岩石泊松比与内摩擦角的关系研究

 在纯张破坏时的泊松比与内摩擦角关系式基础上,推导出纯剪破坏时的泊松比与内摩擦角关系式,定义由泊松比与内摩擦角确定的剪破坏、脆性剪破坏、塑性剪破坏与张破坏及流动变形破坏分布区域。根据试验数据分析,确立张剪破坏与剪张破坏的线性分界线,建立脆性剪破坏判别条件半经验关系式。据此关系式,进行泊松比与内摩擦角的互算、单试样抗剪强度的计算及岩石细观破坏类型的分区。与岩石三轴压缩试验资料进行对比分析,解释岩石试样破坏类型发生的力学机制。实例表明,用泊松比计算单试样抗剪强度的方法具有实用价值,而且利用岩石破坏类型分区图可辅助预测岩石可能的破坏方式与类型。

STUDY OF RELATIONSHIP BETWEEN POISSON′S RATIO AND ANGLE OF INTERNAL FRICTION FOR ROCKS

Based on relationship between Poisson′s ratio and angle of internal friction for pure tensile failure,the relationship between Poisson′s ratio and angle of internal friction for pure shear failure is deduced;the shear,brittle shear,plastic shear and tensile failures as well as creep deformation distribution zones are defined by Poisson′s ratio and angle of internal friction. Based on the analysis of test data,the linear boundary lines for tensile shear and shear tensile failures are determined;the semi-empirical formulae of brittle shear failure criteria are established. According to the semi-empirical formulae,Poisson′s ratio and angle of internal friction and shear strength of single rock specimen can be calculated easily;the mesoscopic failure modes of rock can be zoned. By comparing with the results of triaxial compression tests,the mechanisms for different rock failures are explained. The case study demonstrates that it is practical to use the Poisson′s ratio to calculate shear strength of single rock specimen. The classification of rock failure zones can be used in prediction of failure modes and failure types.