软土区过大堆载将造成邻近桥梁桩基产生明显偏位，对桥梁安全服役极为不利。结合某堆载致软土区桥墩偏移工程案例，考虑软土侧向变形时效性特征，开发软土固结-蠕变材料模型子程序，建立堆载-桩基-桥墩有限元模型，研究堆载作用下软土区桥墩-承台-桩基结构的时效性偏移特性，揭示桥墩-承台-桩基结构横向偏移机理，并针对现场条件提出有效合理纠偏措施。结果表明：随着堆载时间的延长，桩身响应沿深度分布发生显著变化，且堆载引发的软土时效性横向变形致使作用于桩侧的横向附加压力逐渐增大，但其沿深度的分布范围基本不变，并且主要分布在软弱土层深度范围内；基于桩身截面承载极限弯矩的评估，所研究桥墩各桩基仍处于安全状态，但应注意承台与桩基连接处以及软弱层与硬土层界面处的弯矩；提出的卸载+高压旋喷桩加固纠偏措施可以达到预期纠偏效果。

Excessive loading in soft soils will cause significant displacement of adjacent bridge pile foundations, which is extremely detrimental to the safe service of the bridge. Combined with an actual pier deviation case in soft soil caused by surcharge loads, a material model subroutine considering the time-dependent characteristics of lateral deformation of soft soil was proposed, and a finite element model of surcharge load-pile foundation-bridge pier structure was established to study the time-dependent deviation characteristics of bridge pier-cap-pile foundation structure in soft soil area under surcharge loads and to reveal the lateral-deviation mechanism of the bridge pier-cap-pile foundation structure. In addition, effective and reasonable correction measures were proposed for the site conditions. The results show that with the increase of loading time, the pile response distribution along the depth changed significantly, while the time-dependent lateral deformation of the soft soil caused by the surcharge load caused the lateral additional pressure acting on the pile side to gradually increase, but its distribution range along the depth remained unchanged and was mainly distributed in the depth range of the soft-weak soil layer. Based on the assessment of the ultimate bending moment in the pile sections, the pile foundation studied was still in a safe state, but extra attention should be paid to the bending moment at the location of the connection between the cap and the pile foundation and at the interface between the upper soft layer and the lower harder soil layer. In addition, the proposed corrective measure of unloading+high-pressure rotary pile reinforcement can achieve the expected correction effect.

TU473.1

国家自然科学基金（51878670、51878671）；江西省交通运输厅科技项目（2023H0020）；江西省教育厅科学技术研究项目（GJJ2201509）