悬臂式管桩在基坑支护工程中的应用研究

Application of Cantilever Pipe Piles in Foundation Pits Engineering

基于土拱效应及土体M-C屈服准则,建立了桩间土拱计算模型,并得到了悬臂段桩身土反力计算公式;考虑桩身挤土效应及深度效应,利用Vesic圆孔扩张理论,推导出挤土管桩水平承载力与水平位移之间的关系式;在此基础上,利用力和弯矩平衡条件,建立了悬臂式管桩支护结构设计方法。为了验证理论公式的可行性,将计算结果、现场实测结果及朗肯土压力计算结果进行对比分析,结果表明本文计算结果与实测结果桩侧土反力相差较小,且变化趋势基本一致,并且其计算精度相对经典土压力理论得到较大的提高,验证了理论方法的可行性。

Based on soil arching effect and Mohr-Coulomb yield criterion, a calculation model of soil arching between piles was built. The calculation formula for soil resistance on cantilever pipe pile was obtained. Considering the pile soil compaction effect and depth effect and by means of Vesic cavity expansion theory, the relationship between horizontal bearing behaviors and horizontal displacement was derived. And using the force and moment equilibrium conditions, the design technique for supporting structure of cantilever pipe piles was established. The calculation results of the test, the measured results and Rankine soil pressure results were compared and analyzed to verify the feasibility of the theory formula. The research results indicated that there was a small gap between the proposed calculation results and the measured results and the variation tendency of soil resistance around pipe pile was consistent. Moreover, the computational accuracy of the proposed method was remarkably improved when comparing with Rankine earth theory.