大直径现浇薄壁筒桩荷载传递机理现场试验研究

In-situ Research on Load Transfer Mechanism of Thin-wall Tubular Pile

以温州半岛工程为背景,对薄壁筒桩进行现场载荷试验,以研究其荷载传递机理。研究结果表明:薄壁筒桩荷载—沉降曲线属于缓降型曲线,具有较好的承载性能。桩身轴力自上向下逐渐发挥,当桩端持力层较好时,薄壁筒桩表现为端承摩擦型桩;当桩端持力层较差时,薄壁筒桩表现为纯摩擦型桩。桩身上部与下部土层摩阻力异步起作用的主要原因是,随着桩顶荷载的增大,桩土相对位移是从桩身上部到桩身下部逐渐的。

Based on Wenzhou peninsular engineering, in-situ load tests were conducted on thin- wall tubular piles to investigate the load transfer mechanism. Test results indicated that the load-settlement curves represented the properties of slow descent, showing good bearing capacity. The axial force developed from upper to lower. The thin-wall tubular pile worked as end-bearing frictional pile when the bearing course at pile end was good. It worked as pure frictional pile when the bearing course was poor. The outer lateral frictional of upper and lower soils developed asynchronously, resulting that with the loading increase of the pile top, the relative displacement and its gradually developing were from upper to lower.