锚杆托板的力学性能与支护效果分析

Analysis on mechanical performance and supporting function of rock bolt plates

采用实验室试验、数值模拟及井下监测相结合的方法对托板的受力状态、应力分布、变形状况及支护作用进行研究。在实验室,制作专门的测力托板,测试了不同支撑状态下拱形托板变形、应力与载荷的关系,得出不同支撑状态下托板开始屈服的载荷。采用有限元数值模拟方法,分析了拱形托板在面接触、四边支撑、四点支撑及三点支撑状态下的应力分布特征。建立了单根锚杆锚固于围岩中,计算锚杆预应力引起的应力场的数值模型;分析了托板对锚杆预应力场分布的影响,托板应力分布特征及托板对围岩的支护作用。采用测力托板,在潞安屯留矿的回采巷道中进行了托板受力监测,初步分析了托板在锚杆安装预紧阶段、掘进影响与稳定阶段的受力特征与变化规律。

The loading states,stress distribution,deformation and supporting effects of bolt plates were studied by the combination method of laboratory tests,numerical modeling and field monitoring.The gauged plates were designed and manufactured in the laboratory,the relation between deformation,stresses of domed plates and loads under different supporting states were measured,and the loads,at which the plates start to yield,were obtained.By means of finite element method,the stress distribution features of domed plates under the supporting states of face contact,four sides,four points and three points were analyzed.The numerical model with single bolt anchored in the center of surrounding rock,which can simulate the stress field caused by bolt pretension,was built.The affects of plates to the stress field caused by bolt pretension,stress distribution in the plates,and the supporting effects of the plates to surrounding rock were discussed.The gauged plates were applied,and the stresses in the plates were monitored in underground extraction entries in the Tunliu Coal Mine,the Lu＇an coal mining district.The stress distribution features and variation laws in the plates in the stages of bolt pretension,driving affect and stabilization were preliminarily analyzed.