筋箍长度及刚度对加筋碎石桩复合地基承载力影响分析

针对加筋碎石桩复合地基中桩体性能,通过有限元数值模拟与模型试验对比分析,验证了数值模型的可靠性,进而变换加筋长度,研究分析了复合基础下端承加筋单桩与群桩的极限承载能力和破坏模式。研究结果表明:筋材强度较低时,加筋长度不会对桩体破坏模式产生影响,对极限承载能力提高有限;随着筋材强度不断提高,碎石桩在加筋体以下区域发生剪切破坏,并且随着加筋长度的增加向更深土层发展,基础的极限承载能力线性增长。加筋长度对群桩复合地基不同位置处桩体的破坏模式影响不同。相较于边桩,中心桩在桩身较深位置处发生剪切破坏,筋材需达到较深的长度才发挥约束效果。

Influences of length and strength of geosynthetics on bearing capacity of composite foundation with stone columns

The performance of geosynthetic-encased stone columns in composite foundation is investigated through the finite element numerical simulation that is verified by the published experimental results from model tests, and then the effects of length of geosynthetics on the failure modes and the ultimate bearing capacities of single column and group columns are analyzed. The research results show when the stiffness of the geosynthetics is low, the length of the geosynthetics will not affect the shear failure modes, and the improvement of the ultimate bearing capacity is limited. With the increase of the stiffness of the geosynthetics, the shear failure of the stone column occurs in the area below the geosynthetics-encased body, and the ultimate bearing capacity of the foundation increases linearly with the increase of the length of the geosynthetics to the deeper soil layer. The effects of the length of the geosynthetics on the failure modes of stone column at different positions of composite foundation with pile groups are different. Compared with the side columns, the center columns have shear failure at the deeper position of the stone body, and the geosynthetics needs to reach a deeper length to exert the restraint effects.