高长径比锚固树脂动力特性实验研究

Experimental Study on Dynamic Characteristics of Anchoring Resin with High Aspect Ratio

锚杆、锚索的锚固树脂易受岩层断裂引起的冲击载荷影响,研究锚固树脂的动力学特性对提高锚杆、锚索的抗冲击性能具有重要的指导意义。为进行分离式霍普金森压杆实验,首先采用弹性波检测仪测定了分离式霍普金森压杆装置的入射杆(透射杆)、锚固树脂的波速;然后理论分析了锚固树脂在入射杆、透射杆的夹持下的波动特征,得到了基于入射杆、透射杆动态信号的锚固树脂两端动态应力计算式,最后利用分离式霍普金森压杆装置进行了不同长度的锚固树脂试样的动力加载实验。结果表明:长度大于100 mm的锚固树脂具有波动衰减特性、应力不均匀性和破坏模式长度效应;试样长度越长,侧向自由面的反射越强,在有轴向压力情况下的压曲、拉断效应越明显,且其受损破坏强度越低。

The anchoring resin of rock bolt and anchorage cable are vulnerable to the impact load caused by rock stratum fracture. So the study of dynamic characteristics of anchoring resin has important guiding significance to improve the impact resistance of the bolt and anchorage cable. In order to carry out the Split Hopkinson pressure bar experiment,the anchoring resin and the incident/transmitted bar's wave velocity has been determined by the elastic wave detector. The wave characteristics of anchoring resin,which was placed between the incident bar and the transmitted bar was analyzed next. Finally,the dynamic loading test of the different length of the anchored resin sample was carried out. By using the separated Hopkinson pressure bar device and based on the incident bar and transmitted bar,we got the calculation formula of dynamic stress at two ends of anchorage resin. The result shows that anchored resin longer than 100 mm has the characteristic of wave attenuation,stress inhomogeneity and length effect of failure mode. The longer the sample is,the stronger the reflection of lateral free surface stronger is. Under axial compression,the buckling and breaking effect is more obvious,and damage strength is lower.