In order to investigate the failure mechanism of rock joint,a series of laboratory tests including cyclic direct shear tests under constant normal load(CNL)conditions were conducted.Morphology parameters of the rock j...In order to investigate the failure mechanism of rock joint,a series of laboratory tests including cyclic direct shear tests under constant normal load(CNL)conditions were conducted.Morphology parameters of the rock joint surface were precisely calculated by means of a three-dimensional laser scanning machine.All test results were analyzed to investigate the shear behavior and normal displacement behavior of rock joints under CNL conditions.Degradation of rock joint surface during cyclic shear tests was also analyzed.The comparison results of the height parameters and the hybrid parameters of the joint surface during cyclic tests show that the degradation of the surface mostly happens in the first shear and the constant normal loads imposed on the joints have significant promotion effects on the morphology degradation.During cyclic shear tests,joints surfaces evolve from rough state to smooth state but keep an overall undulation.Dilatancy of rock joints degrades with the degradation of joint surface and the increase of normal loads.The closure deformation of joint is larger than that of the intact rock,and the normal stiffness increases with the increase of shearing times.展开更多
Objective： To study the patterns and morphologic characteristics of blunt head injury and analyse its formative mechanism in attempt to provide references for medicolegal expertise. Methods： The statistical analysi...Objective： To study the patterns and morphologic characteristics of blunt head injury and analyse its formative mechanism in attempt to provide references for medicolegal expertise. Methods： The statistical analysis was done in terms of gender, age, as well as the nature, pattern, location, and feature of the injuries. Results： Among the 202 cases of head injury-induced death, 124 were male and 78 female with the age ranging from 1-81 years. Death caused by homicide was dominant （106, 52.5%）, followed by suicide （49, 24.3%） and accident （44, 21.8%）. The majority of suicide-induced death were byfalling from height, and traffic crash was responsible for majority of unexpected death cases. The morphology and pathogenesis of the injuries varied according to differences on the mode, magnitude, and orientation of the outside force giving rise to blunt injury as well as the character of vulnerants. Conclusion： Studies on the morphology and its forma- tive rationale of blunt head injury will offer easy access to medicolegal expertise on the mode and character of the injury.展开更多
基金Project(51274249)supported by the National Natural Science Foundation of ChinaProject(2015zzts076)supported by the Explore Research Fund for Graduate Students of ChinaProject(201406)supported by the Hunan Key Laboratory of Coal Resources and Safe Mining Open-end Funds,China
文摘In order to investigate the failure mechanism of rock joint,a series of laboratory tests including cyclic direct shear tests under constant normal load(CNL)conditions were conducted.Morphology parameters of the rock joint surface were precisely calculated by means of a three-dimensional laser scanning machine.All test results were analyzed to investigate the shear behavior and normal displacement behavior of rock joints under CNL conditions.Degradation of rock joint surface during cyclic shear tests was also analyzed.The comparison results of the height parameters and the hybrid parameters of the joint surface during cyclic tests show that the degradation of the surface mostly happens in the first shear and the constant normal loads imposed on the joints have significant promotion effects on the morphology degradation.During cyclic shear tests,joints surfaces evolve from rough state to smooth state but keep an overall undulation.Dilatancy of rock joints degrades with the degradation of joint surface and the increase of normal loads.The closure deformation of joint is larger than that of the intact rock,and the normal stiffness increases with the increase of shearing times.
文摘Objective： To study the patterns and morphologic characteristics of blunt head injury and analyse its formative mechanism in attempt to provide references for medicolegal expertise. Methods： The statistical analysis was done in terms of gender, age, as well as the nature, pattern, location, and feature of the injuries. Results： Among the 202 cases of head injury-induced death, 124 were male and 78 female with the age ranging from 1-81 years. Death caused by homicide was dominant （106, 52.5%）, followed by suicide （49, 24.3%） and accident （44, 21.8%）. The majority of suicide-induced death were byfalling from height, and traffic crash was responsible for majority of unexpected death cases. The morphology and pathogenesis of the injuries varied according to differences on the mode, magnitude, and orientation of the outside force giving rise to blunt injury as well as the character of vulnerants. Conclusion： Studies on the morphology and its forma- tive rationale of blunt head injury will offer easy access to medicolegal expertise on the mode and character of the injury.
