Experimental Study On Engineering Characteristics Of Inclined-straight Double-row Pile Under Lateral Surcharge

When the expressway(railway)is built on the deep soft soil foundation,the horizontal load will occur when the embankment load is transferred to the foot of the slope,and the subgrade may slip and destroy.In order to reduce the adverse effects of this horizontal load,it is proposed to set up inclined-straight double-row pile at the foot of the slope,and to study the influence of the length of inclined-straight double-row piles on the changing position and failure mode of inclined-straight double-row piles when lateral inclined pile length is changed by model test.The results show that:(1)The whole horizontal displacement of single straight pile is in the mode of"translation around the bottom of the pile ",the peak value of the horizontal displacement is at the top of the pile,and the bending moment,the peak value of the axial force and the earth pressure are all in the middle of the pile body.(2)The horizontal displacement,bending moment,axial force and lateral soil pressure of two-row piles are as follows:the horizontal displacement of straight pile appears in the middle of the pile and decreases with the increase of the length of the lateral inclined pile;the moment increases and decreases along the depth of the pile.and all of them are negative showing tension.the inner soil pressure of straight pile increases first and then decreases along the pile body depth.the peak value is located in the middle and lower part of the pile body.the inner soil pressure of straight pile and inclined pile increases first and then decreases with the increase of pile body depth.(3)The failure mechanism of inclined-straight double-row pile is that the inner straight pile is squeezed by embankment load to bear horizontal soil pressure and bending moment,produce horizontal movement and bending,and transfer the load through connecting beam and soil to the outer inclined pile.The test shows that the top of the middle and outer inclined pile of the inner straight pile is prone to bending failure,and the failure of the inclined-straight double row pile has successively,the straight pile is destroyed first,and the inclined pile is destroyed later.(4)In engineering,in order to improve the slip resistance of slope foot,it is suggested to set up iinclined-straight double-row pile,and increase the bending stiffness of the middle and outer inclined pile top of the inner straight pile.