冲孔灌注桩抗压承载力检测与加固措施探讨——以莆田某工程为例

Discussion on the Detection of Compressive Bearing Capacity of Punching Cast-in-Place Pile and Its Reinforcement Measures:A Case of a Project in Putian

文章利用钻芯法排查、分析某建筑工程试验桩第一次静载检测承载力不足的原因,结论是对入岩层位产生误判,错将中风化花岗岩残留体当成持力层。摸清地质情况,严格把控成孔、成桩深度和质量,是保证工程安全的基础。综合考虑地质条件、桩型、施工工艺、经济效益等因素后,文章采取利用钻芯孔作为通道对桩端进行高压注浆的方式加固并试验验证。结果表明,利用桩端高压注浆可形成桩端扩大头,增大受力面积,提高持力层土体强度,进而提高桩端承载力及总体抗压承载力,同时为设计提供依据。

The core drilling method is used to investigate and analyze the reasons for the insufficient bearing capacity of the first static load test of a building engineering test pile,which is the misjudgment of the rock entry position and the mistaken assumption of the moderately weathered granite residue as the bearing stratum.The prerequisite to ensure the safety of the project is to find out the geological conditions and to strictly control the depth and quality of hole-forming and pile-forming.After comprehensive consideration of geological conditions,pile type,construction technology,economic benefits and other factors,the pile end is reinforced by high-pressure grouting with core drilling holes as channels and then verified by experiments.The results show that high-pressure grouting at the pile tip can form an enlarged head at the pile tip,increase the stress area,further improve the soil strength of the bearing layer,and then improve the bearing capacity of the pile tip and the overall compressive bearing capacity.Meanwhile,it also provides a basis for design.