Abstract: Combined with the actual project, the effect of ultra-soft foundation reinforced by vacuum combined with water bag preloading method of sand free cushion was studied by the tests. The experiment results show that the proposed method can effectively improve the bearing capacity of foundation. Compared with the conventional vacuum preloading method, the reinforcement effect of the proposed method is better, and it can increase the thickness of the hard shell layer and the effective reinforcement depth of the soil. The vacuum film surface overlying water preloading method was compared and analyzed, and its defects and failure especially in the case of “cyclic water” were discussed.

Key words: geotechnical engineering, vacuum preloading, water bag preloading, the bearing capacity of foundation;overlying water preloading

摘要： 结合实际工程，通过试验研究了无砂垫层真空联合水袋预压法加固超软地基的效果，试验结果表明该方法能够有效提高地基承载力，跟常规的真空 预压法比较，加固效果更好，能够增大硬壳层的厚度和土体的有效加固深度；对真空膜面覆水预压法进行了比较、分析，讨论了真空膜面覆水预压法存在 的缺陷，特别是在产生“循环水”的情况下该方法的失效性。

关键词: 岩土工程, 真空预压, 水袋预压, 地基承载力, 覆水预压