| In recent years,with the accelerated construction of the subway,the foundation pit engineering involved has also increased.In order to meet the demand for use,the scale of the foundation pit is increased,and the surrounding environment tends to be complicated,so that the bias phenomenon appears in the foundation pit engineering.The more it is,the more important it is to study the deformation mechanism of foundation pit excavation under bias.Based on the engineering background of Qingxiushan Station of Nanning Metro Line 3,this paper studies the deformation law of biased ultra-deep foundation pits in the Paleogene semi-diagenetic strata.Firstly,the engineering data and monitoring data of the biased foundation pit are collated and analyzed,and the deformation value of the retaining pile and the settlement value of the surface outside the pit are obtained under the bias generated by the superposition of the slope and the management station,and Considering the relevant specifications to determine the safety level of the foundation pit of the Qingxiu Station of the Nanning Metro Line 3 and the maximum value of the foundation pit deformation control,according to which the deformation of the biased foundation pit is evaluated.In addition,the Flac3D finite difference software is used to simulate the excavation and support of the biased foundation pit.The calculation results are compared with the measured data.The results show that the numerical analysis results are consistent with the measured data.The simulation results summarize the deformation law of the biased foundation pit.Finally,under the same engineering background,according to the cause of the foundation pit bias and the design of the supporting structure,different bias conditions and changing the parameters of the supporting structure are selected for numerical simulation research.Through comparison and analysis,it is concluded that: bias voltage and Both the foundation pit distance reduction and the bias voltage increase will cause the deformation of the bias side retaining pile body to increase,and the surface settlement will increase,while the non-biasing side will decrease,and the influence of the bias on the foundation pit will be sufficient.When large,the foundation pit moves away from the bias side,and the displacement of the unbiased side pile head moves to the outside of the pit;increasing the pile diameter or reducing the spacing of the inner support will reduce the deformation of the foundation pit. |
