金属矿山开采过程上覆岩层应力与变形特征

Stress and Deformation Characteristics of Overburden in Mining of Metal Mine

采用数值分析方法,研究了动态开采过程中金属矿山采空区覆岩在拉应力、垂直应力作用下的位移及变形破坏特征。研究发现拉应力对覆岩造成的破坏较其它应力显著,是覆岩垮落的主导因素。分析覆岩内部垂直应力发现:开采初期覆岩内部压应力显著,随着开采进行,在采空区的正上方,压应力逐渐向拉应力过渡;垂直应力呈"凹"形分布在采空区两端部,其形状和应力值随采空区的增大而增大。随着工作面的推进,覆岩下沉范围和下沉量均逐渐增大;下沉曲线的最大下沉点,向工作面推进方向逐渐移动;下沉曲线的光滑程度体现了监测点在覆岩所属区域是弹性区、塑性区还是垮落区。研究结果可为矿山围岩支护提供一定参考依据。

Displacement and deformation characteristics of overburden over gob under the force of tension and vertical stress during active mining of metal mine was studied by using numerical simulation method. It was found that the tension is the dominant factor for the overburden collapse, bringing more notable damage to it than other stresses. The analysis of vertical stress inside the overburden showed that the internal compressive stress was remarkable at the early stage of exploration and the compressive stress of overburden right over gob area would be gradually transforming into tension as exploration going further, while the vertical stress distributed at both sides of the gob area, just like a concave curve, which increased in terms of shape size and stress value with gob expanding. As working face advancing, the magnitude and extent of the overburden subsidence gradually enlarged. It can be seen that the maximum subsidence point in the subsidence curve is gradually moving towards the working face advancement direction. Besides, the smooth curve of subsidence reflects that the monitoring points in the overburden are all within the range of elastic zone, plastic zone or caving zone. Those research results can be taken as reference for the supporting of surrounding rock in metal mine.