Stability Analysis And Numerical Simulation Of Retaining Structure In Subway Foundation Pit Excavation

With the development of economy and the quick growth of urban construction, the ground space is not enough for us. Under this circumstance, the depth of the foundation pit excavation and the scale will increase gradually. So deep foundation pit engineering will be rocketing which provides great practical value to the research on the laws of the deformation of retaining structure in the process of the deep foundation pit excavation.With rapid development of the methods of computer and numerical simulation, geotechnical workers use intelligent method to make a optimized analysis on the soil mechanics characteristic parameters and then use the numerical simulation software to make the simulation analysis on the foundation pit excavation. This paper is based on foundation pit engineering of gateway3rail transit line6engineering expo center in the city of Wuhan. It adopts the genetic neural network algorithm to make the analysis on rock mechanics parameters. It combines the finite difference numerical simulation software FLAC3D to analyze the deformation law of the excavation. It also makes a simulation analysis on deformation law of pit under the bias function.The following are the conclusions of my research:(1) Soil mechanics parameters has a direct impact on the results of the finite element simulation. Based on the intelligence method of genetic algorithm and neural network algorithm, this paper applies the genetic neural network optimization algorithm to engineering. This method combines the advantages of the two, which is very helpful to the realization of the parameter inversion.(2) Combining with the actual engineering and using orthogonal design method, this paper analyzes the sensitivity of the soil mechanics parameters and rank the parameters according to their sensitivity. Based on displacement of the variable selection, it uses displacement back analysis method. Using the genetic neural network algorithm, it makes a back analysis on soil mechanical parameters of foundation pit.(3) It applies the results of the parameters analysis to the model of FLAC3D and analyzes the numerical simulation. It also makes analysis on thehorizontal displacement of retaining piles, the vertical displacement, foundation-pit bottom and support internal force. It compares with the measured displacemen which proves to get good simulation results.(4) As for the design pit under bias, it undergoes the numerical simulation by using reverse analysis of the model. It studies and analyzes the internal force under different high bias and deformation of foundation pit. Then it comes to the conclusion that there are great differnces between the degree of the internal force and deformation of the bias and unbias side of the bias foundation pit under bias cases. It also shows that different bias has great effects on internal force and deformation of foundation pit.