中文摘要：

崩落法开采时，顶板及围岩的崩落过程、岩层移动角的确定一直是国内外众多学者研究的重点。以四川某矿山挂帮矿开采为工程背景，利用MIDAS／GTS软件模拟并分析了该挂帮矿崩落法开采时顶板拉应力及塑性区变化规律。研究结果表明：老顶先于直接顶发生拉破坏。强制崩落顶板拉破坏区后，顶板应力状况明显改善；老顶及直接顶拉应力的面积以及老顶拉破坏区的面积随直接顶暴露面积增大而显著增大，而直接顶拉破坏区面积受暴露面积影响较小。并通过数值模拟法及工程类比法综合确定岩层移动角。

英文摘要：

For the caving method, the caving process of roof and surrounding rock, and the determination of displacement angle of stratum under caving mining, are always the focuses in the study of many scholars at home and abroad. Taking a hanging wall ore in Sichuan as engineering background, the variation of tension stress and plastic zone of roof under caving mining were simulated and analyzed by using software of MIDAS/GTS. The results showed that-the old main roof experienced tensile failure before the direct roof. Stress state of roof was improved significantly after the area of tensile failure of roof was caved forcedly; The area of tension stress of main roof and immediate roof, and of the tension failure of main roof extended significantly with the exposed area of immediate roof. But, the tension failure area of immediate roof wasn＇t influenced evidently by it. Moreover, the displacement angle of stratum was determined by numerical simulation and engineering analogy method.