| In general, the construction of subway tunnels is carried on a shallow foundation and the surrounding rock masses are in complicated geologic conditions. Meanwhile, to construct with the mining method may significantly destroy the original stratum structure and the earth subsidence caused by it can impact the surface buildings greatly.This paper started from the influences of the subway tunnel excavation on the stratum and surface buildings. It targeted on the connecting line of Shezhen subway line5 and line 7 that is under tunneling beneath the Xili Kindergarten. Then it studied on the various of pre-support methods and determined the optimum method as the method of horizontal rotary jet grouting piles. With the mathematical derivation, numerical simulation and field subsidence monitoring data this paper made a study on the tunnel that applied the pre-support method. The contents as well as the main achievements of this paper are as follows:(1) In combined with the specific engineering background and the conditions of the surrounding buildings it comprehensively analyzed the existing pre-support methods from the technological, economic as well as other aspects to screen out the method of horizontal rotary jet grouting piles as the only applicable one.(2) In combined with the field tests, the subsidence prediction was visualized by establishing the mathematical model of the horizontal rotary jet grouting piles and adopting the numeral simulation software to verify the calculation(3) As the field tests and the simulation results were utilized in the construction field,the monitoring data demonstrated that the security of the surrounding building hadn’t been impacted and the selected pre-supporting method was feasible and reasonable. |
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