山东望儿山矿区浅部复采对井筒稳定性影响的数值模拟

Numerical Simulation of Pitshaft Stability Induced by Shallow Second Mining in Wang’ershan Mining Area,Shandong Province

根据望儿山矿区的工程地质与采矿条件,采用数值模拟的手段对浅部复采引起的岩体移动变形及其对竖井井筒的稳定性进行了研究。通过数值模型计算,指出复采过程中岩体应力场和位移场的变化规律,对充填与不充填开采2种条件下井筒的应力和位移变化进行了讨论。研究表明,地下开采破坏了矿岩原有的应力场平衡状态,地下空区形成后对竖井围岩的主应力场产生了较大的影响,在浅表部最大主应力较低,有些位置甚至为拉应力,容易导致竖井井壁发生破裂,不利于竖井的稳定。在对采空区进行充填后,竖井井壁围岩主应力基本为压应力,连续性好,稳定性得到了大大提高。此外,与不充填时相比,对空区进行充填后,竖井井壁位置的位移量大大减小,可见,空区充填对限制围岩移动,维护竖井的稳定起到了很大的作用,为了保障矿山安全生产,浅部矿体复采实施充填法开采是避免竖井变形破坏的有效措施。

Based on the engineering geological and mining conditions of the Wang’ershan gold mine,numerical simulation method was applied to study the mining-induced rock mass movement and shaft deformation.By numerical calculation,the regularities of the disturbed stress and displacement fields of rock body were put forward.The characteristics of shaft deformation were comparatively discussed under filled and non-filled mining conditions.The study results showed that the equilibrium state of the in-situ stress field was destroyed by the underground mining activities.The occurrence of the mine goaf imposed strong impact on the principal stress field of the pitshaft.The maximum principal stresses were small and sometimes turned into tensile stresses at the shallow part of the pitshaft,which was detrimental to the pitshaft stability.In contrast,the displacements of the pitshaft were greatly decreased when the mined-out space was filled.Thus,the filling body played an important part in the restriction of the surrounding rock mass movement and the promotion of the pitshaft stability.It suggested that filling the mining goaf is a necessary measurement to avoid pitshaft deformation and rupture in future mining.