巷道交岔点稳定性影响因素的数值分析

Numerical Simulation of Influencing Factors on Stability of Flat Roadway Intersection

为了揭示巷道交岔点失稳机理,寻求合理的交岔点支护方式,采用FLAC3D程序对不同交岔点形式、深度、围岩强度、开挖顺序及开挖步距大小等因素进行了数值模拟计算.结果表明:目前煤矿使用的各种形式交岔点的变形和破坏都超过普通巷道,其中十字交岔点的变形和破坏最大;就巷道埋深和围岩强度来说,两者均存在一个临界值,当巷道交岔点埋深超过临界值,及围岩强度低于临界值时,巷道交岔点的变形和破坏将会加剧;十字交岔巷道开挖时,应选用较小的开挖步距,并避免支巷从远处向主巷贯通,及两支巷同时开挖对交岔点造成叠加影响.因此,在埋深一定的情况下,应选择较硬的岩层布置交岔点,通过加固措施提高围岩强度,并选择合适的开挖卸载方式,以提高巷道交岔点的稳定性.

In order to study the unstable mechanism of roadway intersection and to find an effective supporting form, factors of intersection styles, depth, strength, excavation order, and excavation interval are numerically studied using Flac3D software. The results show that deforma-tion and failure in areas of all styles of roadway intersections are more serious than those of roadways without any intersection, with the deformation at the cross style of roadway intersection being the most serious. As far as depth and strength of surrounding rock are concerned, each of them has a critical value. Deformation and destruction of roadway intersections will be aggravated when depth is greater than or strength of surrounding rock is smaller than the critical values. When cross style of roadway intersection is excavated, a small excavation interval should be chosen; in addition, in excavating branch lanes, we should prevent the distant branch lanes from connecting the main lane and minimize the superposition effect of two branch lanes being excavated on the stability of intersection. Therefore, when the depth is certain, we should choose the area where the strata is strong for roadway intersections, otherwise the surrounding rocks should be reinforced. Besides, reasonable excavation method and unloading form should be adopted to improve the stability of roadway intersections.