Soil improvement by surcharge and vacuum preloadings

Preloading is a popular soil improvement technique for soft soils. The most common and oldest form of preloading is the use of a sand fill as mechanical surcharging. In recent years, vacuum preloading has been used successfully in a number of projects. Though the results of different preloading techniques are similar, there are differences in the mechanisms of surcharge and vacuum preloadings. The differences have been recognized qualitatively, but quantitative evaluation of the differences has never been performed. This note presents results from laboratory tests conducted on specimens of a soft clay in order to highlight the quantitative differences between...