为更加深入研究不同竖向荷载作用下大直径嵌岩灌注桩的承载特性与荷载传递规律,以印尼地区某工程为依托,对3根直径为800 mm的嵌岩灌注桩进行单桩竖向抗压静载试验与桩身应力测试。试验结果表明:3根试桩的Q-s曲线均为缓变型,沉降量均不超过17 mm,回弹率较大,介于54.8%~70.9%之间,残余沉降较小,承载力较高,均满足设计要求。桩身轴力随桩顶荷载的增加逐渐增大,随深度逐渐递减;桩侧摩阻力的发挥具有异步性,随着荷载的增大,桩侧摩阻力逐渐发挥,在嵌岩段桩侧摩阻力最大,但仍未充分发挥;桩端阻力随桩顶荷载的增加近似呈线性增大,在最大荷载作用下,桩端阻力占比约55%,表现出摩擦端承桩的特性。研究结果对国内桩基规范的完善以及当地桩基规范的制订具有较重要的意义。
Abstract
The bearing characteristics and load transfer mechanism of rock-socketed pile of large diameter under different vertical loads were researched via vertical compression static load test and pile stress test on three rock-socketed cast-in-place piles with diameter of 800 mm in a project in Indonesia. Test results show that the Q-s curves of the three test piles changed slowly, with settlement smaller than 17 mm, large rebound rate ranging from 54.8% to 70.9%, and small residual settlement as well as large bearing capacity, all meeting design requirements. The axial force of pile shaft gradually increased with the rising of the load on pile top, and gradually decreased along with depth. The change of side frictional resistance of pile was asynchronous: as load increased, the side frictional resistance gradually developed to the maximum in the rock-socketed segment, which, however, was still not fully utilized. The pile end resistance increased linearly with the increase of load on pile top. Under the maximum load, the pile end resistance ratio accounted for about 55%. The research results are helpful to the improvement of domestic pile foundation specifications and the formulation of local pile foundation specifications.
关键词
嵌岩灌注桩 /
静载试验 /
承载力预测 /
桩侧摩阻力 /
桩端阻力 /
印尼地区
Key words
rock-socketed pile /
static load test /
forecast of bearing capacity /
side frictional resistance of pile /
pile end resistance /
Indonesia area
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基金
国家自然科学基金项目(51708316,51778312,51809146);山东省重点研发计划项目(2017GSF16107,2018GSF117008);山东省博士后创新项目(201903043);山东省高等学校科技计划项目(J16LG02);青岛市博士后应用研究项目(2018101);中国博士后科学基金面上项目(2018M632641)
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