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Determination of ejection velocity of rock fragments during rock burst in consideration of damage

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Journal of Central South University of Technology 2005年第5期12卷 618-622页

作者：左宇军李夕兵周子龙 School of Resources and Safety Engineering Central South University Changsha 410083 China

The ejection velocity of rock fragments during rock burst, one of the important indexes representing the rock burst strength, is used most conveniently in the supporting design of tunnel with rock burst tendency and is often determined by means of observation devices. In order to calculate the average ejection velocity of rock fragments theoretically, the energy of rock burst was divided into damage consuming energy and kinetic energy gained by unit volume of rock firstly, and then the rock burst kinetic proportional coefficient η was brought up which could be determined according to the rock-burst damage energy index W_D , at last the expression of the average ejection velocity of rock fragments during rock burst was obtained and one deep level underground tunnel was researched using the mentioned method. The results show that the calculation method is valid with or without considering the tectonic stress of tunnels, and that the method can be a reference for supporting design of deep mining.

关键词： rock burst ejection velocity support design energy equilibrium damage

Constitutive model of rock based on microstructures simulation

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Journal of Central South University of Technology 2008年第2期15卷 230-236页

作者：叶洲元洪亮刘希灵尹土兵 School of Resources and Safety Engineering Central South University

The constitutive model of rock can be built by mechanics elements because there are many kinds of damages in rock under varied *** is resumed that rock contains many microstructures and a structure of *** microstructure consists of two embranchments that are the unit of a spring and a gliding slice in series and the unit of a spring and a cementation bar in series,the two units connect each other in *** microstructures are arranged disorderly or in the order of a certain state.A certain distribution of microstructures represents one type of *** kinds of rock's constitutive relationship were deduced by using the *** is the model in which many parallel microstructures and a structure of Bingham connect in *** it is used to homogeneous *** other is the model in which many microstructures and a structure of Bingham connect in *** it is used to the rock with much crack or microcrack in a certain *** two kinds of constitutive relationship were verified by the studied *** constitutive model of rock built by using mechanics elements is verified to be ***,different types of rocks may be described with mechanics elements with different distributions.

关键词： constitutive model microstructure mechanics element connecting type

Energy consumption in rock fragmentation at intermediate strain rate

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Journal of Central South University 2009年第4期16卷 677-682页

作者：洪亮周子龙尹土兵廖国燕叶洲元 School of Resources and Safety Engineering Central South University Department of Civil Engineering Hunan City University

In order to determine the relationship among energy consumption of rock and its fragmentation, dynamic strength and strain rate, granite, sandstone and limestone specimens were chosen and tested on large-diameter split Hopkinson pressure bar (SHPB) equipment with half-sine waveform loading at the strain rates ranging from 40 to 150 s- 1. With recorded signals, the energy consumption, strain rate and dynamic strength were analyzed. And the fragmentation behaviors of specimens were investigated. The experimental results show that the energy consumption density of rock increases linearly with the total incident energy. The energy consumption density is of an exponent relationship with the average size of rock fragments. The higher the energy consumption density, the more serious the fragmentation, and the better the gradation of fragments. The energy consumption density takes a good logarithm relationship with the dynamic strength of rock. The dynamic strength of rock increases with the increase of strain rate, indicating higher strain rate sensitivity.

关键词： rock large-diameter SHPB test intermediate strain rate energy consumption density fragment distribution dynamic strength

Discussion on rheology in petroleum and nature gas teservoir stimulation

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Journal of Central South University 2008年第S1期15卷 362-368页

作者：卢拥军梁冲胥云陈彦东 Research Institute of Petroleum Exploration and Development-Langfang

Petroleum and nature gas not only are important resources,but also are important strategic materials of our *** methods the enhancing the producing degree of petroleum and natural gas reservoir,increasing single well production and extending the stimulation period of validity are important stratagem for petroleum and natural gas *** and acidizing are the main methods for stimulation as well as one of representative examples of rheology theory application in *** on analysis of low permeability reservoir characteristics,the fracturing and acidizing stimulation principles and main controlling factors were *** the mechanical characteristics,chemical reaction and rheological behavior in the stimulation process were *** research trends afterwards including the material and fluid rheology in oil and natural gas production process,the deep rock fracture initiation and extension rheology,and the fracturing and acidizing application rheology were also proposed in this paper.

关键词： fracturing fracturing fluids acid fracturing acid fluids low permeability petroleum rheology

Experiments and analysis for rheological properties of MRF

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Journal of Central South University 2008年第S1期15卷 284-287页

作者：王海霞阮予明孔笋王捷 Fujian Electric Vocational and Technical College Department of Mechanical and Electric Engineering

The work principle of flat-plate structure under shearing mode is expounded based on a vertical type rheometer for MRF which combined data acquisition with treatment and result *** formula to calculate shearing stress is *** on different recipe for MRF,experiments under different working gap length were done by altering the intensity of magnetic *** rheological model for MRF was established and the relationships between shearing stress,viscosity and magnetic field intensity were *** indicate that MRF has the flowing characters:with an increase of the magnetic induction and the nominal shear rate,the shear stress of MRF ***,as the working gap decreases,the shear stress *** has shear thinning property under magnetic field.

关键词： magneto-rheological fluid constitutive equation rheometer experiment

Constitutive model of rock under static-dynamic coupling loading and experimental investigation

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中国有色金属学会会刊：英文版 2006年第3期16卷 714-722页

作者：李夕兵左宇军王卫华马春德周子龙 School of Resources and Safety Engineering Ce ntral South University Changsha 410083 China

The importance of study on constitutive model of statically loaded rock experiencing dynamic load is set forth, and the studying methods on dynamic constitutive model are classified according to the current studying status. By way of combining statistic damage model and viscoelastic model, uni-axial and multi-axial constitutive models of statically loaded rock experiencing dynamic load (static-dynamic coupling constitutive model) under intermediate strain rate are established. The verification experiment on 2D constitutive model under different static stress and dynamic stress with different frequencies is designed and performed. It is found that there is a good agreement between the experimental stress-strain curves and the theoretical stress-strain curves.

关键词：动荷载疲劳速率岩石试验粘弹性损伤本构模型

Probabilistic density function estimation of geotechnical shear strength parameters using the second Chebyshev orthogonal polynomial

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Journal of Central South University of Technology 2006年第3期13卷 275-280页

作者：李夕兵宫凤强邓建 School of Resources and Safety Engineering Central South University Changsha 410083China

A method to estimate the probabilistic density function （PDF） of shear strength parameters was proposed. The second Chebyshev orthogonal polynomial（SCOP） combined with sample moments （the origin moments） was used to approximate the PDF of parameters. X^2 test was adopted to verify the availability of the method. It is distribution-free because no classical theoretical distributions were assumed in advance and the inference result provides a universal form of probability density curves. Six most commonly-used theoretical distributions named normal, lognormal, extreme value Ⅰ , gama, beta and Weibull distributions were used to verify SCOP method. An example from the observed data of cohesion c of a kind of silt clay was presented for illustrative purpose. The results show that the acceptance levels in SCOP are all smaller than those in the classical finite comparative method and the SCOP function is more accurate and effective in the reliability analysis of geotechnical engineering.

关键词： shear strength second Chebyshev orthogonal polynomial probabilistic density function origin moments

Experiments and analysis for rheological properties of MRF

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Experiments and analysis for rheological properties of MRF

Discussion on rheology in petroleum and nature gas teservoir stimulation

The 9th National Conference on Rheology

作者：王海霞阮予明孔笋王捷 Fujian Electric Vocational and Technical College Department of Mechanical and Electric Engineering

＜正＞The work principle of fiat-plate structure under shearing mode is expounded based on a vertical type rheometer for MRF which combined data acquisition with treatment and result *** formula to calculate shearing stress is *** on different recipe for MRF,experiments under different working gap length were done by altering the intensity of magnetic *** rheological model for MRF was established and the relationships between shearing stress,viscosity and magnetic field intensity were *** indicate that MRF has the flowing characters:with an increase of the magnetic induction and the nominal shear rate,the shear stress of MRF ***,as the working gap decreases,the shear stress *** has shear thinning property under magnetic field.

关键词： magneto-rheological fluid constitutive equation rheometer experiment

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Discussion on rheology in petroleum and nature gas teservoir...