Abstract To investigate the development of pore pressures in the air-confined system with a rise of groundwater under a geomembrane, a laboratory test was conducted. Then, a numerical model with the consideration of the water-gas-solid three-phase system was developed based on the hydro-mechanical coupling theory for unsaturated soils. The model was validated by the experimental result and then a numerical study was conducted on the Datun plain reservoir. The result confirms the fact that the rise of groundwater is one of primary driving force for gas pressure under the geomembrane. When there is no surcharge over the geomembrane, air bulge would be produced. As the groundwater under the geomembrane replenished by water infiltration from groundwater around the reservoir, the gas pressure increases from the edge to the center of the reservoir and reaches the same final value with time. The increment of the pore gas pressure is significant during the increase of reservoir water, especially for the soils with larger compression strain. Thus, the coupled deformation is necessary to be considered for the regulating reservoir that undergoes the fluctuation of reservoir water frequently.

中文翻译：

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平原水库地下水上升作用下土工膜下气压的室内试验与模拟

摘要 为了研究土工膜下地下水位上升的气密系统孔隙压力的变化规律，进行了室内试验。然后，基于水力耦合理论建立了考虑水-气-固三相系统的非饱和土数值模型。对模型进行了实验验证，然后对大屯平原油藏进行了数值研究。结果证实了地下水的上升是土工膜下气压的主要驱动力之一。当土工膜上没有附加费时，就会产生空气鼓包。由于土工膜下的地下水由水库周围地下水的渗水补充，气体压力从储层边缘向中心增加，并随时间达到相同的最终值。库水增加过程中孔隙气体压力的增加是显着的，特别是对于压缩应变较大的土壤。因此，对于经常经历库水波动的调节水库，需要考虑耦合变形。