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采用室内模型试验及颗粒流数值模拟研究了密实砂中静压桩沉桩过程,对桩周土体宏细观力学响应进行了分析研究。通过模型试验对浅层土体、桩身周围、桩端处土体的不同位移模式进行了比较分析,揭示了桩周不同位置土体的变位规律,并将孔隙变化场与宏观位移场进行相互印证,发现桩端土体位移模式与压密区基本呈圆孔扩张。对桩体贯入过程中的动端阻力、动侧摩阻力的发展规律以及临界深度等问题作了揭示。以室内模型试验为基础,建立了静压桩沉桩颗粒流模型,将数值结果与试验结果对比分析,通过分析土体细观变化模式揭示沉桩过程中宏观响应的内在机理。研究成果对于进一步明确沉桩挤土效应内在机理和沉桩阻力的发展规律都具有意义。
The indoor model test and numerical simulation of particle flow were used to study the pile jacking process of static pressure pile in the dense sand. The macro-micromechanical response of the pile body was analyzed. Through the model test, the different displacement patterns of soil around shallow soil, around the pile and at the pile tip are comparatively analyzed, and the displacement laws of the soil at different positions of the pile are revealed. And the pore change field and the macro-displacement field are carried out Confirming each other, it was found that the displacement mode of pile-end soil and the pressure-tight zone basically showed a round hole expansion. The end-of-pipe resistance, the law of development of frictional resistance and the critical depth of pile penetration are revealed. Based on the indoor model tests, a particle flow model of pile jacked by static pressure piles was established. The numerical results were contrasted with the experimental results. The internal mechanism of macro response in pile sinking was revealed by analyzing the mode of soil microseismic change. The research results are of great significance for further clarifying the intrinsic mechanism of pile driving and squeezing pile resistance and the development of pile driving resistance.