灌注细石混凝土微型桩基础上拔试验研究

Experimental study on uplift bearing capacity of micropiles by concreting method

通过现场真型试验,对灌注细石混凝土微型桩基础抗拔承载机理及其抗拔承载力计算方法进行了研究。试验表明:在本次试验条件下,微型桩单桩抗拔承载力可由桩身自重和桩周侧摩阻力相加组成;由于承台对上拔荷载的重分配,在上拔荷载作用下,角桩承力最大,边桩次之,中桩最小;微型桩群桩抗拔极限承载力可以通过单桩抗拔极限承载力乘以桩数和群桩效应系数计算得到,本次试验条件下,微型桩抗拔群桩效应系数选取0.75进行计算。

The field tests are carried out to study the uplift hearing mechanism and the uplift design method of micropiles by concreting method. The study shows： in this testing condition, the uplift hearing capacity of single pile is composed of the pile weight and the lateral friction ; under uplift load, the bearing load of the angle pile is maximum, the side pile is the second, and the middle pile is the minimum; the limit uplift bearing capacity of pile group could be obtained from the product of the limit bearing capacity of single pile, the pile number and the effect coefficient of the pile group, in the testing condition, the uplift effect coefficient of the pile group is 0.75.