Laboratory test of vacuum preloading and vacuum combined surcharge preloading

Four kinds of laboratory experiments, those are vacuum preloading, surcharge preloading, vacuum combined surcharge preloading and each direction equal loading, were made to study the consolidation character of soil. The result shows that the deformation and improvement of soil of vacuum preloading is more close to that of each direction equal loading. The vertical deformation of vacuum preloading sample is smaller than that of surcharge preloading; and the improvement degree of soil under vacuum preloading is better than that under surcharge preloading. The vertical deformation of vacuum combined surcharge preloading sample is larger than that of vacuum preloading; and the improvement degree of soil of vacuum combined surcharge preloading is better than that of surcharge preloading. As a whole, the vacuum combined surcharge preloading is most effective to improve the soft soil.