The Research On Soil Deformation Influenced By Shield Tunneling

Tunnel construction inevitably will cause the disturbance of soil, and then it will cause soil deformation.\the three parts of ground deformation before the beginning of subway operation are:(1) the uplift of soil before the of disc cutter's arrival;(2) the settlement caused by shield; (3) consolidation settlement. The research background of the paper is the construction of shield tunnel in Hangzhou. By analyzing the measured data, attempt to identify the rule of surface uplift and settlement. The main contents of the study include:(1) By in-situ monitoring shield tunnel NO.1 construction in Hangzhou, analyzing the correlation of parameters of shield machine and the rule of the development of soil displacement; (2) Research the influence of shield tunneling parameters for ground uplift; (3) To derivate calculation formula of soil displacement during tunneling; (4)To research the mechanism and calculation formula of consolidation settlement. Main work and viewpoint in this dissertation as follows:(1)Research the relationship between the shield tunneling parameters. Find out that the fluctuation for the total thrust force, the earth pressure on chamber and the torque of cutter disc are basically synchronous.(2) To analyze the influence of every shield tunneling parameters for ground uplift before the arrival of disc cutter. Ground uplift induced by shield in Hangzhou is high in case of pentathlon. The better the soil conditions, the more likely cause ground uplift. The most important factor that causes the ground uplift is the maximum total thrust of the ring. The second and third most important factors are the minimum and average of propulsion speed of ring.(3) Ground deformation is caused by three reasons, which are ground loss, the positive thrust and the friction. By solving the three-part respectively, the three-dimensional solution formula can be obtained after superposition of these.(4) Put forward the calculation method of the stress release rate caused by shield tunneling. Get the theoretical calculation formula of the excess pore pressure near the vault of the tunnel. Using the theory for stress transfer, the distribution of excess pore pressure on the top of tunnel is put forward. Theoretical calculation formula of post-construction consolidation settlement is obtained based on Terzaghi's one-dimensional consolidation theory.