Drainage and reinforcement of soft clay tank foundation by sand columns

A series of centrifuge model tests, at acceleration levels of 105 g, is rep orted, in which loosely placed vertical sand columns and densified sand col umns have been used to improve the performance of oil storage tank foundati ons. A simulated rank of 34 m diameter, with a flexible base, has been subj ected to incremental fluid loadings typically to 160 kPa, with foundation d rainage permitted. Model preparation included the installation of as many a s 572 sand columns in a single foundation. Comparison is made between the e xperimental results and the analysis of Priebe, which indicates that that a nalysis will overestimate the improvements if three-dimensional considerati ons are not taken into account, Comments are also included as to the extent to which model column formation may be deficient.