Study On Working Behavior Of Inclined Micro-piles Under Lateral Load

The micro-pile has the advantage of convenient operation, high bearing capacity ofsingle pile, and flexible arrangement, it has been broadly applied in lots of constructionprojects, such as landslide control, foundation reinforcement, building heightening, and thereinforcement of embankments and dams. However, the micro-pile design theory is stillimperfect, especially the bearing mechanism problem of lateral load. This essay is todiscuss the behavior of micro-piles under lateral loads, and carry out some relevant researchto improve inclined micro-pile design theory.Based on the finite difference method, the essay is to numerically simulate the loadtransfer law and deformation behavior under different lateral load and different inclinationmicro pile group, and the following conclusions are reached:(1) The maximum lateral displacement of miniature pile group often appears at thepile head, and the contrast gradient of the pile is0°,15°and25°respectively under thesame vertical load. The lateral displacement decreases with increase of pile inclination.When applying different lateral load on the15°model, the pile head of400kN willinduce5.05mm lateral displacement, and the600kN model is13.19mm. Therefore, thelateral displacement of pile rises as the load increases, and the pile body will appear twozero displacement point, the lateral displacement influence depth is at about2~2.5m.(2) The maximum bending moment of micro-pile groups appears in the pile head.Under the same vertical load, the pile bending moment decreased with pile inclinationangle increase. When applying different lateral load on the model of inclination of15°, thepile bending moment increased with the increase of load. There are three zero bendingmoments points, the influence depth of pile bending moment will appear at about3~3.5m.(3) Under the same load, comparing with pile displacement for inclination angle of0°,15°and25°respectively, pile-soil relative lateral displacement of micro pile decreased withincreasing inclination. When adding different lateral load on the inclination of15°, thepile-soil relative displacement increased with the increase of load, and influence depth ofpile-soil relative displacement will be at about4m(4) Due to pile group effect and pile cap effect, the pile lateral displacement and bending moment behaved similar change law. However, the value of lateral displacementand bending moment at the same depths is different, so is the variation of relative lateraldisplacement of pile and soil around pile. The variation of the relative lateral displacementwith buried depth out of3.5m is more complicated than that in3~3.5m.