不同锚固角加锚无摩擦节理面剪切试验研究

为进一步阐明锚固角对锚固节理抗剪作用的影响,开展了无摩擦锚固节理双面剪切试验。对比不同锚固角情况下锚固节理的抗剪强度,分析锚固角对锚固节理抗剪性能的影响。试验采用应变片测量节理岩体中锚杆在节理面位置处的轴力,研究锚固节理在剪切荷载作用下锚杆的轴力变化规律以及变形特性。试验结果表明,锚固角增大,锚固节理极限荷载、屈服荷载以及抗剪刚度先逐渐增大后逐渐减小,在锚固角为60°时达到最大值;不同锚固角锚杆最终破坏模式不同,锚固角较小时,锚杆发生拉剪破坏;锚固角较大时,锚杆发生拉弯破坏;试验也发现,剪切位移较小时,锚杆的抗剪作用就已经充分发挥。

Study of Shearing Tests of Bolted Frictionless Joints with Different Anchorage Angles

To further elucidate the shear resistance of anchored joints with different anchorage angles, a double shear test of anchored joints with two frictionless surfaces was carried out. The shear influence of anchorage angle on bolted joints was analyzed by comparing the shear resistance of bolted joints with different anchorage angles. Strain gauges were used to measure axial force of rock bolt at joint surface, and axial force variation law and deformation characteristics of bolts were studied when the bolted joints were subjected to shear load. The results show that the ultimate load, yield load and shear stiffness of bolted joints increase firstly and then decrease as the anchorage angle increases, and reach maximum value when the anchorage angle is 60°. The final failure modes are different when the bolted joints anchorage angles are different. When anchorage angle is small, the bolt suffers from shear-tensile failure, and the tensile-bending failure happens when the anchorage angle is larger. The results show shear resistance of bolts is fully exerted when the shear displacement is small.