COMPARATIVE EXPERIMENTAL STUDY ON LIQUEFACTION CHARAC TERISTICS OF CARBONATE AND SILICA SANDS

Carbonate sand has the characteristics of irregular particle shape, high porosity and low particle strength, and thus exhibits more complicated liquefaction characteristics than silica sand. Physical property tests, undrained cyclic triaxial tests and light dynamic penetration tests are conducted to study the differences in physical properties, liquefaction resistance and penetration resistance between carbonate sand and silica sand. Carbonate sand is found to have larger void ratio and internal friction angle than silica sand, which is consistent with the characteristics of carbonate sand particles. The liquefaction resistance increases with increasing relative density for both sands, and it is found that under the same relative density, carbonate sand has higher liquefaction resistance than silica sand. The penetration resistance increases with increasing relative density for both sands, and it is also found that under the same relative density, carbonate sand has higher penetration resistance than silica sand. Combining the results of undrained cyclic triaxial tests and light dynamic penetration tests, it can be concluded preliminarily that the current liquefaction evaluation methods based on the empirical data on terrestrial silica sand foundations can be conservative for evaluating the liquefaction susceptibility of carbonate sand foundations.