为深入探讨黏性土中静压开闭口管桩贯入机制,结合颗粒流数值模拟软件在处理大变形、非线性等问题的优势,考虑到接触粘结模型对模拟黏性土的优越性,建立了黏性土中静压开闭口管桩的离散元数值模型,实现了静压桩的连续贯入过程。探讨了压桩力、桩端阻力、桩侧摩阻力随贯入深度的分布特征,对比分析了静压开闭口管桩桩周土体的运动规律。试验结果表明：压桩力大小与桩径有关,桩径越大压桩力越大；桩外侧摩阻力随贯入深度的增加逐渐发挥,且存在明显得退化效应,开口管桩内侧摩阻力变化范围为50~100 mm,土塞高度约为3.5D；将数值模拟结果与室内试验结果对比分析,结果相吻合。研究成果可为开闭口静压桩贯入机制的研究提供借鉴。

To investigate the penetration mechanism of jacking opened and closed pipe pile in the clayey soil, combined with particle flow numerical simulation software in dealing with the advantage of the large deformation and nonlinear problem, considering the contact adhesive model to simulate the superiority of clayey soil and clayey soil is established in the static pressure open mouths discrete element numerical model of pipe pile, realizes the continuous penetration process of static pressure pile. The distribution characteristics of jacking force, pile end resistance and pile side friction resistance along with penetration depth are discussed. The movement law of soil around the static pressure open closed pipe pile is compared and analyzed. The test results show that the size of the jacking force is related to the pile diameter, the larger the pile diameter, the greater the jacking force. The lateral friction of the pile is gradually exerted with the increase of penetration depth, and there is an obvious degradation effect. The variation range of the lateral friction of the open pipe pile is 50~ 100mm, and the soil plug height is about 3.5d. The numerical simulation results are compared with the laboratory test results, and the results are consistent. The research results can provide reference for the study of the penetration mechanism of opened and closed jacked pile.

TU473.11

国家自然科学基金项目（面上项目，重点项目，重大项目）