岩石在饱和状态下的抗剪强度参数变化研究

Study on the change of rock shear strength parameters in saturation state

基于自然状态和饱和状态下不同种类岩石试件的室内压剪实验,对2种状态下岩石抗剪强度参数(c,Φ)的变化情况进行比较分析.引入抗剪弱化系数η(ηc,ηΦ)以定量地描述参数变化幅度,并将其定义为2种状态下参数差值与自然状态下参数值的比值.实验结果表明:饱和状态下不同种类岩石的抗剪强度参数较自然状态下会有明显但程度不同的降低;ηc的值分布在0.1～0.4之间,ηΦ的值分布在0.2以内,且自然状态下岩石抗剪强度参数越大,η越小,反之亦然,并通过回归分析得出ηc与c,ηΦ与Φ的之间的函数关系,这对岩体工程设计有重要的实际意义.

Compress-shear experiments have been conducted by using varied type of rock samples under natural and saturation states. It can be found through comparison that the shear strength parameters of saturated rock decrease significantly to different degree. In order to the quantify decreased magnitude of the parameters, the concept of weakening coefficient η （ηc,ηФ） has been introduced and assigned its value as the ratio of parameters reduction and the parameters of natural state. Experimental results show that the value of ηc distribute in 0.1-0.4 and the value of ηФ is no more than 0.2. The greater shear strength parameters of natural state is, the smaller weakening coefficient is, and vice versa. Based on regression analysis, we get the functional relationship between ηc and c and the functional relationship between ηФ and Ф. It has importantly practical significance for the design of rockmass engineering.