Key Designing Problems Study Of Frozen Soil Wall On The Project Of Tunnel Restoration

Depending on the case of the restoration project of the 4th Line of Shanghai Metor, the dissertation studies the key designing problems of frozen soil wall of different forms, differen functions and different working conditions by means of theoretical calculatiion, numerical simulation, experiment, site observation. Accordingly, the dissertation brings up some theory and designing methods for the application of frozen soil wall to the tunnel restoration and other similar projects.The main research content includes:(1):After water is abstracted and sludge is cleaned up in the undamaged part of the tunnel, the virtical frozen soil wall is subjected to water and soil pressure on the collapsed side, the key problems of the vertical frozen soil wall are studied in this dissertation. In the dissertation 3-D numerical models of vertical frozen soil wall are established and its pressure is simulated . A suitable thickness of frozen soil wall is given by comparing the stress distribution and deformation with different values of thickness. The original design is conservative acoording to the site observation.(2):The horizonal frozen soil wall key designing problems are studied under the different working conditions. In the dissertation 3-D numerical models are established to simulate the whole construction process on the base of experiment. The stress distribution and deformation are analyzed and the results are compared with that by theoretical calculation.(3):The characterictics of forming and development of the horizonal frozen soil wall are analyzed by finite element heat analysis and its conclusions provide reliable reference for project design and construction..