螺旋钢桩抗拔特性的现场试验研究

根据螺旋钢桩现场抗拔试验中61根试验桩的监测数据绘制Q—S曲线，推算各类桩型的平均极限承载力，分析桩长、叶片数量、叶片间距、首层叶片埋深、叶片直径等参数对螺旋钢桩极限抗拔承载力的影响，试验结果表明螺旋钢桩的极限抗拔承载力随桩长和叶片直径而增加，叶片间距和首层叶片的埋深均存在临界点。分别通过慢速加载法和快速拉拔法测试螺旋钢桩桩极限抗拔承载力，快速拉拔法测得的极限承载力平均值约为慢速加载法极限承载力的2．0倍。

Study on Field Test of Pull-out Property of Screw Steel Pile

According to the pull-out test data on 61 pieces of screw steel piles, Q-s curve is drawn to calculate average ultimate bearing capacities of various piles. The ultimate pull-out capacity of screw steel pile is analyzed in aspects of the distance between helices, the depth of first helix, the length of pile, the diameter of helix and the number of helices. The test results show that the ultimate pull-out capacity of screw steel pile becomes higher with increasing of the length of pile and diameter of helix, and the critical points exist for the distance between helices and the depth of first helix. The average ultimate pull-out capacity of screw steel pile measured by quick pull-out test is about 2.0 times the value measured by slow-speed loading test.