Abstract: The influence mechanism of open caisson sinking in soft soil stratum is complex. The available theoretical research mainly focused on the mechanical characteristics of open caisson for analyzing the sinking process. The kinematic characteristics of open caisson during sinking process are lack of scientific and systematic interpretation. To this end, this paper establishes the mechanical model of open caisson sinking, deduces the kinematic equation of open caisson, and reveals the kinematic characteristics and the influence mechanism of the open caisson during sinking process. The rationality and correctness of the theoretical method is verified based on a practical project. The research results show that the sinking process of open caisson has obvious acceleration sinking stage and deceleration sinking stage. The initial unbalance force before sinking (F1) caused by sinking construction of open caisson is an important factor affecting the sinking characteristics, as well as the primary factor for controlling the sinking movement. Adjusting the parameter b1, which reflects the characteristics of soil layer and open caisson structure, is an effective method to prevent sudden sinking of open caisson.

Key words: open caisson, kinematic characteristics, equation of motion, sinking control