根据特厚煤层大采高综放开采煤壁前方支承压力的分布特征，从煤岩内部缺陷的随机性分布特征出发，基于反映煤岩内部缺陷的微元强度服从韦布分布的概念，建立了支承压力作用下煤岩的损伤统计力学模型，确定了特厚煤层大采高综放面在煤壁片帮不影响生产的情况下的合理采高，并分析了特厚煤层大采高综放面合理采高与煤壁片帮程度、煤层内摩擦角、煤层内聚力和顶煤变形的关系。最后，通过工程实例分析，验证了该模型的合理性。

A statistic-mechanical model of coal damage under abutment pressure is presented in this paper based on the concept that micro-unit strength which eflects the internal defect of coal obeys the Weibull distribution. The model is built on the premise of the random distribution of internal defect in coal and the distribution characteristics of abutment pressure in the front of fullmechanized caving mining with large mining height in ultra thick coal seam. According to the model, the reasonable mining height was determined for caving mining with large height in thick seam under normal mining conditions. The relationship of reasonable mining height respectively with rib spalling degree, internal friction angle, cohesion of coal and the deformation of top coal was also analyzed. Finally, the model was proved to be rational by engineering example analysis.