Research On Mechanical Properties Of Prefabricated Corrugated Plate Lining

During subway construction,there is often a problem of the existence of groundwater,which requires dewatering construction.Past engineering cases have shown that the subway construction will disturb the soil,cause the soil to settle,adversely affect the structures and pipelines,and present safety problems.The fluid-solid interaction is not negligible for the study of the settlement problem of subway construction.It is of great significance to study the influence of the drainage of the pilot tunnel considering the fluid-solid interaction and the tunnel excavation on the settlement.This paper takes the construction of a dewatering pilot tunnel and main tunnel of a subway in Beijing as an example,using Midas GTS NX to carry out numerical simulation to study the influence of dewatering construction of subway on settlement when considering groundwater.Through the comparative analysis considering the fluid-structure coupling and not considering the fluid-structure coupling,the effect of the fluid-structure coupling on the settlement is verified.Through the comparison of the simulation results and the measured data,the applicability of the fluid-solid coupling under three conditions of single-line pilot tunnel construction,double-line pilot tunnel construction,and double-line tunnel construction is studied.The main conclusions are as follows:(1)Comparing the simulation results of the two precipitation processes,it is found that the aquifer in the second precipitation process is deeper,thicker,and more viscous due to different factors such as the thickness of the precipitation layer,buried depth,and the strata.The cohesion is worse,and the subsidence caused is greater than the first precipitation process.Through the analysis of the cloud diagram of the simulation results of the selected 12 important construction nodes,the settlement law of the pilot tunnel and tunnel dewatering excavation under the three working conditions is obtained when the fluid-solid coupling is considered.(2)The simulation and actual measurement results show that the dewatering pilot tunnel of the left line was first excavated and constructed,which affected the soil layer in the construction area of the dewatering pilot tunnel of the right line,resulting in the settlement of the dewatering pilot tunnel construction of the right line being less than that of the left line,and the pilot tunnel construction The settlement curve shows a double-peak asymmetric "W",and the tunnel construction settlement curve shows a "V".The existing pilot tunnel structure can reduce the surface settlement caused by tunnel construction.The settlement of the vault caused by the pilot tunnel and tunnel construction is greater than the surface settlement caused by the tunnel construction.In the three stages of construction,the degree of impact on surface settlement from high to low is pilot tunnel construction,tunnel construction,and precipitation process,and the degree of impact on vault settlement from high to low is pilot tunnel construction,precipitation process,and tunnel construction.(3)Through the comparative analysis of the simulation results considering the fluid-solid interaction and without considering the fluid-solid interaction,it is found that in both cases the simulation curve has the same development trend as the measured curve,and both can analyze and predict the changes and basic laws of the development of surface settlement..The fluidsolid coupling effect has an impact on the settlement.Considering the fluid-solid coupling effect,compared with not considering the fluid-solid coupling effect,the settlement amount is larger overall,and the numerical simulation results are more realistic,and the impact on the settlement is larger.The degree is higher.(4)The comparison between simulation and actual measurement shows that for surface settlement,working condition 1 is compared with working condition 2 and working condition 3.The simulation curves considering fluid-solid coupling and without considering fluid-solid coupling are close to the actual measured curve.The analysis and prediction errors of ground settlement caused by construction are all relatively small.Regarding the settlement of the vault,working condition 1 and working condition 3 are compared with working condition 2.The two simulation curves have a higher degree of fit with the measured curve,and the analysis and prediction errors of the actual construction of the dome settlement are smaller.