Abstract: The main bridge of Yingwuzhou Yangtze River bridge is a three-towers and four-spans suspension bridge, for which north anchorage adopted circular caisson. A diaphragm wall was built surround the caisson before the caisson construction. According to the construction condition and the effect of caisson sinking to adjacent buildings, three dimensional calculation modes were established by MIDAS-GTS combined filed monitor data. It was mainly discussed the displacements agreement between calculation values and filed monitor data through some key points, and analyzed the effect of caisson sinking to diaphragm wall. It provided guidance to practice construction in order to predict the effect of follow conditions to adjacent buildings and the Yangtze River levee. The results show that: simulation results agree well with in-situ measurement; the errors are mostly among 5%-30%; and the adverse effects of construction can be effectively avoided to the adjacent buildings and levee; the deformation of diaphragm wall increases with the increase of sinking length; but the effect is more and more small. The calculation model will provide references in control of caisson sinking.

Key words: anchorage caisson, diaphragm wall, settlement, deformation, finite elements