程潮铁矿地下开采引起岩层移动机制初探

在对矿区地质条件、采矿情况以及监测资料分析的基础上,提出了悬臂梁的力学模型。该悬臂梁是由NWW向节理切割下盘的花岗岩岩体而产生。地下采矿引起的岩层移动分为两个阶段,筒状破坏延伸到地表之前为第1阶段;筒状破坏延伸到地表后,则进入第2阶段。筒状破坏延伸到地表使水平构造应力释放,悬臂梁受力发生变化,而发生弯曲折裂变形和破坏,从而形成了深部岩体破坏的4个区:破裂岩体区、破裂过渡带、变形区和未扰动岩体区。通过对矿区地表测点所测数据进行分析,结合上述岩层移动机制和裂缝产生过程,将变形区域划分为:变形累积区、裂缝产生区、裂缝扩展区和裂缝闭合区。随着采矿的进行,深部岩体4区将逐渐向下延伸,地表4区将逐渐向外扩展。

Mechanism of rock strata movement caused by underground mining in Chengchao iron mine

Based on the geological conditions, underground mining situations, as well as the status of cracks and ground surface deformation of Chengchao Iron Mine, a cantilever beam mechanical model is proposed. The bottom-up tubular collapse in the deep rock mass causes the horizontal tectonic stress release which favors the bending fracture deformation and destruction of the NWW-trending joints. This model can explain the formation of four zones in the deep rock mass: rupture zone, the transition zone of rupture to deformation, the deformation zone and the undisturbed zone. In such a mode, it inevitably leads to different deformation areas on the ground surface related to the different zones in the deep rock mass. So the mine surface is divided into four related areas: cumulative deformation area, crack-producing area, crack-extending area, and crack-closing area. As mining progresses, four zones of the deep rock mass will gradually extend downward, while four areas of the ground surface deformation will gradually expand outward.