Thermo-mechanical coupling analysis of deformation and failure of salt cavern UGS under the influence of sediment particles
During gas injection and production in salt cavern UGS,gas quality,pressure and temperature in the cavity change constantly,and the dynamic internal boundary conditions have a great influence on surrounding rocks,so the surrounding rocks may be locally subjected to large deformation and failure,which can threaten the safe and stable operation of salt cavern UGS.In view that temperature,fluid and sediment have different mechanical mechanisms to surrounding rocks,this paper studies the distribution and variation characteristics of the displacement,stress and plastic zone of surrounding rocks under the condition of gas injection and production based on thermo-mechanical coupling and the FLAC3D-PFC3D coupling method.The following results are obtained.First,as gas production and injection continues,the absolute vertical displacement of salt cavity roof increases gradually,and the plastic failure range of surrounding rocks expands gradually.Second,the influence of sediment particles on the surrounding rocks has a certain spatial effect,and the farther away from the sediment particles,the greater the deformation and plastic failure range of the surrounding rocks.Third,for the gas production process,the larger the size and initial porosity of sediment particles,the smaller the algebraic value of the vertical displacement of surrounding rocks at the top of the cavity,the algebraic value of the first principal stress of surrounding rocks at the waist of the cavity,and the plastic failure range of the surrounding rocks.Fourth,for the gas injection process,the larger the sediment particle size and initial porosity,the larger the algebraic value of the vertical displacement of surrounding rocks at the top of the cavity,the smaller the algebraic value of the first principal stress of surrounding rocks at the waist of the cavity,and the larger the plastic failure range of the surrounding rocks.In conclusion,the mesostructures of sediment particles have an important effect on the deformation,stress and plastic failure zone of surrounding rocks.In practical engineering applications,it is suggested to adopt the discrete element thermo-mechanical coupling method to accurately characterize the sediment particle system,thus evaluating its impact on surrounding rocks.What's more,thermo-mechanical coupling analysis of deformation and failure of salt cavern UGS under the influence of sediment particles is of guidance significance to the construction,sediment utilization and stability evaluation of salt cavern UGS in China.
Continuous-discontinuous couplingThermo-mechanical couplingSalt cavern UGSComputational mechanics of granular materialSedimentDeformation and failure of surrounding rockTime effectGas injection and production
万方数据
维普
