预应力管桩在强风化岩中的承载力分析

Analysis of Pre-Stressed Pipe Pile's Bearing Capacity in Strong Weathered Rock

通过统计归纳南京地区雅居乐住宅小区工程71根PHC管桩的实测静载荷试验数据,对结果进行整理分析,依据文章的资料及计算结果:当以强风化岩层为桩端持力层时,由静载荷试验得出的预应力管桩极限承载力均大于规范计算值,文章参照《建筑桩基技术规范》(JGJ94-2008)对于预应力混凝土管桩的计算方法,考虑土塞效应、挤土效应等因素对管桩承载力的影响,对《建筑桩基技术规范》(JGJ94-2008)关于敞口预应力混凝土空心桩的计算公式规范进行了部分修正,并通过工程实例的计算分析,结果显示该公式的计算精度满足工程设计要求,说明修正系数针对南京地区强风化岩层基本是适用和可行的。

Through statistics it summarized the static load test data of 71 PHC piles in project and analyzed the results, the following conclusions can be obtained. When the pile bearing stratum was the weathered rock, the ultimate bearing capacity of PHC piles by the static load test was greater than the calculated values de rived from related specifications. In reference to the calculation of ＂Building Pile Technical Specifications＂ （JGJ942008） for PHC piles, considering the effect of soil plugging and soil compaction on the pile bearing ca pacity, the formula in ＂Building Pile Technical Specifications＂（JGJ942008） was revised partly in this paper, and it was obtained that the accuracy of the formula could meet the needs of the projects. It showed that the correction factor was applicable and feasible for weathered rock area in Nanjing.