冲击地压巷道锚杆支护金属网静载和动载力学性能试验研究

为揭示冲击地压巷道锚杆支护常用金属网的静载和动载力学性能,从而为冲击地压巷道锚杆支护中金属网的选取提供设计依据,采用专门制作的金属网静载和动载力学性能试验装置对常用的经纬网、菱形网和钢筋网的力学性能进行了测试,分析了常用金属网在静载和动载荷下的受力特征和变形状况。实验结果表明:静载作用下,菱形网、经纬网和钢筋网的最大挠度分别为240,236和225 mm,最大承载能力分别为20,16.2和77 kN,3种金属网的最大挠度差别不大,但承载速率差别较大,钢筋网承载速率最大,其次是经纬网,最小是菱形网;动载作用下,菱形网、经纬网和钢筋网的最大吸能能力分别为1 743,938和2 010 J,最大挠度分别为350,420和360 mm,钢筋网吸能能力最大,挠度中等,而菱形网吸能能力次之,而挠度反而最小。菱形网无论是静载还是动载,其初期刚度较低,承受效率慢,而其受力均匀,能承受较大的静载荷和动载荷,且四周绑丝处不易破断,勾接连接方式有很好的承载和缓冲能力,但其主要的缺陷在于承载效率慢,支护刚度太低,通过提高初期张紧力是提高菱形网支护效果的主要途径;经纬网刚度较高,承载效率快,但强度相对较低,易产生经线和纬线错动失效,且经纬网变形时,受力不均匀,绑丝易断裂,四角固定处受力较小,受力传递效果较差,要想提高经纬网支护效果,需提高经纬网经线和纬线之间的约束力;钢筋网初期刚度高,强度大,吸能能力强,但钢筋网的缺点是强度不能充分利用,尤其是钢筋网焊接处和四周绑丝处强度较低,制约了钢筋网支护效果,要想提高其支护效果,需提高焊接点强度和四周绑丝强度。

Experimental study on static and dynamic mechanical properties of bolting wire mesh in rock burst roadway

In order to reveal the static and dynamic mechanical properties of metal mesh commonly used in rock burst roadway,and provide a design basis for the selection of metal mesh in rock burst roadway,the mechanical properties of longitude and latitude mesh,diamond mesh and reinforcing bar mesh are tested by using a special static and dynamic mechanical testing device,the stress characteristics and deformation of the metal mesh under static and dynamic loads are analyzed.The experimental results show that the maximum deflections of diamond mesh,longitude and latitude mesh and reinforcing bar mesh are 240,236 and 225 mm,respectively.The maximum load carrying capacities of three kinds of metal mesh are 20,16.2 and 77 kN.On the whole,the maximum deflection of three kinds of metal meshes is basically the same,but the load bearing rate is different greatly,the load bearing rate of the reinforcing bar mesh is the largest,followed by the longitude and latitude mesh and the diamond mesh.Under dynamic load,the maximum energy absorption capacities of diamond mesh,longitude and latitude mesh and reinforcing bar mesh are 1 743,938 and 2 010 J,and the maximum deflections are 350,420 and 360 mm,respectively.On the whole,the steel mesh has the largest energy absorption capacity and moderate deflection,followed by the diamond mesh,while the deflection is the smallest.Whether under static or dynamic load,the initial stiffness of diamond mesh is low and its bearing efficiency is slow.However,the diamond mesh has uniform force,can bear larger static and dynamic loads,and is not easy to break around the binder.The hook connection has good bearing and buffering capacity.The main drawbacks of the diamond mesh are that the bearing efficiency is slow and the supporting stiffness is too low,the main way to improve the supporting effect of diamond mesh is to increase the initial tension force.On the contrary,the stiffness of the longitude and latitude mesh is higher and the load carrying efficiency is faster,but the strength is relatively lower,which is prone to the failure of the warp and latitude dislocation.When the longitude and latitude mesh is deformed,it is unevenly stressed,and the connection is easy to break,and the force of the wire is poor.In order to improve the supporting effect of longitude and latitude mesh,it is necessary to improve the binding strength between the longitude and latitude mesh.The reinforcing bar mesh has high initial stiffness,high strength and strong energy absorption capacity,but the weakness of the steel mesh is that the strength cannot be fully utilized,especially the low strength of the welded joints of the longitude and latitude mesh and the surrounding bindings,which restricts the support effect of the steel mesh.In order to improve its supporting effect,the strength of welding joint and binding should be increased.