Compression-shear micro-and macro-failure characteristics of red sandstone  

红砂岩压剪细观与宏观破坏特征

作　　者：LI Xue-feng DU Kun WANG Li-chang ZHOU Jian YANG Tao 李雪锋;杜坤;王李昌;周健;杨涛

机构地区：[1]School of Resources and Safety Engineering,Central South University,Changsha 410083,China [2]School of Geosciences and Info-Physics,Central South University,Changsha 410083,China [3]School of Emergency Technology and Management,North China Institute of Science and Technology,Langfang 065201,China

出　　处：《Journal of Central South University》2025年第2期437-448,共12页中南大学学报(英文版)

基　　金：Project(52374150)supported by the National Natural Science Foundation of China;Project(2021RC3007)supported by the Science and Technology Innovation Program of Hunan Province,China。

摘　　要：The mechanical parameters and failure characteristics of sandstone under compressive-shear stress states provide crucial theoretical references for underground engineering construction.In this study,a series of varied angle shear tests(VASTs)were designed using acoustic emission(AE)detection and digital image correlation technologies to evaluate the mechanical behaviors of typical red sandstone.AE signal parameters revealed differences in the number and intensity of microcracks within the sandstone,with a test angle(α)of 50°identified as a significant turning point for its failure properties.Whenα³50°,microcrack activity intensified,and the proportion of tensile cracks increased.Asαincreased,the number of fragments generated after failure decreased,fragment sizes became smaller,and the crack network simplified.Cracks extended from the two cut slits at the ends of the rock,gradually penetrating along the centerline towards the central location,as observed from the evolution of the strain concentration field.Both cohesion(c)and internal friction angle(ϕ)measured in VAST were lower than those measured under conventional triaxial compression.砂岩在压剪应力状态下的力学参数和破坏特征为地下工程建设提供了重要的理论参考。利用声发射(AE)检测和DIC技术,设计了一系列变角剪切试验(VAST),对典型红砂岩的力学行为进行了评价。声发射信号参数揭示了砂岩内部微裂纹数量和强度的差异,测试角(α)为50°是其破坏特性的显著转折点。当α≥50°时,微裂纹活性增强,拉伸裂纹比例增加。随着α的增加,破坏后产生的碎片数量减少,碎片尺寸变小,裂缝网络简化。从应变集中场的演化可以看出,裂缝从岩石两端的两条切割缝开始延伸,沿中心线逐渐向中心位置渗透。在VAST中测量的黏聚力(c)和内摩擦角(φ)均低于常规三轴压缩下的测量值。

关 键 词：compressive-shear stress acoustic emission failure properties shear parameter 

分 类 号：TU45[建筑科学—岩土工程]