有无褥垫层刚-柔性桩复合地基性状对比研究

由于对刚-柔性桩复合地基的桩土共同作用机理认识不深,工程界对这种复合地基是否设置褥垫层有一定的争议。笔者在温州地区开展了两种不同情况下复合地基静荷载试验,并在承压板下不同深度和位置埋设了钢弦式压力盒、钢筋应力计及应变计。试验结果表明:有褥垫层刚-柔性桩复合地基和无褥垫层刚-柔性桩复合地基的荷载-沉降关系、土反力分布、桩身应力分布、荷载传递机理均有较大的区别,有褥垫层刚-柔性桩复合地基的桩土共同作用情况优于无褥垫层刚-柔性桩复合地基。建议工程实践应用中采用有褥垫层刚-柔性桩复合地基。

Comparative study on behavior of composite foundation of rigid-flexible piles with or without cushion

Composite foundation with rigid-flexible piles is a new type of ground treatment. There are disputes on this kind of foundation with or without cushion because pile-soil interaction mechanism of this foundation is not known clearly. Static load tests of this foundation were carried out under different situations in Wenzhou. Earth pressure cells, strain meters and stress meters were embedded beneath the beating plates at different positions. Sensors were monitored in the process of static load test. It was shown that load-settlement, distribution of soil reaction, pile shaft stress distribution, load transfer mechanism of rigid-flexible piles composite foundation with cushion were different from those without cushion. Since the performance of the former was better than that of the latter, composite foundation with cushion was recommended to be applied.