红黏土具有高含水率、高塑性指数的特殊工程性质,广泛分布于云贵高原及周边区域,成为云南省内高速公路、铁路和工业园区等基础设施建设不可避免的地基土类型。由于冲孔挤密强夯“单次冲孔深度大,同时夯孔内掺砾黏性土可形成散体桩复合地基,能有效加固欠固结土层”等优点,常采用冲孔挤密强夯加固欠固结红黏土场地,但目前对冲孔挤密强夯加固欠固结土动力特性的研究较少。笔者基于冲孔挤密强夯室内模型试验,分析了不同填料配比、夯击能级、夯锤角度,夯击次数4个夯击参数对累计夯沉量、土体响应加速度、土压力峰值的影响。结果表明:累计冲孔深度与夯击次数之间采用对数函数对数据进行拟合是合适的,夯击能为10 000 kN·m时的累计冲孔深度比8 000、9 000 kN·m增加10%左右;冲孔过程中能级越高导致的响应加速度越大,高夯击能级和平底夯锤的夯击参数组合有更好的冲孔效率;碎石-土填料在挤密夯击过程中形成更密实的墩体结构,增加碎石填料比例有助于加固地基土,提高其密实度。
Red clay, characterized by high moisture content and a high plasticity index, is widely distributed across the Yunnan Plateau and commonly serves as a predominant foundation soil for infrastructure development. The Punching-compaction dynamic compaction (PCDC) technique, notable for its deep penetration capacity and for forming granular column-composite foundations through gravel-clay mixtures in compaction holes, is widely adopted to reinforce underconsolidated red clay sites. However, its dynamic behavior remains insufficiently studied. Laboratory model tests were conducted to evaluate the effects of filler ratios, compaction energy (8 000~10 000 kN·m), hammer angles, and blow counts on cumulative penetration depth, soil acceleration, and peak pressure. Results revealed that cumulative penetration depth correlates logarithmically with blow counts, with 10 000 kN·m achieving 10% greater penetration than lower energy levels. Higher energy induced stronger vertical/horizontal accelerations, while flat-bottom hammers combined with high energy optimized efficiency. Gravel-soil mixtures enhance column density during densification, with increased gravel content improving soil compactness.
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