Abstract
The ground strength parameters (cohesion c and internal friction angle φ) are key factors in the seismic performance assessment of geotechnical works. However, the procedure to determinate the ground strength parameter is dependent on the experience of the engineers, and it is not well documented. In this study, a questionnaire survey to 76 civil engineers in Japan is conducted to reveal their empirical procedure of parameter determination. The result of the questionnaire clarify the considerable variation of determined ground strength parameters which depending on the experience of engineers.
