Rigid barrier deflectors can effectively prevent overspilling landslides,and can satisfy disaster prevention requirements.However,the mechanisms of interaction between natural granular flow and rigid barrier deflector...Rigid barrier deflectors can effectively prevent overspilling landslides,and can satisfy disaster prevention requirements.However,the mechanisms of interaction between natural granular flow and rigid barrier deflectors require further investigation.To date,few studies have investigated the impact of deflectors on controlling viscous debris flows for geological disaster prevention.To investigate the effect of rigid barrier deflectors on impact mechanisms,a numerical model using the smoothed particle hydrodynamics(SPH)method with the Herschel–Bulkley model is proposed to simulate the interaction between natural viscous flow and single/dual barriers with and without deflectors.This model was validated using laboratory flume test data from the literature.Then,the model was used to investigate the influence of the deflector angle and multi-barrier arrangements.The optimal configuration of multi-barriers was analyzed with consideration to the barrier height and distance between the barriers,because these metrics have a significant impact on the viscous flow pile-up,run-up,and overflow mechanisms.The investigation considered the energy dissipation process,retention efficiency,and dead-zone formation.Compared with bare barriers with similar geometric characteristics and spatial distribution,rigid barriers with deflectors exhibit superior effectiveness in preventing the overflow and overspilling of viscous debris flow.Recommendations for the rational design of deflectors and the optimal arrangement of multi-barriers are provided to mitigate geological disasters.展开更多
数字贸易是国际贸易的新兴力量。研究数字贸易壁垒的贸易效应是构建贸易壁垒有效应对机制,实现数字贸易高质量发展的重要前提。在Eaton and Kortum(2002)的基础上,文章构建了一个包含绝对贸易壁垒和相对贸易壁垒双重约束的数字贸易出口...数字贸易是国际贸易的新兴力量。研究数字贸易壁垒的贸易效应是构建贸易壁垒有效应对机制,实现数字贸易高质量发展的重要前提。在Eaton and Kortum(2002)的基础上,文章构建了一个包含绝对贸易壁垒和相对贸易壁垒双重约束的数字贸易出口决策模型以探究双重数字贸易壁垒产生出口抑制与替代效应的内在机理。据此,文章运用2014—2019年全球49个经济体的数字贸易数据进行实证分析。研究发现:(1)双重数字贸易壁垒存在显著的出口抑制效应,该抑制效应受到两者交互作用产生的替代效应影响,呈现出“跷跷板”现象。这意味着在数字贸易中依然存在着所谓的“贸易持续保护法则”。(2)双重数字贸易壁垒产生的出口抑制与替代效应在贸易类别、壁垒类别和国别收入层面上均存在着显著的异质性。(3)贸易成本是双重数字贸易壁垒产生出口抑制的重要渠道,国别TFP作为调节变量引发了双重数字贸易壁垒出口抑制的“逃逸效应”,而包含数字贸易规则的自由贸易协定产生双重数字贸易壁垒出口抑制的“弱化效应”。(4)双重数字贸易壁垒在出口二元边际上也呈现出显著的异质性效应。文章的研究为全面理解数字贸易壁垒的多重贸易效应及其作用机制提供了新视角,为有效应对双重数字贸易壁垒提供了科学对策。展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.42120104008 and 42207198).
文摘Rigid barrier deflectors can effectively prevent overspilling landslides,and can satisfy disaster prevention requirements.However,the mechanisms of interaction between natural granular flow and rigid barrier deflectors require further investigation.To date,few studies have investigated the impact of deflectors on controlling viscous debris flows for geological disaster prevention.To investigate the effect of rigid barrier deflectors on impact mechanisms,a numerical model using the smoothed particle hydrodynamics(SPH)method with the Herschel–Bulkley model is proposed to simulate the interaction between natural viscous flow and single/dual barriers with and without deflectors.This model was validated using laboratory flume test data from the literature.Then,the model was used to investigate the influence of the deflector angle and multi-barrier arrangements.The optimal configuration of multi-barriers was analyzed with consideration to the barrier height and distance between the barriers,because these metrics have a significant impact on the viscous flow pile-up,run-up,and overflow mechanisms.The investigation considered the energy dissipation process,retention efficiency,and dead-zone formation.Compared with bare barriers with similar geometric characteristics and spatial distribution,rigid barriers with deflectors exhibit superior effectiveness in preventing the overflow and overspilling of viscous debris flow.Recommendations for the rational design of deflectors and the optimal arrangement of multi-barriers are provided to mitigate geological disasters.
文摘数字贸易是国际贸易的新兴力量。研究数字贸易壁垒的贸易效应是构建贸易壁垒有效应对机制,实现数字贸易高质量发展的重要前提。在Eaton and Kortum(2002)的基础上,文章构建了一个包含绝对贸易壁垒和相对贸易壁垒双重约束的数字贸易出口决策模型以探究双重数字贸易壁垒产生出口抑制与替代效应的内在机理。据此,文章运用2014—2019年全球49个经济体的数字贸易数据进行实证分析。研究发现:(1)双重数字贸易壁垒存在显著的出口抑制效应,该抑制效应受到两者交互作用产生的替代效应影响,呈现出“跷跷板”现象。这意味着在数字贸易中依然存在着所谓的“贸易持续保护法则”。(2)双重数字贸易壁垒产生的出口抑制与替代效应在贸易类别、壁垒类别和国别收入层面上均存在着显著的异质性。(3)贸易成本是双重数字贸易壁垒产生出口抑制的重要渠道,国别TFP作为调节变量引发了双重数字贸易壁垒出口抑制的“逃逸效应”,而包含数字贸易规则的自由贸易协定产生双重数字贸易壁垒出口抑制的“弱化效应”。(4)双重数字贸易壁垒在出口二元边际上也呈现出显著的异质性效应。文章的研究为全面理解数字贸易壁垒的多重贸易效应及其作用机制提供了新视角,为有效应对双重数字贸易壁垒提供了科学对策。
