The goaf may face a series of deformation and settlement problems when the room-pillar mining method is used to excavate ore and pillars in the deep strata.To this end,a deep room-pillar model with two levels was made...The goaf may face a series of deformation and settlement problems when the room-pillar mining method is used to excavate ore and pillars in the deep strata.To this end,a deep room-pillar model with two levels was made,and the pillar recovery was carried out.The instantaneous deformation responses during the pillars recovery and the long-term settlements after the pillar recovery were analyzed.During the pillar recovery,different regions of surrounding rocks suffer from different dynamic disturbances which can be divided into three types,including(I)the combined action of blasting disturbance and unloading disturbance,(II)the sequential action of blasting disturbance and unloading disturbance,and(III)the action of unloading disturbance.After the pillar recovery,the settlement above the first recovering pillar is the largest,which has a traction effect on the settlement in other areas.The settlement process can be divided into two stages,stable displacement stage and unstable displacement stage.When the pillar-room system undergoes the unstable displacement stage,rock spalling and further cascading collapse will occur.展开更多
To determine the relationship between slabbing failure and the specimen height-to-width(H/W)ratio and to analyze the conditions,characteristics,and mechanism of slabbing failure in the laboratory,uniaxial compression ...To determine the relationship between slabbing failure and the specimen height-to-width(H/W)ratio and to analyze the conditions,characteristics,and mechanism of slabbing failure in the laboratory,uniaxial compression tests were conducted using six groups of granite specimens.The entire failure process was recorded using strain gauges and high-speed cameras.The initiation and propagation of fractures in specimens were identified by analyzing the monitoring results of stress,strain,and acoustic emission.The experimental results show that changes in the specimen H/W ratio can transform the macro failure mode.When the H/W ratio is reduced to 0.5,the macro failure mode is dominated by slabbing.Low load-bearing ability is observed in specimens with slabbing failure,and the slabbing fractures are approximately parallel to the loading direction.Moreover,the fracture propagation characteristics and acoustic emission signals of slabbing failure specimens show typical tensile failure characteristics,indicating that slabbing failure is essentially a special tensile failure.展开更多
基金Projects(11972378,41630642)supported by the National Natural Science Foundation of China。
文摘The goaf may face a series of deformation and settlement problems when the room-pillar mining method is used to excavate ore and pillars in the deep strata.To this end,a deep room-pillar model with two levels was made,and the pillar recovery was carried out.The instantaneous deformation responses during the pillars recovery and the long-term settlements after the pillar recovery were analyzed.During the pillar recovery,different regions of surrounding rocks suffer from different dynamic disturbances which can be divided into three types,including(I)the combined action of blasting disturbance and unloading disturbance,(II)the sequential action of blasting disturbance and unloading disturbance,and(III)the action of unloading disturbance.After the pillar recovery,the settlement above the first recovering pillar is the largest,which has a traction effect on the settlement in other areas.The settlement process can be divided into two stages,stable displacement stage and unstable displacement stage.When the pillar-room system undergoes the unstable displacement stage,rock spalling and further cascading collapse will occur.
基金the National Natural Science Foundation of China(Nos.11972378,51904335,51927808)the Fundamental Research Funds for the Central Universities of Central South University,China(No.2021zzts0282).
文摘To determine the relationship between slabbing failure and the specimen height-to-width(H/W)ratio and to analyze the conditions,characteristics,and mechanism of slabbing failure in the laboratory,uniaxial compression tests were conducted using six groups of granite specimens.The entire failure process was recorded using strain gauges and high-speed cameras.The initiation and propagation of fractures in specimens were identified by analyzing the monitoring results of stress,strain,and acoustic emission.The experimental results show that changes in the specimen H/W ratio can transform the macro failure mode.When the H/W ratio is reduced to 0.5,the macro failure mode is dominated by slabbing.Low load-bearing ability is observed in specimens with slabbing failure,and the slabbing fractures are approximately parallel to the loading direction.Moreover,the fracture propagation characteristics and acoustic emission signals of slabbing failure specimens show typical tensile failure characteristics,indicating that slabbing failure is essentially a special tensile failure.