Experimental Study On Reasonable Length Ratio Of Front And Back Row Piles Of Double Row Anti-Slide Short Piles

Anti-slip short pile,also called buried anti-slip pile,is developed on the basis of traditional anti-slip pile,which is a pile type with the top elevation of pile lower than the slope surface at a certain depth.Due to the short length of antiskid short pile,the bending moment and shear force are small,and the pile consumables are less,the project cost is low,so it has good application prospect.However,at present,the force characteristics of anti-slip short pile and its damage form are not well understood at home and abroad,and the reasonable length ratio of front and rear piles in double-row pile is less studied,which leads to the application of anti-slip short pile in the support project is limited to some extent,so it is necessary to do further research on it.In this paper,the indoor model test of double-row anti-slide short piles is designed and carried out.Under the action of slope top load,the stress characteristics of anti-slide short piles from the beginning to the failure process and the failure form of piles after loading are studied.With the help of ABAQUS finite element software,a numerical model of the same size as the test is established,and the reasonable length ratio of the front and rear piles is further discussed.The research results of this paper are as follows :(1)Through the double-row anti-slide short pile model test,the deformation of the sliding body can be divided into three stages : the soil compaction stage,the elastic deformation stage of the pile body,and the failure stage of the pile body.There are certain differences in the degree of stress of the pile body in each stage.In the elastic deformation stage of the pile body,the soil pressure and bending moment around the pile increase rapidly with the application of the slope top load.(2)The landslide thrust behind the anti-slide short pile is roughly triangular or trapezoidal distribution,and the resistance of the sliding bed in front of the pile is roughly inverted triangular distribution.The landslide thrust is not completely borne by the pile,and there will still be weak earth pressure in the soil area at the top of the pile.(3)The bending moment of the anti-slide short pile is ’ S ’-shaped distribution,and the bending moment at the pile top,pile bottom and sliding surface is relatively small.Under the influence of internal force,the pile body has undergone slight ’ S ’-shaped bending deformation and rupture.The rupture point is basically located from the peak moment of the pile body to the sliding surface,and the failure mode of the pile is bending shear failure.(4)In the case of the same length of the embedded section,the length of the force section of the front row pile of the double row short pile should be moderately larger than that of the back row pile,so that the internal force distribution of the front and back row piles is balanced.(5)Based on the equilibrium of internal force distribution,the reasonable length ratio of front and rear row piles is greater than 1,and the ratio will be affected by the row spacing,the length ratio of the stress section to the embedded section,the pile length and other factors.