采动影响下底板应力分布特征及底鼓发生机理

Floor Stress Distribution Characteristics and Mechanism of Floor Heave Under the Influence of Mining

针对底鼓的发生机理开展研究,采用数值计算的方法分析了不同地应力集中程度下(λ=1~3连续变化)底板岩体的受力及变形特征。结果显示:巷道底板在水平方向上按受力状态的差异可分为应力升高区、应力降低区和原岩应力区;在地应力集中程度增加的条件下,巷道底鼓量、巷帮变形量和峰值应力集中程度均明显增加。根据巷道底板围岩变形的差异可分为膨胀区、压缩膨胀区和压缩区。在沿底板水平方向和垂直方向的不同深度,存在椭圆形的底鼓零位移区,该区域内的岩体产生拉伸膨胀、在该区域以外的岩体受载压缩。

In view of the mechanism of floor heave, the stress and deformation behaviour of floor rock mass was studied and analyzed by numerical simulation in the situation of different stress concentration （continuous change of A from 1 to 3）. The results showed that floor rock mass could be divided into three zones in horizontal direction. They were stress raising zone, stress reducing zone and initial stress zone. Under the condition of in-situ stress concentration increasing, the amount of floor heave, deformation of laneway＇s side and peak stress concentration are significantly increased. According to the difference of floor surrounding rock deformation, expansive area, compressing expansive area and compressed area were derided. In the different depth along floor horizontal direction and vertical direction, there is elliptic zero deformation area of floor; the rock mass in this area produces stretching expansion and the rock mass outside the area is compressed.