基于有限元法的堤防工程堤后加设盖重渗透比降影响分析

Analysis of Influence of Adding a Heavy Cover to Levee Back of Embankment Project on Seepage Gradient based on Finite Element Method

堤防现有强透水性卵石层地基,除较薄粉质黏土层外,无其它覆盖层,曾在罕见暴雨时期的高水头差的情况下,在堤后堤脚部位出现管涌现象。文章讨论在背水侧增设适当宽度的反滤层及压重,可否有效预防堤后管涌。选取典型断面,用有限元计算对比堤后堤脚部位加盖重前后的渗透比降,通过对比计算证明堤后加设土工布及砂砾料盖重兼具透水及压重的作用,能够使得原堤后坡坡脚位置的渗透比降有效降低,预防了堤后管涌导致的渗透破坏,达到了“保土排水”的作用。

There exists the pebble bed foundation with strong permeability in the dike,and no overburden except the thin silty clay layer,in the case of high water head difference during the period of rare rainstorm,the piping phenomenon occurs at the dyke toe at the end of the embankment.This paper discusses whether adding a inverted filter with proper width and pressure on the backwater side can effectively prevent the pipe gushing at the end of the dike.Selecting typical sections,the finite elements are used to calculate the seepage gradient before and after weighting at the dike toe at the end of the embankment,through the comparative calculation,it is proved that the weight of geotextile and gravel material is both permeable and heavy,which can make the original after embankment slope foot position effectively reduce seepage gradient,to prevent the dam seepage failure caused by piping,realizing actions of soil conservation and drainage.