Evaluation On Quality And Analysis On Stability Of Adjacent Rock Mass Of The Water-Sealed Underground Oil Tank In Huangdao

Huangdao water sealed underground oil tank lies in Huangdao district, ShanDong province, which is one of strategic oil storages to be built recently and is the first underground oil storage in our country. This thesis takes Huangdao water sealed underground oil tank engineering as study object, and does further researches on equality evaluation of engineering rock mass, analysis of geo-stresses, stability analysis of adjacent rock mass and judgement of rock burst.Quality evaluation of engineering rock mass is necessary for site election and design of underground cave engineering. For most evaluating methods of engineering rock mass, the integrality index is an important assessment factor. However, sometimes the integrality index is more than 1.0 because of unloading effect of rock samples and differentia of frequency between the measurements of rock samples and rock mass. In order to solve this problem, unloading index and frequency correcting coefficient are brought out in the thesis. Moreover, the BQ evaluating method which is put forward in the state standard (GB50218-94) is improved according the unloading index and the frequency correcting coefficient. The improved BQ method is used to evaluate the rock mass of Huangdao water sealed underground oil tank engineering, and the results show that the quality of rock mass in the engineering site are very good.The damping least square method is programmed with the fish language of FLAC which is one of numerical computation software to combine the numerical computation with the fitting computation and realize the automatism of the fitting analysis. With this set of fitting method, the measuring results of the hydraulic fracturing test in the zk17 bore are fitted with the computing results to get the distribution of the geo-stresses in the tank site. According to the fitting results, the maximal horizontal principal stress is 10~12 MPa, the middle principal stress is 6~8 MPa, and the minimal horizontal principal stress is controlled by the weight of the rock mass. The tank site belongs to the low geo-stress zone.In the thesis, the deformation, the stability and the reciprocity of the adjacent rock mass of underground caverns are analyzed with FLAC. In the analysis, many methods to determine the parameters of rock mass are brought forward, and the stress boundary conditions are determined by the fitting results of geo-stress. The numerical computing results show that the adjacent rock mass is made a little deformation, butthey aren't damaged.According to lots of documents, three factors controlling rock burst: the ratio between the maximal principal one of the circumference stresses and the compress intensity of rock samples, the orientation index of rock burst and the integrality index of rock mass, are put forward in the thesis. According to the three factors, the rock burst is judged with the extension method. In the light of analysis with the extension method, rock burst doesn't occur after the underground caverns were excavated.