A new electrical method of conductive carbon-film(with waterproof and anticorrosion ability)was proposed to continuously measure crack propagation rate of brittle rock under THMC coupling condition.A self-designed cou...A new electrical method of conductive carbon-film(with waterproof and anticorrosion ability)was proposed to continuously measure crack propagation rate of brittle rock under THMC coupling condition.A self-designed coupling testing system was used to conduct THMC coupling fracture tests of the pre-cracked red sandstone specimens(where the temperature is only changed)by this new electrical method of conductive carbon-film.Calculation results obtained by the energy method coincide well with the test results.And the higher the temperature is,the earlier the crack is initiated and the larger the crack propagation rate and accelerated velocity are,which can prove the validity of the new electrical method.This new electrical method has advantages of continuously measuring crack propagation rate over the conventional electrical,optical and acoustic methods,and can provide important basis for safety assessment and cracking-arrest design of deep rock mass engineering.展开更多
Although a large number of previous researches have significantly contributed to the understanding of the quasi-static mechanical behavior of cemented tailings backfill,an evolutive porous medium used in underground m...Although a large number of previous researches have significantly contributed to the understanding of the quasi-static mechanical behavior of cemented tailings backfill,an evolutive porous medium used in underground mine cavities,very few efforts have been made to improve the knowledge on its response under sudden dynamic loading during the curing process.In fact,there is a great need for such information given that cemented backfill structures are often subjected to blast loadings due to mine exploitations.In this study,a coupled thermo-hydro-mechanical-chemical(THMC)-viscoplastic cap model is developed to describe the behavior of cementing mine backfill material under blast loading.A THMC model for cemented backfill is adopted to evaluate its behavior and evolution of its properties in curing processes with coupled thermal,hydraulic,mechanical and chemical factors.Then,the model is coupled to a Perzyna type of viscoplastic model with a modified smooth surface cap envelope and a variable bulk modulus,in order to reasonably capture the nonlinear and rate-dependent behaviors of the cemented tailings backfill under blast loading.All of the parameters required for the variable-modulus viscoplastic cap model were obtained by applying the THMC model to reproducing evolution of cemented paste backfill(CPB)properties in the curing process.Thus,the behavior of hydrating cemented backfill under high-rate impacts can be evaluated under any curing time of concern.The validation results of the proposed model indicate a good agreement between the experimental and the simulated results.The authors believe that the proposed model will contribute to a better understanding of the performance of hydrating cemented backfill under blasting,and also to practical risk management of backfill structures associated with such a dynamic condition.展开更多
基金Projects(51474251,51874351) supported by the National Natural Science Foundation of China
文摘A new electrical method of conductive carbon-film(with waterproof and anticorrosion ability)was proposed to continuously measure crack propagation rate of brittle rock under THMC coupling condition.A self-designed coupling testing system was used to conduct THMC coupling fracture tests of the pre-cracked red sandstone specimens(where the temperature is only changed)by this new electrical method of conductive carbon-film.Calculation results obtained by the energy method coincide well with the test results.And the higher the temperature is,the earlier the crack is initiated and the larger the crack propagation rate and accelerated velocity are,which can prove the validity of the new electrical method.This new electrical method has advantages of continuously measuring crack propagation rate over the conventional electrical,optical and acoustic methods,and can provide important basis for safety assessment and cracking-arrest design of deep rock mass engineering.
文摘Although a large number of previous researches have significantly contributed to the understanding of the quasi-static mechanical behavior of cemented tailings backfill,an evolutive porous medium used in underground mine cavities,very few efforts have been made to improve the knowledge on its response under sudden dynamic loading during the curing process.In fact,there is a great need for such information given that cemented backfill structures are often subjected to blast loadings due to mine exploitations.In this study,a coupled thermo-hydro-mechanical-chemical(THMC)-viscoplastic cap model is developed to describe the behavior of cementing mine backfill material under blast loading.A THMC model for cemented backfill is adopted to evaluate its behavior and evolution of its properties in curing processes with coupled thermal,hydraulic,mechanical and chemical factors.Then,the model is coupled to a Perzyna type of viscoplastic model with a modified smooth surface cap envelope and a variable bulk modulus,in order to reasonably capture the nonlinear and rate-dependent behaviors of the cemented tailings backfill under blast loading.All of the parameters required for the variable-modulus viscoplastic cap model were obtained by applying the THMC model to reproducing evolution of cemented paste backfill(CPB)properties in the curing process.Thus,the behavior of hydrating cemented backfill under high-rate impacts can be evaluated under any curing time of concern.The validation results of the proposed model indicate a good agreement between the experimental and the simulated results.The authors believe that the proposed model will contribute to a better understanding of the performance of hydrating cemented backfill under blasting,and also to practical risk management of backfill structures associated with such a dynamic condition.
