This study investigates the possible use of shear wave velocity to evaluate the in-situ state of hydraulic sand fills. Both laboratory and field determined shear wave velocity results were investigated and correlationships between shear wave velocity, void ratio, and confining stress of the marine sands were developed. Extensive measurements of shear wave velocity in triaxial specimens were conducted on six marine sands obtained from various reclamation sites by the use of bender elements technique. In-situ shear wave velocity profiles were also determined by SASW and SCPT technique in a number of land reclamation sites in Hong Kong. Cone tip resistances at different confining stress levels were also measured in large size Calibration Chamber Test for the verification of shear wave velo...[ Read more ]

This study investigates the possible use of shear wave velocity to evaluate the in-situ state of hydraulic sand fills. Both laboratory and field determined shear wave velocity results were investigated and correlationships between shear wave velocity, void ratio, and confining stress of the marine sands were developed. Extensive measurements of shear wave velocity in triaxial specimens were conducted on six marine sands obtained from various reclamation sites by the use of bender elements technique. In-situ shear wave velocity profiles were also determined by SASW and SCPT technique in a number of land reclamation sites in Hong Kong. Cone tip resistances at different confining stress levels were also measured in large size Calibration Chamber Test for the verification of shear wave velocity results.

Several set of non-linear correlation between shear wave velocity, void ratio and confining stress were developed for six marine sands. The presence of water, the specimen preparation method and particularly the stress anisotropy were found to have significant effect on the shear wave velocity. Empirical correlation between normalized cone tip resistance and void ratio was also established. The two sets of correlation were compared and found to be very consistent with each other. Extensive large strain triaxial tests were conducted to establish the steady state line of the six marine sands. With the establishment of modified steady-state line in a e-log(p'/p_a)^alpha space, the state parameter ([Greek capital letter psi]) could be used to mark the contractive and dilative boundary of the marine sands at large strain.

Combined the relationships between shear wave velocity and steady state concept, a non-linear correlation was developed to evaluate the in-situ state of hydraulic sand fills. The reliability and applicability of the proposed correlation for the evaluation of the in-situ state of hydraulic sand fills was discussed. Future research works and possible development of quality control guideline of hydraulic sand fills are also suggested.