A DISCUSSION ON THE MECHANISM OF IMPROVEMENT OF A SANDY GROUND BY CYLINDRICAL CAVITY EXPANSION THOROUGH SOIL-WATER COUPLED ANALYSIS

Abstract

As a countermeasure against possible liquefaction in sandy grounds, a new sand compaction method is developed recently, in which gradual cylindrical cavity expansion of sand is done with least vibration and noise in driving a pile into sand In the present study, the mechanism and some characteristics of the compaction method are investigated by the soil-water coupled elasto-plastic analysis. The numerical results mainly indicate that even the comparatively dense sandy ground is improved not only because most of sand elements near/at the expanded area show hardening with compression below the C. S. L. in p′-q stress space, but also because the sequential operation of expansion followed by pulling the casing pipe makes the frictional resistance between soil and casing to controllable limits.