地下开挖围岩应力响应的数值分析

Numerical Analysis for Surrounding Rock Stress Response of Excavation Underground

为了研究顶板自然崩落规律的应力响应,采用数值计算方法建立三维矿体模型,对工程开挖情况进行模拟计算,分析开挖过程中围岩应力的变化情况.结果显示:当采场进行拉底开挖后,围岩应力发生重分布,最大主应力在空区四周附近集中分布;在空区的周围存在应力松弛的区域,随着开挖面积的不断扩大,空区周围的应力松弛区不断扩大,竖向应力的应力减小区扩展到采场的整个顶板,水平应力的小应力区出现在空区顶板中央,且对称分布;在拉底面积达到一定值后,在拉底顶板中心位置将出现大范围的拉应力区;破坏首先从拉底区上部中间开始,呈拱形向上发展.

In order to study the stress response of the natural roof caving, a numerical method is used to build a three-dimensional model of ore body, and an analog computation of engineering excavation is done to analyze the changes of surrounding rock responses during excavation. By analyzing the changes of stress in surrounding rock during the excavation, we obtain the following results： （a）after the undercutting excava- tion, the stress of the surrounding rock is redistributed, and the maximum principal stress is distributed in a concentrated way in the vicinity of the empty area. （b）The stress relaxation area exists around the empty area. With the expansion of the excavation area, the stress relaxation zone around the empty area expands unceasingly, and then the vertieal stress of stress reduction area expands to the whole stope roof. The small stress area of the horizontal stress appears in the middle of the cavity roof in a symmetric distribution. （e） When the undercutting area reaches a constant value, a large-scale tensile stress area occurs in the center of the undercutting roof. Failure begins in the middle of the upper part of the undercutting area, and develops upward in arch.