The Influence Of Pile End And Side Disturbance On Pile Bearing Capacity And Deformation

The method of pile end and pile side perturbation and tilting correction is to set perturbation holes on one or both sides of pile,and use directional water jet to perturbate soil at the side or end of pile,so as to reduce part of side resistance or end resistance of pile and promote vertical displacement of pile foundation.According to the specific soil conditions,the directional cement slurry jet and other reinforcement methods are adopted to restore the resistance of pile side or pile end.Pile end and pile side perturbation correction is less affected by the type of foundation soil and can also be applied when the surrounding water table is high and the soil quality is poor.To avoid the traditional cut soil water injection correction overmuch,easy out of control shortcomings.There is also no need to dig working Wells,no need for jacking,cutting and other equipment,the method is more economical and cost saving.However,in the process of applying the method of pile end perturbation and inclination correction,the reduction of pile side friction and pile end resistance cannot be determined.If the perturbation wedcens the bearing capacity of the foundation too much,the soil around the pile and at the pile end will form a continuous sliding surface and the foundation stability will be destroyed.Therefore,in order to make this method more safe and controllable,it is necessary to carry out theoretical research and numerical simulation analysis.MD3AS/GTS finite element analysis software was used to establish 3d numerical model.The influence of disturbance depth,disturbance Angle,disturbance position,soil mass around pile,pile end and pile stiffness on single pile bearing capacity and deformation,as well as the influence range of soil mass plastic zone around pile after disturbance are analyzed.The main research contents of this paper are as follows:(1)the influence of the depth,disturbance Angle and position of the perturbed soil around the pile on the bearing capacity and deformation of the pile is analyzed and studied.The results show that the larger the disturbance depth and Angle,the larger the displacement of pile.Under the same conditions,the settlement of the two-side disturbed pile is greater than that of the single-side disturbed pile.With the increase of disturbance depth,the pile penetrates into the soil.The disturbance depth of continuous sliding surface appears in one side disturbance,which is smaller than that in two sides disturbanceModel contrast found that disturbance Angle 60°12 m in bilateral perturbation when single pile settlement is the largest,but the weeks of soil of piles and pile end soil may form a continuous sliding surface.(2)the influence of soil disturbance at the pile end on the bearing capacity and deformation of single pile is analyzed and studied.Under the condition of the same disturbance Angle,the settlement of single pile in the soil at the disturbed pile end is large.However,the plastic zone has a wide range,and if not properly controlled,continuous sliding surface of soil around the pile can easily be formed.(3)the influences of soil modulus around pile,soil modulus at pile end and stiffness of pile body on bearing capacity and deformation of pile are analyzed and studied.The results show that with the same disturbance depth and Angle,the settlement of pile decreases with the increase of soil modulus around pile and soil modulus at pile end.Pile stiffness has little influence on the bearing capacity and deformation of single pile under perturbation,so it is not necessary to consider the influence of pile stiffness.(4)the settlement results simulated by finite element analysis software are compared with the actual settlement data in engineering examples.The results show that the settlement trend is consistent and the data difference is small,indicating that it is feasible to use MIDAS/GTS NX software to establish a three-dimensional numerical model to simulate the correction process of pile end and pile side perturbation method.The analysis and study of the plastic zone around the pile tip can provide certain safety guidance and guarantee for the tilting rectification project using the method of side perturbation of the pile tip.