不同应变率下砂岩动态强度准则的试验研究  

Experimental research of sandstone dynamic strength criterion under different strain rates

作　　者：宫凤强[1] 陆道辉[1] 李夕兵[1] 饶秋华[2] 

机构地区：[1]中南大学资源与安全工程学院,长沙410083 [2]中南大学土木工程学院,长沙410075

出　　处：《岩土力学》2013年第9期2433-2441,2429,共9页Rock and Soil Mechanics

基　　金：国家自然科学基金资助项目(No.41102170);湖南省自然科学基金资助项目(No.12JJ4048);国家重点基础研究发展计划(973)项目(No.2010CB732004);中国博士后科学基金资助项目(No.2012T50658;No.2011M500973)

摘　　要：分别利用RMT-150C和多功能分离式霍普金森压杆（SHPB）试验系统对砂岩进行了不同应变率下的单轴压缩、三轴压缩和拉伸试验。结果表明，在围压为0或围压-定的情况下，应变率低于10^2s^-1。时，抗压强度的增加与应变率的量级呈正比；在应变率高于10^2s^-1时，岩石的抗压强度增加趋势与应变率的l／3次方呈正比。拉伸强度也存在类似规律。针对10^1～10^2s^-1应变率范围内缺少岩石动态强度准则这-现状，根据上述试验规律，结合Mhr-Coulomb准则、Hock-Brown准则和Gfiffith准则的原理，给出了不同应变率范围内动态Mohr-coulomb准则和动态Hock-Brown准则的具体表达形式。研究结果表明，在低应变率情况下，动态Mohr-Coulomb准则和动态Hock-Brown准则均适用，但Griffith准则判别结果误差很大。在高应变率情况下，动态Mohr-coulomb准则比较适用，Griffith准则仅适用于评估高应变率单轴抗压强度和抗拉强度之间的关系。A series of dynamic uniaxial compression, dynamic triaxial compression and dynamic tensile tests with different strain rates are conducted on homogeneous sandstone samples by using the RMT-150C testing machine and the multifunction split Hopkinson pressure bar （SHPB） device. The results show that, when the confining pressure remains constant, the compressive strength of sandstone increases with the magnitude of strain rate when the strain rate is less than 10^2s^-1, the increment trend of the compressive strength is proportional to 1/3 power of the strain rate when the strain rate is larger than 10^2s^-1. The similar rule above also applies to the tensile strength. Currently, no rock dynamic strength criterion is available for the strain rate in the range of 10^1- 10^2s^-1. Based on the analysis of data from dynamic uniaxial tests, dynamic triaxial tests and dynamic tensile tests under low-high strain rates and the principle of Mohr-Coulomb criterion, Hoek-Brown criterion and Griffith criterion, the dynamic Mohr-Coulomb criterion and the dynamic Hock-Brown criterion under different strain rate ranges are formulated. The experimental results show that the dynamic Mohr-Coulomb criterion and the dynamic Hoek-Brown criterion can be applied to estimate the dynamic strength in the low strain rate range. In the high strain rate range, the dynamic strength can be estimated by using the dynamic Mohr-Coulomb criterion; but the dynamic Hoek-Brown criterion is not applicable. The Griffith criterion can be used to estimate the dynamic uniaxial compressive strength and dynamic tensile strength in high strain rate range only.

关 键 词：应变率 岩石 动态强度准则 动态三轴压缩试验 分离式霍布金森压杆 

分 类 号：O319.56[理学—一般力学与力学基础]