Research On The Influence Of The Excavation Of The Foundation Pit Of The Underpass Passage Of Changshui Airport On The Adjacent Control Tower

With the acceleration of China’s urbanization process,the excavation of foundation pits in many urban constructions will certainly have some impacts on the surrounding environment,especially the settlement and deformation of those existing building.Due to the complexity of engineering geological conditions,foundation pit scheme,adjacent building foundation form and building structure,the influence mechanism of foundation pit construction on surrounding buildings is very complicated,and traditional theoretical and empirical methods are difficult to comprehensively reflect the above complex factors.Therefore,it is difficult to judge the risk and predict the subsidence of those buildings according to the existing data.Based on the related project data,this paper studies the influence of foundation pit excavation on the adjacent Changshui Airport air traffic control tower in the soil/rock composite structure stratigraphic zone.The major contents and achievements of this study are as follows.(1)Finishing and summarizing the failure mode of building foundation and the theory of deformation caused by foundation pit excavation,combined with the actual situation of the site,to evaluate the stability of the foundation of the command tower;Evaluating of the pit formed after sidewall slope excavation stability.by qualitative evaluation and quantitative calculation method.Achievements: According to the site engineering geological data,it is judged that the stability of the foundation of the high-rise building of the command tower is mainly affected by the fault-fracture zone and the unevenness of the foundation caused by the uneven dissolution of the carbonate rock stratum;Through the results of on-site rock foundation load test,it is judged that the bearing capacity of the foundation bearing layer is good and there is no large uneven settlement failure;Through stereographic projection and limit equilibrium method calculation results,it is judged that the foundation pit slope formed after excavation may have local sliding failure along the bedding to the muddy interlayer,and local arc-shaped slip damage occurs in the upper soil layer.(2)Numerical simulation.The empirical methods in simulating excavation and surrounding buildings were summarized and analyzed to confirm the simulation schemes of key contents,such as soil constitutive model,building simulation program.The software GTSNX was used to establish two-dimensional finite element analysis model,and set up 4 groups of analysis conditions to carry out analysis and research.Achievements: Under the combined analysis conditions,the calculated values of building settlement are very small.It is preliminarily judged that the foundation pit excavation has less influence on the adjacent airport control tower building;The bedding structure in the rock formation has the greatest impact on the calculation results;There might be inverse relationship between building settlements and modulus of soil;The prediction curve of surface subsidence is put forward,but it needs feedback and verification of field monitoring results.