以云南磷化集团晋宁磷矿6号坑口东采区深部缓倾斜中厚磷矿层露天转地下开采为工程背景,利用底摩擦模型实验仪,进行了不同露天坑境界顶柱厚度边坡高度下的底摩擦模拟模型实验.结果表明：边坡的变形破坏响应特征可分为边坡岩体小范围微破裂和松动→边坡岩体局部范围失稳破坏→边坡岩体整体向采空区滑落失稳破坏三个阶段,边坡岩体变形破坏模式主要是采动边坡岩体向采空的拉裂、破断和滑移破坏.在边坡高度一定情况下,随着露天境界顶柱的厚度由30 m逐渐减小到20 m和10m,边坡的稳定性与境界顶柱的厚度呈正比关系,20～30m是露天境界顶柱比较合理的厚度.在境界顶柱的厚度一定情况下,边坡高度由60 m增大到108 m,边坡的稳定性与坡高的厚度呈反比关系,108 m边坡转入地下开采后是不稳定的.
Based on the gently inclined medium thick phosphate rock at the deep part of the east mining section of Jinning-Six Mine, Yunnan Phosphate Co. Ltd. from open pit mining to underground mining, floor friction model tests under the condition of differ- ent slope heights and boundary thicknesses were carried out with a floor friction model instrument. The results show that the deformation and failure response features of the slope can be divided into three stages： fracture and loose in a small range, unstable failure in a local range, and instability failure in the whole range of slope rock sliding to the goaf. The main deformation and failure modes of the slope are tension cracking, breakage, and sliding failure. When the slope height is fixed, with the boundary thickness gradually decreasing from 30 m to 20 m and 10 m, the stability of the slope is directly proportional to the boundary thickness, and the reasonable boundary thickness is 20 m to 30 m. When the boundary thickness is fixed, with the slope height increasing from 60 m to 108 m, the stability of the slope is inversely proportional to the slope height, and the slope of 108 m from open pit mining to underground mining is unstable.