基于离散介质流固耦合理论的地下石油洞库水封性和稳定性评价

以我国首个大型地下水封石油洞库工程为背景，基于离散介质流固耦合理论，开展地下石油洞库水封性和稳定性评价。通过室内岩石三轴试验和结构面剪切–渗流耦合试验，获得岩石的弹性模量、泊松比和结构面的剪切模量、水力开度等参数。根据施工巷道开挖过程中围岩变形和水位变化情况，对围岩参数进行反分析，获得较为可靠的洞库围岩参数。综合上述成果，分析地下石油洞库的水封性和稳定性特征。研究发现，在水幕压力为50 kPa条件下，该地下水封石油洞库稳定水位位于主洞室上方约60 m，且大于洞内储存介质的压力，满足洞库水封条件；洞库各主洞室位移为9～30 mm，达到洞室稳定相关控制标准；分析8#和9#主洞室边墙附近的水平应力、竖向应力、法向应力和切向应力的变化，并将其划分为3个区域，即松动区、扰动区和未扰动区，其中洞室松动区范围约为6 m。研究为大型地下石油洞库水封性和稳定性评价提供理论依据。

ASSESSMENTS OF CONTAINMENT AND STABILITY OF UNDERGROUND CRUDE OIL STORAGE CAVERNS BASED ON FLUID-SOLID COUPLING THEORY FOR DISCRETE MEDIUM

Based on fluid-solid coupling theory for discrete medium，containment and stability properties of underground crude oil storage caverns were assessed for the first pilot crude oil storage caverns in China. Elastic modulus and Poisson?s ratio were obtained in triaxial compression tests；while shear modulus and hydraulic aperture were obtained in shear-seepage coupling tests. The back analysis for the other parameters of surrounding rock was performed according to the deformation and water table change in rock mass around the service tunnel under construction. The containment property of the crude oil storage caverns subjected to the groundwater pressure of 50 kPa in the curtaining tunnels was assessed based on the laboratory tests and back analysis. It is obtained that the groundwater table would stabilize at 60 m above the crowns of the caverns，and more than storage media pressure inside hole. The crown settlements range from 9 to 30 mm，which satisfy the standard for the stability of the caverns. The distributions of horizontal stress，vertical stress，normal stress and shear stress around the caverns #8，#9 could be divided into three zones，i.e. excavation induced loose zone，disturbance and undisturbed zones. The extent of loose zone is about 6 m. The research provides theoretical basis for the design of curtain system of large-scale underground crude oil storage caverns.