Research On Double Track Tunnel’s Ground Subsidence Caused By Shield Tunneling Construction In Watery&Weak Stratum

Due to space constraints and safety considerations, double-line shield tunnels are often chosen to be the main method of building city metro. Usually the space between tunnels is not enough far and a large number of existing buildings above the tunnels, besides a lot of municipal pipelines in soil around tunnels. So how to predict and control the settlement of surface is of great importance. Mechanism of surface displacement and deformation caused by double-line shield tunnel are more complex than by single hole, and besides two tunnels are not often constructed at the same time, so secondary disturbance will be inevitable, which will result in greater risk。 in terms of both scientific research and Engineering Practice, systematic research on surface displacement and deformation caused by double-line shield tunnel is necessary to carried on. The main contents of this paper are:1. Through the investigation of the latest research achievements both at home and aboard, the categories of parallel shield tunnel are classified and clearing the concept. Meanwhile, the mechanism of ground settlement due to shield construction are made a further theoretical study, and the laws on ground settlement are given.2. Based on numerical Simulation by finite difference software FLAC3D, the law of ground surface settlement and mechanism of ground deformation are studied in different cases.3. According to the results of processing measured data, combining with formation conditions, construction parameter, tunnel spacing, depth, etc. some data and rules are gotten, which are meaningful to engineering practice, analyzing Running Tunnel from Wang Wu Road to Shi Hu Road of Suzhou Rail Transit Line2.4. Combining with boring parameter, the ground surface settlement data are studied and some methods are founded that is how to improve construction parameters to control surface ground settlement.