Experimental And Theoretical Study On The Calculation Of Laterally Loaded Piles In Steep Slope

The calculation of internal force and displacement of piles under lateral load is one of the important contents in the design of pile foundation.With the rapid development of highway and railway construction in China western mountain area,in order to meet horizontal and vertical alignments requirements and to protect the natural environment,a large number of pile foundation,have been built in the high steep slope.because of the existence of slope,pile-soil interaction and pile failure mode in slope is different with the situation in the flat ground,the method applied to horizontal laterally loaded piles in ground can not be applied to the pile in slope,or it will lead to large errors.Therefore,proposeing a calculation method of internal force and displacement has become the key to the design of this kind of pile foundation.Therefore,this paper makes a systematically and deeply theoretical and experimental research on this problem,and puts forward a new design method for the laterally loaded pile in slope.In view of the lack of model test data,this paper designs and implements the lateral load Model comparison test of laterally loaded pile in 45° slope and flat ground?During the test,the deformation of the pile,the internal force and the resistance of the pile foundation are measured,and the failure modes of the pile and the surrounding soil are observed.The test results show that the existence of slope leading to the lack of soil in front of the pile and weaken the the ability of surrounding soil to restrain the displacement of the pile under the same load.Consequently the pile in slope has greater horizontal displacement and bending moment,but smaller interaction force between pile and soilis.In addition,The failure mode of the soil in front of pile in slope is tensile fracture.But there is no similar situation in the pile in ground.Based on the observation from tests,the failure mode of the laterally loaded piles in slope is determined.And cuting the conventional stain wedge along the slope surface and remove the section above the slope surface,the strain wedge model is obtained.Combined with the finite element method,the calculation method of the laterally loaded pile in slope is established,then the Matlab program is compiled,and the calculated results are in good agreement with the experimental results.Finally,Abaqus,a finite element software,is used to establish the three-dimen-sional numerical analysis model of slope pile,to study the influence of different slope angle,soil cohesion and internal friction angle on the bearing capacity of laterally loaded piles,The result of multi-factor sensitivity analysis of pile structure in slope is obtained.The result shows that the bearing capacity of the pile increase with the increase of soil strength and the decreases of angle of slope,However,due to the small variation range of the soil internal friction angle,its influence on the bearing capacity of the pile is relatively smaller than the soil cohesion and slope angle.At the same time,it can be seen that the plastic deformation of the soil in the shallow depth will result in the sharply increase of the pile displacement..