Experiment And Numerical Simulation Study On Rock-Water Interaction In Geotechnical Engineering

Based on the related knowledge of geotechnical engineering,rock mechanics,fluid mechanics and computational fluid mechanics,the interactions between water and rock in geotechnical engineering are studied by the laboratory experiments and numerical analysis.For the static condition of rock –water interaction,the chapter 2 takes the the weathering and salt transport of Dunhuang Mogao Grottoes’ surrounding rock in the local environment as the back ground.Laboratory or field experimental and numerical simulation studies are carried out for the static adsorption of rock and gas.The environment of the Mogao Grottoes in Dunhuang is normally dry and clear,and the four seasons are distinct.As the precious material and cultural heritage of human beings,the environment is threatened by many diseases and weathering erosion.At present,the gas water adsorption characteristics of the samples were studied by the self-developed rock gas water adsorption test system.At the same time,the influence of clay mineral and pore and fracture on the adsorption of gaseous water was analyzed by SEM scanning and X-ray diffraction experiments.In order to isolate the effects of clay minerals on water vapor adsorption,the CFD numerical simulating was performed on the water vapor absorption of rock samples with different angles of cracks and random spreaded cracks,and the experimental results of rock and water vapor adsorption on the time sequence rules were verified.For the dynamic rock-water interaction in geotechnical engineering,heat transfer process is also an important issue in addition to the water adsorption.In order to control the heat hazards in deep coal mining,the HEMS cooling systems were successfully applied in several high temperature deep mines.In this system,the designed shallow cold source extraction part,when the cold from the coal mine inflows were not enough,was significant for the cooling system operation.The chapter 3 discusses the problems in fluid-solid coupled heat transfer roadway part for shallow cold source extraction,considering the surface roughness of surrounding rock and water contained effect,at the same time the boundary conditions was set with the boundary layer replacing the traditional method of wall function settings.The numerical simulation of three-phase heat transfer problem,among cool return air,cold shallow surrounding roadway rock and the hot circulating water from HEMS cooling system,was performed by the FLUENT based on the field project conditons.The monitored parameters in the field experimental cooling system was taken in the model,and the simulating method and results were validated and the monitored outflow water temperature’s error was less than 5%.The the model was applied in Zhangji coal mine cooling system optimization and the wall roughness and the dip of roadway was envalued for the shallow cold source extraction and design the parameter of this section in the whole system.Simulation results showed the cold extraction ability under certain field environment,the length,stairs shape and many other parameters were suggested in the extraction part of the shallow roadway,and this method and multi-phases simulating model could be further applied in the cold source envaluation and cooling system design.In view of the more intense dynamic water and rock interaction,this chapter focuses on the high pressure water jet with high energy and rock cutting ability.According to the needs of higher speed,pressure and efficiency water jet and the demands from the high-energy,low explosion dust crushing drilling tools,such as the 110 and N00 new mining method with pre-roof cutting,the water jet energy envaluation and jet design are of great significance.The self-excited oscillating water jet is a kind of special water jet with high energy than equivalent pump pressure narmal water jet,because of the structure caused impus in the water.The power of this jet relays on the regularity of the oscillation frequency.Based on the theoretical model,the natural frequency calculation equation of Helmholtz resonator,the core element of the self excited oscillation jet,is deduced.Using the method of numerical simulation on the designed self-excited oscillation jet nozzle,the eqation was envaluated by the simulating results.Compared with the results obtained by numerical simulation of nozzle oscillation frequency,verification and correction of the model parameters are possible for more efficient water jet tools design in the application of geotechnical engineering projects in the future.