Numerical Simulation And Experimental Study On Scouring And Erosion Of Bridge Pier Columns By Water And Sand Two-Phase Flow

Water and sand two-phase flow is a very common fluid in rivers,lakes and oceans.Water and sand two-phase flow will generate energy that will cause scour surrounding buildings during the movement.Due to the different hydraulic structures,the abrasive characteristics are different.At present,there are no clear regulations for brittle materials,and the movement characteristics of sand particles.It is of great significance to study the abrasive capabilities of sand particles.Based on this,concrete bridge pier columns are used as abrasive targets,and a combination of experimental research and numerical simulation research is used to study the particle size and sand content of sand in water and sand two-phase flow.In the experimental research,the self-made test equipment was used to perform abrasive concrete pier columns by using similar theory.The effects of different sand solid particles and sand content on scouring of concrete bridge pier columns at different ages were studied.FLUENT fluid software was used to scour the pier of the concrete bridge,and then the experimental results were compared with the results of numerical simulation to predict the mass loss of scouring of the pier of the bridge.Protective measures were taken in advance to reduce the occurrence of dangerous accidents.The following conclusions were reached through numerical simulation and experimental research.(1)Concrete bridge pier are scoured by water and sand two-phase flow with different sand particle sizes.With the increase sand particles,the abrasive mass loss rate gradually decreases.When the particle size is 1.5 mm,sand particles form strong erosion on concrete bridge piers with suspended matter at the bottom of the river bed.The erosion cross section is crescent-shaped on concrete bridge piers,and the direction of water and sand concrete is greater.The larger the particle size,the higher the abrasive loss rate.It’s getting lower and lower,and the abrasive height is lower and lower.The abrasive loss rate of the water and sand two-phase flow and air interface is almost 0,and it’s also concluded that there is a great relationship between sand solid particles and the abrasive clear water is very poor.(2)The higher the sand content of the water and sand two-phase flow,the greater the abrasive loss rate.As the curing age of concrete increases,the rate of abrasion loss gradually weakens.When the concrete reaches the design strength,continued maintenance has little effect on resistance of the abrasion.During abrasive process,the surface of the concrete pier column is relatively intensive abrasion,and the inside of the concrete is gradually weakens.(3)By comparing the numerical simulation with the experimental research results,it can be concluded that the numerical simulation and the experimental results are in good agreement.The most severe abrasive rate occurs at the bottom of the pier of the concrete bridge.The protection of the bottom of the pier needs to be strengthen.