| At present,with the rapid development of economy and technology,China has made breakthroughs in the field of infrastructure construction.With the frequent occurrence of natural disasters,it is not uncommon for major accidents to cause the instability of pile foundation.Therefore,the bearing characteristics of horizontally loaded piles under scouring conditions have become a hot topic of concern in the field of geotechnical engineering.It is found that the water scouring will lead to the instability of the soil around the pile and the bending deformation of the pile body,which will seriously affect the bearing characteristics of the pile foundation and pose a great threat to the engineering safety.In the actual project,there is a very big hidden danger of the pile deformation,which will cause serious engineering safety problems.This article mainly focuses on the impact of erosion on the bearing characteristics of horizontally loaded piles,and the following conclusions are obtained:(1)The p-y curve model under the overall scouring condition is constructed.Based on the p-y curve method,the finite difference method is used to establish a nonlinear simplified analysis method for the bearing characteristics of horizontal single piles under scouring conditions.The correctness of the simplified analysis method is verified by comparing the corresponding three-dimensional finite element models.The bearing characteristics of horizontal single piles under different scouring depths,load levels and pile diameters are studied.The results show that as the scouring depth increases,the lateral stiffness and horizontal bearing capacity of the horizontally loaded pile gradually decrease;When the horizontal load on the pile top is the same,as the scouring depth increases,the horizontal displacement of the pile top and the maximum bending moment of the pile body gradually increase,and the position where the maximum bending moment of the pile body is located gradually moves downwards.The soil loss around the pile caused by water flow erosion will have a significant impact on the horizontal bearing characteristics of the foundation pile.The theoretical research method in this article can provide a theoretical analysis tool for the design of horizontally loaded piles under erosion conditions.(2)Considering the scouring status of pile foundation,a three-dimensional finite element model of pile group under scouring conditions is established to study the influence of brush depth,load grade and upper load on the horizontal bearing characteristics of pile group.The results indicate that as the depth of erosion increases,the horizontal bearing capacity and lateral bending stiffness of the pile group continue to decrease.Applying loads within the allowable range of vertical loads can effectively reduce the displacement of the pile group;Scouring will increase the displacement and internal force of the front row piles,and the horizontal displacement,bending moment,and shear force of the top of the front row piles after scouring are greater than those of the rear row piles.The greater the depth of scouring,the more significant the difference in internal force and displacement between the front and rear row piles.Scouring causes the reverse bending points of the bending moment and shear force of the pile group to develop downwards,and the reverse bending points of the rear pile are higher than those of the front pile;Scouring will cause the remaining soil around the pile to rebound and heave,causing the pile cap to move upwards and tilt.The greater the depth of scouring,the more obvious the degree of tilt of the pile cap.Through the study of single pile and pile group under different influence factors,this paper has obtained further understanding of the horizontal bearing characteristics of pile foundation under scouring.The research results can lay a foundation for evaluating the safety performance of foundation piles after scouring,and also provide theoretical analysis basis for the design of horizontally loaded piles under scouring. |
