细观非均匀性对脆性岩石材料宏观破坏形式的影响

岩石材料的宏观力学特征是材料内部细观力学特性的综合反映。对于脆性岩石材料，其内部的非均匀性对材料的宏观破坏形式有着重要的影响。应用演化细胞自动机方法（ECA）对岩石的非均匀性进行了初步的探讨。该方法以位移、力、应力和应变等矢量和张量作为系统的基本变量，定量计算了反映岩石破坏过程中应力集中以及应力重新分布的过程。在宏观上则认为脆性岩石材料是一种非均匀性材料，并假定脆性岩石材料的非均匀性符合Weibull分布，坡度参数m是Weibull分布中的反映分布非均匀程度的重要参数。通过对符合Weibull分布中不同坡度参数的脆性岩石材料进行数值模拟试验，发现由Weibull分布中的坡度参数表示的非均匀性是影响脆性岩石材料破坏方式的重要因素，材料的坡度参数越小，材料越不均匀，其破坏形式则越具有随机性；材料的坡度参数越大，材料越趋于均匀，其破坏形式越具有规则性，即趋于弹性材料的破坏形式，这与试验结果是吻合的。

Influence of heterogeneity on macroscopical crack form of the brittle rock

The macroscopic mechanical characteristic of the rock material is integrated exhibition of the inner mechanical characteristic of this kind of material in mesoscopic view. While for the brittle rock material, the inner heterogeneity is important to its macroscopic crack form. The primary discussion on the heterogeneity of the brittle rock has been carried out with the method of evolving cellular automata. In this method, displacement, force, stress and strain are taken as basic variables of the system and the stress concentration and stress adjustment are reflected by quantitative analysis. In the macroscopic view, the brittle rock is a kind of heterogeneity material and its heterogeneity distribution is assumed as Weibull distribution. The slope parameter m is a important parameter that reflects the heterogeneity level of the heterogeneity distribution. From the numerical simulation examinations on the brittle rock material when it has different slope parameter in Weibull distribution, it can be drawn out that the heterogeneity expressed by the slope parameter in Weibull distribution is a important factor that influences the crack form of the brittle rock; and the more the slope parameter m is small, the more the composition of the rock is asymmetric, and the more the crack form is stochastic; while the more the slope parameter m is great, the more the composition of the rock is symmetrical, and the more the crack form is regular and similar to the elasticity material. It is consistent with the results of the experimentation.