The Study On The Interaction Between Construction Of Deep Foundation Pit And Loading Of Adjacent Group Pile Foundation

With the deepening development of urban underground space, many foundation pit appears in built-up areas, when there is a building pile foundation near the deep foundation pit constructing simultaneously or constructing with staggered process, especially when the building under construction is close to deep foundation pit, the foundation pit design must take into account influence of adjacent building pile foundation load on the foundation pit, but also consider effect of the foundation pit excavation on neighboring buildings. Therefore, the study on the interaction between construction of deep foundation pit and loading of adjacent group pile foundation has some theoretical significance and practical value.The open excavated deep foundation pit in Shuangliu Airport of Cheng Mianle passenger dedicated lines relied on by the article excavated 20.2m with the largest excavation width of 55.2m, and it was close to the pile caps of group pile foundation of airport terminal which is only 14.8m, and the pile caps had horizontal thrust as high as 12160kN imposed on the foundation pit. With the background of the engineering, the article analyzed the interrelationship about construction of deep foundation pit and loading of adjacent group pile foundation with the help of geotechnical finite element numerical analysis, analytical analysis analytical and construction monitoring data. Topics of this article mainly are as follows:Firstly, the foundation pits with different depth of excavation into group pile load were calculated and analyzed by using the geotechnical finite element numerical analysis method. Based on the results of numerical analysis and calculation, the horizontal displacement of retaining piles and group pile foundation, earth pressure of retaining piles as well as bending moment of retaining piles and group pile foundation were respectively analyzed, resulting in the deformation and stress characteristics of retaining piles and group pile foundation with different depth of excavation into group pile load.Secondly, on the basis of the above-mentioned study, the foundation pits and group pile foundation with different depth of excavation into group pile load were comparatively analyzed, then the influence of group pile foundation load on horizontal displacement, earth pressure and bending moment of retaining pile as well as the influence of foundation pit excavation on horizontal displacement and bending moment of group pile foundation were analyzed, resulting in the interaction between construction of deep foundation pit and loading of adjacent group pile foundation.Finally, the numerical results was compared with the field monitoring data(mainly including the horizontal displacement of retaining pile, horizontal displacement of pile cap and bending moment of retaining pile) in order to verify the rationality and reliability of the numerical analysis.