The Effects On Tunnel In EPB Shield Adjacent Crossing Constructing

In this paper, we take the projects in line 1 and line 2 of Suzhou subway for the project background. And, we analyze and study the security and construction affects of EPB shield tunneling adjacent crossing construction. The main research contents include:(1)The major steps and the key points of shield tunneling via 3-D numerical simulation were analyzed, by analyzing and studying the main construction procedures of shield tunneling.(2)The whole construction procedure of shield tunneling was simulated by using Midas-GTS software. And, we studied the correlated rule of shield tunneling construction through the following factors: stress, displacement and force characteristics. It is obviously that the tendency of stress, displacement are according with the same law, that is to say they are all Axisymmetric. The displacement of shield tunnel rock mass is detected have the principle: subsiding of vault, uplifting of bottom, and extending to outside of hence. The parts of vault and bottom of shield tunnel are distributing of tension stress while the hence is representing the press stress. The stress of the segments is centralized at the neighborhood of vault in the shape of strip.(3)Because of the different of vertical distance between existed tunnel and new building tunnel and that of propulsion force of tunnel face. This paper simulated the whole construction procedure of EPB shield adjacent crossing and analyzed the impact due to the construction of new tunnels to the existed one. Thus, vertical distance is the most important factor in all of that affect the construction of tunnel. And, the littler of the vertical distance the more influence will be imposed on the existed tunnel. Compared with the vertical distance, the impact caused of propulsion force of tunnel face is less noticeable though it indeed affects the stress, displacement of nearby rock mass.This paper studied the security and relevant rule of shield tunnel constructing, and hoping to provide some use of reference for the similar projects in the future.