透水混凝土桩复合地基工后沉降控制特性研究

Research on Control Characteristics of Post-construction Settlement of Pervious Concrete Pile Composite Foundation

透水混凝土桩(PCP)复合地基新技术具备良好的变形控制潜力。以典型路堤下刚性桩复合地基为工程背景,通过多工况有限元数值模拟,对比研究PCP复合地基的工后沉降控制特性。分析表明,将原复合地基的竖向增强体置换为相同尺寸的PCP后不改变地基总沉降量,且在路面交工时刻即可达到97%的固结度,工后沉降仅为1.6 mm。参数分析表明,PCP复合地基总沉降与桩长、置换率均呈负相关,与路堤堆载高度呈线性正相关;桩长、置换率、堆载速度和堆载高度对PCP复合地基工后沉降影响的敏感性逐次递减。优化的PCP复合地基方案将PCP桩长增加2.0 m,并将路堤堆载速度提升1倍,理论上可将原工况路面交工时间由236 d大幅缩短至34 d。PCP复合地基可为软基地区工程建设缩减工后沉降、提升填筑速率提供新的技术选择。

Pervious concrete pile(PCP)composite foundation technology has good potential for deformation control. Taking the typical rigid pile composite foundation under the embankment as theengineering background, the post-construction settlement control characteristics of PCP compositefoundation are compared and studied through multi condition finite element numerical simulation. Analysisshows that replacing the vertical reinforcement of the original composite foundation with PCP of the samesize does not change the total settlement of the foundation, and the consolidation degree of 97% can beachieved at the moment of road completion, with a post-construction settlement of only 1. 6 mm.Parameter study shows that the total settlement of PCP composite foundation is negatively correlated withpile length and replacement rate, and linearly positively correlated with embankment height. Thesensitivity of pile length, replacement rate, embankment load velocity, and embankment height to thepost-construction settlement of PCP composite foundation decreases sequentially. The optimized PCPcomposite foundation scheme increases the PCP pile length by 2. O m and doubles the embankment loadvelocity, theoretically reducing the original construction completion time from 236 d to 34 d. PCPcomposite foundation can provide a new technical option for reducing post-construction settlement andimproving loading rate in soft foundation areas.