Study On The Criterion Of Rock Salt Based On Energy Principles And Its Application In Engineering

It is the worldwide-recognized that rock salt is not only mineral resource but also isenergy reserve and geological disposal of the toxic and hazardous waste material andcarbon dioxide in deep rock salt deposit．As one of the most important research issue，the stability of rock salt carven is closely related to the long-term stability and securityof mineral deposit of rock salt．On the basis of previous research，with integratedexperimental test， theoretical deduction， program composition and numericalsimulation，a new yield and failure criterion has been proposed for evaluation andprediction the stability of rock salt carven．The main works of the thesis can be drawn asfellows：①The strength parameters，compressive strength，ultimate tensile strength，cohesion，friction angle，elastic Modulus，Poisson’s ratio are obtained by the uniaxialand triaxial compressing experiment and Brazilian splitting test of rock；The results alsoindicated that rock salt behaves obvious strain hardening characteristic under highconfining pressure．Based on creep test results，a new constitutive law of rock salt ispresented，the evolvement law of creep rate with parameter variations for Norton-Powerand linear constitutive model is studied．②The revised failure criterion of rock mass is proposed based on the diffusioncoefficient of releasable strain energy，and it is in agreement with the result of triaxialcompressive test on rock；Theoretical analysis indicated that compressive strength ismore important than Poisson’s ratio in revised failure criterion．③The generalized yield and failure criterion based on elastic strain energy hasbeen proposed to instead of criterion so that it is suitable for geomaterial，and D-Pcriterion is special case of generalized criterion for Poisson’s ratio0.5；This study showsthat both cohesion and Poisson’s ratio are linear to the criterion，but，friction angle isultimate valve；Experimental results that criterion is suitable for rock salt and hardrocks．④Based on generalized yield and failure criterion constitutive model of rock saltis established and numerically realized.Self-defined constitutive model was complied tothe interface of FLAC3D by C++，and validity of self-defined constitutive for rock saltwas verified by using M-C model and then the correctness and applicability of theredevelopment computer program was verified by experimental simulation. ⑤Generalized yield and failure criterion constitutive model of rock salt computerprogram was applied to long-term stability analysis of rock salt cavern. According tothe analysis for rock salt caverns，the variation laws of plastic zones, surrounding rockmass deformation and volume closure ratio with time and internal pressure wereanalyzed, and the minimum inter pressure，thickness of intermediate section andreasonable pillar width were determined.⑥The results shows that underground cavern stability of surrounding rock has loweffect on cohesion and friction of rock salt，while friction of mudstone has significantrole.