Study On The Adaptability Of M Method For Calculating The Horizontal Bearing Capacity Of Slope Piles

With the rapid development of China's economy and the proposal of the western development strategy,the state's investment in infrastructure construction,especially in the western mountainous areas,is increasing.Slope piles and even steep slope piles are more and more frequently seen in various types of traffic and civil engineering.At present,the m method is the main calculation method in the design of horizontal bearing capacity of bridge pile foundation in engineering,and the bearing capacity of pile is also considered when the foundation is inclined.However,the degree of foundation tilt,the horizontal bearing capacity of pile and the influence of calculation on M value are not very clear.In order to reasonably consider the bearing behavior of horizontal loaded piles on inclined foundation and the value characteristics of M value.based on the previous theoretical research results of slope pile m method,the applicability of model test and three-dimensional finite element analysis m method in the design and calculation of engineering piles is studied and discussed in this paper.The main work is as follows:(1)Based on the previous theory of strain wedge model for calculating horizontal loaded piles in horizontal and inclined foundations,combined with the m-value finite element calculation results of this method,a reduction coefficient is proposed to describe the m-value variation at different inclination angles of foundations.At the same time,the influencing factors and the characteristics of value selection are discussed with engineering examples.(2)The recent model tests of horizontally loaded piles are introduced and the finite element calculation is carried out.In the test,using PVC pipe as model test material,the soil mechanics index around the pile is obtained by triaxial compression test,and the bending moment and displacement of the model pile are obtained by applying different levels of horizontal load to the model pile.Then,the three-dimensional finite element model is established to calculate the experimental process,and the rationality of the model and parameters selection is verified by comparison test and calculation results.(3)Based on the finite element model of model pile,a three-dimensional calculation model of foundation pile under inclined foundation condition is established.The displacement of pile top and the distribution of bending moment and deformation of pile body are obtained by considering the horizontal behavior of pile body under different inclination angles of foundation,and the corresponding M value and its reduction coefficient are calculated accordingly.According to the distribution characteristics of reduction coefficient,the influence factors and sensitivity under different conditions are discussed by comparing the theoretical calculation results of strain wedge,the observed data of actual engineering piles and the results of three-dimensional finite element calculation.