Research On Bearing Characteristics Of Pile On Hillside Under Combined Load

In recent years, with the improvement of the country's infrastructure, in many practical engineering, due to geographical constraints, many pile foundation had provided on the slopes. Such groups are in a pile composite stress state, on the one hand the upper part of the body structure to withstand vertical load, on the other hand also bear more significant lateral loads. Instantaneous horizontal forces unforeseeable earthquake generated under normal use state such as vehicle braking force. Wind, waves, the huge influx of many bridge pile foundation project will generate forces and moments in the horizontal direction; and when the high-rise buildings, bridges, offshore oil drilling platforms and deep excavation and other works pile design of these norms loads can not be ignored. For the study of composite pile foundation bearing characteristics proposed on the slopes by the horizontal and vertical pile bearing characteristics of the joint action research pile loads. Research and experimental analysis of the current in the field of construction on slopes loaded piles theories are very small. To improve the theoretical and experimental research on the slope of the pile, and the pile-type large-scale promotion application under that condition, the article indoor scale model tests and numerical simulation based on ABAQUS finite element analysis of complex withstand load bearing characteristics of pile on the slopes conducted a more comprehensive discussion and analysis, the main contents are:(1) The use of indoor scale model experimental study, done on the slopes in the interior pile by vertical static load, its bearing characteristics were studied and analyzed, based on the use of scale model tests on large general-purpose finite ABAQUS element software for scale model test numerical simulation analysis and numerical analysis and scale model test results were analyzed, obtained under vertical loading Q-S curve, stress distribution curve and pile side resistance curve.(2) The use of horizontal cyclic loading method calm water on the slope pile load test, compared to the next level loads Numerical analysis and experimental results of Q-S curve, determine the effectiveness of the model parameters on the basis of relying on the pile ABAQUS level test for 1 / 2 3D simulation model to analyze the work of multiple traits pile lateral displacement, bending moment, soil deformation law and the like. The results showed that: when the horizontal load increases, the top of the pile horizontal displacement also increases, but in the pre-load, vertical load due to the role of a small pile sway; horizontal load applied at progressively lower Since earth pressure soil test piles around the moment there are both positive and negative results, to a certain depth will be reversed the moment, and the reduced bending moment along the first increase in depth from top to bottom, and finally It tends to zero, highlighting the characteristics of the flexible pile.(3) In the pre-test and numerical simulation parameters were accumulated pile bearing capacity study on the slopes, pile studies rely on its slopes 1/2 model simulation of vertical and horizontal bearing characteristics. Analysis of Pile different positions of axial force, lateral friction distribution, load-displacement variation between the pile and soil displacement contour analysis the following results:1) When only vertical loads located in the middle of the slope of the pile top level P2 pile lateral, followed by the slope at the bottom of the pile P1, the horizontal displacement of the pile is the smallest slope at the top of the pile P3, when the vertical load remains varying, with the horizontal load increases, the horizontal displacement of the pile also will be larger. When the vertical load is constant, with the depth increases, the earth pressure value was "S" type change.2) Under the vertical loads, and when the horizontal load test pile gage position is the same, the point moment P1> P2> P3. Bending moment showed a decrease with depth from top to bottom after the first increase, and finally to zero in E1 at the impact bending moment mainly at a distance of 3/7 at the top of the pile.3) The maximum skin friction does not appear on top of the pile, P1 appeared in piles at the D1-E1, P2 appear in the pile at the C1-D1, P3 pile appears at the B1-C1. When the horizontal load is the same, the side P1, P2, P3 three test piles at the same position in the frictional resistance strain gages value P1> P2> P3.4) Under the vertical loads, soil modulus of elasticity of the pile when the settlement was about 10 MPa pile 40 MPa when the amount of the settlement three times. Under horizontal loads, soil modulus of elasticity of a small amount of lateral pile pile lateral displacement when compared with the amount of 40 MPa 10MPa time, the amount of lateral pile pile depends mainly on the soil conditions of the pile, when under soil conditions better circumstances amount of lateral pile of small, lateral large pile of soil conditions are poor.5) In the vertical loads on slip surface of soil slope from its base at the corner of occurrence, it is an arc extending to the top of the ramp. By soil tests and numerical simulation comprehensive comparative analysis of results: in the middle of the slope of the test pile helps resist sliding soil deformation, pile design is the most reasonable position.