盾构隧道开挖对邻近桩基影响数值分析

经与离心试验结果对比分析,验证了应用数值模拟研究盾构隧道开挖对邻近桩基影响是可靠的。通过采用Mohr-Coulomb弹塑性屈服准则,建立三维有限元数值模型,研究软土地区盾构隧道开挖对邻近桩基的影响规律。数值模拟结果表明,开挖导致群桩中前排桩变形及内力均大于后排桩,且同排桩水平位移、弯矩和轴力沿桩身分布几乎重合;与同位置单桩相比,群桩中各桩水平位移稍大,而沉降则更小;前排桩最大弯矩与同位置单桩相差不大,而后排桩最大弯矩稍大于同位置单桩,前、后排桩最大轴力均大于同位置单桩。

Numerical analysis on influence of shield tunnel excavation to neighboring piles

It was proved by the comparison with the results of centrifuge experiments that the study on the influence due to shield tunnel excavation on neighboring piles is reliable through numerical analysis. By using Mohr-Coulomb yield criterion, a three-dimensional numerical model was established, and the influential principles of tunnel excavation were also studied. According to the numerical simulation results, the deformation and stress of piles in the front row were larger than those of rear row, and the distribution of horizontal displacement, bending moment and axial force of piles in the same row were almost superposed. In contrast to the single pile at the same position, there was a little horizontal displacement but slighter settlement of the pile in groups. The maximum bending moment of piles in the front row was of little difference with the single pile of the same position, while that of the rear row slightly surpassed the single pile, and also, the maximum axial force of piles both in the front and rear rows exceeded the single pile of the same position.