真空预压法加固软基的排水机制研究

Mechanism of drainage in vacuum preloading

针对真空预压中目前理论难以解释的一些现象,进行了砂性土、黏性土的室内刚性膜和柔性膜的真空预压模型试验以及排水通道连续和不连续的砂性土的刚性膜模型试验。通过对试验结果分析,指出真空预压加固软基中,孔隙水汽化成水蒸气和毛细水上升的排水作用都非常微小。除固结排水机制外,溶解气膨胀驱水机制可以产生有实际效果的排水作用,是另外一种重要的排水机制,溶解气膨胀驱水导致加固区地下水位下降并决定水位下降的深度。从理论上论证了溶解气膨胀驱水机制存在的合理性,解释了真空预压工程中遇到的一些现象。

With regard to some phenomena being difficult to explain by the existing theories in vacuum preloading, vacuum preloading model tests on sand and clay with rigid caps and flexible caps were carded out, and those on sand with rigid caps were also performed by use of continuous and discontinuous drainage passages respectively. Based on the analysis of test results, it was put forward that the effect of vaporization and capillarity of void water was very small, and a new important drainage by expansion of solution gas which could drive void water effectively was given in addition to the drainage by consolidation in vacuum preloading. The drainage by expansion of solution gas in vacuum preloading was proved to be in existence theoretically, and some phenomena in practice were explained more reasonably.