水封洞库群围岩水位变化特性研究

以某水封石油洞库群地质条件为例，建立平面有限元数值模型，基于饱和非饱和非恒定流数值理论，研究渗透系数、初始地下水位及降雨补给对洞库群围岩水位影响的变化特性.研究结果表明：（1）围岩渗透系数越小，地下水位下降越不明显，对水封条件的形成越有利；对于渗透性较大的岩体，初始水位的提高对水封条件的形成作用不大；（2）围岩渗透系数越小，洞周围岩水力梯度越大，两侧洞库围岩水力梯度整体上比中间洞库更大，初始水位的提高对围岩水力梯度的影响不大；（3）受开挖施工排水影响，洞库围岩水位降低较快，降雨补给并不能对地下水位造成明显影响，但形成的悬挂饱和区对油气的逃逸依然有一定的阻滞作用.

英文摘要:

Taking the geological conditions of a water-sealed petroleum cavern group as an example，a 2D FEM model is established.Based on the saturated unsaturated non-constant flow numerical theory，the effects of permeability coefficient，initial groundwater level and rainfall recharge on the surrounding rock water level of the cavern group are studied.The results show that：（1）The smaller the permeability coefficient of surrounding rock，the less obvious the drop of groundwater level，and the more favorable the formation of water seal conditions；for the rock mass with higher permeability，the initial water level increase has little effect on the formation of water seal conditions. （2）The smaller the permeability coefficient of surrounding rock，the larger the hydraulic gradient around the cave.The hydraulic gradient of the surrounding rock of the caverns on both sides is larger than that of the middle cavern.The initial water level has little effect on the hydraulic gradient of the surrounding rock. （3）Affected by the excavation drainage，the water level of the surrounding rock of the cavern is reduced rapidly，and the rainfall recharge does not have a significant impact on the groundwater level，but the formed suspension saturation zone still has a certain retardation effect on the escape of oil and gas.

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