基于钻孔测试的岩体抗剪强度参数取值方法及其工程应用

ESTIMATION OF ROCK MASS SHEAR STRENGTH PARAMETERS BASED ON BOLE TEST AND ITS APPLICATION TO ENGINEERING

针对岩体抗剪强度参数取值问题,提出一种利用钻孔测试成果获取岩体抗剪强度参数新方法和新途径。该方法首先建立岩体地质强度指标GSI值与岩体基本质量指标BQ值、岩块饱和单轴抗压强度、岩块天然纵波波速的数学关系式,而后采用钻孔电视对钻孔岩体进行分段。在此基础上,利用钻孔声波和室内岩芯试验等测试成果计算得出相应岩段的BQ值及GSI值。最后,运用Hoek-Brown强度准则,得到每段岩体的抗剪强度参数。经工程应用并对比现场岩体剪切试验结果,本方法在确定岩体抗剪强度参数上具有较好的可靠性。

For the researching of the shear strength parameters of rock mass,the method proposed by this paper provides a new method and a new way. First,based on the deficiency of existing empirical formula,the mathematical relation between the geological strength index(GSI) and the basic quality index of rock mass(BQ),the uniaxial compressive strength of saturated rock,the P-wave velocity of natural rock are established. For the rock masses uncovered by drilling,based on the results of borehole TV test,borehole ultrasonic velocity detection and laboratory core sample test,using the Hoek-Brown strength criterion,this paper puts forward a method for the estimation of rock shear strength parameters. Then this method is applied to a project under construction and the results show that the shear strength parameters of rock mass estimated by the method are close to actual values.