Research On The Influence Of Deep Foundation Pit Excavation And Supporting Process On The Subgrade Deformation Of Adjacent City Road

With the development process of the cities,the buildings in the urban area are becoming more and more higher;the building foundation pit is also becoming more and more deeper in order to meet the requirement on its bearing capacity;in this case,the impact of the construction and excavation of the deep foundation pit on the nearby urban road has become more and more obvious.From the perspective of the current domestic and overseas investigation status,the foundation pit scheme design and the foundation pit structure deformation studies have already turned into maturity,but the study on the impact of the foundation pit scheme design and the foundation pit excavation process targeting the existing road deformation nearby on the nearby road deformation still needs to be improved further.Based on the deep foundation pit project of Hunan Armed Police Hospital,this article analyzes the deformation rules of the adjacent existing roadbed during the excavation of the foundation pit through the support structural design of the foundation pit,the finite element analysis on the impact of the foundation pit excavation on the adjacent existing roadbed deformation,the project site deformation monitoring,and the prediction on the existing roadbed deformation.The studies are conducted as follows:(1)The deformation of retaining structure and adjacent ground surface,the road surface and the road disease caused by the deformation of foundation pit adjacent to the foundation pit are analyzed,according to the standard,the control standard of the existing road subgrade deformation is obtained in the process of foundation pit excavation;The research methods and the research process of the roadbed deformation are analyzed,providing a theoretical basis for the analysis on the impact of the foundation pit excavation on the adjacent roadbed deformation in the following parts.(2)By drilling on the project site,reconnaissance,indoor geotechnical tests identified foundation pit engineering geological environmental and hydrological environment,according to the actual situation of the project and the adjacent roadbed deformation requirements,through the calculation of the foundation pit construction process of preliminary alternative support scheme,multi objective decision model is established,and the optimal scheme is obtained.(3)Based on the already defined foundation pit support scheme,adopt the finite element to simulate the top surface vertical deformation and deep horizontal deformation of the adjacent roadbed under the combination of the factors like the excavation depth of the foundation pit,the layer thickness of the foundation pit excavation,the tendon spacing and the pre-stressing force and the vehicle load,etc.during the foundation pit excavation process,and conclude the impact rules of the excavation of the foundation pit on the adjacent existing roadbed deformation by comprehensive analysis.In the actual engineering layout dependent deformation monitoring sites,figure out the deformation situation of the roadbed by analyzing the monitoring data,conduct the deformation prediction analysis based on the existing deformation monitoring data,and summarize the deformation rules and deformation rationality of the roadbed by combining with the actual measured results and predicted results.