循环荷载下砂岩力学特性及破坏特征分析
Study on mechanical properties and failure characteristics of sandstone under cyclic loading
谈坤 1刘洋 1朱志刚 1沈志伟 1倪双喜1
作者信息
- 1. 安徽建筑大学建筑结构与地下工程安徽省重点实验室,安徽 合肥 230601;安徽建筑大学土木工程学院,安徽 合肥 230601
- 折叠
摘要
为研究循环荷载下岩石力学特性及破坏特征,对砂岩试样进行不同围压下的常规三轴加载和不同应力水平(峰值应力40%、60%和80%)下等幅值循环加卸载试验,结果表明:常规三轴加载下,砂岩强度随着围压的增大而增大,弹性模量基本保持一致.相同围压条件下,等幅值循环加卸载后再次加载,随着上限应力水平的增加,岩砂岩强度降低;试样的破坏形式以剪切裂纹为主,局部区域生成横向或竖向的张拉裂纹;循环加卸载过程中砂岩的加载和卸载变形模量均保持较强的一致性,相同应力水平下,加载和卸载变形模量随着围压的升高而增大;相同围压、不同应力水平条件下卸载变形模量整体上仍具有较好的一致性,加载变形模量均呈缓慢增加趋势;相同应力水平条件,循环加卸载下岩样首次相对残余应变值具有随着围压增加而增加的趋势.
Abstract
In order to study the mechanical properties and failure characteristics of rock under cyclic loading,the sandstone samples were subjected to conventional triaxial loading under different confining pressures and equal amplitude cyclic loading and unloading tests under different stress levels(peak stress 40%,60%and 80%).The results show that under conventional triaxial loading,the strength of sandstone increases with the increase of confining pressure,and the elastic modulus remains basically the same.Under the same confi-ning pressure condition,the strength of rock sandstone decreases with the increase of the upper limit stress level.The failure mode of the specimen is dominated by shear cracks,and transverse or vertical tensile cracks are gen-erated in local areas.During the cyclic loading and unloading process,the loading and unloading deformation modulus of sandstone maintain a strong consistency.Under the same stress level,the loading and unloading de-formation modulus increase with the increase of confining pressure.Under the same confining pressure and differ-ent stress levels,the unloading deformation modulus still has good consistency on the whole,and the loading de-formation modulus increases slowly.Under the same stress level,the first relative residual strain of rock samples under cyclic loading and unloading has a tendency to increase with the increase of confining pressure.
关键词
砂岩/循环加卸载/力学特性/残余应变Key words
rock mechanics/sandstone/mechanical activation behavior/residual strain引用本文复制引用
基金项目
安徽省自然科学基金(2108085ME192)
安徽省高校优秀拔尖人才培育资助项目(gxyq2020033)
国家自然科学基金(51604006)
出版年
2024
NETL
NSTL
万方数据