强间断分析方法在土工结构物渐进破坏过程中的应用

Application of strong discontinuity analysis to progressive failure process of geotechnical structures

对于超固结黏土和密实砂土等软化材料或非关联塑性材料组成的地基、边坡及挡土墙墙后土体,在其破坏过程中,会产生应变局部化现象,使得控制方程的类型发生改变,从而导致出现数值解不惟一和解的网格相关性等现象。为了克服这些数值困难,基于强间断分析方法,及单元内嵌不连续面的有限元模型,对地基、土坡、墙后土体的渐进破坏过程进行了数值模拟。计算结果表明,单元内嵌不连续面模型可以有效地模拟土工结构失稳破坏过程,并且能够明显地改善采用常规有限元方法所产生的网格尺寸相关性问题。这一方法可作为传统极限平衡法进行稳定分析、承载力分析的有益补充。

For the foundation,slope and backfill supported by retaining wall,which consist of the over-consolidation clay,dense sand or non-associated plasticity material,the appearance of strain localization during the gradual process of the failure and instability of these geotechnical structures will lead to the change of the type of governing partial differential equation.Furthermore,this change results in non-unique and the mesh-dependence of solutions obtained by standard finite element method（FEM）.In order to overcome these difficulties,on the basis of the strong discontinuity analysis（SDA）,the embedded discontinuity finite element model is employed to investigate the failure processes of foundation,slope and backfill.Numerical examples show that this model can effectively simulate the post-failure processes of geotechnical structures and improve the objectivity of response with respect to the mesh size.The results also show that,this method can be taken as a beneficial supplement to traditional limit equilibrium method in stability analysis of slope and foundation.