综放沿空巷道顶部锚杆剪切变形分析

Analysis on shearing deformation of roof support bolt in gob-side entry of fully-mechanized caving face

针对煤矿大量采用的小煤柱锚网支护,尤其是综放沿空巷道锚网支护,在巷道围岩大变形过程中,锚杆可能会承受较大的剪切变形情况,从理论上分析了综放沿空巷道顶部全长锚固锚杆承受剪切变形的机理,并用数值模拟的方法计算出了其锚杆上的剪切力分布、最大剪切力和最大剪切应力.计算分析表明:在围岩大变形情况下,综放沿空巷道顶部锚杆上的最大剪切应力有可能接近或超过其材料的许用剪切应力,此时锚杆的剪切作用效应将不可忽视.

The bolt probably supports larger shearing deformation in the course of huge deformation of roadway surrounding rock, for instance the cable bolts-metal mesh reinforcement of small pillar adopted largely in coalmine, especially that in gob-side entry of fully-mechanized caving face （FCF）, the mechanism that the full-column roof support bolt sustains sheafing deformation in gob-side entry of FCF was analyzed by theoretical research, and the sheafing stress distribution, the maximum shearing force and the maximum sheafing stress in bolts were obtained with the help of numerical simulation. It is indicated that the maximum shearing stress of the roof support bolt in gob-side entry of FCF will approach or exceed the allowable shearing stress of bolt materials in condition of large deformation in surrounding rock, and here, the shearing effect of bolt is not to be neglected.