基于应力与位移分析的地表沉陷区圈定

Delineation of surface subsidence area based on stress and displacement analysis

地表沉陷区是判定地表建(构)筑物稳定性的重要依据,一般认为沉陷区内地表的下沉值较大,不利于建(构)筑物稳定。充分采动时通常在垂直和平行矿体走向的主断面上,从采空区边界按照查手册确定的地表移动角向地表绘出矿体两侧的地表临界变形点,再连接这些临界变形点形成地表移动区。不充分采动或充填法采矿时还没有地表移动区的圈定方法,只能沿用充分采动的圈定方法,导致圈定的范围过大或评价结论不可靠。基于房柱式留矿法对地表滑坡影响的理论分析和数值模拟,得出不充分采动时绘制地表移动区的启示,并结合充填采矿的地压规律研究,探讨了充填采矿的地表移动区绘制方法。结果表明:充填采矿时应根据主断面开采的应力与位移分析确定地表沉陷区绘制的参考面及地表移动角;附近几乎受拉或地压与原岩应力区别很大的位移等值线与水平面所成的角应为地表移动角,否则,根据附近不受拉或处于原岩应力状态的位移等值线确定的移动角偏小,圈定的地表沉陷区过大;主断面内位移变化明显的平面应为参考面,如矿柱稠密或充填法采矿时最顶部采场的顶板。

The surface subsidence/movement area is an important basis for judging the stability of surface buildings(structures).It is generally believed that the surface subsidence value in the subsidence area is large,which is not conducive to the stability of buildings(structures).During full mining,the surface critical deformation points on both sides of the ore body are usually drawn on the main section of the vertical and parallel ore body strike from the abandoned stope boundary to the surface according to the surface movement angle determined in the manual,and then these critical deformation points are connected to form the surface movement area.There is no delineation method of the surface movement area in the mining with insufficient mining or filling method,and only the delineation method with sufficient mining can be used,resulting in too large delineation range or unreliable evaluation conclusion.Based on the theoretical analysis and numerical simulation of the influence of room and pillar shrinkage method on the surface landslide,the enlightenment of drawing the surface movement area in case of insufficient mining is obtained,and the method of drawing the surface movement area in filling mining is discussed in combination with the research on the ground pressure law of filling mining.The results show that the reference plane and the surface movement angle drawn in the surface subsidence area should be determined according to the stress and displacement analysis of the main section during the filling mining or insufficient mining;The angle between the displacement isoline and the horizontal plane,which is almost under tension or the ground pressure is very different from the initial stress,should be the surface movement angle,otherwise,the movement angle determined according to the displacement isoline which is not under tension or in the initial stress is too small,and the delineated surface subsidence area is too large;The plane with obvious displacement change in the main section shall be the reference plane,such as the roof of the topmost stope in case of dense ore pillars or filling mining.