摘要
针对砂岩岩样,探讨了在不同围压作用下和轴向循环加载时岩样的动力力学性质,研究围压对砂岩岩样的动力力学性质的影响。采用的试验设备是MTS-815岩石和混凝土试验系统,5组围压分别为10、20、30、40、50 MPa。岩样为汶川地区的干砂岩,轴向荷载施加的频率为1 Hz。结果表明,(1)随着围压的逐渐增加,试样的残余轴向应变和体变逐渐增加,且剪胀发生时的残余体变也逐渐增加;(2)动力荷载作用时岩样在高围压比低围压下的初始刚度和强度高;(3)不同围压作用下,当应力比Rs较大时,岩样在较小的循环次数下发生破坏;(4)试样的破坏模式为剪切破坏,动力荷载作用下试样形成的局部化破坏带更宽。
The dynamic properties of intact sandstone samples subjected to axially cyclic loading under confining pressures conditions in the laboratory are presented.Five sets of confining pressures,10,20,30,40,50 MPa,were employed by MTS-815 Rock and Concrete Test System.Tests were conducted on dry sandstone samples obtained from areas near ＂5？12＂ 2008 Wenchuan Earthquake location with axial loading frequency of 1 Hz and different amplitudes corresponding to different confining pressures.Results demonstrate that：（1） With increased confining pressure,the residual axial and volumetric strain of the rock samples and the residual volumetric strain when dilatancy occurred both become larger.（2） The rock samples subjected to dynamic cyclic loading responded with a significantly higher initial strength and stiffness at higher confining pressures than at lower confining pressures;and the stiffness decreased more rapidly at lower confining pressures than at higher confining pressures.（3） When the stress ratio（Rs） is larger,the sample failed after fewer cycles under confining pressure conditions.（4） The failure modes of the samples are shear failure and the localized band is wider upon dynamic loading.
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2011年第10期3009-3013,共5页
Rock and Soil Mechanics
基金
地质灾害防治与地质环境保护国家重点实验室开放基金资助(No.SKLGP2011K006)
国家自然基金资助项目(No.51009103)
中国科学院山地灾害与地表过程重点实验室开放研究基金资助项目(2009年)
关键词
动力特性
循环荷载
周围压力
动力刚度
dynamic properties
cyclic loading
confining pressure
dynamic stiffness
