砂性土地区超长预制混凝土管桩承载特性试验研究

Experimental study on bearing characteristic of super-long precast pipe pile in sandy soil area

目前有关预制混凝土管桩竖向承载力的计算公式较少,更无一种相对精确的计算方法.结合扬州某砂性土工程场地,通过单桩竖向承载力静载试验,分析了超长预制混凝土管桩的竖向承载特性,同时基于试验数据对比分析了规范公式及文献公式在砂性土地基中计算超长预制混凝土管桩承载力的可靠性.结果表明：在最大试验荷载作用下,8根试桩发生刺入性破坏,2根试桩发生缓变型破坏;超长预制混凝土管桩单桩承载力的确定,按照规范法计算可靠性大于文献法;采用3种公式计算所得的各试桩端阻比在16.15%-21.11%之间,表明该地区超长混凝土管桩为摩擦型桩.

Few formulas can be used for calculating vertical bearing capacity of the precast concrete pipe pile at present, and none of them are relatively accurate. According to the static load test of single piles in a sandy soil field in Yangzhou, the bearing characteristic of super-long concrete precast pipe pile was analyzed. At the same time, based on the test data, we compared and analyzed the reliability of code formula and document formula used for calculating the bearing capacity of super-long precast concrete pipe pile in sandy soil foundation. Results showed that eight test piles had punch-through failure and two test piles had slowly-changed failure under maximum test load. The reliability of determination of bearing capacity of the super-long precast pipe pile by standard method is greater than that obtained by document method in calculation. The ratio of tip resistance of all test piles calculated by three kinds of formulas were between 16. 15 % -21.11%, indicating that the super-long concrete pile was friction pile in that area.