顶管推进对邻近桩基的影响分析

研究了顶管正面附加推力、掘进机和后续管道与土体之间的摩擦力在邻近桩基上引起的总的附加荷载的分布规律。研究结果表明，附加荷载的变化规律与桩基和掘进机的相对位置密切相关，是一个三维问题；在顶进方向和垂直于管壁方向，随着掘进机开挖面通过前后，附加荷载由压力变为拉力，顶进方向的附加荷载值和影响范围较垂直于管壁方向大；竖直方向的附加荷载较小，靠近管道轴线附近的桩基部位受到的附加荷载方向与两端相反，曲线呈“弓”型分布；随着桩基与管道距离的减小，附加荷载急剧增大。

Analysis of influence of pipe jacking construction on adjacent piles

The distribution regularity of total additive load induced by bulkhead additive thrust, force of friction between shield and soil, and force of friction between follow-up pipes and soil during pipe jacking construction is studied. The analytical results show that, the distribution regularity of additive load is closely related with the relative position of pile and shield; and it is a three-dimensional problem. Toward the pipe jacking direction and perpendicular to the pipe wall, the additive load is changed from pressure to pull force along with the pass of shield excavation face. In addition, the value and influence bound of additive load in pipe jacking direction is bigger than that of perpendicular to the pipe wall. Value of additive load in vertical direction is small. Direction of additive load close to the axes of pipeline is opposite with that of both ends; and the force distribution curve is arch-shaped. The value of additive load is increased rapidly with decrease of distance between pile foundation and pipeline.