非饱和土粘弹性地基一维固结特性分析

Analysis of Consolidation Characteristic of One-Dimensional Visco-Elastic Consolidation for Unsaturated Soils

基于Fredlund的非饱和土一维固结理论,采用李氏比拟法,研究有限厚度粘弹性非饱和土层在大面积均布瞬时加荷时的一维固结问题.针对Merchant粘弹性模型,采用Laplace变换及Cayley-Hamilton等数学方法,引入边界及初始条件,得到Laplace变换域内顶面排气不排水、底面不渗透情况下粘弹性非饱和土地基一维固结时的超孔隙水压力、超孔隙气压力以及土层沉降的解,采用Crump及Durbin方法实现Laplace逆变换,获得半解析解;分析在不同气、水渗透系数比ka/kw下,Merchant粘弹性模型的Kelvin体中弹性模量E1和粘滞系数η等对粘弹性非饱和土地基一维固结特性的影响,揭示粘弹性非饱和土地基的固结特性;最后通过与弹性解析解的对比,验证了半解析解方法的正确性.

On the basis of Fredlund＇ s analytical consolidation theory for one-dimensional consolidation for unsaturated soils and by application of Lee＇ s match method, one-dimensional consolidation for an unsaturated soil layer with a finite thickness, and with one-dimensional load applied, is proposed. By using the Merchant visco-elastic ground model, and Laplace transform and Cayley-Hamilton method, solutions of the excessive pore-air pressure are obtained. Excessive pore-water pressure and the settlement rate of soil while the surface are air exhausted but water impermeable, and the bottom is impermeable to water and air. By adopting the Crump and Durbin method to perform Laplace inversion, we can get semianalytical solutions. Moreover, we analyze tile relevant behavior of one-dimensional visco-elastic consolidation for unsaturated soils. The effect is related to many factors such as air-water coefficient rate of penetration and the visco-elastic parameters. The visco-elastic semi-analytical solutions are compared with the elastic analytical solutions. The results show effectiveness of the methods.