不同地质后注浆钻孔灌注桩承载力试验研究

发布时间：2019-02-16 17:46

【摘要】：为了研究不同地质土层对后注浆钻孔灌注桩的桩端承载力和桩侧摩阻力的影响和作用机理,通过3根桩端后注浆钻孔灌注桩的静载荷试验和内力测试,取得了注浆前后单桩承载力、桩身轴力和桩顶的沉降数据,推算出桩端承载力和各土层的桩侧摩阻力。通过分析荷载-沉降曲线、桩身轴力分布图,探讨了不同桩端土层强度的桩端后注浆对桩端承载力和桩侧摩阻力影响的作用机制,进一步研究不同地质条件钻孔灌注桩后注浆技术的承载力改善性状,分析承载力提高的机理和效果各不相同的原因。对比不同地质条件桩端后注浆对桩端承载力和桩侧摩阻力的影响程度,验证了桩端承载力和桩侧摩阻力在不同桩端土层强度条件下会产生不同的相互作用和影响。试验结果表明:钻孔灌注桩后注浆技术的应用可以有效地提高钻孔灌注桩的单桩承载力,明显地减少桩顶的沉降。不同地质土层的桩端后注浆可以不同程度地提高桩端承载力和桩侧摩阻力,桩端承载力和桩侧摩阻力的提高幅度均与桩端土的力学性质密切相关,粗粒土提高幅度大于细粒土。实际工程中,为充分利用注浆后单桩承载力所能提高的潜力储备,可根据桩端地质条件不同,合理调整端阻力、侧阻力增强系数取值。
[Abstract]:In order to study the influence and mechanism of different geological soil layers on pile end bearing capacity and pile side friction of post-grouting bored pile, the static load test and internal force test of three post-grouting bored cast-in-place piles are carried out. The bearing capacity of single pile before and after grouting, the axial force of pile body and the settlement data of pile top are obtained, and the bearing capacity of pile end and the pile side friction of each soil layer are calculated. Based on the analysis of load-settlement curve and axial force distribution map of pile body, the mechanism of the influence of post-grouting on pile end bearing capacity and pile side friction is discussed. This paper further studies the improvement of bearing capacity of grouting technology after grouting under different geological conditions, and analyzes the mechanism of bearing capacity increase and the reasons why the effect is different. By comparing the influence of post-grouting on pile end bearing capacity and pile side friction under different geological conditions, it is verified that pile end bearing capacity and pile side friction will have different interaction and influence under different pile end soil strength conditions. The test results show that the application of post-grouting technology can effectively improve the bearing capacity of single bored pile and reduce the settlement of pile top. The pile end bearing capacity and pile side frictional resistance can be increased to some extent by post-grouting of pile end in different geological soil layers. The increasing range of pile end bearing capacity and pile side friction is closely related to the mechanical properties of pile end soil, and the increase of coarse grained soil is larger than that of fine grained soil. In actual engineering, in order to make full use of the potential reserve of the bearing capacity of single pile after grouting, the end resistance can be adjusted reasonably and the side resistance enhancement coefficient can be selected according to the different geological conditions of the pile end.
【作者单位】：莆田学院土木工程学院;福建船政交通职业学院;
【基金】：福建省教育厅科技项目(JA15451)
【分类号】：U445.551

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