土工膜防渗平原水库膜下气场数值模拟

以多相孔隙介质理论为基础推导了考虑孔隙中水气二相流的非饱和土固结理论方程,在一定的简化假设基础上编写了相应的有限元耦合计算程序。针对某土工膜全库盆防渗的平原水库进行了不同地下水位与库水位组合方案的三维有限元计算,通过整理库底和过渡平台两处膜下气压与地下水位及库水位变化关系曲线分析了土工膜下气压变化规律。计算结果表明:地下水位快速上升会引起膜下气压迅速增大,使得土工膜的气胀成为可能;当地下水位与土工膜间距小于1m时,膜下气压会随着库水位上升迅速增大。

Numerical Simulation of Air Field under Geo-membrane in Anti-seepage Plain Reservoir

According to the theory of multiphase porous media,a consolidation equation for the unsaturated soils was derived considering the water-air two phase flow in the porous media,and the corresponding finite element coupling calculation program was compiled based on some assumptions.The equation and program were used for the three-dimensional finite element calculation of a plain reservoir with the anti-seepage geo-membranes,which took into account different scenarios with the combination of the groundwater level and reservoir water level.The relationship curves among the pore pressure under the geo-membrane,groundwater level,and reservoir water level were analyzed at the reservoir bottom and transition platform to investigate the variation characteristics of the pre pressure under the geo-membrane.The results showed that the pore pressure increased rapidly with the quick rising of groundwater level,which can induce the flatulence of the geo-membrane.When the distance between the groundwater level and geo-membrane is less than 1 m,the pore pressure under the geo-membrane can increase with the rising of reservoir water level.