两种Lagrangian大变形比奥固结有限元法及其与小变形法的比较

从非线性连续介质力学出发,采用Jaumann应力率和Biot平面固结理论,用同一程序结构和土性参数计算比较了饱和土体大变形Lagrangian法(TL和UL法)与小变形法的沉降和孔压差异。计算结果表明,当应变较小时,三种方法计算的变形和孔压值相同;当应变很大时,大变形法和小变形法计算的沉降和孔压差异很大。因此,大小变形法分析结果的比较应采用总应力法。文中还指出,大变形分析地基最终沉降小于小变形法,而且时间步长对计算沉降值有严重影响

The comparison of large strain method using Total and Updated Lagrangian finite element formulation and small strain method

On basis of nonlinear continuous mechanics, the rate of Jaumann stress and the theory of Biot consolidation for saturated soil, the settlements and pore water pressure of a ground are calculated and compared by large strain method using Total and Updated Lagrangian formulation and small strain method. The results show that the deformation and pore water pressure are same for the three methods at small strain, but very different at large strain. So the comparison of large strain method and small strain method should be carried out with total stress method. The paper also points out that the final settlements of large strain method are smaller than that of small strain method, and they are seriously affected by the length of time step.