竖向荷载下变刚度群桩变形性状研究
Displacement characteristics of pile groups with varying rigidity under axial load
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摘要: 在试验室进行了一系列变刚度群桩和均布群桩基础的静载荷物理模型试验,并对试验结果进行了分析对比。结果表明,变刚度群桩的位移分布方式是边桩大于中心桩,正好和一般均匀布桩的沉降分布形式相反。其总沉降略有增加,但差异沉降显著减少。变桩长与均布群桩相比,增加中心桩桩长,还能提高桩基的极限承载力和承台下地基土的承载能力,说明均布群桩中边桩的承载能力还有富余。群桩中基桩的侧摩阻力表现与单桩不同,侧摩阻力的发挥是自桩身下部某点向上逐步发挥。桩距越小,这种趋向越明显。Abstract: A series of physical simulation experiments for pile groups with varying rigidity and those with uniformly distributed piles under static axial load were done,and the test results were analyzed and compared.It was indicated that for the displacement distribution type of the pile group with varying rigidity the displacement of the side piles was larger than that of middle piles,this was quite the contrary of uniformly distributed piles.The total settlement increased slightly and differential settlement decreased markedly.Increasing the length of middle pile could increase the bearing capacity both of the pile groups and soils under the pile cap for varying rigidity pile groups,indicating that the bearing capacity of the side piles was latent in uniformly distributed piles.The shaft friction developed along the lower part to the middle of the pile in pile groups,different from that of single pile.The less the pile spacing,the more obvious this trend.