Experimental Research On Bending Characteristics Of U-shaped Composite Steel Sheet Pile

The steel sheet pile is a lightweight,high-strength,environmentally-friendly,easy-toconstruct,flexible support structure that can be reused many times,and its excellent interlock design is effective to keep water outside,so it is used in different types of projects,such as flood control and disaster relief work,foundation pit support and dock construction projects.Ushaped steel sheet piles are the most commonly used.In practical use,the interlocking joints on both sides of the pile are connected to form a steel sheet pile retaining wall,and the actual connection of the locks between adjacent steel sheet piles is not absolutely complete,so there will be mutual slip along the length of the adjacent steel sheet piles,which will result in the steel sheet pile wall not working as a complete whole,so that the bending stiffness of the actual pile wall will be less than the bending stiffness of the ideal pile wall.This phenomenon is called the "stiffness reduction effect".Due to the uncertainty of the bending stiffness of the steel sheet pile wall,it's engineering application has been affected.At present,domestic and foreign scholars have a lack of analysis and research on the value of stiffness in the use of steel sheet piles.The values according to the specific conditions of use have not been summarized to form a unified reference.So the research work on the bending resistance of steel sheet pile walls is meaningful to be carry out for finding the mechanism contained in it and providing a clearer guidance for the design of steel sheet piles.This paper aims to study the bending resistance of composite steel sheet pile walls through experimental and theoretical analysis and finite element method.The main work is as follows:1.To achieve the research purpose,the section form of testing subject was newly designed.Two sets of static load tests were carried out on the U-shaped composite steel sheet pile.The values of deflection,cross-section normal strain,the line strain along the interlock joints and the relative slip between interlock joints were measured during the test.2.Combined with the test deflection data,the variation of the stiffness of the composite member with the load and the distribution along the length of the pile are analyzed.According to the cross-sectional strain data,the distribution of strain and the variation of the neutral axis of the section are obtained and the development of plastic zone in the cross section is analyzed.According to the value of relative slip,the connection state of locking joints can be estimated.3.ABAQUS is used to establish a model matching the first test for strengthening the analysis and understanding of the test,and its results show that the variation trend of stiffness is basically consistent with the test.4?Combined with the deflection test data,the incremental calculation method is used to estimate the stiffness of the steel sheet pile in the first set of tests.