大直径超长钻孔灌注桩竖向承载力自平衡试验

Self-balancing Test for the Vertical Bearing Capacity of Large Diameter Super-long Bored Piles

以天津站交通枢纽工程为背景,采用自平衡试桩法对大吨位钻孔灌注桩进行静载荷试验,成功并灵活地检测大直径超长钻孔灌注桩的抗压抗拨承载力、桩身上下段的极限侧阻力及极限端阻力。结果表明,该法既节省费用又节约时间,是传统静载试验方法无法做到的。

Self-balancing test was carried out for the static load test of the extra large tonnage cast-in-place bored piles at a traffic hub project of Tianjin Station. Vibrating-string reinforcement stress gauges were adopted to measure the axial forces. According to the field test data of piles, the point resistances and side frictional resistances of soil layers around piles were calculated with pile-soil load transfer behavior revealed. The increase in point and side frictional resistances of piles after cement grouting was also tested.