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以某实际工程桩为原型,考虑坡度和桩长的影响,根据相似理论设计并完成了竖向荷载作用下斜坡段桥梁基桩室内模型试验,获得了不同坡度及不同桩长下基桩的荷载-位移曲线、桩身轴力与桩侧摩阻力沿深度的分布规律以及基桩极限承载力,据此通过非线性拟合,建立了斜坡桥梁基桩竖向承载折减系数与桩长及坡度直接的关系式。试验研究表明:竖向荷载相同时,桩顶沉降与水平位移均随坡度及桩长的增加而增大,基桩的荷载-位移曲线均无明显拐点,并呈现出因变形过大导致基桩屈曲失稳的破坏模式;斜坡效应对基桩竖向承载的影响约限于8倍桩径深度范围内;与平地桩相比,斜坡桩的桩侧摩阻力更易达到极限值,实际工程设计时应对其进行适当折减;边坡坡度越大、自由段越长,基桩竖向承载力越小。
Taking a practical engineering pile as a prototype and considering the influence of slope and pile length, the model test of the pile foundation of a slope section bridge under vertical load is designed and completed according to the similarity theory. The load of the pile with different grade and pile length is obtained - the displacement curve, the axial distribution of the pile axial force and the friction along the pile side and the ultimate bearing capacity of the foundation piles, and through the nonlinear fitting, the vertical bearing reduction coefficient of the pile foundation of the inclined bridge and the pile length and slope Direct relationship. The experimental results show that when the vertical load is the same, the settlement and the horizontal displacement of the pile top increase with the increase of the slope length and pile length, and there is no obvious inflection point of the load-displacement curve of the pile. Buckling instability failure mode; the effect of slope effect on the vertical load of pile is limited to 8 times the depth of pile diameter; compared with the ground pile, pile side frictional resistance of the pile is easier to reach the limit value, the actual engineering design should deal with Its appropriate reduction; slope slope, the longer the free section, the smaller the vertical bearing capacity of the pile.