不同后注浆类型下大直径灌注桩承载性能分析

发布时间：2018-06-02 19:30

本文选题：大直径灌注桩 + 桩端后注浆　；参考：《沈阳建筑大学学报(自然科学版)》2017年06期

【摘要】：目的针对黄河中下游冲积地层,研究不同后注浆类型下大直径灌注桩承载性能及其内在机理,为该类地层条件的大直径灌注桩及其后注浆的设计与施工提供参考.方法整理大量现场试桩实测数据,对比分析相同场地条件下桩端后注浆桩与桩端桩侧复式后注浆桩承载变形、荷载传递、桩侧阻力与桩端阻力及水平承载的异同,在此基础上,进行后注浆类型影响机理的探讨.结果两类后注浆大直径灌注桩竖向承载变形性状相近,荷载传递规律基本一致,桩端阻力占承载比例均较小,但复式后注浆桩承载变形性能发挥更为稳定;复式后注浆桩在桩身上部侧阻软化范围较大,其在浅层土中侧阻小于桩端后注浆桩,但在深层土体中,复式后注浆桩桩侧摩阻力极限值普遍大于桩端后注浆桩;桩侧注浆对桩周土体加固作用使得复式后注浆桩水平承载性能明显高于桩端后注浆桩.结论对于该类场地条件的大直径灌注桩,承受竖向荷载时,在确保后注浆施工可靠的前提下,可仅采用桩端后注浆提高其竖向承载力,若承受较大的水平荷载时,增加桩侧注浆可显著提高其水平承载性能.
[Abstract]:Aimed at the alluvial strata in the middle and lower reaches of the Yellow River, the bearing capacity and internal mechanism of large-diameter cast-in-place piles under different types of post-grouting are studied, which provides a reference for the design and construction of large-diameter cast-in-place piles and post-grouting in this kind of formation conditions. Methods A large number of field test pile data were collected and compared with each other under the same site conditions. The load transfer, resistance of pile side and resistance of pile end and horizontal bearing capacity were compared and analyzed, on the basis of which, the deformation and load transfer of post grouting pile and composite post grouting pile were compared and analyzed under the same site condition, and on the basis of this, the difference between pile end resistance and pile end resistance was analyzed. The influence mechanism of post grouting type was discussed. Results two types of post-grouting large-diameter cast-in-place pile have similar vertical bearing deformation characteristics, the law of load transfer is basically the same, the resistance of pile tip is small, but the bearing deformation performance of compound post-grouting pile is more stable. The side resistance of compound post grouting pile is larger than that of post grouting pile in shallow soil, but in deep soil, the limit value of side friction of composite post grouting pile is generally larger than that of post grouting pile. The horizontal bearing capacity of composite post grouting pile is obviously higher than that of post grouting pile due to the reinforcement effect of pile side grouting on soil around pile. Conclusion for large diameter cast-in-place piles with large diameter under the condition of this kind of site, under the premise of ensuring the reliability of post-grouting construction, the vertical bearing capacity can be improved only by post-grouting at the end of the pile, if the pile is subjected to large horizontal loads. The horizontal bearing capacity of pile can be improved significantly by adding pile side grouting.
【作者单位】：郑州大学土木工程学院;郑州大学综合设计研究院有限公司;
【基金】：国家自然科学基金项目(51508522)
【分类号】：TU473.1

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