考虑灌注桩侧外表面的随机起伏特征,利用蒙特卡罗方法进行随机起伏表面建模,开展了不同起伏高度等条件下的桩—土随机起伏接触面直接剪切试验,分析了法向应力、平均起伏高度等对桩—土随机起伏接触面剪切强度、破坏模式和剪切应力—位移关系的影响。结果表明:原位成桩桩侧外表面的径向起伏符合高斯分布特征,起伏高度主要集中在0~8%桩径范围;随着桩—土随机起伏接触面起伏高度的增大,嵌入桩—土接触面凹陷部位的土颗粒逐渐增多,桩—土接触面剪切黏聚力与内摩擦角开始增大,桩—土随机起伏接触面破坏模式由桩—土接触面滑移剪切破坏逐渐向土体内部剪切破坏发展,桩—土随机起伏接触面的剪切应力—应变曲线逐渐趋向土的剪切应力—应变曲线。
Monte Carlo method is used to establish a random fluctuation surface model by considering the random ups and downs characteristics of the outer surface of the cast-in-place pile. Direct shear tests of the pile-soil random fluctuation surface under different normal stress and fluctuation height are carried out. The effects of normal stress and average fluctuation height on the shear behavior of the cast-in-place pile-soil random fluctuation interface are analyzed, such as shear strength, failure mode, shear stress-displacement relationship, etc. The results show that: Radial fluctuation of the outer side of the cast-in-place pile agrees with the Gaussian distribution, and the fluctuation height is mainly concentrated in the range of 0~8% of the pile diameter. With the increase of the fluctuating height, the number of soil particles embedded in the concave part of the pile-soil interface increases. The failure mode of the pile-soil random fluctuation interface gradually develops from pile-soil interface sliding shear failure to internal shear failure of the soil. The cohesion and internal friction angle of the pile-soil random fluctuation interface also increase, and the shear stress-strain curve of the random fluctuation pile-soil random fluctuation interface gradually approached to the shear stress-strain curve of soil.
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