| The ground deformation and disturbance that excavation brings will affect the safety of the surrounding buildings, especially in deep foundation pit close to metro. Appropriate supporting structure is often designed to control the deformation and reduce the influence of foundation pit excavation on metro structure to the allowable range. In order to study the deformation control effect of expansive soil excavation on subway construction nearby, this paper takes the actual foundation pit excavation engineering as the background, combined with numerical simulation and field monitoring to do research, which can provide new material for the study of deep foundation pit deformation of expansive soils and many evidence and ideas for improving design and calculation methods of expansive soil foundation.In order to study the deformation control effect of expansive soil excavation on subway construction nearby, firstly, the supporting design of foundation pit is carried out according to the basic survey data, and the design scheme of supporting structure is obtained. Then the numerical model of the foundation pit is established by using the numerical simulation software FLAC3D based on the supporting scheme. After that, based on the expansion stress distribution from the same period research topics, numerical simulation results are obtained in the ordinary conditions and the rainfall conditions taking into account the expansion stress. At the same time, in order to get the actual deformation data in excavation, many monitoring elements are laid around the foundation pit to get the deformation and stress data during the process of excavation. Finally, the actual deformation data of foundation pit, the numerical simulation data and the design of deformation data are compared. After the numerical simulation data and the actual deformation data being compared and verified, we can get the metro structure deformation data from numerical simulation results and analysis the deformation control effect of expansive soil excavation on subway construction nearby.Through the analysis of this paper, it is found that the deformation control of foundation pit support is successful,and the deformation control effect of metro construction is remarkable. In numerical simulation, the deformation of foundation pit under the expansion stress is larger than that of the original working condition, indicating that the effect of expansive soil on the deformation of foundation pit is obvious, and it has a certain degree on the deformation of metro, which needs to be paid attention to in engineering.Besides, because of the lack of consideration on expansive soil effect in design calculation, compared with the actual monitoring results, the design calculation results tend to be small,which is not conducive to the safety of the foundation pit, and the optimization calculation method needs more in-depth study. |
