EVALUATION OF THE ACTIVE DEPTH OF FOUNDATIONS UNDER ACAISSON BREAKWATER SUBJECTED TO IMPACT WAVES

摘要

The mode of failure of a caisson breakwater subjected to impact waves is characterised by a progressive sliding and tilting movement along the rubble mound foundation (Kim & Takayama 2004). For the sliding evaluation the model of Shimosako & Takahashi (2000) can be used, and the tilting can be approximated using the model by Esteban & Shibayama (2006). This model uses a classic stress-strain soil mechanics approach to determine the vertical displacement at the shoreside of the caisson. However, uncertainties in the active depth of the foundations (the deepest level of the foundations to which there are movements in the gravel) prevent an accurate estimation of the vertical displacement. The present paper shows how the traditional soil mechanics theory developed by Bousinesq appears to be valid to estimate the active depth of foundations in the top region of the rubble mound foundation.