To study the mechanism of rockburst and its spatio-temporal evolution criterion,a rockburst simulation experiment was performed on granite specimens,each with a prefabricated circular hole,under different lateral load...To study the mechanism of rockburst and its spatio-temporal evolution criterion,a rockburst simulation experiment was performed on granite specimens,each with a prefabricated circular hole,under different lateral loads.Using micro camera,acoustic emission(AE)system,and infrared thermal imager,the AE characteristics and thermal radiation temperature migration were studied during the rockburst process.Then,the failure mode and damage evolution of the surrounding rock were analyzed.The results demonstrate that increasing the lateral load can first increase and then reduce the bearing capacity of the hole.In this experiment,the hole failure process could be divided into four periods:quiet,particle ejection,stability failure and collapse.Correspondingly,the AE signals evolved from a calm stage,to have intermittent appearance;then,they were continuous with a sudden increase,and finally increased dramatically.The failure of the surrounding rock was mainly tensile failure,while shear failure tended to first increase and then decrease.Meanwhile,damage to the hole increased gradually during the particle ejection period,whereas damage to the rockburst mainly occurred in the stability failure period.The thermal radiation temperature migration exhibited warming in shallow parts,inward expansion,cooling in the shallow parts with free surface heating,inward expansion,a sudden rise in temperature of the rockburst pits,and finally specimen failure.The initial reinforcement support should fully contribute to surface support.Furthermore,an appropriate tensile capacity and good energy absorption capacity should be established in support systems for high-stress roadways.展开更多
Damage in rock salt has significant implication on permeability, which affects the tightness of underground salt cavern gas storage in further. During the leaching of a salt cavern, the brine with formation temperatur...Damage in rock salt has significant implication on permeability, which affects the tightness of underground salt cavern gas storage in further. During the leaching of a salt cavern, the brine with formation temperature and pressure can promote the self-healing of rock salt in the excavation damage zone (EDZ). Laboratory tests were conducted to study the promoting effect. The permeability of two intact rock salt specimens was tested. Then they were damaged into two kinds of the state respectively through uniaxial compression. After that, they were put in saturated brine (with a temperature of 50℃ and pressure of 12 MPa, which we called the repair environment in this paper) for 7 d. Finally, the permeability and mechanical properties were obtained after the damaged specimens being repaired. The results show that the permeability of intact rock salt is below 10^-19 m^2;the permeability increases by more than two orders because of damage;the permeability decreases significantly after being repaired, which can be comparable to its intact state. Discussions of the repair mechanisms are presented (especially the mechanism of recrystallization), which may help to provide significant guidance for the study of the tightness and stability of gas storage facilities in China.展开更多
基金Project(2017YFC0603003)supported by the National Key Research and Development Project of ChinaProjects(51974009,51674008)supported by the National Natural Science Foundation of China+3 种基金Project(201904a07020010)supported by the Key Research and Development Program of Anhui Province,ChinaProject(2018D187)supported by the Leading Talent Project of Anhui“Special Support Program”,Anhui Provincial Academic and Technology Leaders Research Activities Funding,ChinaProject(gxbjZD2016051)supported by the Excellence Talent Training Program of High School,ChinaProject(2019CX2008)supported by the Graduate Innovation Fund of Anhui University of Science and Technology,China。
文摘To study the mechanism of rockburst and its spatio-temporal evolution criterion,a rockburst simulation experiment was performed on granite specimens,each with a prefabricated circular hole,under different lateral loads.Using micro camera,acoustic emission(AE)system,and infrared thermal imager,the AE characteristics and thermal radiation temperature migration were studied during the rockburst process.Then,the failure mode and damage evolution of the surrounding rock were analyzed.The results demonstrate that increasing the lateral load can first increase and then reduce the bearing capacity of the hole.In this experiment,the hole failure process could be divided into four periods:quiet,particle ejection,stability failure and collapse.Correspondingly,the AE signals evolved from a calm stage,to have intermittent appearance;then,they were continuous with a sudden increase,and finally increased dramatically.The failure of the surrounding rock was mainly tensile failure,while shear failure tended to first increase and then decrease.Meanwhile,damage to the hole increased gradually during the particle ejection period,whereas damage to the rockburst mainly occurred in the stability failure period.The thermal radiation temperature migration exhibited warming in shallow parts,inward expansion,cooling in the shallow parts with free surface heating,inward expansion,a sudden rise in temperature of the rockburst pits,and finally specimen failure.The initial reinforcement support should fully contribute to surface support.Furthermore,an appropriate tensile capacity and good energy absorption capacity should be established in support systems for high-stress roadways.
基金Project(201704910741) supported by the China Scholarship CouncilProjects(51874274,51774266,51874273,51621006) supported by the National Natural Science Foundation of ChinaProject(2018YFC0808401) supported by the National Key Research and Development Program of China
文摘Damage in rock salt has significant implication on permeability, which affects the tightness of underground salt cavern gas storage in further. During the leaching of a salt cavern, the brine with formation temperature and pressure can promote the self-healing of rock salt in the excavation damage zone (EDZ). Laboratory tests were conducted to study the promoting effect. The permeability of two intact rock salt specimens was tested. Then they were damaged into two kinds of the state respectively through uniaxial compression. After that, they were put in saturated brine (with a temperature of 50℃ and pressure of 12 MPa, which we called the repair environment in this paper) for 7 d. Finally, the permeability and mechanical properties were obtained after the damaged specimens being repaired. The results show that the permeability of intact rock salt is below 10^-19 m^2;the permeability increases by more than two orders because of damage;the permeability decreases significantly after being repaired, which can be comparable to its intact state. Discussions of the repair mechanisms are presented (especially the mechanism of recrystallization), which may help to provide significant guidance for the study of the tightness and stability of gas storage facilities in China.
