The determination of collapse margin ratio(CMR)of structure is influenced by many uncertain factors.Some factors that can affect the calculation of CMR,e.g.,the elongation of the structural fundamental period prior to...The determination of collapse margin ratio(CMR)of structure is influenced by many uncertain factors.Some factors that can affect the calculation of CMR,e.g.,the elongation of the structural fundamental period prior to collapse,the determination of earthquake intensity measure,the seismic hazard probability,and the difference of the spectral shapes between the median spectrum of the ground motions and the design spectrum,were discussed.Considering the elongation of the structural fundamental period,the intensity measure Sa(T1)should be replaced with *aS in the calculation of CMR for short-period and medium-period structures.The reasonable intensity measure should be determined by the correlation analysis between the earthquake intensity measure and the damage index of the structure.Otherwise,CMR should be adjusted according to the seismic hazard probability and the difference in the spectral shapes.For important long-period structures,CMR should be determined by the special site spectrum.The results indicate that both Sa(T1)and spectrum intensity(SI)could be used as intensity measures in the calculation of CMR for medium-period structures,but SI would be a better choice for long-period structures.Moreover,an adjusted CMR that reflects the actual seismic collapse safety of structures is provided.展开更多
The impact of greenization on the marginal utility of the intensity of carbon emissions in China and factors influ-encing this relationship are explored in this study.China’s level of greenization is evaluated by usi...The impact of greenization on the marginal utility of the intensity of carbon emissions in China and factors influ-encing this relationship are explored in this study.China’s level of greenization is evaluated by using an index system developed based on the comprehensive index method.The intensity of carbon emissions is determined by using the standards for the coefficients of conversion of coal equivalent and coefficients of carbon emission.The impact of greenization on the marginal utility of the intensity of carbon emissions is then evaluated by using an elastic formula and factors affecting this relationship are verified by regression analysis.The results are as fol-lows:(1)China’s level of greenization has exhibited a trend of constant increase.The intensity of carbon emissions has followed a continual downward trend while the impact of greenization on the marginal utility of the intensity of these emissions has been declining.(2)Urbanization as well as scientific and technological developments have slowed the reduction in the marginal utility of the intensity of carbon emissions,whereas the structure of energy consumption has expedited it under the diminishing impact of greenization.The standard of living of the popu-lation,intensity of environmental regulation,and environmental quality have had different influences under dif-ferent conditions.展开更多
A dynamic mechanism, "lower lithospheric delamination and extension of the Cathaysian Diwa-type orogens" , has been put forward to explain the formation of the Cenozoic continental-margin-spreading-belt in S...A dynamic mechanism, "lower lithospheric delamination and extension of the Cathaysian Diwa-type orogens" , has been put forward to explain the formation of the Cenozoic continental-margin-spreading-belt in Southeast China. The processes of formation and develop-ment for the belt are from the stage of the Cathaysian Diwa-type orogens at which compression and thickening of curstobodies prevailed, to the stage of the basin-and-range-type structures at which the late orogenic crustal extension occurred, and then to the stage of the epicontinental Diwa-type rifts at which the lithospheric extension took place.展开更多
Many geophysical and geological data have been used to interpret the tectonic evolution of the south-eastern part of the Tunisian margin and to analyze the dominant structures in the area.The Menzel Habib Plain(MHP)an...Many geophysical and geological data have been used to interpret the tectonic evolution of the south-eastern part of the Tunisian margin and to analyze the dominant structures in the area.The Menzel Habib Plain(MHP)and surroundings,targeted by this study,exhibits thick siliciclastic and carbonate formations attributed to the Early Cretaceous period.Integration of seismic and gravimetric data coupled with analysis of the syndepositional faults affecting these formations prove that the Tunisian margin is dominated,during this period,by N-S to NE-SW extensional directions.The geodynamic evolution of the MHP is mainly due to the irregular normal movement of the N-S faults,which represents the southernmost branch of the N-S Axis(NSA)and of the NW-SE faults,which constitutes the SE segment of the South Atlasic fault corridor(SAFC).In addition,the NE-SW and E-W oriented faults contributed to this evolution.Over extensive periods,this network of faults determines horst and grabens basin geometry or tilted blocks inducing formation of several distinct areas with different subsidence rates.Simultaneously,the normal activity of the major faults promotes the vertical mobilization of the Triassic salt resulting in the individualization of several diapiric bodies,some of which pierced their sedimentary cover.These dynamics reflect echoes of the sinistral drifting of Africa with respect to Europe,integrated in a long Tethyan rifting cycle,and the beginning of opening of the Mesogean Sea,respectively.展开更多
基金Projects(51161120359,90915005)supported by the National Natural Science Foundation of ChinaProject(NCET-08-0096)supported by the Program for New Century Excellent Talents in University of the Ministry of China
文摘The determination of collapse margin ratio(CMR)of structure is influenced by many uncertain factors.Some factors that can affect the calculation of CMR,e.g.,the elongation of the structural fundamental period prior to collapse,the determination of earthquake intensity measure,the seismic hazard probability,and the difference of the spectral shapes between the median spectrum of the ground motions and the design spectrum,were discussed.Considering the elongation of the structural fundamental period,the intensity measure Sa(T1)should be replaced with *aS in the calculation of CMR for short-period and medium-period structures.The reasonable intensity measure should be determined by the correlation analysis between the earthquake intensity measure and the damage index of the structure.Otherwise,CMR should be adjusted according to the seismic hazard probability and the difference in the spectral shapes.For important long-period structures,CMR should be determined by the special site spectrum.The results indicate that both Sa(T1)and spectrum intensity(SI)could be used as intensity measures in the calculation of CMR for medium-period structures,but SI would be a better choice for long-period structures.Moreover,an adjusted CMR that reflects the actual seismic collapse safety of structures is provided.
基金supported by National Natural Science Foundation of China(72004124)the Social Sciences Planning Project of Shandong Province(20BJJJ06).
文摘The impact of greenization on the marginal utility of the intensity of carbon emissions in China and factors influ-encing this relationship are explored in this study.China’s level of greenization is evaluated by using an index system developed based on the comprehensive index method.The intensity of carbon emissions is determined by using the standards for the coefficients of conversion of coal equivalent and coefficients of carbon emission.The impact of greenization on the marginal utility of the intensity of carbon emissions is then evaluated by using an elastic formula and factors affecting this relationship are verified by regression analysis.The results are as fol-lows:(1)China’s level of greenization has exhibited a trend of constant increase.The intensity of carbon emissions has followed a continual downward trend while the impact of greenization on the marginal utility of the intensity of these emissions has been declining.(2)Urbanization as well as scientific and technological developments have slowed the reduction in the marginal utility of the intensity of carbon emissions,whereas the structure of energy consumption has expedited it under the diminishing impact of greenization.The standard of living of the popu-lation,intensity of environmental regulation,and environmental quality have had different influences under dif-ferent conditions.
文摘A dynamic mechanism, "lower lithospheric delamination and extension of the Cathaysian Diwa-type orogens" , has been put forward to explain the formation of the Cenozoic continental-margin-spreading-belt in Southeast China. The processes of formation and develop-ment for the belt are from the stage of the Cathaysian Diwa-type orogens at which compression and thickening of curstobodies prevailed, to the stage of the basin-and-range-type structures at which the late orogenic crustal extension occurred, and then to the stage of the epicontinental Diwa-type rifts at which the lithospheric extension took place.
文摘Many geophysical and geological data have been used to interpret the tectonic evolution of the south-eastern part of the Tunisian margin and to analyze the dominant structures in the area.The Menzel Habib Plain(MHP)and surroundings,targeted by this study,exhibits thick siliciclastic and carbonate formations attributed to the Early Cretaceous period.Integration of seismic and gravimetric data coupled with analysis of the syndepositional faults affecting these formations prove that the Tunisian margin is dominated,during this period,by N-S to NE-SW extensional directions.The geodynamic evolution of the MHP is mainly due to the irregular normal movement of the N-S faults,which represents the southernmost branch of the N-S Axis(NSA)and of the NW-SE faults,which constitutes the SE segment of the South Atlasic fault corridor(SAFC).In addition,the NE-SW and E-W oriented faults contributed to this evolution.Over extensive periods,this network of faults determines horst and grabens basin geometry or tilted blocks inducing formation of several distinct areas with different subsidence rates.Simultaneously,the normal activity of the major faults promotes the vertical mobilization of the Triassic salt resulting in the individualization of several diapiric bodies,some of which pierced their sedimentary cover.These dynamics reflect echoes of the sinistral drifting of Africa with respect to Europe,integrated in a long Tethyan rifting cycle,and the beginning of opening of the Mesogean Sea,respectively.
