大倾角三软煤层回采巷道围岩变形破坏特性研究

Study on deformation and failure characteristics of surrounding rocks inlarge dip angle "three soft" coal seam mining roadways

采用相似模拟方法进行不同应力条件下大倾角煤层回采巷道的围岩破坏特性研究,结果表明,随着顶压系数k的增加,顶底板逐渐出现离层、剪切、滑移直至冒落,0≤k≤2时,锚网索支护起到了良好的锚固作用。k>2.5时,锚网索支护逐渐失效,巷道两帮中部及顶板中部破坏明显;随着顶压系数的增加,顶底范围的巷道分维数增速较快,增量显著,两帮范围的分维数D在增量和增速方面比顶底较低,说明顶底受顶压的影响大于两帮。顶板锚杆锚索轴力大于两帮,左侧顶部、帮部应力大于右侧;顶压系数0≤k≤2时,测点位移量较小,断面收缩率较低,锚网索支护效果较好,顶底板的变形量大于两帮,左侧(留三角煤处)变形量大于右侧,顶板及两帮中部变形量最大。

The similar simulation methods was used to study the surrounding rock failure characteristics of large dip angle coal seam mining roadways under different stress conditions,the results showed that as the roof pressure coefficient k increased,separation,shear,sliding and even collapse gradually occured on the roof and floor.When 0≤k≤2,anchor mesh cable supporting played a good anchoring role.When k>2.5,the anchor mesh and cable supporting gradually failed,and the middle of the two sides of the roadway and the roof were significantly damaged;as the roof pressure coefficient increased,the fractal dimension of the roadway in the roof and floor ranges increased rapidly and significantly.The fractal dimension D of the two sides ranges was lower in terms of increment and growth rate than that of the roof and floor,indicating that the influence of roof pressure on the roof and floor was greater than that on the two sides.The axial force of the roof anchor rod anchor cable was greater than that of the two sides,and the stress at the roof and side of the left side was greater than that on the right side.When the roof pressure coefficient 0≤k≤2,the displacement of the measuring point was small,the cross-sectional shrinkage rate was low,the anchor mesh cable support effect was good,the deformation of the roof and floor was greater than that of the two sides,the deformation of the left side(left triangular coal)was greater than that of the right side,and the deformation of the roof and the middle part of the two sides was the largest.