EPS颗粒混合轻量土的动变形特性及修正Hardin-Drnevich模型研究

Dynamic deformation characteristics and modified Hardin-Drnevich model for light weight soil mixed with EPS particles

为探究EPS颗粒混合轻量土的动变形特性,通过动三轴试验研究了不同配比、围压对轻量土骨干曲线、Hardin-Drnevich模型参数的影响规律,建立了修正Hardin-Drnevich模型,并对修正模型进行了验证。结果表明:轻量土的骨干曲线呈现出明显的非线性特性与应变硬化特征。轻量土动剪切模量的倒数与剪应变关系曲线符合线性递增的变化规律,其动变形特性可以由Hardin-Drnevich模型描述。最大动剪切模量的倒数和最大动剪应力的倒数随着围压和水泥掺量的增大而减小,随EPS颗粒体积比的增大而增大。在Hardin公式的基础上,引入相对结构度k和广义孔隙比e’,提出了模型参数的表达式,建立了修正Hardin-Drnevich模型。通过改变应力状态和应力路径对轻量土进行动三轴验证试验,发现模型计算值与试验值间的相对误差均小于11%,修正Hardin-Drnevich模型对轻量土骨干曲线的预测结果良好,这表明修正Hardin-Drnevich模型可以描述轻量土特殊结构性在复杂受力条件下的动力响应。

To investigate the dynamic deformation characteristics of light weight soil mixed with EPS particles,the influences of different mixed ratios and confining pressures on the backbone curve and the parameters of Hardin-Drnevich model for light weight soil are studied through the dynamic triaxial tests,and the modified Hardin-Drnevich model is established and verified.The results show that the backbone curve of light weight soil exhibits obvious nonlinear and strain-hardening characteristics.The relationship between reciprocal of dynamic shear modulus and shear strain of light weight soil increases linearly,indicating that the dynamic deformation characteristics of light weight soil can be described by the Hardin-Drnevich model.The reciprocal of the maximum dynamic shear modulus and that of the maximum dynamic shear stress decrease with the increase of confining pressure and cement content,and increase with the increase of volume ratio of EPS particles.On the basis of the Hardin formula,the expression for model parameters is proposed by introducing the relative structure k and the generalized pore ratio e',and the modified Hardin-Drnevich model is established.By changing the stress state and stress path,the relative error between the calculated value and the test value is less than 11%.The predicted results by the modified Hardin-Drnevich model for the backbone curves of light weight soil are good,which shows that the modified Hardin-Drnevich model can describe the dynamic response of the special structure of light weight soil under complex stress conditions.