节理岩体巷道顶板预应力锚杆加固作用研究

为了深入探讨预应力锚杆对节理岩体巷道顶板的加固机理和作用,采用ANSYS数值模拟软件,研究了不同节理位置和节理倾角等节理特征下,预应力锚杆支护前后节理面及巷道稳定性变化规律.结果表明：位于巷道顶板中央附近的小角度节理,是影响巷道稳定性的主要因素.预应力锚杆支护可以将节理面压应力提高2-3 MPa,顶板表面处压应力增大3-4 MPa,消除了垂向拉应力,顶板应力松弛区内的压应力提高了约2 MPa.角度越小,越靠近巷道中央,锚杆支护后的节理面压应力及松弛区内压应力的增加率越大,预应力锚杆支护作用越明显.与锚杆不穿节理相比,穿过节理的预应力锚杆支护效果更显著.

Research on Pre-Tensioned Bolts Reinforcing Roadway Roof in Joint Rock Mass

In order to discuss the reinforce mechanism and effect of pre-tensioned bolts on roadway roof, the variation rule of joint faces and roadway stability before or after pre-tensioned bolts supporting at different joint positions and angles were studied using the numerical simulation method ANSYS. The results show that the small angle joint near the middle of the roadway roof is the main factor that influences the roadway stability. The pre-tensioned bolts supporting can make the joint face press stress increase by 2-3 MPa, the roof press stress increase by 3-4 MPa which relief the vertical tension stress, the press stress in stress relaxation areas increase by about 2 MPa.. The smaller the joint angle is and the closer the joint nears the middle of the roadway, the greater the press stress increasing ratios of joint faces and stress relaxation areas are, and the more remarkable the pre-tensioned bolts supporting action is. Compared with bolt which does not drill though joint, the pre-tensioned bolt supporting effect is more notable while bolt drills through joint.