Model Test Of Pulling Anchor Supporting Structure Of Adjacent Deep Foundation Pit And Research Of Optimizing Construction Sequence

With the development of urban construction, high-rise buildings and super high-rise buildings emerged constantly.Deep foundation pit engineering is also becoming more and more intensive, which inevitably causes the problem on adjacent deep foundation pit.In some cases, the slope between adjacent deep foundation pit could not be excavated due to some special reasons. And because of the short distance between them, General pile- anchor supporting structure can not support the slope effectively.Pulling anchor supporting structure is a kind of supporting structure rising in recent years which is used for adjacent short distance foundation pit supporting. The current researches on pulling anchor supporting structure are mainly concentrated on its engineering application,while the researches on its theory and construction process are relatively less. And theoretical research is lagging behind its engineering application. So this paper uses practical adjacent deep foundation pit project as the basis, doing research on mechanical characteristics, soil pressure distribution, construction sequence optimization of pulling anchor supporting structure by means of a self-designed model test, numerical simulation, engineering applications after reading a large amount of relevant literature.The main contents of this paper are as follows:(1)Pulling anchor supporting structure used in adjacent deep foundation pit is different from general pile-anchor supporting structure in deep foundation pit:pulling anchor supporting structure has no anchoring section,fixed by anchor at both ends. Both sides of the slope need to be excavated. And pulling anchor supporting structure can only be constructed after both sides of the soil excavation completed. So this part designed the indoor model test programmes of pulling anchor supporting structure independently in different construction sequence according to its characteristics from several aspects such as model box design, testing materials selection, testing original layout and experimental design based on the reference of a larger number of pit and slope model test.(2)According to designed experiment,we obtained the soil pressure distributing characters of pile body and baffle of pulling anchor supporting structure, the bending moment characters of supporting pile, the changing characters of displacement of pile top along with the change of the construction process. Besides, we analyzed importance of construction sequence in the excavation and support construction for adjacent deep foundation pit supported by pulling anchor supporting structure.(3)Through the analysis of model test results, we found that the construction sequence had great influence on the supporting structure and the slope deformation. So this paper focuses on studying the impact of construction sequence to adjacent deep foundation pit supported by pulling anchor supporting structure. On the basis of actual engineering, this part analyzed the impact of different construction sequence to the support construction and the deformation of slope by using FLAC3 D analysis software, thus optimizing the construction sequence of adjacent deep foundation pit supported by pulling anchor using the way of comparing and analyzing the calculated results.(4)This part used above optimized construction sequence conclusions to guide the actual construction of the actual adjacent deep foundation pit project to verify the rationality and effectiveness of optimization of construction sequence and feasibility of pulling anchor supporting structure through the long-term monitoring in the field and the analysis of the monitoring results.