从微观角度分析土的动力学性质,是本构模型探索的重要方向之一。根据架空孔隙是导致弹塑性黄土产生动残余变形动力因素的微观机制,结合气固表面和颗粒理论以及双曲线公式,采用动三轴试验参数、架空孔隙面积、围压等数据建立震陷模型,获得动应力作用下土的残余变形系数计算公式。通过主要黄土沉积区土样的残余变形系数计算值与试验值对比,两者吻合较好。研究结果表明,所获得的微孔隙一维动变形模型能较好地反映不同围压、含水量和干密度下,不同地区黄土微结构差异导致的残余变形强弱,能较普遍反映黄土的弹塑性变形特征。
Analysis of dynamic properties of loess from microstructure perspective is one of the most important direction to explore loess constitutive model. According to the micromechanism that overhead pore is the dynamic factors causing the residual deformation of elasto-plastic loess,combined with air-solid surface theory and hyperbolic formula,the pore-overhead seismic subsidence models is established by using data such as dynamic triaxial test parameters , overhead pore area and confining pressure. Computational formula for residual deformation coefficient of loess under dynamic loading is acquired in the model. By test contrast of the main loess deposition samples,the residual deformation coefficient calculated by the computational formula is very closed to the experimental value. The comprehensive analysis results show that the one-dimensional micro-pore dynamic residual model can well reflect the residual deformation actual situation induced by loess microstructure difference under different confining pressures,water contents and dry densities. The model can generally reflect the characteristics of elasto-plastic deformation of loess.