巷道松软两帮锚固支护原理

在煤矿巷道中,许多巷道的两帮岩体比较破碎,而且破碎区域较大,往往超出了锚杆可锚固范围,由于该类巷道两帮岩体的内聚力极小或几近丧失,因此,在这种岩体内形成的锚固体只能承受一定的挤压和剪切作用,而不能承受明显的拉应力.固体力学中根据厚度与宽度比不同的板状物分为薄膜、薄板和厚板(或"体").当物体具有薄膜或薄板的形状特征时(物体厚度与宽度之比小于1/5),内部产生的拉应力将主导其变形和破坏;当物体具有"厚板"或"体"的形状特征时,内部的剪应力或拉应力将成为其破坏的决定因素.故在巷道松软两帮内形成的锚固体必须具有"厚板"或"体"的形状特征,据此,提出巷道松软两帮厚锚固体支护原理.基于力学理论分析以及大量的数值模拟实验结果,进一步提出在巷道松软两帮内形成的锚固体厚度与巷道高度之比达到3:10较为合理.

Study on Bolt Support of Loose Ribs in Roadway

The rock mass of two ribs in many coal roadways is broken and the broken zone is larger than possible bolting range. Because the cohesion of the loose rock mass in ribs is very small, the bolted mass in these ribs can bear only compression stress or shear stress but not the stronger tensile stress. In this paper the supporting principle of the thick bolted mass has been presented because the tensile stress will lead the object in thin plate form to failure and the object failure will depend on compression stress or shear stress when the object has the shape of thick plate in solid mechanics. Based on the mechanics and numerical modeling analysis, in this paper it is presented that the ratio between thickness and width of bolted mass of 3:10 is rational.