分级循环加卸载下砂岩损伤力学特性研究  

Research on damage mechanical characteristics of sandstone under graded cyclic loading and unloading

作　　者：蔡国军[1,2] 孙文鹏 陈锡锐 杨森林 贾俊 李林[1,2] CAI Guojun;SUN Wenpeng;CHEN Xirui;YANG Senlin;JIA Jun;LI Lin(State Key Laboratory of Geohazard Prevention and Geoenvironment Protection,Chengdu University of Technology,Chengdu 610059,China;National Geological Engineering Experimental Teaching Demonstration Center,Chengdu University of Technology,Chengdu 610059,China;Key Laboratory for Geo-hazards in Loess Area,MNR Xi'an Center of China Geological Survey/Northwest China Center for Geoscience Innovation,Xi'an 710054,China)

机构地区：[1]成都理工大学地质灾害防治与地质环境保护国家重点实验室,四川成都610059 [2]成都理工大学地质工程国家级实验教学示范中心,四川成都610059 [3]中国地质调查局西安地质调查中心/西北地质科技创新中心自然资源部黄土地质灾害重点实验室,陕西西安710054

出　　处：《中国测试》2023年第1期161-168,共8页China Measurement & Test

基　　金：自然资源部中国地质调查局地质调查项目(DD20190714);国家自然科学基金(41202209,41977255);国家重点实验室自主课题(SKLGP2019Z017);四川省科技计划(2019YJ0403)资助。

摘　　要：通过选取陕西省略阳市某滑坡表层的中风化砂岩进行静态单轴压缩试验与三轴循环加卸载试验,研究低围压循环加卸载条件下岩石的损伤力学特性,得到力学参数、损伤参数、滞回环面积等随循环过程的演化规律及循环荷载作用下砂岩的变形破坏机制。结果表明:循环加卸载试验过程中,围压增强砂岩抵抗变形破坏能力,随着围压增大,动弹性模量明显增大而动泊松比逐渐降低,砂岩试样内凹现象逐渐“模糊”;滞回环面积受围压与轴向载荷影响明显,与围压变化呈负相关,与轴向载荷变化呈正相关,轴向载荷增大时,不可逆应变逐渐累积,砂岩损伤加剧;砂岩内部原始裂隙在初始较低循环荷载作用下压密,后过渡到弹性变形与裂纹稳定扩展阶段,随着试验进行,裂纹加速演化不稳定扩张,岩样逐渐变形失稳破坏。By selecting a medium-weathered sandstone from a landslide surface layer in Lueyang City,Shanxi Province for static uniaxial compression tests and triaxial cyclic loading and unloading tests,the author studies the mechanical properties of the damage under the cyclic loading and unloading conditions with low circumferential pressure,thus obtaining the evolution of mechanical parameters,damage parameters,the area of hysteresis loop and other parameters with the cyclic process,and the deformation and damage mechanism of the sandstone under cyclic loading.The results show that:during the cyclic loading and unloading tests,the circumferential pressure enhances the resistance of sandstone to deformation and damage,and the dynamic elastic modulus increases significantly with the increase of circumferential pressure while the dynamic Poisson’s ratio decreases gradually,and the concavity of sandstone specimens is gradually "blurred";the area of hysteresis loop is affected by the circumferential pressure and axial load,and is negatively correlated with the change of circumferential pressure and positively correlated with the change of axial load.When the axial load increases,the irreversible strain gradually accumulates and the damage of sandstone intensifies;the original fracture inside the sandstone is compressed and dense under the initial low cyclic load,and then transitions to the stage of elastic deformation and stable expansion of fracture,and as the test proceeds,the fracture accelerates the evolution of unstable expansion and the rock sample gradually deforms and destabilizes.

关 键 词：岩石力学 砂岩 循环加卸载 损伤力学特性 滞回环特性 

分 类 号：TU47[建筑科学—结构工程] TB9[建筑科学—土工工程]