区段配筋管桩抗弯性能研究和施工管理——基于预应力支护桩受力特性分析

Research on Bending Resistance of Partial Reinforcement Pipe Pile and Construction Management by the Analysis of Stress Characteristics of Prestressed Retaining Pile

以天津地区80个基坑工程为样本,探究了单支撑排桩和倾斜桩支护体系桩身弯矩沿桩长的分布规律,并进行了管桩抗弯承载力试验。研究结果显示:单支撑排桩和倾斜桩支护体系的桩身最大弯矩位置及不同弯矩区间所占桩身长度比值均会出现在某一特定范围内,其分布形式均为正态分布;倾斜桩最大弯矩点深度和最大弯矩区间与桩长的比值小于单支撑排桩;区段配置非预应力钢筋可以提高桩身抗裂、极限承载和桩身抗弯变形等能力,并明显抑制桩身裂缝的进一步发展,证明了区段复式配筋预应力混凝土管桩可以在减少钢筋用量的前提下满足其在基坑工程中的应用,并可采用锤击法和静压法等工艺进行沉桩施工。

Taking 80 foundation pits projects in Tianjin area as samples,the bending moment distribution laws of single support row pile and inclined pile support systems along the rectangular direction of the piles was investigated in this study,and bending bearing capacity tests were conducted on pipe piles.The research results show that the maximum bending moment position of the pile body and the ratio of different bending moment intervals to the length of the pile body of the single support row pile and inclined pile support system will appear within a specific range,and the distribution forms are all normal distribution;The ratio of the maximum bending moment point depth and maximum bending moment interval to pile length of inclined piles is smaller than that of single support row piles;The configuration of non prestressed steel bars in sections can enhance the ability of pile body to resist cracking,ultimate bearing capacity,and bending deformation,and significantly improve the further development of pile body cracks.This proves that the section partial reinforcement prestressed concrete pipe pile can meet the application of composite reinforced prestressed concrete pipe piles in foundation pit engineering under reducing the amount of steel bars;The pile sinking techniques of hammering and static pressure can be adopted.