Research On Dilatancy And Creep Damage Of The Saplt Rock Caverns Under Cyclic Loading

Salt rock is internationally recognized ideal place to reserve energy and dispose of nuclear waste for its performance including good creep properties,plastic deformation capacity,recovery and anti-permeability.In this paper,we mainly study the sealing property of the cavern under different cyclic loading conditions.According to the research,promotion of the maximum pressure and minimum pressure in the cyclic loading will be help to restraining contraction of the caverns;As loading and unloading rate could be lower deformation difference could be reduced between mudstone and salt rock so as to reduce the tensile stress near the mudstone interlayer;Considering the damage factors,damage have a great influence on stress and displacement.In the cylic loading process,with the increase of the partial stress the salt rock maybe appear expansion.Dilatancy will lead to the increase of porosity and permeability in exponential form.Therefore the phenomenon expansion of rock salt should be studied.Through this study,it is found that the expansion of salt rock is affected by not only the stress state such as the partial stress and confining pressure,but also various other factors,such as the high temperature mudstone interlayer.According to experimental data of the triaxial compression tests and the rheological tests,the relationship between deviatoric stress and the volumetric strain was acquired,and an incremental expansion model is proposed,which was proved that the theoretical model calculation results and the experimental data are in good agreement.The results of simulation show that the maximum compression volume increases with the increase of confining pressure.Compression expansion boundary can be regarded as a warning point for the destruction of surrounding rock of salt reservoir.