不同孔隙率红砂岩的动力响应特性试验

Dynamic response characteristics experiment of red sandstone under different porosity

采用分离式霍普金森压杆冲击试验系统，对现场采集的试样加工后进行相似速率条件下的冲击试验，得到了冲击荷载作用下一定范围内的不同孔隙率红砂岩的相关动力特性。即在相似冲击速率下，随着红砂岩的孔隙率从5．67％增大到11．86％，其反射波幅值逐渐增大，透射波幅值逐步减小，透射波峰值出现时间随着孔隙率的增大而提前；动力传递率随着孔隙率的增大呈指数下降；动态弹性模量和峰值强度随着孔隙率的增大而明显减小，峰值强度降低率随孔隙率的增加基本呈直线上升；当孔隙率在5．67％～8．32％区间变化时，峰值强度对应的应变相差不大，但是当孔隙率增为11．86％时，无论是峰值强度还是峰值对应的应变都显著减小。

Impact experiment under similar velocity on field specimen after being processed was carried out with the split Hopkinson pressure bar(SHPB)apparatus.Dynamic response characteristics of red sandstone with different porosity were achieved in a certain range of impact loading.From the experiment,the following conclusions were obtained,under the similar impact velocity,as the red sandstone porosity increased from 5.67%to 11.86%,the reflection amplitude value increased gradually,but the transmission amplitude value reduced little by little.The peak value of transmission wave turned out in advance with the increasing of porosity.Power transmission rate reduced exponentially with the increasing of porosity.Dynamic elastic modulus and peak strength decreased with the increasing of porosity and peak intensity reduction rised in a straight line with the increasing of porosity.The strain corresponding with peak intensity changed unconspicuously when the porosity varied from 5.67%to 8.32%,but when the porosity increased to 11.86%,both the peak value strength and the corresponding strain were significantly reduced.