常规三轴压缩条件下的负乘方型岩石强度准则  

Negative power rock strength criterion under conventional triaxial compression

作　　者：李斌[1] 王大国[1] LI Bin;WANG Daguo(School of Environment and Resource,Southwest University of Science and Technology,Mianyang 621010,China)

机构地区：[1]西南科技大学环境与资源学院,四川绵阳621010

出　　处：《煤田地质与勘探》2020年第2期152-160,共9页Coal Geology & Exploration

基　　金：国家自然科学基金项目(51904248);四川省科技计划项目(2019YFH0088);四川省教育厅科研项目(18ZB0598)。

摘　　要：为较高精度地评估岩石在不同围压条件下的三轴强度,根据岩石破坏时的主应力差与围压呈上凸的非线性特征,提出负乘方型强度准则。通过将该准则与Mohr-Coulomb准则和Hoek-Brown准则进行精度比较,结果表明,乘方型准则参数对围压变化具有较低的敏感度,且该准则可以更高精度地评估岩石三轴强度。应用公开发表文献中多种不同类型岩石的三轴试验数据,对负乘方型强度准则的适用性进行验证,结果显示,在不同围压条件下,该准则评估的岩石三轴强度与试验强度均非常一致,说明负乘方型准则对评估不同类型岩石的三轴强度具有较好的适用性;同时,通过与目前岩石力学界认为较好的指数型准则的比较,得到两种准则评估的岩石三轴强度平均相对误差MRE均在5%以内,其中负乘方型准则具有更高的精度。该准则可为深部岩石工程开挖与支护等设计提供参考。In order to evaluate accurately the rock strength under different confining pressures,a negative power rock strength criterion was proposed according to the upward convex nonlinear relationship between deviator stress and confining pressure during rock failure.The accuracy of the proposed criterion was compared with Mohr-Coulomb criterion and Hoek-Brown criterion.The results showed that the parameters of the negative power criterion are less sensitive to the range of confining pressure,and the negative power criterion could evaluate rock triaxial strength with higher precision.Meanwhile,the applicability of the proposed criterion was verified by using an extensive database of rock triaxial strength tests from literatures.The results showed that the evaluated strength values were very consistent with the test strength values.Thus,the negative power criterion has good applicability to evaluate the triaxial strength of different types of rock.Furthermore,by comparing with the exponential criterion,regarded as an outstanding criterion in rock engineering,the mean relative errors of the rock strengths evaluated by the two criteria were all within 5%,and the negative power criterion has higher accuracy in predicting rock triaxial strength.The proposed criterion can provide scientific reference for the design of exaction and support in deep rock engineering.

关 键 词：三轴强度 强度准则 非线性 指数型准则 负乘方型准则 

分 类 号：TU451[建筑科学—岩土工程]