|
|
|
题名
|
作者
|
年代
|
出处
|
被引量
|
| 1 | Longwall mining “cutting cantilever beam theory” and 110 mining method in China——The third mining science innovation显示文摘With the third innovation in science and technology worldwide, China has also experienced this marvelous progress. Concerning the longwall mining in China, the 'masonry beam theory'(MBT) was first proposed in the 1960 s, illustrating that the transmission and equilibrium method of overburden pressure using reserved coal pillar in mined-out areas can be realized. This forms the so-called '121mining method', which lays a solid foundation for development of mining science and technology in China. The 'transfer rock beam theory'(TRBT) proposed in the 1980 s gives a further understanding for the transmission path of stope overburden pressure and pressure distribution in high-stress areas. In this regard, the advanced 121 mining method was proposed with smaller coal pillar for excavation design,making significant contributions to improvement of the coal recovery rate in that era. In the 21 st century,the traditional mining technologies faced great challenges and, under the theoretical developments pioneered by Profs. Minggao Qian and Zhenqi Song, the 'cutting cantilever beam theory'(CCBT) was proposed in 2008. After that the 110 mining method is formulated subsequently, namely one stope face,after the first mining cycle, needs one advanced gateway excavation, while the other one is automatically formed during the last mining cycle without coal pillars left in the mining area. This method can be implemented using the CCBT by incorporating the key technologies, including the directional presplitting roof cutting, constant resistance and large deformation(CRLD) bolt/anchor supporting system with negative Poisson's ratio(NPR) effect material, and remote real-time monitoring technology. The CCBT and 110 mining method will provide the theoretical and technical basis for the development of mining industry in China. | Manchao He Guolong Zhu Zhibiao Guo | 2015 | Journal of Rock Mechanics and Geotechnical Engineering2015，7，5： | 57 |
| 2 | Innovation and future of mining rock mechanics显示文摘The 121 mining method of longwall mining first proposed in England has been widely used around the world.This method requires excavation of two mining roadways and reservation of one coal pillar to mine one working face.Due to considerable excavation of roadway,the mining roadway is generally destroyed during coal mining.The stress concentration in the coal pillar can cause large deformation of surrounding rocks,rockbursts and other disasters,and subsequently a large volume of coal pillar resources will be wasted.To improve the coal recovery rate and reduce excavation of the mining roadway,the 111 mining method of longwall mining was proposed in the former Soviet Union based on the 121 mining method.The 111 mining method requires excavation of one mining roadway and setting one filling body to replace the coal pillar while maintaining another mining roadway to mine one working face.However,because the stress transfer structure of roadway and working face roof has not changed,the problem of stress concentration in the surrounding rocks of roadway has not been well solved.To solve the above problems,the conventional concept utilizing high-strength support to resist the mining pressure for the 121 and 111 mining methods should be updated.The idea is to utilize mining pressure and expansion characteristics of the collapsed rock mass in the goaf to automatically form roadways,avoiding roadway excavation and waste of coal pillar.Based on the basic principles of mining rock mechanics,the“equilibrium mining”theory and the“short cantilever beam”mechanical model are proposed.Key technologies,such as roof directional presplitting technology,negative Poisson’s ratio(NPR)high-prestress constant-resistance support technology,and gangue blocking support technology,are developed following the“equilibrium mining”theory.Accordingly,the 110 and N00 mining methods of an automatically formed roadway(AFR)by roof cutting and pressure releasing without pillars are proposed.The mining methods have been applied to a large number of coal mines with different overburdens,coal seam thicknesses,roof types and gases in China,realizing the integrated mode of coal mining and roadway retaining.On this basis,in view of the complex geological conditions and intelligent mining demand of coal mines,an intelligent and unmanned development direction of the“equilibrium mining”method is prospected. | Manchao He Qi Wang Qunying Wu | 2021 | Journal of Rock Mechanics and Geotechnical Engineering2021，13，1： | 28 |
| 3 | Deformation mechanism and excavation process of large span intersection within deep soft rock roadway显示文摘The FLAC3D software was used to simulate and analyze numerically the displacement, stress and plastic zone distribu-tion characteristics of a large span intersection in a deep soft rock roadway after the surrounding rock was excavated. Our simula-tion results show that there are two kinds of dominating factors affecting roadway stability at points of intersection, one is the angle between horizontal stress and axial direction of the roadway and the other are the angles at the points of intersection. These results are based on a study we carried out as follows: first, we analyzed the failure mechanism of a large span intersection and then we built a mechanical model of a rock pillar at one of the points of intersection. At the end of this analysis, we obtained the failure characteristics of the critical parts on the large span intersection. Given these failure characteristics, we proposed a new supporting method, i.e., a Double-Bolt Control Technology (DBCT). By way of numerical simulation, DBCT can effectively control the deformation of the surrounding rock at the points of intersection in roadways. | LI Guofeng, HE Manchao, ZHANG Guofeng, TAO Zhigang Institute of Geotechnical Engineering, China University of Mining & Technology, Beijing 100083, China | 2010 | Mining Science and Technology2010，20，1： | 24 |
| 4 | Latest progress of soft rock mechanics and engineering in China显示文摘The progress of soft rock mechanics and associated technology in China is basically accompanied by the development of mining engineering and the increasing disasters of large rock deformation during construction of underground engineering.In this regard,Chinese scholars proposed various concepts and classification methods for soft rocks in terms of engineering practices.The large deformation mechanism of engineering soft rocks is to be understood through numerous experiments;and thus a coupled support theory for soft rock roadways is established,followed by the development of a new support material,i.e.the constant resistance and large deformation bolt/anchor with negative Poisson’s ratio effect,and associated control technology.Field results show that large deformation problems related to numbers of engineering cases can be well addressed with this new technology,an effective way for similar soft rock deformation control. | Manchao He | 2014 | Journal of Rock Mechanics and Geotechnical Engineering2014，6，3： | 22 |
| 5 | Rockburst mechanism research and its control显示文摘A new rockburst classification, innovative works in developing a ‘‘strainburst test machine' and an‘‘impact-induced rockburst test machine' that can reproduce rockbursts in laboratory were researched.New concepts were proposed regarding the stress paths that take into account both the static and dynamic stresses analogous to that at excavation boundaries for generating artificially-induced strainburst and impact-induced rockburst. As an important method for rockburst control, a novel energyabsorbing bolt was developed, which has a constant-resistance under both static and impact loadings and a large-elongation capacity for containing large deformations of rock masses under burst-prone conditions. | Manchao He Fuqiang Ren Dongqiao Liu | 2018 | International Journal of Mining Science and Technology2018，28，5： | 21 |
| 6 | Studies on classification,criteria and control of rockbursts显示文摘This paper attempts to present the findings involving rockbursts classification,rockburst failure criteria,and related control measures.Experimental investigations were performed using the strainburst testing machine and impact-induced rockburst testing machine.According to the stress paths and experimental methods,rockbursts were classified into two major groups,i.e.the strainbursts and impact-induced bursts.The mechanisms and criteria of rockburst obtained from experimental investigations were discussed.Then,the developments of constant-resistance and large-deformation bolt(CRLDB),which can adapt itself to the external loading at a constant resistance by elongating continually,were introduced.The deformation energy of country rocks with large deformation can be absorbed by CRLDBs.Finally,the principles and the experimental results for control and prevention of rockburst using the CRLDBs were presented. | Manchao He Hongman Xia Xuena Jia Weili Gong Fei Zhao Kangyuan Liang | 2012 | Journal of Rock Mechanics and Geotechnical Engineering2012，4，2： | 21 |
| 7 | Principles and technology for stepwise utilization of resources for mitigating deep mine heat hazards显示文摘As is well known, deep mines are hot. As mining depth increases, the temperature of the surrounding rock also increases. This seriously affects mine safety and production and has restricted the exploitation of deep coal resources. Therefore, reducing the working face temperature to improve working conditions by controlling these heat hazards is an urgent problem. Considering problems in cooling deep mines both domestically and abroad along with the actual conditions of the Zhangshuanglou coal mine, we propose a HEMS technology that uses heat resources from deep mines in a stepwise manner. HEMS means a high temperature ex-change machinery system. Mine inrush-water is used as a source of cooling. Twice the energy is extracted from the mine inrush water. Heat is used for building heating in the winter and cold water is used for cooling buildings in the summer. This opens a new technology for stepwise utilization of heat energy in deep mines. Energy conservation and reduced pollution, an improved environment and sustainable economic development are realized by this technique. The economic and social effects are obvious and illustrate a good prospect for the application and extension of the method. | HE Manchao CAO Xiuling XIE Qiao YANG Jiahua QI Ping YANG Qing CHEN Xueqian | 2010 | Mining Science and Technology2010，20，1： | 15 |
| 8 | Microcrack analysis of Sanya grantite fragments from rockburst tests显示文摘Fractures running along a plane reflect the cracking progress.In this paper uniaxial and rockburst tests on a group of granite specimens from Sanya province are described.Scanning electron microscopic imaging was used to characterize the fragments.Fractal fracture mechanics were used to analyze the microcracks in terms of both the crack type and the mineral constituent.A statistical analysis showed that the area of inter-granular cracking exceeds that of intra-granular cracking.Several types of crack were observed in the cracked areas.The percentage of intra-granular cracks in fragments from rockburst tests exceeds that from uniaxial compression tests.The results also showed that feldspar deformation was the main cause of fracture and that the consolidation along quartz grain boundaries was another weak area in the granite.Cracking along quartz grains had enough energy to enter the quartz crystal in the rockburst samples.All these results contribute to further research on rockburst mechanics. | HE, Manchao NIE, Wen HAN, Liqiang LING, Lijing | 2010 | Mining Science and Technology2010，20，2： | 11 |
| 9 | Dynamic mechanical characteristics and application of constant resistance energy-absorbing supporting material显示文摘In deep underground engineering,rock burst and other dynamic disasters are prone to occur due to stress concentration and energy accumulation in surrounding rock.The control of dynamic disasters requires bolts and cables with high strength,high elongation,and high energy-absorbing capacity.Therefore,a constant resistance energy-absorbing(CREA)material is developed.In this study,the dynamic characteristics of the new material are obtained via the drop hammer tests and the Split Hopkinson Pressure Bar(SHPB)tests of the new material and two common bolt(CB)materials widely used in the field.The test results of drop hammer test and SHPB test show that the percentage elongation of CREA material is more than 2.64 and 3.22 times those of the CB material,and the total impact energy acting on CREA material is more than 18.50 and 21.84 times,respectively,indicating that the new material has high elongation and high energy-absorbing capacity.Subsequently,the CREA bolts and cables using the new material are developed,which are applied in roadways with high stress and strong dynamic disturbance.The field monitoring results show that CREA bolts and cables can effectively control the surrounding rock deformation and ensure engineering safety. | Qi Wang Shuo Xu Manchao He Bei Jiang Huayong Wei Yue Wang | 2022 | International Journal of Mining Science and Technology2022，32，3： | 9 |
| 10 | Pore Structure Characteristics and Permeability of Deep Sedimentary Rocks Determined by Mercury Intrusion Porosimetry显示文摘Pore structure characteristics of rock are a great concern for researchers and practitioners in rock mechanics and rock engineering fields. In this study, mercury intrusion porosimetry(MIP) was used to measure pore size distribution, as well as several important index parameters of pore structure, for seven common types of deep sedimentary rocks with a total of fifty rock samples. Results show a similar pore size distribution pattern of the rock samples in the same lithological group, but remarkable differences among different lithological groups. Among seven investigated rock types, mudstone has the smallest porosity of 3.37%, while conglomerate has the largest value of 18.8%. It is also found that the porosity of rock types with finer grain size is lower than those with coarser grain size. Meanwhile, a comparison of frequency distribution at ten intervals of pore-throat diameter among seven types of sedimentary rocks reveals that different rock types have different dominant pore-size ranges. Furthermore, permeability of the investigated sedimentary rock samples was derived based on MIP data using reported theoretical equations. Among seven rock types, mudstone has the lowest averaged permeability(3.64×10^(-6) mD) while conglomerate has the highest one(8.59×10^(-4) mD). From mudstone to conglomerate, rock permeability increases with an increase of grain size, with only an exception of siltstone which has a relatively larger porosity value. Finally, regression analysis show that there is a good fitting(R^2=0.95) between permeability and porosity which could be easily used to derive reliable permeability values of similar kinds of engineering rocks. | Na Zhang Manchao He Bo Zhang Fengchao Qiao Hailong Sheng Qinhong Hu | 2016 | Journal of Earth Science2016，27，4： | 9 |
| 11 | Hydrophilic and strength-softening characteristics of calcareous shale in deep mines显示文摘To better understand the mechanism of the strength weakening process of soft rocks in deep mines after interacting with water, a self-developed experimental system, Intelligent Testing System for Water Absorption in Deep Soft Rocks (ITSWADSR), is employed to analyze the hydrophilic behavior of deep calcareous shale sampled from Daqiang coal mine. Experimental results demonstrate that the relation between water absorption and time can be expressed by power functions, and the soakage rate decreases while the soakage increases with time. In order to quantitatively calculate the weight coefficients of the influential factors for water absorbing capacity of rocks, a series of testing methods are adopted, including scanning electron microscope (SEM), X-ray diffraction and mercury injection test. It is demonstrated that the effective porosity has a positive correlation with the water absorbing capacity of rocks and the contents of illite and illite/smectite. The initial water content presents a negative correlation with the water absorption capacity of rocks. According to the absolute value of weight coefficients of various influential factors, the order of magnitude from high to low is captured: initial water content, illite, illite/smectite formation (S=5%), and the effective porosity. After water absorption tests, uniaxial compressive strength (UCS) tests were performed on rock specimens allowing a linear relationship between the UCS and the water content of rock to be established, indicating that the strength of calcareous shale decreases linearly with the increasing water content. | Hongyun Guo Manchao He Chonghua Sun Bing Li Feng Zhang | 2012 | Journal of Rock Mechanics and Geotechnical Engineering2012，4，4： | 8 |
| 12 | An Innovative Non-Pillar Coal-Mining Technology with Automatically Formed Entry: A Case Study显示文摘A non-pillar coal-mining technology with an automatically formed entry is proposed,which reduces the waste of coal resources and the underground entry drivage workload.Three key techniques in this technology cooperate to achieve automatic formation and retaining of the gob-side entry,and to realize nonpillar mining.Constant-resistance large deformation(CRLD)support ensures the stability of the entry roof;directional presplitting blasting(DPB)separates the entry roof and the gob roof;and a blockinggangue support system(BGSS)integrates the caved rock material as an effective entry rib.An industrial test was conducted to verify the engineering effects of these key techniques.The field application results showed that the retained entry was under the pressure-relief zone due to the broken-expansion nature of the caved rock mass within the DPB height.After going through a provisional dynamic pressure-bearing zone,the retained entry entered the stability zone.The final stable entry meets the requirements of safety and production.The research results demonstrate the good engineering applicability of this technology.By taking the framework of the technology design principles into consideration and adjusting the measures according to different site conditions,it is expected that the proposed non-pillar coal-mining technology can be popularized on a large scale. | Xingyu Zhang Manchao He Jun Yang Eryu Wang Jiabin Zhang Yue Sun | 2020 | Engineering2020，6，11： | 8 |
| 13 | Comparative study of model tests on automatically formed roadway and gob-side entry driving in deep coal mines显示文摘Automatically formed roadway(AFR)by roof cutting with bolt grouting(RCBG)is a new deep coal mining technology.By using this technology,the broken roadway roof is strengthened,and roof cutting is applied to cut off stress transfer between the roadway and gob to ensure the collapse of the overlying strata.The roadway is automatically formed owing to the broken expansion characteristics of the collapsed strata and mining pressure.Taking the Suncun Coal Mine as the engineering background,the control effect of this new technology on roadways was studied.To compare the law of stress evolution and the surrounding rock control mechanisms between AFR and traditional gob-side entry driving,a comparative study of geomechanical model tests on the above methods was carried out.The results showed that the new technology of AFR by RCBG effectively reduced the stress concentration of the roadway compared with gob-side entry driving.The side abutment pressure peak of the solid coal side was reduced by 24.3%,which showed an obvious pressure-releasing effect.Moreover,the position of the side abutment pressure peak was far from the solid coal side,making it more beneficial for roadway stability.The deformation of AFR surrounding rock was also smaller than the deformation of the gob-side entry driving by the overload test.The former was more beneficial for roadway stability than the latter under higher stress conditions.Field application tests showed that the new technology can effectively control roadway deformation.Moreover,the technology reduced roadway excavation and avoided resource waste caused by reserved coal pillars. | Qi Wang Manchao He Shucai Li Zhenhua Jiang Yue Wang Qian Qin Bei Jiang | 2021 | International Journal of Mining Science and Technology2021，31，4： | 8 |
| 14 | Advances in interaction mechanism of water(gas) on clay minerals in China显示文摘Dealing with large-scale deformations in soft-rock tunnels is a very important issue in soft-rock tunnel engineering. The mechanism of this large-scale deformation is closely related to the physical and chemical properties of soft rock, interaction between soft rock and water, and interaction between soft rock and gas contained in soft rock. In order to gain a better predictive understanding of the governing principles associated with this phenomenon, we used experimental and theoretical methods to study the effects of point defect on physical and chemical properties of soft rock and mechanism of interaction between water(gas) and soft rock. Firstly, we calculated the impurity formation energies and transition energy levels of defects by using the first-principle calculation, the results showed the microscopic mechanism of defects substitution in kaolinite and effects of defects on the structure of kaolinite. Moreover,comparing the experimental and theoretical results, we found the mechanism of interaction between water and soft rock. The results show that water is one of the most important factors which can induce various kinds of geological disasters. At last, the interaction between soft rock and surrounding gas as CO2, CH4 and CO is disused, the influence of surrounding gas on soft rock should not be ignored. | He Manchao Sun Xiaoming Zhao Jian | 2014 | International Journal of Mining Science and Technology2014，24，6： | 8 |
| 15 | Principles of the roof cut short-arm beam mining method (110 method) and its mining-induced stress distribution显示文摘Since the 1960 s, mining science and technology in China has experienced two technical innovations, i.e.the ‘‘Masonry Beam Theory(MBT)' and ‘‘Transfer Rock Beam Theory(TRBT)'. Based on those theories, the conventional mining method(being called the 121 mining method) was established, consisting of excavating two tunnels with a pillar left for mining a working panel. However, with increasing mining depth,engineering geological disasters in the underground caverns have been frequently encountered. In addition, the use of the coal-pillar mining results in a large amount of coal resources unexploited. In order to address the problems above, the ‘‘Roof Cut Short-Arm Beam Theory(RCSBT), being called the 110 mining method)' was proposed by He Manchao in 2008. The 110 mining method features the mining of one coal seam panel, excavating necessarily only one roadway tunnel and leaving no pillars. Realization of the 110 mining method includes the following steps:(1) directional pre-splitting roof cutting,(2) supporting the roof by using high Constant Resistance Large Deformation bolt/cable(CRLD), and(3) blocking gangue by hydraulic props. This paper presents an overview of the principles, techniques and application of the 110 mining method. Special emphasis is placed on the numerical simulation of the geostress distribution found in the mining panel using the 110 method compared to that of the 121 method. In addition, the stress distribution on the ‘‘short beam' left by the roof cutting when performing the 110 method was also investigated using both numerical simulation and theoretical formulation. | Tao Zhigang Song Zhigang He Manchao Meng Zhigang Pang Shihui | 2018 | International Journal of Mining Science and Technology2018，28，3： | 8 |
| 16 | HEMS technique for heat-harm control and geo-thermal utilization in deep mines显示文摘With the increasing exploitation scope and intensity,the shallow resources would be exhausted in the future;and the deep mining will become an essential choice.In deep tunnel engineering,the heat-harm becomes one of the mainbariers.Investigations on high temperature coal mine have been done in Nothem China,with the construting of threemodels of high temperature mines suffering heat-harm,at the Jiahe mine,Sanhejian mine and Zhangshuanglou mine.Thedomestic and abroad cooling technologies of the mine respectively are also summarized after comparatively analyzing theadvantages and disadvantages of each technology.Finally,we find that the high temperature exchange machinery system(HEMS)technology that use mine discharge as the cold source,is excellent to heat-ham control in deep mines.Taking theJiahe coal mine as an example,we systematically introduce this teclnology by disposing three main workstations.HEMStechnology with its operations and functions in different exploitation levels are accomplished,including the extraction ofrefrigerating output,the transportation of chilled water by closed circulation line,the decompression of circulation linesand equipment by pressure transformation machine,and the heat exchange and cooling of workplace by heat exchangebetween wind stream and the chilled water.The exchanged heat source from the workplace is taken to ground heating bythe circulating water which acts as a carrier.It shows that the HEMS-technology benefit in environment protection andemission reduction.Results of this project illustrate that it is efficient in heat-ham control with the temperature decrease ofthe workplace down to 26-29℃,and being 4-6℃ lower than the original,and the relative humidity 5%-15%lowerthan before.It greatly improves the working environment of underground workplace suffering heat-ham of high tem-perature and high humidity.In addition,by the extracting of deep geothermal enery,ground fired boiler for heating hasbeen replaced,reducing environmental pollution.This technology is worth generalization in deep mines and related fields. | Pingye Guo Guolong Zhu Manchao He | 2014 | International Journal of Coal Science & Technology2014，1，3： | 7 |
| 17 | An experimental investigation on acoustic emission characteristics of sandstone rockburst with different moisture contents显示文摘Rockburst occurred frequently during deep mining in China. The mechanism of rockburst is very complicated and related to many factors. In order to investigate the influence of moisture contents of rockmass on rockburst, we conducted a series of laboratory rockburst experiments of sandstone under three different moisture contents by the Modified True-Triaxial Apparatus (MTTA),in which the acoustic emission (AE) system was employed to monitor the internal damage of rock mass. A high-speed video camera was utilized to record the detail of rockburst. Based on the experimental results, the AE characteristics, such as AE count,AE energy, and AE frequency, were analyzed. The rockburst process, type, and indensity under different moisture contents were discussed. The research results show that with the increase of moisture contents, rock strength was soften, the elastic and the cumulative damage of the rock were reduced, resulting in a gradual decrease in AE cumulative counts and cumulative energy over the course of rockburst. This study provides an experimental basis and reference for better understanding to the rockburst mechanism and control. | SUN XiaoMing XU HuiChen ZHENG LianGe HE ManChao GONG WeiLi | 2016 | Science China(Technological Sciences)2016，59，10： | 7 |
| 18 | Compensation excavation method control for large deformation disaster of mountain soft rock tunnel显示文摘In recent years,the mine tunneling method and the new Austrian tunneling method have been considered the main theories of tunneling approaches in China.It is difficult for the traditional technique to overcome the large deformation problems imposed by complex geological conditions of mountain soft rock tunneling.Hence,the compensation excavation method has been proposed to solve this issue under the consideration that all damage in tunneling originates from the excavation.It uses supportive strategies to counteract the excavation effects successfully.This paper provides an overview of the fundamental ideas of the compensation excavation method,methodologies,and field applications.The scientific validity and feasibility of the compensation excavation method were investigated through the practical engineering study of the Muzhailing and Changning tunnels. | Manchao He Qiru Sui Mengnan Li Zhijiao Wang Zhigang Tao | 2022 | International Journal of Mining Science and Technology2022，32，5： | 6 |
| 19 | A review of rockburst:Experiments,theories,and simulations显示文摘Rockburst is becoming a huge challenge for the utilization of deep underground space.Extensive efforts have been devoted to investigating the rockburst behavior and mechanism experimentally,theoretically,and numerically.The aim of this review is to discuss the novel development and the state-of-the-art in experimental techniques,theories,and numerical approaches proposed for rockburst.The definition and classification of rockburst are first summarized with an in-depth comparison among them.Then,the available laboratory experimental technologies for rockburst are reviewed in terms of indirect and direct approaches,with the highlight of monitoring technologies and data analysis methods.Some key rockburst influencing factors(i.e.size and shape,rock types,stress state,water content,and temperature)are analyzed and discussed based on collected data.After that,rockburst theories and mechanisms are discussed and evaluated,as well as the microscopic observation.The simulation approaches of rockburst are also summarized with the highlight of optional novel numerical methods.The accuracy,stability,and reliability of different experimental,theoretical and numerical approaches are also compared and assessed in each part.Finally,a summary and some aspects of prospective research are presented. | Manchao He Tai Cheng Yafei Qiao Hongru Li | 2023 | Journal of Rock Mechanics and Geotechnical Engineering2023，15，5： | 6 |
| 20 | Micro-and macro-fractures of coarse granite under true-triaxial unloading conditions显示文摘We studied the mechanical behavior of rock under different boundary conditions, based on the fractal characteristics of fractures in terms of microscopic and macroscopic investigations. Three rectangular granite specimens of similar dimensions were tested by a triaxial rock testing machine under uniaxial compression (UC), confined compression (CC) and true-triaxial unloading conditions (RB) under rock burst boundary conditions. The failure processes of these specimens were investigated via examinations of their fracture behavior on a macro-scale by laser profilometers and on a micro-scale by a scanning electron microscopic (SEM) imaging technique. The SEM images, showing the spalling features of RB fragments, are compared with the grain dislocations under UC and CC conditions. Based on a variogram method, two fractal parameters, i.e., fractal dimensions (D rld ) and the scale dependent fractal parameter K v , were induced to present the surface roughness of scanning profiles in all directions. The fitted ellipses of D rld distribution show that RB surface has the smallest eccentricity, followed by the CC surface, while the UC surface had the largest eccentricity. As a result of this assessment, we conclude that rocks are affected by shear traction in an intermediate stress direction, which will cause fractures generated during rock bursts to twist rather than to tilt as shown in the uniaxial compression and the confined compression tests. | He Manchao Nie Wen Zhao Zhiye Cheng Cheng | 2011 | Mining Science and Technology2011，21，3： | 6 |
您所在的机构暂未开通此部分的功能，请联系管理员