摘要
为探究不同加载方式下岩石变形及峰后能量演化特征,开展不同围压条件下砂岩峰前单向加载峰后循环加卸载、峰前峰后均循环加卸载的三轴压缩试验。研究结果表明:峰前同一应力水平,循环加卸载产生的变形略小于单向加载;相比单向加载,循环加卸载的岩样均出现从端部发育、终于主裂纹的不同长度和角度的非贯通细小裂纹,相同围压下形成的主裂纹角度较大;同一围压下,2种加载方式的峰后应力跌落形式近似相同,但循环荷载使跌落过程中岩石试样总输入能量W、损伤耗散能Wd、摩擦耗散能Wf较单向加载试验小,而可恢复弹性应变能We偏大;2种加载方式的峰后残余应力阶段均表现为理想塑性变形,残余强度均随循环荷载次数的增加而减小;循环加卸载试验残余应力阶段的残余强度及总输入能量W、损伤耗散能Wd、可恢复弹性应变能We、摩擦滑移过程中单位应变摩擦耗散能wf均大于单向加载试验,2种加载方式下的wf均具有围压效应。
In order to study on the evolution characteristics of rock deformation and post-peak energy under different loading methods,the triaxial tests with pre-peak unidirectional loading and post-peak cyclic loading,and the triaxial tests with pre-peak and post-peak cyclic loading were carried out with different confining stress. Results showed that at the same pre-peak stress level,the deformation caused by cyclic loading was little smaller than unidirectional loading,meanwhile,the specimens of cyclic loading appeared non-penetrating tiny crack with different lengths and angles,which developed form the end to the main crack,and the angles of main crack were relatively large under the same confining stress. The post-peak stress drop form of two loading methods was similar,while the total energy(W),the dissipation energy(W_d),and the frictional dissipation energy(W_f) of specimens during the process of stress drop caused by cyclic loading were smaller than unidirectional loading,and the elastic strain energy were larger. The residual strength stage of two loading methods showed ideal plastic deformation characteristics,and the residual strength was decreased with the increasing number of cycles. The W,the W_d,and the W_f,and the W_e,and the frictional dissipation energy per unit strain(w_f) of rock specimens at residual strength stage of cyclic loading test were larger than unidirectional loading test,and the w_f of two loading methods had confining pressure effect.
作者
杨小彬
程虹铭
裴艳宇
YANG Xiaobin;CHENG Hongming;PEI Yanyu(School of Emergency Management and Safety Engineering,China University of Mining and Technology,Beijing 100083,China;School of Coal Engineering,Shanxi Datong University,Datong,Shanxi 037003,China)
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2020年第S02期3229-3236,共8页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(50904071,51274207)
大同市科技局项目(2019159)。
关键词
岩石力学
峰后
循环加载
变形演化
能量特征
摩擦耗散能
rock mechanics
post-peak
cyclic loading
deformation evolution
energy characteristics
frictional dissipation energy
