采高对煤层底板破坏深度的影响

Influence of mining height on coal seam floor failure depth

随着埋深增大,原底板破坏深度经验公式对不同采高工作面底板破坏深度的预计误差增大。以赵固二矿为背景,通过有限元数值计算方法对底板破坏规律进行研究、采用矿井对称四极电剖面法对不同采高底板破坏深度进行实测并运用Spass软件对4个底板采动破坏影响因素与底板破坏深度的关系进行多元统计回归分析。研究得出,煤层埋深较大时采高对底板破坏深度的影响明显;随着采高的增大,底板垂直应力减小,围岩竖直位移增大,位移等值线梯度减小,底板破坏深度增大;考虑采高因素的底板破坏深度线性回归公式对煤层开采工作面底板破坏深度的预计准确率高,适用性强。

With the increase of mining depth, the initial empirical formula has high error in predicting floor failure depth at different mining height working faces. Research on the floor failure law under large burial depth coal face was conducted at Zhaogu No. 2 Coal Mine through finite element numerical computation, utilizing the direct current electric method to observe actual depth and using Spass software to analyze the relationship between floor failure depth and four influence factors. The study show that mining height has a great influence on floor failure depth when the burial depth of coal seam is large. With the increase of mining height, the vertical stress of floor becomes less and the vertical displacement of surrounding rock increases, the gradient of displacement contour decreases and the floor failure depth becomes larger. The formula with the consideration of mining height factor has a high accuracy rate and good applicability to predict the floor failure depth. © 2015, China Coal Society. All right reserved.