated hydraulic fracturing cracks converging with the previous cracks. Regarding the arrangement of injection holes on the cross section, when two or three injection holes undergo synchronous fracturing, there is a notable tendency for the fracturing cracks to propagate obliquely and intersect with each other. This inter section results in the rock mass being segmented into smaller blocks, significantly reducing the required fracturing time. Additionally, this process enhances the frag mentation of the rock mass, leading to more efficient tunnel boring machine (TBM) tunneling operations. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.

关键词： Rock mechanics

来源：评论

学校读者我要写书评

暂无评论

Numerical Investigation of Rock Mechanical Characteristics in Post-peak Curve Based on Combined Finite-discrete Element Method

引用

Journal of engineering Science and Technology Review 2022年第1期15卷 58-67页

作者： Li, Peitao Deng, Penghai Liu, Quansheng Liu, Ping Key Laboratory of Safety for Geotechnical and Structural Engineering of Hubei Province School of Civil Engineering Wuhan University Wuhan430072 China State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University Wuhan430072 China

To explore the influence of confining pressure on rock mechanical properties in post-peak curve, the combined finitediscrete element method was used and the post-peak stress and fracture characteristics of rock under different confining pressures and damage degree were analyzed. Results show that the post-peak axial stress increases linearly with the confining pressure, but the higher confining pressure will also increase the fracture number. However, the fracture number is sensitive to the damage degree. Therefore, the coordination of confining pressure and damage degree provide a possibility to control the post-peak stress and fracture number simultaneously. While a smaller damage degree at the loading time is contribute to the control of rock post-peak mechanical property. The increase of post-peak stress and decline of fracture number can be achieved by an appropriate combined loading scheme. The coordination of support strength and applying time has a good prospect for the development of combined support technology. © 2022. School of Science, IHU. All rights reserved.

关键词： Rock pressure

来源：评论

学校读者我要写书评

暂无评论

TBM tunnelling under adverse geological conditions: Case study of a long-distance and deep-buried water conveyance tunnel 58

TBM tunnelling under adverse geological conditions: Case stu...

引用

58th US Rock Mechanics / Geomechanics Symposium 2024, ARMA 2024

作者： Xie, Wei-Qiang Zhang, Xiao-Ping Liu, Xiao-Li Qian, Rui-Peng Liu, Quan-Sheng State Key Laboratory of Hydroscience and Engineering Tsinghua University Beijing100084 China The Key Laboratory of Safety for Geotechnical and Structural Engineering of Hubei Province School of Civil Engineering Wuhan University Wuhan430072 China Yunlong Lake Laboratory of Deep Underground Science and Engineering Xuzhou221003 China

ISBN: (纸本)9798331305086

The adverse geological conditions have significant influences on the safety and efficiency of tunnel boring machine (TBM) tunnelling. Feasible solutions for TBM tunnelling under adverse geological conditions are summarized based on a long-distance and deep-buried water conveyance tunnel. The engineering background of the tunnel is briefly presented. Then the challenges of TBM tunnelling encountered in adverse geological conditions are highlighted, including fractured and faulted rock mass, squeezing rock mass and deep-buried rock mass. Series of solutions carried out successfully in the field to overcome these challenges are elaborated. It is necessary to install a geological drilling rig on TBM. The hazards frequently occur in the L1 zone in TBM tunnel. The noxious gases present within 6-12 meters away from the tunnel face. The large squeezing deformation commonly occurs at the TBM shield. Most rockburst events occur within 1 hour after the surrounding rock is revealed. A commonly used construction technology system for assisting TBM tunnelling under adverse geological conditions is proposed. Copyright 2024 ARMA, American Rock Mechanics Association.

关键词： Boring machines (machine tools)

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：