The Key Techniques Of Steel Cofferdams In Deep Water Foundations Construction

his paper was financially supported by the program of Changxiang expressway two-typetechnology demonstration engineering of resource economization and environmentconservation. This paper based on the number 58 and 59 pile caps of CHANG-XIANGhighway XIANG-JIANG bridge. Main completed work and achievements are as follows:(1) Outline the structure of the steel cofferdam form and characteristics, analyzed thesteel cofferdams of the main causes of the accident.(2) The comparison and analysis of the concrete filled steel tube concrete and steel andbottom sealing between the bonding between the cylinder stress difference, proposed thereduction coefficient value, will existing steel tube concrete bonding strength is applied tothe design of the steel cofferdam, get a more accurate the back cover concrete and steeltube of the bond between the stress, and use the value of ANSYS simulation get basicallythe same.(3) Based on the construction site of the characteristics and the second get the adhesiveof the stress value, to optimize the back cover concrete thickness. With economic results asoptimal objective function and the back cover concrete thickness and heavy pressure asdesign variables, in the most unfavorable conditions bottom sealing the stability of thestrength of concrete and cofferdam requirements as the constraint condition, finally usingMATLAB algorithm. After the optimization of the back cover concrete thickness is theoriginal design value by 17%.(4) Using the finite element optimization technique, overcome the third point numericaloptimization of strength control factors only simplified calculation by faults, for bottomsealing concrete finite element optimization, get on a finite element analysis methods forthe optimization results.(5) Establish the xiangjiang river bridge, big bridge xiangjiang river double-wall steelcofferdams of the finite element model, analyzed the most unfavorable conditions in thewhole construction components under the stress and deformation of the value, the resultsshow that the overall structure of steel box stiffness, the strength of the components can bemeet the requirements for steel cofferdam construction provides technical guidance.(6) Discusses the distance and wall thickness truss structure parameters on cofferdamoverall stress influence, to get the conclusion.This number of 58 and 59 main piers pile caps is already in October 2010 afterconstruction, the research results to ensure the smooth progress of the project, accord with two-type technology demonstration engineering of resource economization andenvironment conservation, and good effects were obtained.