Quick Triaxial Consolidated Drained Test on Gravelly Soil

Gravelly soil, a mixture of clay and gravel, has been widely used as a core material of high earth core rock fill dams. The triaxial consolidated drained (CD) test for gravelly soil is time-consuming, especially for larger scale test samples because of its low permeability caused by the high content of clay. This study presents a quick triaxial consolidated drained (QCD) test, which can greatly accelerate the CD test on gravelly soil. In the QCD test, the traditional cylindrical specimen was modified to a sand-core cylindrical specimen containing a hollow cylindrical specimen, and the sand column filled in the central hollow. As a result, the sand column in the center of the specimen greatly accelerates the water drainage of the specimen, and both the consolidation stage and the shear stage of the test can be finished quickly. Based on gravelly soil, the comparative tests, including CD tests and QCD tests, are performed. It is concluded that the QCD tests can be conducted more rapidly than CD tests, and the test results of QCD tests, for both stress–strain curves and the parameters of the Duncan–Chang model, are basically identical with that of the CD tests. The QCD test can greatly shorten the studying time on gravelly soil, i.e., the core material of earth core rock fill dams, thus speeding up the future design of dams.