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
Three CeO_2 samples with different morphologies, i.e., cubes, rods, and spindles, were synthesized and investigated for 2-chloroethyl ethyl sulfide（2-CEES） degradation. The samples were characterized using scanning ...Three CeO_2 samples with different morphologies, i.e., cubes, rods, and spindles, were synthesized and investigated for 2-chloroethyl ethyl sulfide（2-CEES） degradation. The samples were characterized using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, the Brunauer-Emmett-Teller method, and temperature-programmed CO_2 desorption. It was found that morphologies of CeO_2 could strongly affect the surface properties and the 2-CEES degradation activities. The surface basicity and the continuous 2-CEES degradation activity of spindle-like CeO_2 were much better than those of the other CeO_2 samples, although all the samples had identical chemical compositions. That was benefited by the largest surface area, abundant microcracks, and surface oxygen vacancies of the spindle-like CeO_2.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.
基金supported by the National Key Research and Development Program of China(2016YFC0205001)
文摘Three CeO_2 samples with different morphologies, i.e., cubes, rods, and spindles, were synthesized and investigated for 2-chloroethyl ethyl sulfide（2-CEES） degradation. The samples were characterized using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, the Brunauer-Emmett-Teller method, and temperature-programmed CO_2 desorption. It was found that morphologies of CeO_2 could strongly affect the surface properties and the 2-CEES degradation activities. The surface basicity and the continuous 2-CEES degradation activity of spindle-like CeO_2 were much better than those of the other CeO_2 samples, although all the samples had identical chemical compositions. That was benefited by the largest surface area, abundant microcracks, and surface oxygen vacancies of the spindle-like CeO_2.
