Study On Field Experiment And Numerical Simulation Based On Liquid-Solid Coupling Model Of Water-Air Two Phase Flow

At present,many areas are involved in water-gas two phase flow-solid coupling effect,such as underground engineering,water resources and hydropower engineering,environmental engineering and oil-gas resources development,therefore it is of great significance to carry out the study of this problem.The difficulty of using numerical analysis method to solve the problem of saturated-unsaturated seepage is that the determination of soil constitutive model,boundary conditions and calculation parameters.Obtaining a large number of measured data by field test will promote the improvement of numerical method.Based on this,problem was studied through field test and numerical simulation in this paper.The main research contents and results are as follows:(1)Introduced the basic control equation of water-gas two phase flow model and stress model,and made the coupling relation equation between stress and strain clear,and laid a theoretical foundation for the coupling relation equation between the deformation of solid skeleton and water-gas two phase flow.(2)The field compressed air test used the original design scheme,which was formed by the gas supply system,pressure control system and data acquisition system.the working condition of air pressure at 170 kpa and air time in 24 h was mainly introduced,under which condition the maximum uplift was 8 mm and the affect range was about 120 m.(3)Numerical simulation part described the establish of water-gas two phase flow-solid coupling model by using loose coupling method.According to the principle of loose coupling,the simulation of water-gas two phase flow-solid coupling model by using multiphase flow simulation program TOUGH2 and geotechnical mechanics simulation program FLAC3 D was discussed,and the orderly operation of TOUGH2 and FLAC3 D was controlled by using COUPLING.exe interface program developed by C++.Through the analysis of simulation results,such as gas saturation,pore pressure,air loss and ground uplift amount,etc,and comparison of the above simulation results and the measured values at the same time,the final result showed the rationality of the coupling model and laid a good foundation for the related engineering application.(4)Simulation analysis was carried out on different working conditions,such as inflation time,inflation pressure and pumping medium,from which we can get the following conclusion: when inflation pressure is in a certain value,inflation time affects the deformation range;when inflation time is in a certain value,inflation pressure both has an impact on the maximum deformation and deformation range;when inflation pressure and inflation time all are in a certain value,fresh water pumping has an very weak effect on deformation.