Study on the bottom resistance during sinking stage of super-sized caisson foundation

Abstract Open caisson foundation sinks by overcoming the buoyancy and soil resistance by means of its own gravity and sinking auxiliary measures. Bottom resistance is a dominant variable in the sinking stage of super-sized caisson foundation. The magnitude of bottom resistance is of great importance to the safe sinking of the caisson foundation. Based on the super-sized caisson foundation of the main tower of a long-span bridge, a method is proposed for calculating the bottom resistance on the basis of the field monitoring data of earth pressure on the food blade, the bottom resistance of different zones within the bottom of the caisson foundation is calculated by the proposed method, and the distribution characteristics and variation of the bottom resistance are analyzed. The calculating results of the engineering practice show that in the process of soil sampling from the internal area to the external area within the bottom, the bottom resistance of inner bulkhead and inner partition walls decreases, while the bottom resistance of outer bulkhead and outer partition walls increases. The distribution characteristics and variation of the bottom resistance can actually reflect the global mechanical behavior of caisson foundation, which helps guide the safe sinking of the caisson.