Study On Mechanical Properties And Energy Dissipation Rule Of Red Sandstone Soil Under Impact Load

Red sandstone soil is a kind of argillaceous cemented soil which widespread in Gannan area.The study on static and quasi-static aspects of red sandstone soil has been more in-depth.But there is not much study on the mechanical properties and energy dissipation law.This paper makes an research on the mechanical properties and energy dissipation law in the three cases of single axis impact,static and dynamic combined action and lateral confining pressure impact by using impact loading test and numerical simulation.Under these three conditions,the influence of the ratio of length to diameter and the impact velocity on the peak stress value is researched.Also the effect of incident energy,strain rate,length diameter ratio and impact velocity on energy dissipation law efficiency is researched.The main contents include the following:(1).In the single axial impact test,the compressive strength of red sandstone soil is low and the energy dissipation efficiency is low.With the impact velocity increasing,the compressive strength increases and the strain becomes large obviously.While the increase of the sample length makes the peak stress decrease and the strain reduce and the compressive strength is low,mainly about shear failure.This paper reveal the energy dissipation efficiency of red sandstone soil is a bit low,more than 90% of the incident energy ending with reflection,using the numerical simulation software ANSYS/LS-DYNA.(2).Under the condition of lateral confining pressure,the red sandstone soil has stronger compressive strength than it under the single axial state.The energy transfer efficiency is slightly improved.Under the constraints of casing,with the impact velocity increasing,the peak stress increased significantly,the peak strain increased significantly.When the casing is applied,the sample is no longer damaged.But the energy transfer efficiency of the sample is not greatly improved.There are still nearly 90% of the incident energy ending with reflection.The results of numerical simulation is close to them of the test.(3).Under the combined action of static and dynamic loads,the stress peak of red sandstone soil increases at a higher rate,and the energy transfer efficiency increases significantly.And the results of numerical is same to them of the test.In the axial 0.5MPa,peak stress and peak strain increase with the impact speed growth in multiple and decrease obviously with the increase of the sample length.With the increase of the impact velocity,the reflection is becoming smaller,nearly 50% of incident energy transit to transmission energy and dissipated energy.With the sample length increasing,the dissipated energy increases and the efficiency decrease.(4).The compressive strength and energy transfer efficiency of red sandstone soil are improved by applying axial compression.And increasing the value of the axial compression,the effect is more significant.