Abstract: How to correctly calculate the sinking resistance of caissons has been a difficult problem in the design of caisson structure. In order to comprehensively study the sinking resistance and distribution law of the caisson, the sinking simulation of the caisson in four different depth conditions is carried out through the centrifuge model test. Side pressure, earth pressure on foot blade incline, earth pressure on tread of foot blade and deformation of the earth surface have been analyzed. The results show that the side pressure increases first and then decreases, and its value and distribution can be simplified by piecewise function. Distribution of earth pressure on foot blade incline is cubic polynomial. With the increase of the depth of the foot blade, the soil pressure of incline and tread significantly increases, and the resistance ratio of incline and tread per unit width remains the same. Sinking of caisson will lead to subsidence of the earth surface outside the caisson, subsidence of the earth surface adjacent to caisson wall inside the caisson, and uplift of the earth surface which has a certain distance away from the caisson. The experimental and analytical results reported in this study can provide reference for theoretical research and engineering design.

Key words: bridge engineering, caisson, centrifuge model test, sinking resistance