Experiment And Numerical Simulation Of P-y Curves Method For Laterally Loaded Pile Near A Slop

The analysis of bearing characteristics for laterally loaded pile is one of the important contents of pile foundation calculation.The previous study of the load-bearing pile is mostly aimed at pile in horizontal ground.And with the rapid development of infrastructure construction in the western mountainous areas of our country,in order to meet the horizontal and vertical linearity and to protect the natural environments,a large number of piles are built near the slope.Compared with the pile in horizontal ground,the capacity of the pile near the slope carring horizontal load is weakened due to the lack of soil of the side of the slope.Therefore,the load-bearing mechanisms of the pile in sloping ground and horizontal ground are different,and it has become an urgent problem to be solved in the design and calculation of pile that how to consider the influence of the slope on the horizontal bearing capacity of the pile.In order to solve the problem,the model test on lateral static and numerical simulation are carried out for single pile.The static bearing capacity and failure mode of the single pile in sloping ground are discussed deeply.Finally,the new p-y criteria for satic loading of the pile in sloping ground are proposed,and the factors affecting the bearing capacity of the pile in sloping ground are discussed.The speific work is as follows:Firstly,in order to explore the horizontal bearing characteristics of single pile in sloping ground and horizontal ground,the model test on lateral static loading is carried ourt for single pile,and the differences of load-displacement curves of pile head,bending moment along the pile and p-y curves are analyzed.The results show that when the load of pile head reachs 600N,compared with the pile in horizontal ground,the displacement of pile top increases sharply under the conditon of the load increasing slightly.The bending moment of pile in sloping ground is larger than that in horizontal ground in the shallow,and the depth of bending moment being zero is deeper.Finally,the p-y curves of the depth being 2D,4D and 6D were compared.When the displacement of p-y curves are the same,the resistance of soil in the slope is signigicantly smaller than that in horizontal ground.The results are acquired from the above phenomenon that the capacity of the soil near pile to resist the deformation of pile is weakened compared with that in horizontal ground.Secondly,in order to consider the reduction effect of soil to resisit the deformation of pile near the slope,the calculation models of horizontal load-bearing pile under different slope angles are established based on ABAQUS numerical analysis software.The p-y curves at different depths of single pile near different slopes are obtained,and the key parameters including initial stiffness and ultimate resistance are analyzed.The results show that the reduction of initial stiffness and ultimate resistance decrease with the increase of depth,and the phenomenon of reduction can be negligible after reaching a critical depth associated with the slope angle.Based on that and other researcher's achievements,the formulas considering the slope effect of the initial stiffness ki and the ultimate resistance pu are proposed.And the p-y curves of laterally loaded pile under the slope is obtained.Thirdly,According to the basic theory of finite difference method,the pile is regarded as elastic foundaton beam and the soil is regarded as elastic deformation.The soil around pile and the pile are dibided into several micro elements,and the interaction between the pile and the soil is replaced by a non-linear spring.Finally,the finite defference formula of the internal force and displacement of the pile under the slope is obtained.According the iterative principle,the Matlab caculation program is implemented using the modified p-y curves in this paper.To validate the proposed p-y curves and the Matlab caculation program,two well documented lateral load tests and the model test of the paper are analyzed.The results show that the calculation error of the method is controlled within 15%,The method proposed in this paper can be used to predict the horizontal bearing capacity of the pile and can be used as reference for the design of horizontal loaded piles under the slope.