Water-Tight Underground Oil Storage Caverns Rock Stability And Seepage Field Analysis

As China's economic growth, oil consumption is increasing rapidly. China's oil storage system must be established. For security, economic considerations, nations and regions which have construction conditions will choose underground oil storage as the main storage means. The rock stability and seepage field analysis are two key issues in the design of water-tight underground oil storge canverns. Facing these problems, the author relies on the the construction project of Da Lian underground oil storge canverns to carry out the research work of rock stability and seepage field analysis.In the first place, based on regression model of site stress test data, directly giving the model element corresponding stress, inversion of initial stress field is completed with the programming language FISH embedded within FLAC3D after stress transformation; meantime, inversion of initial seepage filed is obtained with the model of fl_anisotropic within FLAC3D, anisotropy of permeability is responsed based on joins network simulation technique. The above work provides more reasonable initial stress field and initial seepage filed for posterior calculation.In the next place, the impact of caverns excavation on rock stability and seepage fields are analyzed, immediately, support method analysis. Aim at the engineering characteristics of Da Lian underground oil storge canverns, considering the coupling effect of stress and seepage, the corresponding deformation, stress, plastic zone and seepage are obtained through simulation of excavation. It is to use water level and vertical hydraulic gradient as evaluation criteria of water-tight referring to foreign. Point safety factor method is used to quantificationally evaluate stability of caverns. In addition, Da Lian underground oil storge canverns may have local bad rock mass conditions. Comparing numerical simulation of different support methods, rock deformation, stress and the plastic zone are obtained to assess the static and dynamic support effects.After that, influencing factors of caverns stability are analyzed. Considering rock mechanical properties, stress distribution, permeability properties, the ratio of the width and span and other factors, based on uniform design, statistical model of point safety factor is established. The regularity of the influencing factors are found according to the model.Subsequently, the influence of excavation process on caverns stability are analyzed. On the one hand excavation step, on the other hand excavation sequence. Through comparison of numerical simulation results, it is convenient to select the optimum excavation process.In the end, the operation stability of Da Lian underground oil storge canverns is analyzed. According to rock properties, caverns rheology mechanical behavior is simulated using the generalized Kelvin visco-plastic rheological constitutive model. Considering possible extreme weather, the water supply caused by seasonal changes in groundwater level, the long-term seepage filed is also studied in the operation period. In addition, numerical simulation analysis and Sharma-Judd's survey analysis methods are used to carry out seismic safety assessment subjected to the earthquake.