Prediction Of Riverbed Scour Depth Of West-to-East Gas Pipeline Crossing Longjin River

The two-phase flow model can reveal the mechanism of water and sand movement and describe the interaction accurately between water and sand.It is of great significance for solving engineering sediment problems by constructing a high-precision,highly applicable water-sediment two-phase flow model.Based on the hydrological engineering geological conditions of the Longjin River crossing of the east section of the West-East Gas Pipeline,this paper uses the Delaunay triangulation method to mesh the calculation area,and uses the SIMPLE algorithm based on the same grid to deal with the coupling relationship between water depth and velocity in the flow equation.The Gauss iteration method was used to solve the algebraic equations to establish a two-phase two-phase mathematical model of water-sediment flow.Five typical river sections were selected for calibration verification and error calculation.At the same time,the model was used to simulate the pipeline crossing the river.The water and sand movement of the river has been studied and calculated under different flood combinations,and the law of erosion and siltation of the Longjin River crossing project section and its nearby riverbed.On this basis,the maximum erosion depth and siltation swing law of the main channel are predicted and analyzed.research shows:1.Using a two-dimensional mathematical model,the calculated value of the velocity on the velocity measurement section during the actual measurement is basically the same as the actual measured value.The error between the two is generally less than 0.15m/s,and the maximum error is generally not more than 0.25m/s.The mathematical model of sand two-phase flow can accurately simulate the water movement of the engineering section and calculate the maximum scouring depth of the main channel where the pipeline crosses(the lowest point of the river bed).2.Calculate the erosion depth of 5 typical sections under different flood combinations through simulation research of water and sediment movement.From the calculation results,it is relatively close to the erosion situation of similar projects collected.The state of river erosion and scouring and its erosion depth The data is reliable.3.the calculated value of the velocity and water level on the velocity measurement section during the actual measurement is basically the same as the actual measured value.The results show that the two-phase two-phase mathematical model of water-sediment flow can be used to predict and analyze the maximum scour-depth and siltation swing of the main channel in the reach where the pipeline crosses.