基于断裂理论的节理岩体等效弹模的研究

Study on Equivalent Modulus of Jointed Rock-mass Based on Fracture Theory

为了研究无填充断续节理岩体的力学特性,假定岩体中的节理类似于断裂力学中的裂纹,利用裂纹扩展的能量释放率理论,结合弹性力学中的Betti互易定理,推导出了在平面应力状态下一组闭合节理平板的等效弹模,并考虑到节理之间的相互影响,对其进行了相应的修正;同时进一步推导了三维含无填充断续节理岩体在闭合状态下的等效弹模。最后得出节理岩体的等效弹模与节理的几何形态及其力学参数以及节理是否闭合有关。

To study the mechanical characteristics of the unfilled intermittent jointed rockmass, the joints in the rockmass are assumed as cracks in fracture mechanics. The theory of energy release rates in crack growth is applied, combining with Betti reciprocity theorem of elastic mechanics, to derive the equivalent modulus of a plate containing a group of close joints under plane stress condition, which is revised by considering the mutual effects of the joints. Furthermore, equivalent modulus of the three-dimensional unfilled intermittent joints of rockmass is derived. At last, it is concluded that the equivalent modulus of jointed rockmass is related to the geometrical shapes and mechanical parameters of joints and whether the joints are closed or not.