Development of high precision direct shear apparatus for liquefaction testing

Abstract

A newly developed direct shear apparatus for cyclic tests is, first, introduced. It is shown that liquefaction strength on Toyoura sand obtained using a newly developed direct shear apparatus and test procedure coincides well with that obtained from cyclic triaxial tests. Then, two series of cyclic direct shear tests were carried out on samples of sandy silt, which was excavated by a grab bucket at a construction site in Naruto City, Tokushima Prefecture. Therefore, considerable disturbance was expected. Results were compared with those from a series of cyclic triaxial tests on undisturbed samples by a triple-tube technique at the site. It was found that liquefaction strength from the direct shear tests coincided well with that obtained from cyclic triaxial tests. It is deduced that disturbance of a sample was well cured in the consolidation process, which is one of the advantages of the newly developed apparatus.