地下复杂采空区引起地表塌陷渐进发展过程数值模拟研究

Numerical Simulation of Progressive Development Process of Surface Subsidence Caused by Underground Complex Goaf

为了得到查干敖包铁锌矿塌陷区渐进发展情况,以现场调查为基础,建立含地下采空区、塌陷坑三维数值分析模型,模拟矿体开采情况,得到了塌陷区位移与塑性区分布情况。研究结果表明:塌陷坑东西南三侧形成了陡立的岩体临空面,主要以倾倒形式破坏垮塌,不断向岩体临空面后侧发展;塌陷坑北侧目前已形成了滑坡,主要以弧形滑坡形式向后侧发展;随着地下矿体的开采,塌陷区逐渐扩大,主要发展方向为西及北西向,上盘岩体会逐渐垮塌崩落;以塌陷区现状为基础,当井下矿体开采完毕后,上盘岩体垮塌崩落范围预测为长轴412 m、短轴312 m的椭圆形;现有塌陷区岩体以及上盘岩体均有塑性区分布,现有塌陷坑会进一步垮塌崩落,且发展方向为上盘塑性区分布的方向。通过数值模拟分析得到的塌陷区发展方向与通过现场调查分析的结论一致。研究结果可为塌陷区治理设计提供参考。

In order to investigate the progressive development of the collapse area in Qagan Obo Iron Zinc Mine, a three-dimensional numerical analysis model of underground mind-out area and collapse pit was established based on the field investigation to simulate the mining of ore body, with which the displacement of the collapse area and distribution of plastic zone were obtained. It is found from the research that a steep rock mass free face is formed on the east, west and south sides of the collapse pit and mainly collapse in the form of toppling failure, developing towards the back side of the free face of the rock mass. At present, landslides have been formed in the north side of the collapse pit, mainly developing towards the backside in the form of arc-shaped landslide. As the mining of underground ore body proceeds, the collapse area will gradually expand, mainly in the direction of west and northwest, and the hanging wall rockbody will collapse gradually. Based on the current situation of the collapse area, the collapsed hanging wall rock mass is predicted to be an ellipse with 412 m in long axis and 312 m in short axis after the underground mining is finished. There are plastic zones distributed in the existing collapse area and hanging wall rock mass, which will lead to the further collapse and caving in the existing collapse pit, developing along the distribution direction of the plastic zone of the hanging wall. The development direction of the collapse area obtained by the numerical simulation analysis is consistent with the conclusion of field investigation and analysis. Thus, this research results can provide reference in the design for controlling of collapse area.