砂岩加卸载条件下能耗特征试验研究  

Experimental study of energy features of sandstone under loading and unloading

作　　者：许国安[1,2] 牛双建[2] 靖洪文[1,2] 杨圣奇[1] 王文龙[2] 

机构地区：[1]中国矿业大学深部岩土力学与地下工程国家重点试验室,江苏徐州221008 [2]中国矿业大学力学与建筑工程学院,江苏徐州221116

出　　处：《岩土力学》2011年第12期3611-3617,共7页Rock and Soil Mechanics

基　　金：国家自然科学基金项目(No.50674083;No.50709008);国家十一五科技支撑计划(No.2008BAB36B07);江苏省土木工程研究生科技创新基金资助

摘　　要：采用MTS815刚性伺服试验机,对砂岩进行了单轴、三轴压缩和三轴峰后卸围压试验,对比研究了砂岩在加卸载试验条件下的能耗特征。结果表明,单轴压缩各能耗指标值均小于三轴压缩和三轴峰后卸围压,三轴峰后卸围压介于单轴与三轴压缩之间。三轴压缩和三轴峰后卸围压各能耗指标均具有明显的围压效应,随着围压的升高而线性增大。单轴压缩时砂岩表现为突发性的脆性破坏,初期储存的弹性应变能瞬间几乎全部转化为耗散能,成为岩样破坏时所表现出的一切现象的源动力;三轴压缩时砂岩表现为从局部破坏到整体失稳的渐进过程,耗散能所占吸收能量的比例越来越大,表现为明显的能量耗散,能量耗散发展到一定程度表现为明显的能量释放,随即岩石整体失稳破坏。In order to get the features of energy absorption and dissipation of sandstone under loading and unloading,the tests of uniaxial compression,triaxial compression and post-peak unloading confining pressure have been performed on sandstone with the MTS81.5 servo-controlled test machine.The results show that the dissipated energy of sandstone increases from uniaxial compression test through post-peak unloading test to triaxial compression test.The dissipated energy in triaxial compression and post-peak unloading confining pressure tests increases linearly with the confining pressure.Under uniaxial compression,the sandstone presents abrupt brittle failure and the elastic strain energy initially stored in the sandstone is instantly transformed into dissipated energy which is the power source of all phenomena of the rock failure.Under triaxial compression,the sandstone demonstrates progressive failure,i.e.the failure of sandstone is the process of from local cracking to global destruction in which the dissipated energy gradually increases with deformation.When the deformation reaches a critical level,the residual energy stored in sandstone will be rapidly released and the sandstone globally destructed.

关 键 词：应力路径 能量耗散 能量释放 三轴压缩 峰后卸围压 

分 类 号：TU452[建筑科学—岩土工程]