(复合)土工膜防渗土石坝饱和-非饱和渗流特性

分别采用完全饱和渗流及饱和 非饱和渗流有限元计算理论,对(复合)土工膜防渗土石坝进行渗流场仿真分析,重点研究土工膜等效处理时不同厚度放大倍数下大坝渗流场变化规律,同时结合坝体土石料不同渗透特性,计算得到大坝渗流量和浸润线与土工膜厚度放大倍数之间的关系,并比较了按完全饱和渗流理论与饱和 非饱和渗流理论计算结果的差别。结果表明:在坝体土石料渗透特性相同的情况下,土工膜不同厚度放大倍数时浸润线仅在土工膜等效区有较大差别,在膜后坝体部位基本保持不变;大坝渗流量与土工膜厚度放大倍数及坝体填料的渗透特性相关,按饱和渗流理论计算所得的大坝渗流量大于按饱和 非饱和渗流理论计算得到的渗流量。

Partial saturated seepage properties of (composite) geomembrane earth-rock dams

In this study,the seepage field of earth-rock dams with impervious(composite) geomembrane was analyzed with the finite element method based on the full saturated and partial saturated seepage theory respectively.The variation of the dam seepage with different amplified thicknesses of the geomembrane was mainly studied.The relationship between the dam seepage flux,the phreatic line and the magnification of the thickness was obtained by the calculations with regard to different permeability values of the dam body materials.The computational results based on the full saturated and partial saturated seepage theories were also compared.The results show that the position of the phreatic line is significantly different in the equivalent zone and remains unchanged in the zone behind the geomembrane if the magnification of the geomembrane thickness is different and the seepage properties of the dam body material are identical.The dam seepage flux is correlated to the magnification of the geomembrane thickness and the permeability of the dam body materials.The seepage flux calculated with the full saturated seepage theory is greater than that with the partial saturated seepage theory.