Application Of Double Wall Steel Cofferdam Technology In North River Bridge Deep Water Foundations

In recent 30 years,with the economic and technical development of our country,bridges overcrossing great rivers become more and more. To solve the difficult problems for the construction of bridge foundation in deep water. Various research and practice for the construction methods of deep water foundation has gone ahead like wildfire,and has reached great achievement.In consideration of waterproofing,earth standing and scour prevention and so on,the constructions of deep bridge foundation usually use cofferdam to cooperate with. The purpose to construct a cofferdam is to prevent the water and the soil outside the cofferdam to rush into the cofferdam during cofferdam construction and foundation construction. The cofferdam shall be dismantled after the foundation, abutment and pier being constructed above the water level in order not to block the waterway and the stream. Double wall steel cofferdam, as a kind of waterproofing cofferdam widely used for the construction of deep bridge foundation, due to its characteristics of high structural strength and good waterproof performance , has been widely applied in many super large bridge deep water foundation.This thesis first describes the application and current development of deep bridge foundation and double wall steel cofferdam, then introduces the design and construction of double wall steel cofferdam detailedly by combining with construction examples of North River Bridge deep water foundation in the fourth project tender of Foshan to Zhaoqing inter-city rail of Guangdong. Among them, two methods are used in the cofferdam design calculations. One is the traditional manual calculation method, another is the method of 3D modeling calculation of"MIDAS"finite element analysis software by considering the space effect of the structure. And the results of the two methods are compared and analyzed.By comprehensive and detailed analysis of the double wall steel cofferdam, the obtained results can provide the beneficial reference for the similar project implementation.