压力型锚杆抗拔能力模拟实验研究

压力型锚杆的应变分布情况反映锚杆损伤破坏位置,利用3次实验室小比例尺模型进行拉拔试验,可以对锚杆的应变分布等进行研究,取得合理的结果。(1)对各级拉拔荷载作用下的锚杆顶部位移进行记录分析,得到了拉力顶部位移与拉力关系图,其曲线的形态说明拉力达到一定程度将引起位移的迅速增加;(2)对锚杆各部位直径增加量做了分析,发现在离承压板锚杆一定位置处直径增加量最大;(3)对锚杆的轴向应变、径向应变的数值和分布情况进行了对比,发现轴向应变是锚杆应变的主要形式,但轴向应变、径向应变分布规律基本一致,都随远离承压位置呈负指数衰减。因此,在提高锚杆的锚固效果方面,减小锚杆承压板附近的形变是一个有效的途径。

Research on Pullout Simulation Experiments of Pressure-type Anchoring Rock Bolts

The strain distributions of pressure-type anchoring rock bolts represent the damage and destroy positions. Three laboratory small scale simulation pullout experiments are carried out. And the strain distributions can be analyzed. The results are reasonable. (1) The displacements at the top of anchoring rock bolts are recorded and studied under different pullout forces. The relational graph between displacements at the top of anchoring rock bolts and pullout forces is obtained. And the graph suggests that the displacements would increase rapidly when the pullout forces reach some value. (2)The diameter increments along the radial direction at different positions of the bolts are compared and the increment at special position near the bearing plate is the largest. (3) The values and distributions situations of the axial strains and radial strains are compared with each other. And the axial strains are the dominated parts. But the distribution regularities of the axial strains and radial strains are fundamentally consistent. They both decrease in the form of negative index function. Thus, it is a valid way to minish the strains near the bearing plates for improving the rock bolts’anchoring effects.