Research On Grouting Mechanism And Enviromental Effects Of Pipe Jacking

As one of the non-excavation methods, pipe-jacking has many advantages and been widely used in various fields. But pipe-jacking will inevitably cause the disturbance of soil. If the disturbance is too large, it will affect the surrounding environment. In order to make a long-distance pipe-jacking go ahead smoothly, bentonite slurry must be used in the construction process. Grouting can reduce the friction between the soil and the tube wall, and fill the soil void to avoid the collapse of soil and ground movement. Based on the pipe-jacking construction project of Huaxia West Road electric power, the properties and mechanism of bentonite slurry, and the ground settlement caused by construction is researched. The major works and results of this dissertation are as follows:(1)The properties and effect of bentonite slurry is studied. Through the model test, the grouting parameter optimization program has been proposed.(2)The disturbance mechanism of soil disturbance which is caused by pipe-jacking is analyzed. Together with the engineering situation, the surface displacement and the building subsidence are monitored in order to analysis the distribution of the settlement.(3)Through the simulation of the pipe jacking construction process by the three-dimensional finite element method, the grouting capacity and the grouting pressure are provided, to avoid serious consequences due to improper grouting parameters. The process of pipe jacking passing through the Huangpu River flood wall is simulated too. The displacement field and stress field of soil will change when the pipe-jacking driving because of the retaining wall.(4) Through the modeling and optimization analysis of large section of pipe-jacking, gasket properties are researched. Eccentric compression and contact will cause stress concentration increased, and will have harmful effects on the strength of pipe.