上拔荷载作用下挤扩支盘桩试验与荷载传递机理的分析

Experimental Study of Loading Transfer Behavior for Squeezed Branch Piles under Pulling Loading

支盘桩是近年来新应用的一种桩型,它相对于等截面桩而言具有较高的抗拔承载力和较小的上拔位移,具有良好的经济和社会效益,但是它作为一种新技术在理论研究上尚不够成熟。本文在已有的挤扩支盘桩研究成果的基础上,通过抗拔桩静载荷试验对上拔荷载作用下挤扩支盘桩的荷载传递性状进行了分析。试验结果表明:随着荷载的增加,由上往下各承力盘先后发挥其端承作用,各承力盘下端一定范围内侧摩阻力不能发挥出来。侧摩阻力的发挥也存在时间效应,自上而下逐渐发挥作用。

The squeezed branch pile is a new type of piles emerged recently.Compared to the uniform pile,it has higher antipulling bearing capacity and smaller deformation.It is more economical also.However,as a newly introduced technology,the theory of this type of piles has not fully developed.Based on in situ pulling load tests,the loading transferring mechanism of the squeezed branch pile is discussed,and some analysis is conducted in this paper.It is found that with the loading increasing,the plates make a full of function from the top to the bottom in turn.In a certain length of the pile under the plates,the skin friction is almost none.Similar to the plates,the skin friction of the pile develops also from the top to the bottom.