裂纹线场分析方法在岩石力学中的应用

 将岩体破坏主控结构面上的裂纹视为共线等间距裂纹，利用裂纹线上的合理条件将共线裂纹受压剪应力的问题简化为有限宽岩体内含有一条裂纹受压剪应力的问题；把岩体材料的屈服准则作为求解该问题的基本方程，运用线场分析方法在裂纹线附近区域得到弹塑性解析解。分析裂纹面闭合所产生的裂纹面上的摩擦强度对裂纹线附近应力场的影响，通过在裂纹线上提出的合理条件和弹塑性应力场在其边界上的匹配条件，得出裂纹线上塑性区范围与压剪荷载的关系，并获得岩体沿主控结构面的裂纹贯通破坏的强度准则。通过与试验结果的对比分析后发现所提出理论是合理的，研究结果可为岩体断裂力学的发展提供有力依据。

APPLICATION OF ANALYTICAL METHOD OF CRACK LINE FIELDS TO ROCK MECHANICS

The fractures of rock mass in engineering are originated from the cracks located in it，and the solution to stress fields in multi-crack body is one of the most difficult problems in fracture mechanics. The cracks on main- controlled surface in rock mass damage are regarded as uniformly-spaced collinear cracks. When the reasonable equations on crack line are applied，the problems of collinear multi-crack loaded by shearing- compressive stresses are simplified as the issues of a crack in finite-dimension rock. The methodology to solve this problem is yielding criterion of rock mass material. An analytic solution near the crack line in an elastic-perfectly plastic rock mass is obtained，when the line field analysis method is applied. The influence of frictional strength on crack surface towards the shearing-compressive stresses is analyzed，which results from closure of crack surfaces on the stress fields. By proposing the reasonable equations on the crack line and the matching conditions of the elastoplastic stress fields at their boundaries，the relations between the length of plastic zone on the crack line and shearing-compressive stresses are obtained. Also，the failure criterion of the rock mass with collinear cracks along the main-controlled surface is yielded. The correctness of the analysis method is verified by the experimental results of a model test. The study serves as an important basis for the development of rock mass fracture mechanics.