Research On Mechanical Properties Of Cantilevered Retaining Walls Under Chloride Salt Erosion Environment

The cantilever retaining wall is a type of retaining structure that is strongly tied to the surrounding environment.Together with the vast expansion of resources in coastal areas,the soil salinization is increasing due to the backflow of seawater.Contrary to uniform corrosion caused by concrete carbonation,non-uniform corrosion of reinforcement caused by chloride salt erosion is more frequent and dangerous in real-world engineering.As a result,it’s crucial to comprehend how a cantilevered retaining wall’s mechanical properties degrade from a material level to a structural one in a chloride salt environment.At present,domestic,and foreign scholars have proposed some solutions put forth for the service safety monitoring techniques of rusted cantilever retaining walls,but there has been less research done on the law governing service time and mechanical property deterioration,and more study is still required to serve as a guide for decisions regarding structural durability design and maintenance schedules.In this study,theoretical calculations and numerical simulations are used to investigate and explain the time-varying mechanical characteristics of cantilevered retaining walls.The study’s specifics are as follows:(1)A modified time-varying prediction model for the bearing capacity of cantilevered retaining walls under chloride salt erosion environment was established,and the effects of the non-uniform corrosion coefficient R,protective layer thickness d_cand water-cement ratio w/b on the time-varying law of flexural bearing capacity of cantilevered retaining walls were quantitatively evaluated.The analysis found that the incorporation of appropriate amount of fly ash into the concrete can delay the corrosion of reinforcement to a greater extent and ensure the durability of the structure while ensuring its strength.When ordinary concrete(OPC)is used in the design of the structure,increasing the thickness of the protective layer,or decreasing the water-cement ratio of the material can delay the initial corrosion time of the reinforcement to varying degrees and delay the degradation of the bearing capacity of the cantilever retaining wall.(2)The structural mechanical properties of cantilever retaining walls under different corrosion degrees and distributions are revealed,and their internal load transfer mechanisms are discussed.Based on the quasi-static method,a simplified force model of the rusted cantilever retaining wall is established using ABAQUS/Explicit module.The analysis and calculation results show that the flexural bearing capacity,flexural stiffness,and ductility of the structure decrease with the increase of corrosion rate,and the loss of ductility of the structure under the condition of non-uniform corrosion distribution is smaller than that under uniform corrosion distribution when the average corrosion rate is the same.Meanwhile,it is proposed to evaluate the overall corrosion level of cantilevered retaining walls by means of monitoring the stress level of reinforcement at key locations and the displacement of the top of the wall.(3)The time-varying reliability of cantilever retaining walls under chloride salt erosion environment was investigated.Based on the structural reliability theory,a functional function of the cantilever retaining wall considering the time-varying effect is constructed,and the reliability indexes of the structure during its lifetime are solved by Monte Carlo method simulation.The analysis found that when the corrosion rate is low and the damage mode has not changed from ductile to brittle damage,the time-varying law of reliability index conforms to the exponential function;when the corrosion rate is high and the damage mode has changed to brittle damage,the time-varying law of reliability index conforms to the logistic function.In order to prolong the service life of the structure,increasing the thickness of the protective layer and reasonably reducing the water-cement ratio of concrete materials are effective measures.