煤层预裂爆破复合型宏观裂纹扩展的断裂理论分析

An analysis of fracture theory on the expansion of complex macroscopic cracks caused by pre-fracturing of coal seams

以断裂力学理论为基础,分析了煤层宏观裂纹所处的应力场分布特性和应力强度因子,按照最大周向应力原理确定了裂纹扩展方向、断裂准则和扩展长度。结合工程应用实际情况,得出了爆破孔周围宏观裂纹扩展的最大长度和最小长度。

Based on the fracture mechanics theory,this paper analyzes the distribution characteristics of stress field and the stress＇s strength factors in areas where the macroscopic cracks are seen in coal seams.The expansion direction,fracturing rule and expansion length of cracks are determined in light of the maximum circumferential stress theory.Combined with the actual situations of project applications,this paper works out the maximum and minimum lengths of the macroscopic cracks expanded around explosion holes.