改进的有自由面非稳定渗流分析复合单元渗透矩阵调整法

The improved variable seepage matrix method of the compound element for unsteady seepage flow with free surface

应用连续的罚函数,提出了一种改进的自由面边界条件渗流分析复合单元渗透矩阵调整法,优化了此类算法的稳定性,提高了收敛速度和精度,并将此改进算法编制成相应的有限元分析程序,应用于上海地铁4号线董家渡隧道修复基坑降水工程的优化设计,解决了基坑降水过程中复杂三维渗流场的高效精细模拟问题,同时预测了基坑中心水位降至地面以下40 m,位于承压含水层顶面以下,基坑内外自由面落差很大时基坑周边渗流场以及地面沉降的分布特征。

The improved variable seepage matrix method of the compound element was presented for the seepage problem with free surface in the light of usage of continuous penalty function. Then the disad- vantage of unsteady solution was optimized and the speed and precision were improved. The improved method was used for programming the finite element method on optimizing the reconstructed foundation pit dewatering of Dong Jia-du subway part of four line in Shanghai. It was utilized for simulating three dimension complex seepage field efficiently and subtly. At the same time, it was used to forecast the character of groundwater seepage filed and land subsidence around the foundation pit when the groundwater level of the foundation pit center reduced to forty meters below ground, under the top of confined aquifers and the free surface had larger difference inside and outside of foundation pit.