Research On Problem For Subway Parallel Shield Tunnel

With the rapid development of infrastructure construction in our country, the Shield Method as a safe tunnel construction method with high efficiency has been widely applied in tunnel engineering such as urban subway and underground pipe lines and so on. At the present, the double-tube parallel tunnels are much popular than the single tunnel, then it has brought a series of problems on construction to be solved. So proving up the disturbed mechanism of the ground and the changing laws of the ground displacement during the dynamic construction process is valuable both for academia and application.Based on the twin shield tunnel of the ChengDu Metro, laboratorial model test and numerical simulation are used to simulate the dynamic construction process with Earth Pressure Balance Shield Machine, research the change laws of the ground displacement and the influence on the existent tunnel of the new construction tunnel in the parallel tunnels during the dynamic shield construction process, then bring up some reasonable proposal on the parallel tunnels construction. The main work has been done is as follows:1,Based on the truth that the disturbance of the shield construction to the ground is essentially the disturbance of the soil, the sources of the disturbance has been analyzed; At last the computational method of the mechanical effect,the geometrical effect and the secondary consolidation effect of the soils was put forward.2,The parameter which can show the characteristic of the shield-ground system was analyzed, and then the parameter which can evidently influence the result of the test was chosen. The similarity law was got based on the similarity theory using dimensional analysis method which taken ground,shield machine and the interaction boundary of the shield and the ground into consideration. And then the laboratorial model test was carried out.3,The universal laws of the ground displacement during the dynamic shield construction process was got by analyzed the data of the model test; The dynamic construction process was simulated by three-dimensional numerical simulation, research the change laws of the ground displacement and the influence on the existent tunnel of the new construction tunnel in the parallel tunnels during the dynamic shield construction process, then bring up some reasonable proposal on the parallel tunnels construction.