为研究红粘土上硬下软地层中管桩上浮问题,对3组不同桩径的闭口管桩进行室内沉桩模型试验,分析单桩、群桩上浮量的变化规律和红粘土地层管桩上浮的机理。结果表明:静压单桩的桩身上浮量主要由桩顶卸荷回弹变形引起,桩径越大则回弹变形越大,但单桩上浮量远小于群桩引起的上浮量。沉桩过程中,邻桩上浮量并不随桩的贯入深度的增加而均匀持续增长,管桩压入上部硬塑土层对邻桩上浮的影响大于压入下部可塑土层对邻桩上浮的影响。在红粘土软硬土层交界处一定范围内,桩上浮的增长趋势会出现短暂的休止情况。 In order to study the problem of pipe pile floating in hard clay under red clay, three groups of closed pipe pile with different pile diameters were subjected to indoor pile model test. The variation law of the floating volume of single pile and group pile and the floating rule of red clay pipe pile The mechanism. The results show that the floating of the pile under static pressure is mainly caused by the unloading and rebound deformation of the top of the pile. The larger the pile diameter is, the larger the rebound deformation is. However, the floating capacity of the pile is much smaller than that caused by the pile group. During pile sinking, the buoyancy of the adjacent pile does not increase uniformly with the penetration depth of the pile. The effect of the pipe pile pressing into the upper hard plastic layer on the adjacent pile floating is greater than that of the adjacent pile pushed into the lower plastic layer influences. In the red clay at the junction of hard and soft soil within a certain range, the upward trend of pile floating there will be a brief pause.