循环荷载下加筋砾性土填料的动三轴试验分析

为探究循环动载作用下加筋砾性土填料的动力特性,在不同加筋层数和围压下对加筋砾性土进行了固结不排水动三轴试验,研究加筋层数和围压对加筋砾性土动力特性的影响,并进一步分析了加筋砾性土轴向累积应变发展机制。研究表明:加筋层数增加时,轴向累积应变减小,回弹模量增大,且加筋作用的影响幅度逐渐衰减;增大围压时,土体轴向累积应变减小,回弹模量和动孔压均随之增大;随着加筋层数和振次的增加,滞回曲线逐渐向应力轴靠近,滞回圈面积逐渐减小,土体耗能作用减弱。基于安定理论和间接影响带理论,揭示了加筋作用对轴向累积应变发展的影响机制。建立了能够反映加筋层数的加筋砾性土轴向累积应变预测模型,其条件参数a、b、g与加筋层数呈线性关系,可有效预测循环荷载下加筋砾性土路基沉降变形规律。

Dynamic triaxial test analysis of reinforced gravel soil under cyclic loading

In order to investigate the dynamic characteristics of reinforced gravel soil under cyclic loading, the consolidated undrained dynamic triaxial tests were carried out on the reinforced gravel soil with different numbers of reinforcement layers and confining pressures. The effects of the number of reinforcement layers and confining pressure on the dynamic characteristics of reinforced gravel soil were studied, and the development mechanism of axial cumulative strain of reinforced gravel soil was further analyzed. The results show that when the number of reinforced layers increases, the axial cumulative strain decreases, the rebound modulus increases, and the influence of reinforcement gradually decreases; when the confining pressure is increased, the axial cumulative strain of the soil decreases, and the rebound modulus and the dynamic pore pressure increase accordingly. As the number of reinforced layers and the number of cycle increase, the hysteresis curve gradually approaches the stress axis, and the hysteresis loop area gradually decreases, and the energy consumption of the soil weakens. Based on the stability theory and the indirect influence band theory, the mechanism of the influence of reinforcement on the development of axial cumulative strain is revealed. An axial cumulative strain prediction model of reinforced gravel soil that accounts for the effect of number of reinforcement layers is established. The parameters ?, ?, ? are linear with the number of reinforcement layers, and the model can effectively predict the deformation of reinforced gravel subgrade under cyclic loading.