The Study On Horizontal Force Parameters M-value Of Pile On The Composite Pile Foundation Of Gravel Soil And Bedrock

There is a lot of hydropower resources in the West, but the power load is mainly concentrated in the eastern and southern regions. So, the power must be transferred from the rich areas to the high load area to support the energy consumption in the development of economic construction.In the process of power transmission, safe and effective design of transmission tower is very important. Because of the steep topography and complex geological conditions, it is very important to choose a reasonable parameters of foundation during the tower design.At present, m method is usually used to calculate the horizontal load in the design of pile foundation.In the m method, the difficulty and the key point is how to determine the proportional coefficient “m-value” of the foundation’s horizontal resistance coefficient.Based on the practical pile foundation of the selected power transmission line, selecting actual topography and soil type that the transmission lines usually crossed and referencing to the relevant norms, this paper uses physical simulation and numerical simulation to research the variation of pile displacement,pile’s bending moment, soil pressure and the proportional coefficient “m-value” of foundation’s horizontal resistance coefficient.The following are the main cognition and conclusions:(1) The horizontal load lead to the pile’s horizontal displacement, and while the forces transferred to the soil, the compression deformation from the pile will lead to the rupture in the soil around the pile.Besides, from the front of the pile to the post of the pile, the angle between the fracture and horizontal force is increasing.(2) While the horizontal load increased, the slope of the horizontal load and load point displacement curve is increasing. That is, with the increase of horizontal load, the change of pile body displacement is gradually increasing, especially in the later stage of loading.(3) The bending moment of the piles are located on one side of the horizontal load point.With the increase of depth, the bending moment increased first and then decreased.The moment of the pile gradually increased with the increase of horizontal load, but in the later loading the maximum bending moment point have a slightly downward trend.(4) Under horizontal loads the pile rotate around an axis. Above the axis there is resistance force before the pile while below the axis there is resistance force behind the pile.At the same time, the maximum variation of earth pressure is in the depth of 2(d+1).(5) With the increase of the horizontal displacement, the m-value changes greatly, especially in the small displacement the m-value decreases rapidly. With the increase of horizontal load, m-value decreased as hyperbolic.(6) Under the same horizontal load, m-value increased with slope, pile length, pile width and rock socketed depth; and decreased with the decrease of loading position.(7) By using the professional data statistical and analysis software to conducting multiple linear regression analysis, and get the equation between m-value and gravel soil thickness, socketed depth, pile width, slope, loading position.