单幅值动载下加筋红黏土路基动三轴试验分析

为探究红黏土路基在循环荷载作用下的动力特性,以柳州红黏土为试验研究对象,在不同加筋层数下对加筋红黏土进行固结不排水动三轴试验,研究加筋层数对加筋红黏土动力特性的影响。试验结果表明: 加筋红黏土的轴向累积应变随着加筋层数的增加而减小,但加筋的增幅作用呈现递减趋势,从无筋试样开始,相邻加筋层数轴向累积应变降低的幅度分别为14.5%、10.6%和6.4%；随着加筋层数和振次的增加,加筋红黏土的回弹模量逐渐增大,但是加筋对土体回弹模量的增强效果并不显著；加筋能有效减小加筋红黏土的体应变,且随着加筋层数的增加,加筋效果越显著,3层加筋相比于2层加筋,体应变降低的幅度达75.04%；利用滞回圈斜率k描述土体刚度和弹性性能,随着加筋层数和振次的增加,k值先平缓上升,随后迅速增大,说明土体的刚度和弹性得到提高,但加筋效果与加筋层数并不成正比。

Dynamic triaxial test analysis of reinforced red clay embankment under single amplitude dynamic load

In order to explore the dynamic characteristics of red clay subgrade under cyclic loading, taking Liuzhou red clay as the test object, the consolidated undrained dynamic triaxial were carried out on reinforced red clay under different reinforcement layers to study the influence of reinforcement layers on the dynamic characteristics of reinforced red clay.The test results show that the axial cumulative strain of reinforced red clay decreases with the increase of reinforcement layers, but the increase of reinforcement shows a decreasing trend. From the unreinforced sample, the decrease of axial cumulative strain of adjacent reinforcement layers is 14.5 %, 10.6 % and 6.4 %, respectively. With the increase of reinforcement layers and vibration times, the resilient modulus of reinforced red clay increases gradually, but the reinforcement effect on the resilient modulus of soil is not significant. The reinforcement can effectively reduce the volumetric strain of reinforced red clay, and with the increase of reinforcement layers, the reinforcement effect is more significant. Compared with the 2-layer reinforcement, the 3-layer reinforcement can reduce the volumetric strain by 75.0 %. The slope k of hysteresis loop is used to describe the stiffness and elastic properties of soil. With the increase of reinforcement layers and vibration times, the value of k increases slowly at first, and then increases rapidly, indicating that the stiffness and elasticity of soil are improved, but the reinforcement effect is not proportional to the reinforcement layers.