地下石油洞库水幕设计原则与连通性判断方法研究

 地下水封石油洞库建设技术在我国刚刚起步，其水幕系统设计理念和方法还不成熟。结合我国首个大型地下水封石油洞库工程，研究水幕系统设计原则与连通性判断方法，分析水文地质条件对水封方式选用、水幕系统布置和水幕连通性测试的影响，并根据现场试验结果，研究水幕连通性判断方法，提出改进的连通性测试方法。通过研究发现，地下水封石油洞库水封方式的选择需充分考虑库区水文地质情况，而垂直水力梯度是判断洞库水封性的重要参数；人工水封方式中水幕孔应尽量垂直于结构面走向布置；水幕连通性判断可综合单孔注水试验与分区有效性试验结果进行，并考虑库区渗流场分布与变化规律对试验结果的影响；改进的水幕连通性测试方法适用于不同水文地质条件下水幕孔连通性测试。该研究成果可为地下水封石油洞库水幕设计提供重要依据，并为岩体渗流特性研究提供不可多得的工程实例。

DESIGN PRINCIPLES AND INTER-CONNECTIVITY DETERMINATION METHOD OF GROUNDWATER CURTAINING SYSTEM FOR UNDERGROUND CRUDE OIL STORAGE CAVERNS

The construction technology of underground storage caverns was introduced into China a few years ago. At present，there is no extensive experience on the design and construction of groundwater curtaining system. Design principles and inter-connectivity determination method of groundwater curtaining system were investigated with reference to a case study on a pilot underground crude oil storage caverns in China. The influences of hydrogeological condition on the sealing method，arrangement method of groundwater curtaining system and inter-connectivity determination method were obtained. From field tests on the inter-connectivity of groundwater curtaining system for the pilot caverns，an improved inter-connectivity testing procedure was proposed to determine the inter-connectivity of boreholes in the curtaining system. From this study，it is found that the sealing method of underground storage caverns depends on the hydrogeological conditions of the sites；and vertical hydraulic gradient is an important parameter for the sealing property of storage caverns. For artificial sealing method，the axes of boreholes in groundwater curtaining system are suggested to be perpendicular to the orientation of dominant joints. The inter-connectivity of the boreholes could be determined using a procedure combining groundwater pressure dropdown test of single boreholes with inter-connectivity test for multiple boreholes. The distribution and variation of groundwater seepage field around the site could impose great influence on the testing results. The improved testing procedure could be employed to determine the inter-connectivity of groundwater curtaining system in different hydrogeological conditions. This study will provide an important reference for the construction of underground storage caverns with groundwater curtaining system；and provide a critical benchmark for the study of seepage behavior of jointed rock mass.