摘要:
针对某储煤仓沉降较大的现象,通过分析产品仓在结构施工、初步储煤、局部空仓 3 个不同阶段的基础沉降变化规律,给出了造成该构筑物基础沉降和整体倾斜的原因,即桩端持力层较差、结构加载不当、水泥土搅拌桩施工质量不明 3 个方面的原因。基于变形控制考虑,提出了利用微型桩的单桩竖向极限承载力和适当折减原复合地基承载力的减沉桩基设计理念,减少加固用桩数量 50% 以上。采用二次压浆微型桩满足了储煤仓地基基础对强度和变形的双重要求,同时微型桩桩顶与原承台通过新增承台和插筋的连接保证了上部荷载传递至微型桩上。该工程加固前后的沉降观测对比表明,考虑单桩极限承载力的变形控制设计方法是安全合理可行的。
Abstract:
With regard to the phenomenon of large settlement of a coal storage warehouse, by analyzing its foundation settlement variation rules at three different stages of the structural construction, initial coal storage and local empty warehouse, the causes leading to structural foundation settlement and the overall tilt are given, namely three causes of bad bearing stratum at end of micro-piles, improper service load and poor quality of cement deep mixing piles. Considering settlement control, a design concept of using the ultimate vertical bearing capacity of micro-piles and appropriately reducing the bearing capacity of the original composite foundation, reducing the number of reinforced piles by 50%, is proposed. By using the secondary grouting micro-piles, the dual requirements of coal storage warehouse foundation on strength and deformation are met, while the top micro-piles and the original caps, by adding cap and dowel-bar reinforcement, ensures the load on the upper part being transferred to the micro-piles. The comparison of settlement observation data before and after reinforcement shows that the proposed design method for the settlement control using the ultimate vertical bearing capacity of micro piles is safe, reasonable and practicable.
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