Analysis Of Structural Characteristics In Construction Of Deep Water Double-Row Steel Sheet Pile Cofferdam

With the continuous construction and development of bridge projects in China,as bridge construction continues to mature,many bridges across the river and across the sea have emerged.As the foundation of the standing bridge,the bridge foundation is also constantly advancing to deeper waters,the deep water foundation has become a key part of these large-span bridges,and with the deep water foundation,a variety of cofferdams matching it are derived construction technology.In which the double steel sheet pile cofferdam is an emerging cofferdam structure,because it can adapt to bridge projects with larger spans,deeper water depths,and higher difficulties,and effectively compensate for the disadvantages of other cofferdam structures,The performance of span bridge construction is particularly prominent.But for now,due to the less use of double-row steel sheet pile cofferdams,there is no more standardized calculation theory for double-row steel sheet pile cofferdams in China,and the semi-theoretic and semi-empirical design methods based on experience are still used.Each construction condition and structural reliability analysis of the cofferdam has great limitations.Based on the engineering background of Sixianjiao Special Bridge 347~#main pier double-row steel sheet pile cofferdam,this paper studied the deformation and stress characteristics of deep water double-row steel sheet pile structure through the method of theoretical analysis and finite element analysis.The following content:(1)Summarize the application and research status of the double-row steel sheet pile cofferdam,briefly describe the bridge foundation conditions and the construction stage division applicable to the structure,analyze the external load distribution and soil characteristics between the double-row steel sheet pile cofferdam,and obtain the soil destruction forms and theoretical calculations.By analyzing the calculation method of the double-row piles in the foundation pit,the basic assumptions and calculation models suitable for the double-row steel sheet pile cofferdam are derived,the stress and displacement of the cofferdam in various working conditions are calculated and checked;(2)Using ANSYS software,according to the actual construction situation of the project,a three-dimensional solid model of the double-row steel sheet pile cofferdam is established.The Mohr-Coulomb model is used to reflect the ideal elastoplasticity of the soil between the piles.Under different working conditions,the stress and strain results of steel sheet piles,internal supports and soils between piles and their changing laws.Comparing the theoretical calculation results with the finite element analysis,the feasibility of calculating the soil theory between the piles and the deficiencies of the calculation model are obtained.The dangerous points of the cofferdam construction and the different internal force responses of the inner and outer steel sheet piles are analyzed,and the interaction between the pile and soil in the cofferdam and the necessity of analysis in the construction phase.