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将单桩视为平面问题,采用二维离散单元法分析了砂土中单桩竖向抗压承载机制。首先利用离散元模拟地基的形成、挖孔灌注桩的成桩过程以及地基土的双轴压缩试验;然后通过离散元模拟单桩竖向抗压静载试验,分析其承载机制。结果表明:随着桩的沉降增大,桩端阻力一直增大,桩侧摩阻力先增大后达到稳定值;单位桩长侧摩阻力从桩顶到桩端呈非线性增长趋势;当荷载达到桩的极限承载力时,桩端发生刺入破坏,导致桩侧与桩端附近土体的转动场梯度、应力场梯度增大,主应力发生大角度旋转。
Taking the single pile as the plane problem, the vertical compression bearing mechanism of single pile in sandy soil is analyzed by two-dimensional discrete element method. Firstly, the formation of foundation, pile-forming process of bored piles and biaxial compression test of foundation soil are simulated by discrete element method. Then, the vertical bearing capacity of single pile under static load is simulated by discrete element method. The results show that with the settlement of the pile increasing, the resistance at the pile end increases and the friction resistance at the pile side first increases and then reaches a steady value. The friction on the long side of the pile increases nonlinearly from the pile top to the pile tip. When the load When the ultimate bearing capacity of the pile is reached, the penetration and failure of the pile tip occur, resulting in the gradient of the rotating field of the soil near the pile side and the pile tip. The gradient of the stress field increases and the principal stress rotates at a large angle.