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以厦深客运专线韩江特大桥潮安县段桩基选型工程为研究背景,通过室内静载模型试验,对承受竖向荷载时低承台倾斜桩基与竖直桩基的荷载-沉降曲线、桩体荷载分担比等工作特性进行了研究。结果表明:在荷载-沉降曲线特征方面,倾斜桩基较竖直桩基率先呈现非线性变化,承台顶部荷载达到8 kN之前倾斜桩基的沉降量小于竖直桩基的相应值,随上部荷载的增大倾斜桩基的沉降量逐渐大于竖直桩基的相应值;在桩体荷载分担量方面,竖直桩基和倾斜桩基的相应值都随上部荷载增大而逐渐增大;但在桩体荷载分担比方面,与竖直桩基单调增加不同,倾斜桩基呈现出先增大后减小的特征。受桩间距由上到下逐渐增大的影响,倾斜桩基承台下侧桩间土体的随深度遮拦作用逐渐减小,由此引发土体绕桩滑动作用的增强,从而造成中桩与桩间土体承载能力的不同发挥,成为引起2种不同类型桩基承载特性不同的主要原因。
Taking the pile foundation selection project of Chaoan county section of Hanjiang Special Bridge in Xiamen-Shenzhen Passenger Dedicated Railway as the research background, through the indoor static load model test, the load-settlement curve of inclined pile foundation and vertical pile foundation under vertical load , Pile load sharing ratio and other working characteristics were studied. The results show that the slope pile exhibits a nonlinear change with respect to the vertical pile foundation first in the characteristics of load-settlement curve. The settlement of inclined pile foundation is smaller than that of the vertical pile foundation before the top load of the platform reaches 8 kN, The settlement of inclined pile foundation is larger than that of vertical pile foundation with increasing load. The corresponding values of vertical pile foundation and inclined pile foundation increase with the increase of upper pile load. However, in terms of pile load sharing ratio, different from the monotonous increase of vertical pile foundation, the inclined pile foundation firstly increases and then decreases. Due to the influence of pile spacing increasing from top to bottom, the depth of soil between the piles under the pile foundation of inclined pile gradually decreases with the depth, which leads to the enhancement of soil sliding around the pile, The different play of soil bearing capacity between piles has become the main reason causing the different bearing characteristics of two kinds of piles.