Design Strengthening And Finite Element Analysis Of Pile-Anchor Supporting Structure After Deepening Of Foundation Pit

In recent years,with the rapid development of urbanization in China,the utilization rate of land is getting higher and higher.At the same time,the development and utilization of urban underground space has become a topic of increasing concern.The development and utilization of underground space can not be separated from the foundation pit engineering,and in the process of foundation pit support,we will encounter various problems.For example,when the supporting structure of some foundation pits has been completed,the need for deep excavation of foundation pits is caused by various reasons such as basement storey addition.In this paper,a deep foundation pit project in Jinan is taken as the background.Under the condition that the original pile-anchor supporting structure has been completed,it is necessary to deepen the excavation of the foundation pit and solve the insufficient supporting force of the supporting structure caused by the deep excavation of the foundation pit.Deepening the excavation of the original foundation pit will inevitably lead to the redistribution of the supporting structure.The supporting force of the original supporting structure is insufficient.It is necessary to strengthen the supporting design of the original foundation pit in order to ensure the safety and stability of the foundation pit.This paper checks the overall stability of the supporting structure after deep excavation of foundation pit,finds that it can not meet the requirements of deep excavation of foundation pit,and puts forward various design strengthening schemes for foundation pit.According to the effectiveness and economy of the design strengthening schemes,this paper compares and chooses various design strengthening supporting schemes,and finally decides to add one or more on the basis of the original pile-anchor supporting structure.Design and reinforcement scheme of road anchor cable.By using MIDAS/GTS finite element software,the horizontal and vertical displacements of foundation pit soil under three conditions,namely,the original supporting structure of foundation pit,the supporting structure of foundation pit after deep excavation and the reinforced supporting structure after design,are simulated and compared,and compared with the field monitoring data.The analysis shows that the design strengthening scheme of adding one or more anchor cables on the basis of the original pile-anchor supporting structure can effectively control the deformation of foundation pit,and the problem of insufficient embedded depth of supporting piles can ensure the stability of foundation pit by adding prestressing anchor cables.This design strengthening scheme is reasonable and effective,and can provide reference for similar deep design and strengthening projects of foundation pit.