| With the development of national society and economy,bridges,as an important part of transportation hub projects,not only represent the highest level of transportation infrastructure construction,but also become an important symbol to show the great achievements of reform and opening up and comprehensive national power.However,the construction of bridge pier foundation is required to be carried out in a relatively stable environment.In order to create a relatively stable construction environment,double-row sheet pile cofferdam becomes the preferred choice for construction under complex geological conditions.At the same time,the dike as an important water conservancy project,the overload effect brought by the slope of the dike brings new problems to the construction when cofferdam construction is carried out on the dike.Therefore,it is of great practical significance to study the double-row sheet pile cofferdam under overload.This paper based on the actual construction project cases and summarize domestic and international research results,using a combination of theoretical and simulation analysis to evaluate the safety and stability of cofferdam construction under overload,and analyze the load effect of overload on the cofferdam structure.To provide a basis for the construction of similar bridge projects.The main research work and results are as follows.(1)Theoretical calculation: Summarized the existing research status of double-row steel sheet pile and foundation excavation,calculated the actual overload construction cases,and simplified the steel sheet pile and inter-pile soil into a laminated beam structure,and combined the stress characteristics of double-row steel sheet pile and inter-pile soil,checked the stresses and deflections of the steel sheet pile in each construction stage.Because of existing models are all simplify the internal support as a support,which is not consistent with the actual situation.This paper simplifies the support as a spring support of the laminated beam,using the principle of minimum potential energy to solve stress distribution and deflection distribution of laminated beams,and the accuracy of the results is verified by using a simple model.(2)Simulation analysis: Established a three-dimensional refined ABAQUS simulation analysis model of the actual overload case construction,and different construction stages in the project were simulated by using raw and dead units to obtain the stress and deflection distribution of steel sheet piles and supports under different construction stages,and checked the safety and stability of the support structure.Meanwhile,the influence of the cofferdam construction on the stability of the surrounding soil was analyzed by extracting the stresses and deformations of the external soil body.In addition,the stress and deflection distribution of the support structure and soil body under the cofferdam construction without overload were obtained by using the same method,and the load effect of overload soil was analyzed by comparing the inner and outer sheet pile deformation and soil surface settlement,which provides a basis for guiding the cofferdam construction under overload environment. |
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