Application Of Block Theory In The Analysis Of The Stability Of The Rock In LPG Underground Storage

Block theory as one model of the mechanics of discrete, do detailed reseach of the com-bination of the block and its movability by analysissitus and set theory under the exsiting space and plane, and has been proved by accurate mathematical justification, the theory itself is precise and has unique advantage in analyzing the massive rock block.FLAC3D which can get the Governing Differential Equations by explicit finite differ-ence method and FEM clement models, can accurately simulate the flaxation of material, plastic deformation flow, softerning up to maximum deformation, especially it has uniquie advantage on simulating the large deformation. Besides, the deformation process can be seen by users in the process of accuculation being realized by the software. It is crucial for the data acquirement by anlyzing the accuculation result and material parameter in the deformation process.The thesis do analysis of the section 1 K0+125--145 of the water curtain gallery of one underground storage project, the calculation result shows there are two key block exists on the vault, and two others exist on the right and left abutment wall each. The sliding key block only exist on the vault part according to the judgement by the accurate joint pattern in project site, one joint pattern used for the judgement just existing on the left abutment wall, does not extend to the vault, so the block of the vault is tetrahedron combined by three blocks and free face, the volumn of the blocks can be calculated by the attitude and trace of the joint pattern.This thesis aims to get the data of effect on displacement and stress of the surrounding blocks caused by the tunnel excavation and supporting measure need to be adopt by seting model of the underground storage to simulate the process of excavation. In which the block model can only be set in pyramid according to the requirement of the unit layout not the ac-tual tetrahedron, but the block volume should be basically equal to the actual volume. The joint pattern surface between block and surrounding rocks gotten by moving the blocks, which leads to the result of the model after blocks moved shows on the deformed contour ir-reasonable. But the two maps are totally the same by comparison between the maximum prin-cipal stress contours and stable blocks, it is acceptable. The test results shows the vertical movement of surrounding blocks caused by tunnel excavation is so samll, which is neglectful comparing with the tunnel size, that supporting measure for the surrounding blocks is not needed. But the block fall in the corresponding section of the tunnel model has to be rein-forced by bolt, the blocks are stable and the bolt does not slide after the supporting measures taken according to the size and parameter of bolt, besides the unit layout readystate of the material parameter of the model is reasonable can be fixed by model deformation.Totally speaking, the underground storage in good stability, if no sliding blocks exists, supporting measures is not needed, considering of the water loss in the canny and fall of samll blocks in the projector, shot-crete technology for massive part of the tunnel and bolt rein-forcement supporting measures is reasonable.