Abstract: Bender-extender element test is performed to measure shear wave velocity of dry sand and compression wave velocity of deaerated water. Effects of different boundary constraints on the measurement result of shear wave velocity and compression wave velocity by bender-extender element test are investigated, and the causes of the results are explained. Test results of shear wave velocity are between the shear wave velocity of dry sand and the shear wave velocity of material of boundary constraints. The results of shear wave velocity are indeed affected by the material of constraints, length of constraints and thickness of constraints; but the results of compression wave velocity are less affected by boundary constraints. In tests with different materials of constraints, the results of shear wave velocity are related to the stiffness of the material of constraints. The smaller stiffness of the material, the smaller impact on the test results of shear wave velocity. The correlation of excitation frequency is independent of the boundary constraints and is only relevant to the soil. This study is conducive to obtain accurate test results of bender-extender element.

Key words: dry sand, bender-extender element, boundary constraint, shear wave, compression wave