Shear wave velocity measurement of Bangkok clay under triaxial testing with various stress paths

Abstract

Orientation paths of shear wave velocity for clayey soil subjected to multiple triaxial loading tests are dependent on complicated factors direction of stresses, void ratio, coefficient of earth pressure at rest, etc. However, most suggested the mean effective stress could provide a suitable correlation as well. In the present study, an identify the shear wave velocity under triaxial undrained small loading-unloading test , monotonic triaxial drained compression test , triaxial drained loading-unloading test , triaxial stress control test , drained triaxial extension , and undrained triaxial extension measured using the bender elements was presented. These results are indicated that the vertical stress and horizontal stress were found to be more favorable in only drained conditions while the mean effective stress for entire experimental triaxial testing could clarify the orientation paths of shear wave velocity and elastic shear modulus, especially when shear wave velocity were properly normalized by void ratio function. The shear wave velocity during drained and undrained mode shearing at small strain to large strain levels were almost linear. Based on tests data, straight trend lines from the relationship between the mean effective stress with shear wave velocity and elastic shear modulus could be established. The proposed identification of shear wave velocity and elastic shear modulus with various stress paths could well provide a new empirical expression to evaluate the stiffness Bangkok clay.