压力注浆螺旋钢管桩抗拔承载性能试验研究

针对海相软土地区螺旋钢管桩承载力低与腐蚀问题,提出一种新型压力注浆螺旋钢管桩,并设计5根足尺试验桩,进行现场抗拔承载性能试验,研究螺旋叶片直径与排布方式对成桩直径与桩基抗拔承载性能的影响.结果表明,成桩直径与螺旋叶片直径呈正相关,在每节延长段钢管末端设置螺旋叶片利于提高水泥土柱完整性,使成桩直径更为饱满,提高桩基的抗拔承载性能.将试验结果和现行规范抗拔极限承载力计算结果进行对比,计算结果约为实测平均值的94％,在此基础上提出压力注浆螺旋钢管桩抗拔承载力计算参数修正建议,为后续的设计提供参考.

Experimental study on uplift capacity of pressure grouted helical piles

Given the low bearing capacity and corrosion of the helical pile in marine soft soil area, this paper proposes a new type of the pressure grouted helical pile (PGHP), which is designed with five full-scale test piles to carry out the field uplift bearing performance test and study the effect of helix plates diameter and arrangement on the pile diameter and uplift bearing performance of pile foundation. The result shows that the diameter of pile formation is positively correlated with the diameter of helix plates, and setting helix plates at the end of each extension section of steel pipe helps maintain the integrity of the soil-cement column, which makes the diameter of the formed pile fuller and improves the uplift bearing performance of pile foundation. Compared the test results with the calculation of pullout bearing capacity of the current specification, the calculation is about 94% of the average value of the actual measurement, on which the PGHPs pullout bearing capacity calculation parameters are proposed to provide a reference for the subsequent design.