Research On Impact Effect Of Debris Flow On Bridge Pier Based CFX

Debris flow is a common natural disaster phenomenon in mountain areas.It is a special fluid composed of mud,sand and other loose solid materials mixed with water It is widely distributed in southwestern China.In the southwest mountainous areas where debris flows are widely distributed,bridges have become the preferred way to cross the debris flow area.Bridges are a key part of road traffic and no problems are allowed.Once the bridge is damaged by the impact of debris flow,it will inevitably cause traffic stagnation and huge economic losses.In order to ensure smooth road traffic and reduce the damage of debris flow to the pier,it is of great practical significance to analyze the impact effect of debris flow on piers..At present,most of the research on the impact force of debris flow on bridge piers is based on The semi theoretical,semi empirical and relatively conservative calculation formula based on the summary of the debris flow disasters.It can not truly reflect the force status of the bridge piers under the debris flow impact.Therefore,this article studies the impact effect of debris flow on the pierFirst of all,this article introduces the relevant parameters of debris flow movement,gives the calculation methods of debris flow parameters such as bulk density,velocity,flow and impact force,and analyzes the control equation,rheological mechanics model and numerical simulation analysis method of debris flow in detail to determines the rheological mechanics model and numerical method of this simulationWith the help of the CFX module of ANSYS Workbench computational fluid dynamics,the numerical simulation analysis of debris flow impact is carried out for three common types of piers:double column pier,solid pier and hollow pier.By changing the parameters such as the shape of pier section,the distance between piers,the width of upstream face,the area of cross section and the wall thickness of hollow pier,the difference between the volume distribution of debris flow slurry,the streamline trace,the pressure distribution of piers,the impact force and the tensile stress of piers are compared and analyzed for the selection,design and protection of piers in debris flow area.All of them have important engineering reference value and theoretical significance.Using ANSYS Workbench simulation analyzes the influence of the change of velocity,bulk density and impact height of debris flow imp act parameters on the impact effect of piers,comparing and analyzing the difference between the numerical simulation and the existing calculation formula of the overall impact force of debris flow slurry.On the basis of the existing calculation formula,the formula of the overall impact force of debris flow slurry is simplified and modified by combining with the data from simulation.Finally,the calculation formula of the whole impact force of debris flow based on the numerical simulation analysis is obtained.The formula reflects the distribution of the impact of debris flow along the piers,and provides a certain basis for the design of disaster reduction and prevention of piers in debris flow area.