大红山铁矿采用无底柱分段崩落法开采形成了3个规模巨大的采空区,采空区上覆岩层移动与地表开裂塌陷将导致露天采场发生滚石地压灾害、井下采场产生空气冲击波次生地质灾害、地表与井下发生泥石流地质灾害等。针对上述问题,采取了多通道微震监测、非接触式岩移实时监测、基于手持式GPS仪的地表开裂范围监测和基于全站仪的地表沉降与水平移动监测的多种综合地压监测手段,对上覆岩层崩落高度、上覆岩层下沉变形量、地表开裂范围和地表沉降与水平移动等进行了监测,通过两年的监测获取了大量的监测数据,经分析表明,采空区上覆岩层崩落高度约在+1 090~+1 060 m,上覆岩层+1 090 m平巷内观测点累计沉降量为1 350 mm,地表开裂范围位于以岩移角为75°划定的地表岩移范围内,地表测点最大累计沉降与水平移动量为1 779与948 mm,上覆岩层与地表的变形移动活动处于稳定渐进可控的状态,目前不会发生上述地压地质灾害。
Dahongshan iron mine which uses sublevel caving method without sill pillar has three extra-large mined-out area, the displacement of overburden and surface subsidence will lead to ground pressure and geological disasters, like rolling stones in open stope, air-blast wave in the underground stope, mud-rock flow in surface and underground, and so on. In order to monitor the natural caving height and displacement of overburden and subsidence range and displacement of surface, we use many means of monitoring methods, like multi-channel microseismic monitoring system, non-contact displacement monitoring system, handheld GPS device, total-station instrument. We obtained a lot of data after two years of monitoring;these data show that the natural caving height of overburden is between 1 090 m and 1 060 m elevation, the total settlement of observation point in+1 090 m tunnel is 1 350 mm, the subsidence range of surface is within the scope of the designed surface displacement based on traveling
