In this paper,we utilize the variational limiting equilibrium(LE) procedure to theoretically determine the slope stability of homogeneous coral sand in the South China Sea.By establishing a reasonable functional and c...In this paper,we utilize the variational limiting equilibrium(LE) procedure to theoretically determine the slope stability of homogeneous coral sand in the South China Sea.By establishing a reasonable functional and calculating its extremum,we can deduce the stability factor of a coral reef identical to that obtained by upper bound analysis.To determine the accuracy of the results obtained using the variational LE procedure,we present some classical examples of homogeneous sand slopes without a hard shell and compare our results with those obtained by the upper bound theorem of plasticity.A series of extensive calculations and comparisons reveal that the results obtained by our proposed analysis method and those obtained using classical methods are slightly different,but the variational results are believable.On the other hand,our method solves some stability factors for reef slopes covered with a hard shell,which indicates that the existence of a hard reef shell may significantly enhance the stability of a reef slope,and that there is strong nonlinear relationship between reef stability and the mechanical characteristics of the reef shell,such as its thickness and strength.Finally,based on the variational results presented in this paper,we present a useful chart that offers a convenient and straightforward way to determine the maximum stability factor of reef slopes.Taking into account the influence of the hard reef shell,we found that,in some limit equilibrium cases,the limit stability factor and critical height of a coral slope could be improved significantly.Therefore,this issue deserves careful attention in engineering practice.展开更多
Through the description of the deformational features of the surrounding rockaround high stress engineering soft rock roadways,the coupling stabilization principle ofinner and outer structures in surrounding rock was ...Through the description of the deformational features of the surrounding rockaround high stress engineering soft rock roadways,the coupling stabilization principle ofinner and outer structures in surrounding rock was put forward.The supporting principlesof high stress engineering soft rock roadway (high resistance and yielding support,timelysupport,high strength and high stiffness supports) were proposed,which were applied inengineering practices,and obtained better achievements.展开更多
This study was based on self-report of a MOOC school-based college English classroom teaching practice flip. Firstly, it is based on the analysis of the typical characteristics of MOOC leveraging MOOC college English ...This study was based on self-report of a MOOC school-based college English classroom teaching practice flip. Firstly, it is based on the analysis of the typical characteristics of MOOC leveraging MOOC college English courses on the basis of the next report on the concrete practice of school-based college English MOOC construction and flipped classroom teaching. Quantitative and qualitative data on learner feedback in the survey analysis shows that based MOOC flip mode is suitable for classroom teaching college English teaching, MOOC and flipped classroom have been highly recognized by students, which gives full play to both collaborative IT and foreign language teaching the depth of integration of blended learning potential.展开更多
基金supported by the National Science and Technology Ministry(No.2014BAB16B03)the National Natural Science Foundation of China(No.5167 9224)
文摘In this paper,we utilize the variational limiting equilibrium(LE) procedure to theoretically determine the slope stability of homogeneous coral sand in the South China Sea.By establishing a reasonable functional and calculating its extremum,we can deduce the stability factor of a coral reef identical to that obtained by upper bound analysis.To determine the accuracy of the results obtained using the variational LE procedure,we present some classical examples of homogeneous sand slopes without a hard shell and compare our results with those obtained by the upper bound theorem of plasticity.A series of extensive calculations and comparisons reveal that the results obtained by our proposed analysis method and those obtained using classical methods are slightly different,but the variational results are believable.On the other hand,our method solves some stability factors for reef slopes covered with a hard shell,which indicates that the existence of a hard reef shell may significantly enhance the stability of a reef slope,and that there is strong nonlinear relationship between reef stability and the mechanical characteristics of the reef shell,such as its thickness and strength.Finally,based on the variational results presented in this paper,we present a useful chart that offers a convenient and straightforward way to determine the maximum stability factor of reef slopes.Taking into account the influence of the hard reef shell,we found that,in some limit equilibrium cases,the limit stability factor and critical height of a coral slope could be improved significantly.Therefore,this issue deserves careful attention in engineering practice.
基金Supported by the National Natural Science Fundation of China (50674045)the National "973" Planning Project(2007CB209403)
文摘Through the description of the deformational features of the surrounding rockaround high stress engineering soft rock roadways,the coupling stabilization principle ofinner and outer structures in surrounding rock was put forward.The supporting principlesof high stress engineering soft rock roadway (high resistance and yielding support,timelysupport,high strength and high stiffness supports) were proposed,which were applied inengineering practices,and obtained better achievements.
文摘This study was based on self-report of a MOOC school-based college English classroom teaching practice flip. Firstly, it is based on the analysis of the typical characteristics of MOOC leveraging MOOC college English courses on the basis of the next report on the concrete practice of school-based college English MOOC construction and flipped classroom teaching. Quantitative and qualitative data on learner feedback in the survey analysis shows that based MOOC flip mode is suitable for classroom teaching college English teaching, MOOC and flipped classroom have been highly recognized by students, which gives full play to both collaborative IT and foreign language teaching the depth of integration of blended learning potential.
