冲击载荷作用下红砂岩土能耗规律试验

Experimental study on energy consumption of red sandstone soil under impact load action

选取寻乌南桥-龙川上坪公路路基红砂岩土为试验材料,利用动静组合加载试验装置,研究了红砂岩土峰值应力、吸收能、体积吸收能等与冲击次数和干密度之间的关系.结果表明:随着冲击次数增加,峰值应力呈"缓慢增长-急剧增长-平稳发展"3个发展阶段,拟合关系为logistic函数;随着冲击次数增加,红砂岩土试样的吸收能逐渐增加,且达到一定冲击量时,吸收能有减小趋势,吸收能与冲击次数存在二次函数关系,且相同冲击次数,干密度越大,试样吸收能越大;体积吸收能变化曲线呈S递增型,材料吸收能挤压土体颗粒间孔隙,主要表现为土体颗粒滑移,使土颗粒重新排列,增强了红砂岩土体抵抗外界冲击力;干密度对红砂岩土体积吸收能影响较大.

Taking the red sandstone soil of the highway subgrade from Xunwu south bridge to Longchuan as the test material, using the static and dynamic loading test device, this experiment studied the relation between the influence of red sandstone soil peak stress, energy absorption, volume absorption energy and the impact times and dry density. The results show that with the increase of impact times, the peak stress has three stages of ＂slow growth-sharp growth-steady development＂, and the fitting relation is logistic function; With the increase of the impact times, the absorption energy of the red sandstone soil samples gradually increases, when it reaches to a certain amount, the absorption energy has a decreasing trend. The absorption energy has quadratic function relation with impact times. With the same impact times, the larger the dry density is, the greater the absorption energy of the sample is. The change curve of volume absorption energy is S increasing type and the energy absorption material used to squeeze the pores between soil grains, the soil particles rearrange the internal structure of distribution and enhance the ability of red sandstone soil resistance to external shocks. Dry density has a great influence on the volume absorption energy of red sandstone soil.