On the basis of Betti's theorem,the constitutive relation of multi- crack rockmass which considers the effect of crack-closure is developed in this paper. Meanwhile,based on mathematical elasticity,the paper gives...On the basis of Betti's theorem,the constitutive relation of multi- crack rockmass which considers the effect of crack-closure is developed in this paper. Meanwhile,based on mathematical elasticity,the paper gives an analytical formula for the compression transmitting coefficient and the shearing transmitting coefficient. A damage evolution equation of rock-mass is presented and an engineering application is given as well.展开更多
Post failure rheology, as an important deformable behavior of average to very poor rockmass,is discussed in this paper. Three kinds of deformations, transition deformation, post failure rheological deformation and swe...Post failure rheology, as an important deformable behavior of average to very poor rockmass,is discussed in this paper. Three kinds of deformations, transition deformation, post failure rheological deformation and swelling deformation, are also introduced for they are totally different from that of traditional concepts. Transition and post failure deformations are sensitive to the environmental factors, and need to be studied in the future.展开更多
On 12 May 2008, the magnitude 8.0 Wenchuan Earthquake occurred along the Longmen Shan nappe, Sichuan, China. This devastating earthquake led to a heavy death toll of greater than 80,000. The seismic origin of this ear...On 12 May 2008, the magnitude 8.0 Wenchuan Earthquake occurred along the Longmen Shan nappe, Sichuan, China. This devastating earthquake led to a heavy death toll of greater than 80,000. The seismic origin of this earthquake is currently hotly debated. We suppose that it is a special type of intraplate earthquake called an active-nappe-type earthquake. Using a holistic methodology, incorporating rockmass structure cybernetics and Byerlee's law, we present a comprehensive study on the geological origin of macroseisms in the Longmen Shan area and the seismic origin of the 2008 Wenchuan earthquake. Previous studies of neotectonic activity indicate that the Longmen Shan nappe moves at a rate of 1~3 mm/yr, due to horizontal compressive stress from the Tibetan Plateau. The difference between movement rates in the Bayankala block, Longmen Shan nappe and Sichuan Basin cause slow shear stress and strain accumulation in the Longmen Shan nappe. It is exhibited a relatively simple linear relations for the shear strength and the buried depth of the structural planes, and the detachment layer of the nappe has a higher shearing-sliding strength compared to the overlying fault planes and the underlying ductile shear belts, thus making it more prone to stick-slip deformation. Therefore, the detachment layer was the main section responsible for the Wenchuan earthquake. The initial rupture burst in the detachment layer under the Yingxiu-Beichuan fault, the rupture area nearly 1.4454 × 104 km2,encompassed the cross point of the Yingxiu and the Anxian-Guanxian faults with the detachment layer, then caused the Yingxiu-Beichuan and Anxian-Guanxian faults took an active part in this earthquake, so this earthquake might consist of three chain-like earthquake stages, totally increasing the duration of this earthquake an unusually large amount, to 120 s. The focal depth spanned range of 10-20km,consistent with the observed result of this focal depth by several agencies.展开更多
The desired economics of hard rock surface mining is mainly determined by the parameters of process design which minimize the overall cost per tonne of the rock mined in drilling, blasting, handling and primary crushi...The desired economics of hard rock surface mining is mainly determined by the parameters of process design which minimize the overall cost per tonne of the rock mined in drilling, blasting, handling and primary crushing in given rockmass conditions. The most effective parameters of process design could be established based on the regression models of the cumulative influence of rockmass and mine design parameters on the overall cost per tonne of the rock drilled, blasted, handled and crushed. These models could be developed from the huge data accumulated worldwide on the costs per tonne of hard rock surface mining in drilling, blasting, handling and primary crushing vs the parameters of rockmass and mine design. This paper only dwelt on the development of regression models for oversize generation, blasthole productivity and blasting cost for iron ore surface mines, whose data is available. The SPSS standard statistical correlation – regression analysis software was used in the analysis. Interpretation of the models generated shows that the individual effects of the determinant rockmass and blast design parameters on oversize generation, blasthole productivity and blasting cost are all in compliance with the findings of other researchers and the theory of explosive rock fragmentation and could be used for the estimation of oversize generation, blasthole productivity and blasting cost in rockmass and blast design conditions similar to those of the iron ore surface mines examined in this study. However, the regression models obtained here could not be used alone for the optimization of blast design because most of the determinant parameters also have conflicting effect on the other processes of drilling, handling and primary crushing the blasted rock. Also, the quality and content of the regression models could be enhanced further by increasing the content of rockmass and blast design parameters and the volume of data considered in the regression analysis.展开更多
The strength of rockmass from two aspects is analyzed.Firstly,the strength of the rockmass is mainly controlled by the critical stress value of rock,and the contribution of joints is to increase the effective stresses...The strength of rockmass from two aspects is analyzed.Firstly,the strength of the rockmass is mainly controlled by the critical stress value of rock,and the contribution of joints is to increase the effective stresses of rock and to decrease the damage strength of rockmass according to the macro damage mechanics of rockmass.Secondly,the strength of rockmass is mainly controlled by the fracture strength of joints.Based on the comprehensive analysis and comparison for the damage strength of rockmass and the fracture strength of joints,a composite damage theory of rockmass may be established.展开更多
基金Project(42130810)supported by the National Natural Science Foundation of ChinaProject(2022JJ20057)supported by the Natural Science Foundation for Excellent Young Scholars of Hunan Province,China+1 种基金Project(2023CXQD063)supported by Central South University Innovation-Driven Research Programme,ChinaProject(2022-01)supported by Natural Resources Science and Technology Project of Hunan Province,China。
基金The project supported by the National Natural Science Foundation of China(59493600 and 59939190)
文摘On the basis of Betti's theorem,the constitutive relation of multi- crack rockmass which considers the effect of crack-closure is developed in this paper. Meanwhile,based on mathematical elasticity,the paper gives an analytical formula for the compression transmitting coefficient and the shearing transmitting coefficient. A damage evolution equation of rock-mass is presented and an engineering application is given as well.
文摘Post failure rheology, as an important deformable behavior of average to very poor rockmass,is discussed in this paper. Three kinds of deformations, transition deformation, post failure rheological deformation and swelling deformation, are also introduced for they are totally different from that of traditional concepts. Transition and post failure deformations are sensitive to the environmental factors, and need to be studied in the future.
文摘On 12 May 2008, the magnitude 8.0 Wenchuan Earthquake occurred along the Longmen Shan nappe, Sichuan, China. This devastating earthquake led to a heavy death toll of greater than 80,000. The seismic origin of this earthquake is currently hotly debated. We suppose that it is a special type of intraplate earthquake called an active-nappe-type earthquake. Using a holistic methodology, incorporating rockmass structure cybernetics and Byerlee's law, we present a comprehensive study on the geological origin of macroseisms in the Longmen Shan area and the seismic origin of the 2008 Wenchuan earthquake. Previous studies of neotectonic activity indicate that the Longmen Shan nappe moves at a rate of 1~3 mm/yr, due to horizontal compressive stress from the Tibetan Plateau. The difference between movement rates in the Bayankala block, Longmen Shan nappe and Sichuan Basin cause slow shear stress and strain accumulation in the Longmen Shan nappe. It is exhibited a relatively simple linear relations for the shear strength and the buried depth of the structural planes, and the detachment layer of the nappe has a higher shearing-sliding strength compared to the overlying fault planes and the underlying ductile shear belts, thus making it more prone to stick-slip deformation. Therefore, the detachment layer was the main section responsible for the Wenchuan earthquake. The initial rupture burst in the detachment layer under the Yingxiu-Beichuan fault, the rupture area nearly 1.4454 × 104 km2,encompassed the cross point of the Yingxiu and the Anxian-Guanxian faults with the detachment layer, then caused the Yingxiu-Beichuan and Anxian-Guanxian faults took an active part in this earthquake, so this earthquake might consist of three chain-like earthquake stages, totally increasing the duration of this earthquake an unusually large amount, to 120 s. The focal depth spanned range of 10-20km,consistent with the observed result of this focal depth by several agencies.
文摘The desired economics of hard rock surface mining is mainly determined by the parameters of process design which minimize the overall cost per tonne of the rock mined in drilling, blasting, handling and primary crushing in given rockmass conditions. The most effective parameters of process design could be established based on the regression models of the cumulative influence of rockmass and mine design parameters on the overall cost per tonne of the rock drilled, blasted, handled and crushed. These models could be developed from the huge data accumulated worldwide on the costs per tonne of hard rock surface mining in drilling, blasting, handling and primary crushing vs the parameters of rockmass and mine design. This paper only dwelt on the development of regression models for oversize generation, blasthole productivity and blasting cost for iron ore surface mines, whose data is available. The SPSS standard statistical correlation – regression analysis software was used in the analysis. Interpretation of the models generated shows that the individual effects of the determinant rockmass and blast design parameters on oversize generation, blasthole productivity and blasting cost are all in compliance with the findings of other researchers and the theory of explosive rock fragmentation and could be used for the estimation of oversize generation, blasthole productivity and blasting cost in rockmass and blast design conditions similar to those of the iron ore surface mines examined in this study. However, the regression models obtained here could not be used alone for the optimization of blast design because most of the determinant parameters also have conflicting effect on the other processes of drilling, handling and primary crushing the blasted rock. Also, the quality and content of the regression models could be enhanced further by increasing the content of rockmass and blast design parameters and the volume of data considered in the regression analysis.
文摘The strength of rockmass from two aspects is analyzed.Firstly,the strength of the rockmass is mainly controlled by the critical stress value of rock,and the contribution of joints is to increase the effective stresses of rock and to decrease the damage strength of rockmass according to the macro damage mechanics of rockmass.Secondly,the strength of rockmass is mainly controlled by the fracture strength of joints.Based on the comprehensive analysis and comparison for the damage strength of rockmass and the fracture strength of joints,a composite damage theory of rockmass may be established.
