以国内首个大型地下水封石油洞库工程为背景,在考虑洞库围岩节理裂隙的随机分布特征基础上,采用离散介质流-固耦合理论对大型地下石油洞库水封性进行了评价。介绍了地下水封储油洞室水封原理与水封准则。通过室内结构面剪切试验获得了结构面参数,采用Barton-Bandis剪胀模型对结构面参数进行了校验。根据库区节理裂隙统计结果,建立了洞库围岩的随机节理裂隙网络模型。分析了不同水幕压力条件下洞室开挖后地下水压力分布情况、涌水量大小和洞库围岩变形与受力情况。分析表明:在水幕压力大于或等于75 kPa的条件下,洞室周围地下水压力满足水封准则;在水幕压力为75 kPa条件下各洞室涌水量在0.003~0.015 m3/d之间,拱顶沉降量在16-32 mm之间。研究结果可为地下水封石油洞库水幕系统设计提供依据。
Based on the joints random distribution characteristics of surrounding rock of the China's first large underground crude oil storage caverns, containment properties of underground crude oil storage caverns were assessed by using flow-solid coupling theory for discrete medium. Water seal principle and water seal standards of underground crude oil storage caverns are introduced. The structural plane parameters are obtained by the indoor structural plane shear test; and structural plane parameters are checked by using Barton-Bandis shear dilatancy model. According to the joint statistical results, a random joint network model of the surrounding rock is established. The groundwater pressure distribution, water inflow and surrounding rock deformation and stress distribution are analyzed after the excavation under the conditions of different water curtain pressures. The results show that groundwater pressure around caverns meets water seal standard when the water curtain pressure is greater than or equal to 75 kPa conditions. Under the water curtain pressure of 75 kPa, water inflow rates for the caverns range from 0.003 to 0.015 m3/d and crown settlements range from 16 to 32 mm. The results provide a theoretical basis for water seal evaluation of underground water seal oil caverns.