Ansysis And Evaluation On Stability Of Surrounding Rock For Huizhou Water Sealed Underground Oil Storage Caverns In Rock

Facing of the oil consumption toal amount and the oil imports increased year by year.It's immediately to start the consttuction of strategic oil reserve base to meet the needs of economic development and protect national energy security. In various kinds of storage methods, water sealed underground oil storage caverns is more safer and economicaly .The planning of Huizhou water sealed underground oil storage caverns is the lagest storage caverns in designing till this year.Such engineering project is still lack of the engineering practice in China. The analysis and evaluation of surrongding rock in the process of large caverns excavating is a serious problem to solve.This thesis takes Huizhou water sealed underground oil storage caverns as study object,using the numerical simulaton software FLAC3D,does further researches on the design of caverns ,the optimization of excavation project, analysis and evaluation of stability of surrounding several.The specific work as follows:(1)Corrected the physical and mechanical parameters of rock in the library site region. Using complex-variable function theory based on elastic mechanics method is deduced the straight wall round arch type cavern hole weeks tangential stress calculation formula.(2)Calculatied with the finite difference numerical simulation software FLAC3D,propesed the appropriate distance between the main tunnels and the appropriate distance between the main tunnels and the roadway. Elected the best construction sequence of the tunnels.Owned a in-depth understanding about group tunnels effective.(3) Using the complex function analytical method,Based on signal hole,anslysis the stability of surrounding rock under different levels of rock grade. For the gradeâ…¡,â…¢rock,the rock at foot corner and arch existed stability problems.In addition,Simulated the whole process of tunnels excavation with the software FLAC3D.The results show that three steps forward excavation method is appropriate for this large underground cavern project as Huizhou.(4) Using fluid-solid coupling method for the process of tunnels excavation. In the excavating procession,the distribution of stress field is similar as the situation which not consider the case of groundwater,but the stess has been reduced; the displacement field is reflected in terms of subsidence into the multiplied increased. In flow conditions,the expansion of the plastic zone around the rock, controled by the speed and time of water drainage.Drainage bad,the plastic zone increased dramatically, and fully drained,the plastic zone is significantly reduced.(5) The area of Huizhou water sealed underground oil storage caverns,abundant rainfall,groundwater recharge is adequately. It's conducive to the formation of water-sealed environment.Seepage conditions,the excavation of caverns will change the distribution of seepage field, At the hole week will form a regional cone of depression, the overall water level decline is also obvious.Simulation results show that the pore water pressure can not reached the required to operated security after the constructions project completed. It is necessary to arrange the water curtain system and vertical water injection holes in the roof above.