深厚软土基坑长短桩组合支护体系的简化设计方法与应用

Simplified Design Method and Application of Long-short Pile Combined Support System for Deep Soft Soil Foundation Pit

在深厚软土地质条件下,基坑支护采用长短组合结构不仅可以极大地节约工程造价,也在一定程度上节省了施工工期,但受理论发展水平限制,仍缺少合理的设计方法。该文结合某长短桩组合支护结构基坑实践及监测分析成果,采用不同计算方法对长短组合结构的变形、内力和稳定性进行深入分析,短桩满足变形控制要求,长桩满足稳定性要求,桩配筋按照包络设计,计算结果也偏安全,可以避免支护结构等长度的常规设计。项目实施效果比较良好,可为类似项目提供参考。

Based on the geological condition of deep soft soil,the use of long-short combination structures for foundation pit support can not only greatly save the project cost,but also shorten the construction period to a certain extent.However,due to the limitation of theoretical development,there is still a lack of reasonable design method.Combined with a long-short piles combined support practice and monitoring analysis results,the deformation,internal force and stability of long-short composite structures are deeply analyzed by different calculation methods,short pile satisfies the requirement of deformation control,long pile meets the requirements of stability,while pile reinforcement is defined according to the envelope result.From the safety aspect,the calculation methods comply with strength requirements,which can optimize the pile length better than the traditional equal length design.The implementation effect of the project is relatively good,which can provide a reference for similar projects.