Force Analysis And Structure Optimization Of Arc Occlusal Pile Supporting Structure In Deep Foundation Pit

As a new technology and new technology,occluding pile support structure has received wide attention and application in deep foundation pit engineering support structure in recent years.Many domestic scholars have also conducted research on its force mechanism and construction technology.A lot of results have been achieved.However,with the gradual deepening of the foundation pit engineering,the more complex and diverse engineering profiles,and higher requirements for the safety and economy of the occluding pile support structure,special-shaped occluding pile support structures have emerged.Compared with the more widely used linear occluding piles,the arc-arranged occluding piles support structure has obvious differences in force,and there is little research on it at present.In this paper,the force analysis and structural optimization of the arc occluding pile structure are carried out,and the calculation and analysis method for the force of the arc occluding pile support structure of deep foundation pits under complex geological conditions is established to provide technical support for the application of large-scale support engineering.Relying on the deep foundation pit project of the arch abutment of the Minjiang super large arch bridge,this paper uses a combination of theoretical research,numerical simulation and field measurement to research and analyze the supporting structure of arc bored occlusal piles.The main research results are as follows:(1)Based on the shell theory,pure arch theory and two-dimensional classical theory,a theoretical calculation model of arc occluding piles is established,and the force and deformation of the arc occluding pile supporting structure are theoretically solved.By comparing the theoretical calculation results with the field measurement results,it can be seen that starting from the shell theory,the arc occlusal pile is equivalent to a thin shell of equal thickness,combined with the corresponding boundary conditions,the displacement value obtained is more consistent with the measured value.(2)Using ABAQUS to simulate each excavation stage of the foundation pit of the arch abutment of the super large arch bridge,the correctness of the model was verified by comparison with the measured value;the overall displacement of the foundation pit,the force and deformation of the arc occluding pile structure and the surrounding ground The analysis of the settlement of the soil and the house shows that the arc-shaped occlusal pile supporting structure has reasonable forces and can effectively control the deformation of the soil.(3)Through the comparative analysis of structural stress and deformation by changing the structural parameters,it is concluded that the amount of inter-piles,the cross-sectional size of the pile,the setting of the tie beam and the position of the reinforced pile have a greater impact on the force and deformation of the structure,and the rigidity of the tie beam The change of φ has little effect on the force and deformation of the structure.Therefore,on the basis of meeting the support strength,appropriate optimization methods can be adopted for the amount of inter-pile occlusion,the crosssectional size of the pile and the position of the reinforced pile.