单排与双排挤扩支盘桩支护特性试验

Experimental on squeezed pan piles in single and double rows under loading for protecting foundation excavation

采用室内试验和数值分析相互验证的方法,对单排挤扩桩和悬臂直桩基坑支护的桩顶位移和受力特征进行了研究,进而对基坑双排挤扩桩支护特性进行了分析.土工模型试验和数值模拟试验表明,与悬臂直桩相比,挤扩桩支护桩顶位移小,支盘提供的抗倾覆力矩有效改善了挤扩桩的工作性状;与单排挤扩桩相比,双排挤扩桩基坑支护结构刚度大,在桩身内力分配以及控制基坑变形等方面有较大的技术优势,可降低风险.

The displacement characteristic in the top of the cantilever piles and the squeezed branch piles, and the axial force and the distribution of bending moment of these single row piles for protecting foundation excavation were analysed by model test and numerical simulation individually, and that were studied for the double rows squeezed branch piles also. The results show that the displacement in top of the squeezed branch pile is reduced, the multiple bendind moments are distributed more evenly, and the maximum bending moment is decreased compared with the cantilever piles. It is concluded that the double rows squeezed branch piles have many siginifieant advantages, including displacement, structure stiffness, axial force and bending moment comparing with the single row ones, and little risk.