旋喷搅拌加劲桩抗拔试验及荷载传递分析

Uplift Tests and Load Transfer Analysis of Jet Mixing Anchor Pile

介绍了高压旋喷搅拌加劲桩与普通锚杆之间的异同及其工程应用情况。总结了江苏省靖江市某基坑工程旋喷搅拌加劲桩抗拔试验过程和抗拔试验加载-卸载曲线。采用双曲线荷载传递函数对单根加劲桩进行了荷载-位移分析;并与试验结果进行了对比。在荷载传递函数的基础上,提出了单根加劲桩周边土体的变形计算公式、土体剪应力的衰减模式;继而分析了单桩的影响范围,给出加劲桩最小间距确定方法来避免群桩效应。

The engineering features of jet mixing anchor pile as well as the difference between it and normal anchor bolt are introduced. The uplift tests of 2 jet mixing anchor piles are presented in detail to obtain the ultimate bearing capacity and load-deformation relationship of the piles. Load-transfer analysis is carried out on the piles with a hyperbolic calculation model. The load transfer method focuses on the interface between pile and soil,with which the non-linear behavior,the bearing capacity and the engineering features of the anchor piles can be fully studied. The calculated load-displacement curves of the piles have close agreement with that of the pullout tests,indicating that the proposed analytical solution is reasonable and feasible in predicting the bearing capacity of the piles. Thus,with this study,the supporting stiffness of the anchor pile can be predicted in the design stage of the foundation pit engineering,which is very important and meaningful in practical engineering. The decay curve of shear stress of soil surrounding the pile is derived with the load-transfer method,through which the minimum transverse space of each two piles can be decided against the pile group effect. Engineers can optimize the length and spacing of group piles through this.