在粘土和沙土中的模型试验证实了负压对短的空心桩柱（负压桶）抵抗上拨力的有益作用。对于沙土，“负压桶”的上拨阻力与其内部的负压成比例地增加；对于粘土，由于负压可使“负压桶”失稳方式从基土沿桶体轴向的局部失稳过渡向桶体反向承我能力失效的整体剪切失稳，这种过渡会使“负压桶”的上拨阻力加大． Model tests in clay and sand have demonstrated the negative effect of negative pressure on the short hollow pillars (negative pressure barrels) against the drag force. For sand, the drag force of “negative pressure barrel” increases proportionally to the negative pressure inside it; for clay, negative pressure causes the “negative pressure barrel” instability mode to move from base soil along the barrel axis The partial instability transition to the body of the barrel to reverse my ability to failure of the overall shear instability, this transition will make “negative pressure barrel ” on the dial resistance increased.