Mechanical Characteristics Analysis And Key Technology Research Of Single Wall Steel Cofferdam In Deep Water Construction

With the advancement of scientific and technological strength,the construction of domestic transportation infrastructure is advancing rapidly,and bridges of deep water,high piers and large spans are becoming more and more common.However,in the construction of bridge foundations in deep water areas and the reinforcement of bridges in old bridges,the construction of a water-blocking cofferdam to provide the dry construction environment has become a common construction mode in the engineering community.However,at present,there are no relevant standards and norms for guiding the design and construction of cofferdams at home and abroad.As a result,in the implementation stage of the project,technicians can only design the cofferdam form that is suitable for the project objectives by virtue of experience and reference to other relevant specifications.Not uniform.In addition,the cofferdam is greatly affected by unfavorable factors such as external loads.These factors may be the main source of safety accidents in the construction of cofferdams in recent years.The construction of the cofferdam is uncertain and complicated.In order to ensure the safety of the cofferdam construction process,the mechanical characteristics analysis and stress monitoring of the structure are carried out to determine the reasonable combination form of the construction load,and the optimization design of the cofferdam structure is far-reaching significanceBased on the bridge pier reinforcement project of an old bridge,according to the hydrogeological conditions of the site,after the comparison and optimization of the scheme,the wateroroof cofferdam form strengthened by the pier body is determined as the large ship assembly plan plus the bottomless rectangular single-wall steel box enclosure.weir.By consulting relevant data,the load and mode of action of the box cofferdam during construction are calculated.Referring to the combination effect method in "bridge gauge" and "construction regulation",the MIDAS/civil is used to establish the box cofferdam model,and the mechanical characteristics of each key construction condition in the cofferdam construction are comprehensively analyzed,and the cofferdam is obtained.An empirical formula for the relationship between the displacement and stress maximum of each component and the height of the inner cavity.It can quickly infer the most unfavorable force parts under each construction stage of the cofferdam,and can locally strengthen and strengthen the weak and stress concentration parts in the actual project.The force analysis of the back cover concrete gave the minimum thickness of the back cover concrete.Filling concrete inside a single-walled box coam is a new process.Through the analysis and comparison of the displacement,stress and internal force of each member of the cofferdam,the variation law of the force is obtained.Through the optimal design of the cofferdam structure,the reasonable thickness of the cofferdam-filled concrete is discussedAccording to the measured data of on-site monitoring and the finite element calculation results,the rationality and accuracy of the calculation of the cofferdam system model are verified.Through the optimization of the action combination coefficient,an empirical formula of a relatively reasonable combination effect is summarized.It provides reference for the design calculation and specification of steel cofferdam structure,and can also provide reference for the design and construction of similar projects in the future.