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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。
In order to study the effect and mechanism of pile-end bearing capacity and pile-side friction resistance of post-grouting cast-in-place bored pile in different geological formations, the static load test and internal force test of three grouting cast- The bearing capacity of the single pile before and after grouting, the axial force of the pile and the settlement data of the top of the pile were obtained, and the bearing capacity of the pile end and the pile-side friction of each soil layer were calculated. By analyzing the load-settlement curve and the axial force distribution of the pile, the mechanism of post-grouting with different pile-end strength on pile-end bearing capacity and pile-side frictional resistance is discussed, The post-grouting technology of grouting piles improves the performance of the bearing capacity, and analyzes the mechanism and effect of different bearing capacity. Contrasting the influence of post-grouting with different geological conditions on pile-end bearing capacity and pile-side frictional resistance, it is verified that pile-end bearing capacity and pile-side frictional resistance will produce different interactions under different pile-end soil strength influences. The test results show that the application of post-injection grouting technology can effectively improve the bearing capacity of single-pored bored piles and obviously reduce the settlement of pile-tops. The pile tip grouting in different geological strata can improve the bearing capacity of pile tip and pile side frictional resistance to varying degrees, and the increase of pile end bearing capacity and pile side frictional resistance are closely related to the mechanical properties of pile-end soil. Soil improvement is greater than fine-grained soil. In practical engineering, in order to make full use of the potential reserves which can be increased by the bearing capacity of the single pile after grouting, the values of the end resistance and the side-resistance enhancement coefficient may be reasonably adjusted according to the different geological conditions at the pile end.