圆形深基坑排桩框架支护结构算法

圆形深基坑工程在我国西南地区渐有出现，在其中的以砂卵石地层为主的地区深基坑支护结构型式多为排桩结合多道圈梁构成的排桩框架结构，但实践中一直没有合适的结构计算方法.针对工程实际的迫切需要，基于结构力学分析方法，提出了确定圆形深基坑排桩框架结构内力和变形的理论计算方法，即按多跨连续梁和弹性地基梁模型分段分析围护桩内力与变形，并考虑桩梁变形协调分析圈梁内力及变形，推导出了围护桩和圈梁的内力及变形理论计算公式.开展了模型试验研究，结果表明，桩顶侧向位移理论值与试验值分布规律整体上具有相似性，说明了理论计算方法具有一定的合理性.最后，给出了一具体实际工程的排桩和圈梁的内力及位移分析结果.

A calculation method of retaining piles with circular beams for round deep foundation excavations

In some areas of Southwest China consisting mainly of sandy cobble strata,circular deep foundation excavation engineering has gradually emerged in recent years.The support structures are almost retaining piles with circular beams connecting their tops and waists.But there has been no suitable calculation method for the structures.Based on structural mechanics analysis method,a calculation method of internal force and deformation for the structure is put forward in the paper.That is to say,according to the multi span continuous beam and elastic foundation beam model,internal force and deformation of a retaining pile segment above and below exca-vation face can be calculated respectively.Meanwhile,based on deformation compatibility relationship between the piles and beams,internal force and deformation of a beam can be analyzed further,and the theoretical calcu-lation formulas are deduced.In order to verify the calculation method,a laboratory model test is conducted.The results show that,experimental distribution of lateral displacement of a pile is similar to theoretical one,which indicates the theoretical calculation method is reasonable.Finally,analysis results of a practical engineering are given in detail.