Stability Analysis And Deformation Study Of Deep Excavation Near River

With the need of urban development,a large number of deep foundation pit projects are built along the river.Deep foundation pit excavation is a difficult engineering problem.When it is close to the river,it will be subjected to obvious asymmetric load,and the complexity will be greatly deepened.In order to analyze the influence of the asymmetric load brought by the river on the deformation and stability of the foundation pit,this paper takes a deep foundation pit near the river in Suzhou as the engineering background,uses the finite element software ABAQUS to establish a three-dimensional fluid-structure coupling model,and uses the modified Cambridge model to simulate the whole process of the foundation pit excavation.The main research contents are as follows:Firstly,the main forms and stability analysis of foundation pit deformation are introduced in detail.Based on the foundation pit of a river in Suzhou,the geological parameters,support structure design and dewatering process are analyzed.The typical section of the foundation pit was selected for modeling and numerical simulation.The main conclusions are as follows: the horizontal displacement of the retaining wall presents a flattening "parabolic" shape along the depth direction,and the variation range of the retaining wall on the riverside is greater than that on the non-riverside;The surface subsidence on both sides of the foundation pit increases with the excavation,but the range of surface subsidence on the riverside is larger than that on the non-riverside.Then,the numerical simulation results of the foundation pit and the field monitoring data were compared and analyzed.Although the results were slightly different,they basically accord with the deformation laws of the surface settlement,the displacement of the supporting structure and the axial force of the support obtained from the simulation calculation,which verified the rationality of the numerical analysis.Finally,the influence of five factors(the distance between the foundation pit and the river,the river level,the river width,the river depth and the embedded depth of the connecting wall)on the excavation deformation of the deep foundation pit adjacent to the river is considered through numerical simulation.The results show that the decrease of riverside distance,the increase of river level,the increase of river width and the increase of river depth will all lead to the increase of horizontal displacement of riverside envelope structure,while the influence on the non-riverside is small.