Focusing on the stability of surrounding rock around the roadway driving along next goaf with a narrow coal pillar, a mechanics model of the triangle block structure of main roof above the roadway is established, and ...Focusing on the stability of surrounding rock around the roadway driving along next goaf with a narrow coal pillar, a mechanics model of the triangle block structure of main roof above the roadway is established, and the sliding stability coefficient K 1 and the rotation stability coefficient K 2 are proposed to describe the stability of the triangle block structure quantitatively. The structure can keep a self stability before and after the roadway excavation, at the stage of mining induced effect, the stability of the structure is lowered, and the structure may become instability with decreasing the coal strength, increasing the mining height of working face and the mining depth.展开更多
Underground mines require complex construction activities including the shaft, levels, raises, winzes and ore passes. In an underground mine based on stoping method, orebody part(s) maximizing profit should be determi...Underground mines require complex construction activities including the shaft, levels, raises, winzes and ore passes. In an underground mine based on stoping method, orebody part(s) maximizing profit should be determined. This process is called stope layout optimization (SLO) and implemented under site-specific geotechnical, operational and economic constraints. For practical purpose, the design obtained by SLO shows consecutive stopes in one path, which assists in defining the mining direction of these stopes. However, this direction may not accommodate the spatial distribution of the ore grade: if the orebody orientation and mining direction differ, the value of the mining operation may decrease. This paper proposes an approach whereby paths in the SLO are defined as decision variables to avoid the cost of mining in the wrong direction. Furthermore, in the genetic-based formulation, which accounts for orebody uncertainty, a robust cluster average design process is proposed to improve SLO’s performance regarding metal content. A case study in narrow gold vein deposit shows that the profit of an underground mining operation could be underestimated by 25%-48% if the algorithm ignores stope layout orientation.展开更多
Comparison between the NEIC broadband radiated energy catalogue and the Harvard CMT catalogue provides information about apparent stress. In spite of its significant uncertainties and limited reliability, the clues ob...Comparison between the NEIC broadband radiated energy catalogue and the Harvard CMT catalogue provides information about apparent stress. In spite of its significant uncertainties and limited reliability, the clues obtained from this comparison seem interesting in the physics of earthquakes. Scaling of apparent stress provides information about the dynamic friction along an earthquake fault. Relation between reduced energy and seismic moment implies that for strike-slip earthquakes, velocity-dependent friction plays a predominant role, while for non-strike-slip earthquakes, slip-dependent friction is predominant. It is also found that strike-slip events with extremely low apparent stress tend to occur “in single”, which is applied to the prediction of the seismic tendency following the 2001 Qinghai-Xizang (Tibet) border M W7.8 earthquake.展开更多
According to the geological and mining technical conditions of No.18128 sub- level caving face with suspend-shift support,the first working face of the working area,the distribution laws of abutment pressure were stud...According to the geological and mining technical conditions of No.18128 sub- level caving face with suspend-shift support,the first working face of the working area,the distribution laws of abutment pressure were studied by jointly employing FIAC^(3D) numerical simulations and field tests.With the full consideration of these laws and the service time- limit of the mining district,the optimal location of the terminal mining line,should be 60 m away from the W4-B8 track dip,which was 20 m shorter than the 80 m distance deter- mined according to traditional experiences.The retained coal safety pillar for the protect- ing of dips,already proved by the industrial practice,can not only improve the rate of coal recovery and satisfy the subsequent service requirement for the following working faces, but also decrease the maintaining expenditure and thus increase profits.展开更多
Presented the concept of the natural support strength.The natural support strength,the strike sill,the multifunction retractors (developed by the author) and etc.were used with the technical measures to change the pas...Presented the concept of the natural support strength.The natural support strength,the strike sill,the multifunction retractors (developed by the author) and etc.were used with the technical measures to change the passive support to the initiative support, and the soft rock entry was supported.And its process is simple and less equipment is needed,and the cost is low and the advance rate is high,which can meet the require- ments of actual mining.It solves many support difficult problems.展开更多
By analyzing high-resolution SPOT images and in combination with fieldwork and chronometry, three typical fault-offset sites on the south-middle Altyn Tagh strike-slip fault were studied to obtain the sinistral horizo...By analyzing high-resolution SPOT images and in combination with fieldwork and chronometry, three typical fault-offset sites on the south-middle Altyn Tagh strike-slip fault were studied to obtain the sinistral horizontal slip rate of the fault. At Annanba, the left-lateral strike-slip rate on a branch of the south Altyn Tagh fault is 7.5±1.7 mm/a since 9.36±0.73ka BP. At Seven Spring, the fault has four branches and the left-lateral strike-slip rate on one of them is 2.3±0.5mm/a since 13.86±1.07ka BP, and it is deduced that the total slip-rate of all the four branches is 6.9±1.5～ 9.2±2.0 mm/a since Holocene. At Yuemakeqi, the left-lateral strike-slip rate of the fault is 10.6±3.0mm/a since 4.73±0.38 ka BP. A slip-rate of 7～11mm/a on the middle segment of the Altyn Tagh fault (between 88°30’E and 93°05’E) since Holocene can be deduced from the three sites mentioned above and the result is similar to the latest GPS observation.展开更多
By taking moderate-strong earthquakes in South,North and West China as the research subjects and taking into consideration the fault strikes in these regions,this paper selects 8 kinds of seismology indexes with clear...By taking moderate-strong earthquakes in South,North and West China as the research subjects and taking into consideration the fault strikes in these regions,this paper selects 8 kinds of seismology indexes with clear physical significance and strong independence to carry out spatial scanning of the parallel,vertical and oblique slip of fault along the fault strike.Based on the size of correlation coefficients between the scanning curve and source region curve we quantitatively analyze the difference between scan results among different slip modes and study the impact of fault strike in different tectonic divisions on scanning results and variation rules of seismological parameters.The results show that not only does the change of spatial parameters have a great influence on seismological parameter scanning,but so does the fault strike in the source region.This paper presents the optimum condition parameters with least spatial influencing scanning scope for different magnitude seismology indexes and analyzes the possible influence of fault strike on seismological parameter scanning results.展开更多
文摘Focusing on the stability of surrounding rock around the roadway driving along next goaf with a narrow coal pillar, a mechanics model of the triangle block structure of main roof above the roadway is established, and the sliding stability coefficient K 1 and the rotation stability coefficient K 2 are proposed to describe the stability of the triangle block structure quantitatively. The structure can keep a self stability before and after the roadway excavation, at the stage of mining induced effect, the stability of the structure is lowered, and the structure may become instability with decreasing the coal strength, increasing the mining height of working face and the mining depth.
基金Project(488262-15)supported by the Natural Sciences and Engineering Research Council of Canada
文摘Underground mines require complex construction activities including the shaft, levels, raises, winzes and ore passes. In an underground mine based on stoping method, orebody part(s) maximizing profit should be determined. This process is called stope layout optimization (SLO) and implemented under site-specific geotechnical, operational and economic constraints. For practical purpose, the design obtained by SLO shows consecutive stopes in one path, which assists in defining the mining direction of these stopes. However, this direction may not accommodate the spatial distribution of the ore grade: if the orebody orientation and mining direction differ, the value of the mining operation may decrease. This paper proposes an approach whereby paths in the SLO are defined as decision variables to avoid the cost of mining in the wrong direction. Furthermore, in the genetic-based formulation, which accounts for orebody uncertainty, a robust cluster average design process is proposed to improve SLO’s performance regarding metal content. A case study in narrow gold vein deposit shows that the profit of an underground mining operation could be underestimated by 25%-48% if the algorithm ignores stope layout orientation.
文摘Comparison between the NEIC broadband radiated energy catalogue and the Harvard CMT catalogue provides information about apparent stress. In spite of its significant uncertainties and limited reliability, the clues obtained from this comparison seem interesting in the physics of earthquakes. Scaling of apparent stress provides information about the dynamic friction along an earthquake fault. Relation between reduced energy and seismic moment implies that for strike-slip earthquakes, velocity-dependent friction plays a predominant role, while for non-strike-slip earthquakes, slip-dependent friction is predominant. It is also found that strike-slip events with extremely low apparent stress tend to occur “in single”, which is applied to the prediction of the seismic tendency following the 2001 Qinghai-Xizang (Tibet) border M W7.8 earthquake.
基金the National Natural Science Foundation of China(50674002)the Educational Department of Anhui Province(KJ2008B109)
文摘According to the geological and mining technical conditions of No.18128 sub- level caving face with suspend-shift support,the first working face of the working area,the distribution laws of abutment pressure were studied by jointly employing FIAC^(3D) numerical simulations and field tests.With the full consideration of these laws and the service time- limit of the mining district,the optimal location of the terminal mining line,should be 60 m away from the W4-B8 track dip,which was 20 m shorter than the 80 m distance deter- mined according to traditional experiences.The retained coal safety pillar for the protect- ing of dips,already proved by the industrial practice,can not only improve the rate of coal recovery and satisfy the subsequent service requirement for the following working faces, but also decrease the maintaining expenditure and thus increase profits.
基金the Educational Department of Liaoning Province(20081220)
文摘Presented the concept of the natural support strength.The natural support strength,the strike sill,the multifunction retractors (developed by the author) and etc.were used with the technical measures to change the passive support to the initiative support, and the soft rock entry was supported.And its process is simple and less equipment is needed,and the cost is low and the advance rate is high,which can meet the require- ments of actual mining.It solves many support difficult problems.
文摘By analyzing high-resolution SPOT images and in combination with fieldwork and chronometry, three typical fault-offset sites on the south-middle Altyn Tagh strike-slip fault were studied to obtain the sinistral horizontal slip rate of the fault. At Annanba, the left-lateral strike-slip rate on a branch of the south Altyn Tagh fault is 7.5±1.7 mm/a since 9.36±0.73ka BP. At Seven Spring, the fault has four branches and the left-lateral strike-slip rate on one of them is 2.3±0.5mm/a since 13.86±1.07ka BP, and it is deduced that the total slip-rate of all the four branches is 6.9±1.5～ 9.2±2.0 mm/a since Holocene. At Yuemakeqi, the left-lateral strike-slip rate of the fault is 10.6±3.0mm/a since 4.73±0.38 ka BP. A slip-rate of 7～11mm/a on the middle segment of the Altyn Tagh fault (between 88°30’E and 93°05’E) since Holocene can be deduced from the three sites mentioned above and the result is similar to the latest GPS observation.
基金sponsored by sub-project ofNotional Key Technology R&D Program (2006BAC01B020105)the Key Technology R&D Program of AnhuiProvince (08010302204),China
文摘By taking moderate-strong earthquakes in South,North and West China as the research subjects and taking into consideration the fault strikes in these regions,this paper selects 8 kinds of seismology indexes with clear physical significance and strong independence to carry out spatial scanning of the parallel,vertical and oblique slip of fault along the fault strike.Based on the size of correlation coefficients between the scanning curve and source region curve we quantitatively analyze the difference between scan results among different slip modes and study the impact of fault strike in different tectonic divisions on scanning results and variation rules of seismological parameters.The results show that not only does the change of spatial parameters have a great influence on seismological parameter scanning,but so does the fault strike in the source region.This paper presents the optimum condition parameters with least spatial influencing scanning scope for different magnitude seismology indexes and analyzes the possible influence of fault strike on seismological parameter scanning results.
