检索结果-南通市图书馆

Assessing the range of blasting-induced cracks in the surrounding rock of deeply buried tunnels based on the unified strength theory

引用

Journal of Central South University 2024年第7期31卷 2341-2364页

作者： LI Liang CHEN Jia-jun ZHAO Lian-heng HE Ke-pei HU Shi-hong LI Hua-long School of Civil engineering Central South UniversityChangsha 410075China key laboratory of heavy-haul railway engineering structure Ministry of EducationCentral South UniversityChangsha 410075China Hunan Provincial key laboratory for Disaster Prevention and Mitigation of Rail Transit engineering structure Central South UniversityChangsha 410075China

Blasting-induced cracks in the rock surrounding deeply buried tunnels can result in water gushing and rock mass collapse,posing significant safety ***,previous theoretical studies on the range of blasting-induced cracks often ignore the impact of the in-situ stress,especially that of the intermediate principal *** particle displacement−crack radius relationship was established in this paper by utilizing the blasthole cavity expansion equation,and theoretical analytical formulas of the stress−displacement relationship and the crack radius were derived with unified strength theory to accurately assess the range of cracks in deep surrounding rock under a blasting *** analysis showed that the crushing zone size was positively correlated with in-situ stress,intermediate principal stress,and detonation pressure,whereas negatively correlated with Poisson ratio and decoupling *** dilatancy angle-crushing zone size relationship exhibited nonmonotonic *** relationships in the crushing zone and the fracture zone exhibited opposite trends under the influence of only in-situ stress or intermediate principal *** the in-situ stress increased from 0 to 70 MPa,the rate of change in the crack range and the attenuation rate of the peak vibration velocity gradually slowed.

关键词： deep drilling and blasting cracks in surrounding rock unified strength theory intermediate principle stress in-situ stress cavity expansion dilatancy characteristics

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Three-dimensional limit variation analysis on the ultimate pullout capacity of the anchor cables based on the Hoek-Brown failure criterion

引用

Journal of Mountain Science 2024年第3期21卷 1036-1047页

作者： ZUO Shi ZHAO Lianheng HU Shihong College of Civil engineering Changsha UniversityChangsha 410022China Hunan Provincial key laboratory for Disaster Prevention and Mitigation of Rail Transit engineering structure Key Laboratory of Heavy-Haul Railway Engineering StructureMinistry of EducationCentral South UniversityChangsha 410075China College of Civil engineering Central South UniversityChangsha 410075China

Only simplified two-dimensional model and a single failure mode are adopted to calculate the ultimate pullout capacity(UPC)of anchor cables in most previous *** study focuses on a more comprehensive combination failure mode that consists of bond failure of an anchorage body and failure of an anchored rock *** three-dimensional ultimate pullout capacity of the anchor cables is calculated based on the Hoek-Brown failure criterion and variation analysis *** numerical solution for the curvilinear function in fracture plane is obtained based on the finite difference theory,which more accurately reflects the failure state of the anchor cable,as opposed to that being assumed in *** results reveal that relying solely on a single failure mode for UPC calculations has limitations,as changes in parameter values not only directly impact the UPC value but also can alter the failure model and thus the calculation method.

关键词： Anchor cable Ultimate pullout capacity(UPC) Failure model Variation analysis Hoek-Brown failure criterion

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Stability analysis of intermittently jointed rock slopes based on the stepped failure mode

引用

Journal of Mountain Science 2024年第3期21卷 1019-1035页

作者： LI Dejian FU Junwen LI Hekai CHENG Xiao ZHAO Lianheng ZHANG Yingbin PENG Xinyan School of Civil engineering Southwest Jiaotong UniversityChengdu 610031China Institute for Disaster Management and Reconstruction College of Architecture&EnvironmentSichuan UniversityChengdu 610065China School of Civil engineering Key Laboratory of Heavy-Haul Railway Engineering StructureMinistry of EducationHunan Provincial Key Laboratory for Disaster Prevention and Mitigation of Rail Transit Engineering StructureCentral South UniversityChangsha 410075China

In practical engineering,due to the noncontinuity characteristics of joints in rock slopes,in addition to plane failure,stepped sliding failure may occur for intermittently jointed rock *** for intermittently bedding jointed rock slopes,the correlation and difference in strength parameters between joints and rock bridges,along with the various failure modes and intermittency of rock bridges,contribute to the complexity of stepped failure modes and the unpredictability of failure *** on the upper-bound limit analysis method and multi-sliders step-path failure mode,considering the shear and tensile failure of rock bridges and the weakened relationship between the strength parameters of rock bridges and jointed surfaces,by introducing the modified M-C failure criterion and the formula for calculating the energy consumption of tensile failure of rock bridges,two failure mechanisms are constructed to obtain the safety factor(F_(s))of intermittently jointed rock *** sequential quadratic programming method is used to obtain the optimal upper-bound solution for F_(s).The influence of multiple key parameters(slope height H,horizontal distance L,Slope angleβ,shear strength parameters of the rock bridgeφr and cr,Dimensionless parameter u,weakening coefficients of the internal friction angle and cohesion between the rock bridges and joint surfaces Kφand Kc)on the stability analysis of intermittently jointed rock slopes under the shear failure mode of rock bridges as well as under the tensile failure mode is also *** reliability of the failure mechanisms is verified by comparative analysis with theoretical results,numerical results,and landslide cases,and the variation rules of F_(s)with each key parameter are *** results show that F_(s) varies linearly withφr and cr of the rock bridge and with K_(φ)and K_(c),whereas F_(s)changes nonlinearly with H and *** particular,with the increase in Kφand Kc,Fs increases by approximately 52.

关键词： Jointed rock slopes Stepped sliding failure Weakening characteristics Modified M‒C failure criterion

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

基于统一强度理论的深埋隧道围岩爆破致裂范围评估（英文）

引用

Journal of Central South University 2024年第07期 2341-2364页

作者：李亮陈嘉骏赵炼恒何可培胡世红李华隆 School of Civil engineering Central South University key laboratory of heavy-haul railway engineering structure Ministry of EducationCentral South University Hunan Provincial key laboratory for Disaster Prevention and Mitigation of Rail Transit engineering structure Central South University

深埋隧道围岩的爆破致裂可能导致地下涌水和岩体坍塌，存在重大安全隐患。然而，现有关于围岩爆破致裂范围的理论研究通常忽略了中主应力和地应力的影响。为准确评估深埋隧道围岩的爆破致裂范围，本文以炮孔空腔膨胀的两阶段Jones-Mille... 详细信息

深埋隧道围岩的爆破致裂可能导致地下涌水和岩体坍塌，存在重大安全隐患。然而，现有关于围岩爆破致裂范围的理论研究通常忽略了中主应力和地应力的影响。为准确评估深埋隧道围岩的爆破致裂范围，本文以炮孔空腔膨胀的两阶段Jones-Miller绝热方程为基础，建立了围岩位移与裂隙半径的动力控制方程；并基于统一强度理论推导了围岩应力、位移和裂隙半径的理论解析式。参数分析表明，在爆破荷载作用下，围岩的粉碎区范围与地应力、中主应力和孔壁压力呈正相关，与泊松比和不耦合系数呈负相关，随剪胀角取值的改变而呈现非单调特性。与粉碎区相比，破裂区范围分别在剪胀角、泊松比、孔壁压力和不耦合系数影响下的变化趋势一致，而在地应力或中主应力影响下呈现相反的变化趋势。随地应力从0增大至70 MPa，围岩爆破致裂范围的变化速率和围岩振速峰值的衰减速率逐渐减缓。本文研究成果可为深埋隧道钻爆工程实际中围岩裂隙范围的控制与安全评估提供理论指导。

关键词：深部钻爆围岩裂隙统一强度理论中主应力地应力空腔膨胀剪胀特性

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

On the Polygonal Wear Evolution of heavy-haul Locomotive Wheels due to Wheel/Rail Flexibility and Its Mitigation Measures

引用

Chinese Journal of Mechanical engineering 2024年第1期37卷 40-61页

作者： Yunfan Yang Feifan Chai Pengfei Liu Liang Ling Kaiyun Wang Wanming Zhai State key laboratory of Mechanical Behavior and System Safety of Traffic engineering structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China State key laboratory of Rail Transit Vehicle System Southwest Jiaotong UniversityChengdu 610031China

Wheel polygonal wear can immensely worsen wheel/rail interactions and vibration performances of the train and track,and ultimately,lead to the shortening of service life of railway *** present,wheel/rail medium-or high-frequency frictional interactions are perceived as an essential reason of the high-order polygonal wear of railway wheels,which are potentially resulted by the flexible deformations of the train/track system or other external *** this work,the effect of wheel/rail flexibility on polygonal wear evolution of heavy-haul locomotive wheels is explored with aid of the long-term wheel polygonal wear evolution simulations,in which different flexible modeling of the heavy-haul wheel/rail coupled system is ***,the mitigation measures for the polygonal wear of heavy-haul locomotive wheels are *** results point out that the evolution of polygonal wear of heavy-haul locomotive wheels can be veritably simulated with consideration of the flexible effect of both wheelset and *** of mixed-line operation of heavy-haul trains and application of multicut wheel re-profiling can effectively reduce the development of wheel polygonal *** research can provide a deep-going understanding of polygonal wear evolution mechanism of heavy-haul locomotive wheels and its mitigation measures.

关键词： heavy-haul locomotive Wheel polygonal wear Wheel/rail flexibility Long-term polygonal wear evolution Mitigation measures

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Upper bound analysis of ultimate pullout capacity of shallow 3-D circular plate anchors based on nonlinear Mohr-Coulomb failure criterion

引用

Journal of Central South University 2018年第9期25卷 2272-2288页

作者： ZHAO Lian-heng TAN Yi-gao HU Shi-hong DENG Dong-ping YANG Xin-ping School of Civil engineering Central South University key laboratory of heavy-haul railway engineering structure of Ministry of Education Central South University

Based on the nonlinear Mohr-Coulomb failure criterion and the associated flow rules,the three-dimensional(3-D)axisymmetric failure mechanism of shallow horizontal circular plate anchors that are subjected to the ultimate pullout capacity(UPC)is determined.A derivative function of the projection function for projecting the 3-D axisymmetric failure surface on plane is deduced using the variation *** using difference principle,the primitive function of failure surface satisfying boundary condition and numerical solution to its corresponding ultimate pullout capacity function are *** influences of nonlinear Mohr-Coulomb parameters on UPC and failure mechanism are *** result shows that UPC decreases with dimensionless parameter m and uniaxial tensile strength increases but increases when depth and radius of plate anchor,surface overload,initial cohesion,geomaterial density and friction angle *** failure surface is similar to a symmetrical spatial funnel,and its shape is mainly determined by dimensionless parameter m;the surface damage range expands with the increase of radius and depth of the plate anchor as well as initial cohesion but decreases with the increase of dimensionless parameter m and uniaxial tensile strength as well as geomaterial *** the dimensionless parameter m=2.0,the numerical solution of UPC based on the difference principle is proved to be feasible and effective through the comparison with the exact *** addition,the comparison between solutions of UPC computed by variation method and those computed by upper bound method indicate that variation method outperforms upper bound method.

关键词： shallow circular plate anchors ultimate pullout capacity variation analysis nonlinear Mohr-Coulomb failure criterion upper bound limit analysis

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Variation analysis of ultimate pullout capacity of shallow horizontal strip anchor plate with 2-layer overlying soil based on nonlinear M-C failure criterion

引用

Journal of Central South University 2018年第11期25卷 2802-2818页

作者： ZHAO Lian-heng TAN Yi-gao NIE Zhi-hong YANG Xin-ping HU Shi-hong School of Civil engineering Central South UniversityChangsha 410075China key laboratory of heavy-haul railway engineering structure of Ministry of Education Changsha 410075China

Based on the nonlinear Mohr-Coulomb failure criterion and an associated flow rule,a kinematic admissible velocity field of failure mechanism of the 2-layer soil above a shallow horizontal strip anchor plate is *** ultimate pull-out force and its corresponding failure mechanism through the upper bound limit analysis according to a variation principle are *** the 2-layer overlying soil is degraded into single-layer soil,the model of ultimate pullout force could also be degraded into the model of single-layer *** the comparison between results of single-layer soil variation method and those calculated by rigid limit analysis method proves the correctness of our *** on that,the influence of changes of geotechnical parameters on ultimate pullout forces and failure mechanism of a shallow horizontal strip anchor with the 2-layer soil above are *** results show that the ultimate pull-out force and failure mechanism of a shallow horizontal strip anchor with the 2-layer soil above are affected by the nonlinear geotechnical parameters ***,it is very important to obtain the accurate geotechnical parameters of 2-layer soil for the evaluation of the ultimate pullout capacity of the anchor plate.

关键词： shallow strip anchor plate 2-layer soil ultimate pullout capacity variation analysis nonlinear failure criterion

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Model test to investigate reasonable reactive artificial boundary in shaking table test with a rigid container

引用

Journal of Central South University 2020年第1期27卷 210-220页

作者： LEI Ming-feng ZHOU Bo-cheng LIN Yue-xiang CHEN Fu-dong SHI Cheng-hua PENG Li-min School of Civil engineering Central South UniversityChangsha 410075China key laboratory of engineering structure of heavy haul railway(Central South University) Changsha 410075China

When conducting dynamic tests of underground structure by a rigid container, reasonable boundary conditions are one of the essential factors related to the accuracy of test results, especially the artificial boundary perpendicular to the excitation direction. On the basis of numerous studies, shaking table tests with four different typical boundaries are performed in this study. The tests consider the seismic intensity and seismic wave types. Then, the simulation effects of the four boundary conditions are evaluated from four aspects as follows: the differential rate of peak acceleration, acceleration curve, similarity of Fourier frequency spectra, and uneven soil settlement in rigid containers. Results show that the simulation effects of the boundary conditions are not only affected by the nature of the boundary material but also related to the seismic intensity, types of seismic waves, and filter characteristic of the filling medium in containers. In comparison with the other three types of boundary condition, foamed polyethylene shows the best simulation effect and its effect decreases gradually with the increase in earthquake intensity. Finally, on the basis of existing studies, the evaluation criteria of boundary effect, the principle for the selection of boundary material type and the thickness of boundary material are discussed and summarized, and the corresponding design methods and suggestions are then provided.

关键词： shaking table test artificial boundary conditions rigid container

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Mechanical properties of bimrocks with high rock block proportion

引用

Journal of Central South University 2019年第12期26卷 3397-3409页

作者： LIN Yue-xiang PENG Li-min LEI Ming-feng YANG Wei-chao LIU Jian-wen School of Civil engineering Central South UniversityChangsha 410075China key laboratory of engineering structure of heavy haul railway(Central South University) Changsha 410075China

For the investigation of mechanical properties of the bimrocks with high rock block proportion,a series of laboratory experiments,including resonance frequency and uniaxial compressive tests,are conducted on the 64 fabricated bimrocks *** results demonstrate that dynamic elastic modulus is strongly correlated with the uniaxial compressive strength,elastic modulus and block proportions of the *** addition,the density of the bimrocks has a good correlation with the mechanical properties of cases with varying block ***,three crucial indices(including matrix strength)are used as basic input parameters for the prediction of the mechanical properties of the *** than adopting the traditional simple regression and multi-regression analyses,a new prediction model based on the optimized general regression neural network(GRNN)algorithm is *** that,the performance of the multi-regression prediction model is better than that of the simple regression model,owing to the consideration of various influencing ***,the comparison between model predictions indicates that the optimized GRNN model performs better than the multi-regression model *** validation and verification based on fabricated data and experimental data from the literature are performed to verify the predictability and applicability of the proposed optimized GRNN model.

关键词： block-in-matrix-rock high rock block proportion resonance frequency test general regression neural network

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Fourier-shape-based reconstruction of rock joint profile with realistic unevenness and waviness features

引用

Journal of Central South University 2019年第11期26卷 3103-3113页

作者： NIE Zhi-hong WANG Xiang HUANG Dong-liang ZHAO Lian-heng School of Civil engineering Central South UniversityChangsha 410075China key laboratory of heavy-haul railway engineering structure(Ministry of Education) Central South UniversityChangsha 410075China

Rock joint shape characteristics,waviness and unevenness play essential but distinct roles in shear mechanism of rock *** study presents a novel method to generate virtual rock joint profiles with realistic waviness and unevenness ***,joint profiles are obtained by 3D laser scanning ***,quantification of waviness and unevenness is conducted by traditional method,including digital filtering technique and roughness parameter ***,the discrete Fourier transform(DFT)method is employed to analyze the joint *** representative Fourier shape descriptors(D3,D8)for characterization of waviness and unevenness are ***,the inverse discrete Fourier transform(IDFT)is adopted to reconstruct the joint profiles with random values of phase angles but prescribed amplitudes controlled by D3 and *** traditional method is then applied to the reconstructed joint profiles to examine statistically the relationships between D3 and D8 and parameters RL of waviness and unevenness,*** results show that larger D8 tends to result in larger waviness while higher D3 tends to increase *** charts for estimation of waviness and unevenness with different pairs of D3 and D8 are also provided to facilitate implementation of random joint reconstruction.

关键词： rock joint profile joint shape analysis discrete Fourier transform joint reconstruction

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

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

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

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

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

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：