The impacts of the Hong Kong-Zhuhai-Macao Bridge(HKZMB)on suspended sediment content(SSC)were analysed in the Zhujiang River Estuary based on data from HY-1C,which was launched in September 2018 in China,carrying Coas...The impacts of the Hong Kong-Zhuhai-Macao Bridge(HKZMB)on suspended sediment content(SSC)were analysed in the Zhujiang River Estuary based on data from HY-1C,which was launched in September 2018 in China,carrying Coastal Zone Imager(CZI)and Chinese Ocean Color and Temperature Scanner on it.A new SSC inversion model was established based on the relationship between in-situ SSC and the remote sensing reflectance in red and near-infrared bands of CZI image.HY-1C satellite data obtained from October to December 2019 were applied to retrieve SSC in the Zhujiang River Estuary.The results show that SSC around the HKZMB is ranging from 20 mg/L to 95 mg/L.SSC change obviously on two sides of the bridge.During flooding and ebbing period,SSC increases obviously downstream of the bridge.SSC difference between upstream and downstream is ranging from 5 mg/L to 20 mg/L.Currents flowing across the HKZMB,the change trend of SSC in most places upstream and downstream is almost the same that SSC downstream of the bridge is higher than SSC upstream.The tidal currents interact with bridge piers,inducing vortexes downstream,leading the sediment to re-suspend downstream of the bridge piers.Other factors,including seafloor topography and wind,can also contribute to the distribution of SSC in the Zhujiang River Estuary.展开更多
Marine engineering geology is mainly based on the actual project to study the seabed.This provides a variety of engineering geological parameters for the development of marine engineering(Zhu et al.,2016).This is an e...Marine engineering geology is mainly based on the actual project to study the seabed.This provides a variety of engineering geological parameters for the development of marine engineering(Zhu et al.,2016).This is an early展开更多
In this paper the characteristics of tidal flow and seasonal variation of seidment content in the Hangzhou Bay and their affecting factors are studied. Field investigations and data analysis indicate that the sediment...In this paper the characteristics of tidal flow and seasonal variation of seidment content in the Hangzhou Bay and their affecting factors are studied. Field investigations and data analysis indicate that the sediment movement is mainly influenced by the Yangtze estuary and the sediment of the Yangtze estuary is induced by wind wave and tidal flow. Owing to the variation of dynamic conditions, the instantaneous sediment content is controlled by tidal flow, wind wave, depth of water and tidal range synthetically. A sediment content relationship formula is established with related factors. A non-equilibrium 2-dimensional numerical model of suspended sediment transportation is set up, and the finite element method is applied. The computation results of the model is in accordance with field data.展开更多
Gravelly soils are made up of gravel, sand, silt and clay. They are widely used in engineering applications such as rock-fill dams with clay cores, which are the main researches at present. The strength and mechanical...Gravelly soils are made up of gravel, sand, silt and clay. They are widely used in engineering applications such as rock-fill dams with clay cores, which are the main researches at present. The strength and mechanical properties of the gravelly soils are affected by the content of coarse grain, fine particles, and their adhesive states. These Properties can be verified by laboratory unconsolidated undrained triaxial tests with grain size less than 5 mm and by large scale direct-shear tests with original grain content. Fine particles of the loose gravelly slopes are released under rainfalls, alternated the structures and mechanical properties, even affected the slope stability. There are a series of large scale direct-shear tests with different coarse grain contents to study the influence of fine particles releasing and migration, results showed the strength behavior of the gravelly soils were affected by the coarse grain content （5） and the inflection coarse grain contents. In order to study the erosion features of the gravelly soil slopes on rainfall conditions and the slopes stability alteration, we had carried out one sort of artificial rainfall local and model experiments, the runoff sediment contents were monitored during the experiments. Result showed that the shapes of the slopes surface transformed periodically, runoff sediment contents were divided into five phases according to the experiment phenomena, runoff sediment contents maintained downtrend during the rain time and the downtrend was obviouslyinterpreted by one descend belt no matter the rainfall intensity and the slope angels. Particle size analysis released the deposit on the slope surface lost almost all of the clay, most of the silt and sand after the experiments, this meant the fine particles releasing, migration and accumulation process on condition of rainfall resulted in the instability factor of the slopes even induced landslide or debris flow.展开更多
Between April 2002 and April 2003,in situ measurements of water depth,current velocity and suspended sediment content were carried out in edge region of East Chongming salt marsh and neighboring bald flat in the Chang...Between April 2002 and April 2003,in situ measurements of water depth,current velocity and suspended sediment content were carried out in edge region of East Chongming salt marsh and neighboring bald flat in the Changjiang （Yangtze） Estuary under different weather conditions.Cross-shore suspended sediment flux was calculated and analyzed.The results show that under calm weather conditions,the current velocity process in bald field and salt marsh area varied differently during semidiurnal tidal cycles.Owing to current velocity asymmetry,mean SSC during flood tide phase was 1.8 times higher than that of ebb tide phase.As a result,net onshore sediment flux controlled cross-shore suspended sediment transport process and salt marsh pioneer zone was generally accreting.There was significant positive correlation between total sediment flux and quartic power of maximum water depth.It indicates that tidal ranges dominate suspended sediment transport and sedimentation process in the salt marsh pioneer zone under the calm weather condition.The sedimentation rate on the adjacent mudflat was higher than the salt marsh,which induced stable accreting of salt marsh towards the sea.The wind events enhanced SSC and current velocity during the semidiurnal tides.And the remarkable onshore net sediment flux could occur on the high marsh and mudflat close to the marsh fringe during the short period under the rough weather condition.展开更多
基金The Zhejiang Key Science and Technology Project under contract No.2020C02004the National Key Research and Development Program of China under contract Nos 2017YFA0604901 and 2017YFA0604902+3 种基金the Basic Public Welfare Research Program of Zhejiang Province under contract No.LGF21D010004the National Key Research and Development Program of China under contract No.2016YFC1401605the National Natural Science Foundation of China under contract No.41776183the Curriculum Ideological and Political Teaching Research Project in the Universities of Zhejiang Province(Grouped Ideological and Political Teaching Model Research in the Subject of Marine Remote Sensing)。
文摘The impacts of the Hong Kong-Zhuhai-Macao Bridge(HKZMB)on suspended sediment content(SSC)were analysed in the Zhujiang River Estuary based on data from HY-1C,which was launched in September 2018 in China,carrying Coastal Zone Imager(CZI)and Chinese Ocean Color and Temperature Scanner on it.A new SSC inversion model was established based on the relationship between in-situ SSC and the remote sensing reflectance in red and near-infrared bands of CZI image.HY-1C satellite data obtained from October to December 2019 were applied to retrieve SSC in the Zhujiang River Estuary.The results show that SSC around the HKZMB is ranging from 20 mg/L to 95 mg/L.SSC change obviously on two sides of the bridge.During flooding and ebbing period,SSC increases obviously downstream of the bridge.SSC difference between upstream and downstream is ranging from 5 mg/L to 20 mg/L.Currents flowing across the HKZMB,the change trend of SSC in most places upstream and downstream is almost the same that SSC downstream of the bridge is higher than SSC upstream.The tidal currents interact with bridge piers,inducing vortexes downstream,leading the sediment to re-suspend downstream of the bridge piers.Other factors,including seafloor topography and wind,can also contribute to the distribution of SSC in the Zhujiang River Estuary.
基金support ed by NSFC Open Research Cruise (Cruise No. NORC2 015-05 and Cruise No. NORC2015-06)funded by Shipti me Sharing Project of NSFC
文摘Marine engineering geology is mainly based on the actual project to study the seabed.This provides a variety of engineering geological parameters for the development of marine engineering(Zhu et al.,2016).This is an early
基金This work was financially supported by the funds for Youth Scholar of the Ministry of Communications,P.R.China
文摘In this paper the characteristics of tidal flow and seasonal variation of seidment content in the Hangzhou Bay and their affecting factors are studied. Field investigations and data analysis indicate that the sediment movement is mainly influenced by the Yangtze estuary and the sediment of the Yangtze estuary is induced by wind wave and tidal flow. Owing to the variation of dynamic conditions, the instantaneous sediment content is controlled by tidal flow, wind wave, depth of water and tidal range synthetically. A sediment content relationship formula is established with related factors. A non-equilibrium 2-dimensional numerical model of suspended sediment transportation is set up, and the finite element method is applied. The computation results of the model is in accordance with field data.
基金financially supported by National Natural Science Foundation of China (Grant Nos. 41172283, 41372313)National Basic Research Program of China (2012CB026103)
文摘Gravelly soils are made up of gravel, sand, silt and clay. They are widely used in engineering applications such as rock-fill dams with clay cores, which are the main researches at present. The strength and mechanical properties of the gravelly soils are affected by the content of coarse grain, fine particles, and their adhesive states. These Properties can be verified by laboratory unconsolidated undrained triaxial tests with grain size less than 5 mm and by large scale direct-shear tests with original grain content. Fine particles of the loose gravelly slopes are released under rainfalls, alternated the structures and mechanical properties, even affected the slope stability. There are a series of large scale direct-shear tests with different coarse grain contents to study the influence of fine particles releasing and migration, results showed the strength behavior of the gravelly soils were affected by the coarse grain content （5） and the inflection coarse grain contents. In order to study the erosion features of the gravelly soil slopes on rainfall conditions and the slopes stability alteration, we had carried out one sort of artificial rainfall local and model experiments, the runoff sediment contents were monitored during the experiments. Result showed that the shapes of the slopes surface transformed periodically, runoff sediment contents were divided into five phases according to the experiment phenomena, runoff sediment contents maintained downtrend during the rain time and the downtrend was obviouslyinterpreted by one descend belt no matter the rainfall intensity and the slope angels. Particle size analysis released the deposit on the slope surface lost almost all of the clay, most of the silt and sand after the experiments, this meant the fine particles releasing, migration and accumulation process on condition of rainfall resulted in the instability factor of the slopes even induced landslide or debris flow.
基金The National Natural Science Foundation of China under contract Nos 40901010 and 40730526Leading Academic Discipline Project of Shanghai Normal University under contract No.DZL809
文摘Between April 2002 and April 2003,in situ measurements of water depth,current velocity and suspended sediment content were carried out in edge region of East Chongming salt marsh and neighboring bald flat in the Changjiang （Yangtze） Estuary under different weather conditions.Cross-shore suspended sediment flux was calculated and analyzed.The results show that under calm weather conditions,the current velocity process in bald field and salt marsh area varied differently during semidiurnal tidal cycles.Owing to current velocity asymmetry,mean SSC during flood tide phase was 1.8 times higher than that of ebb tide phase.As a result,net onshore sediment flux controlled cross-shore suspended sediment transport process and salt marsh pioneer zone was generally accreting.There was significant positive correlation between total sediment flux and quartic power of maximum water depth.It indicates that tidal ranges dominate suspended sediment transport and sedimentation process in the salt marsh pioneer zone under the calm weather condition.The sedimentation rate on the adjacent mudflat was higher than the salt marsh,which induced stable accreting of salt marsh towards the sea.The wind events enhanced SSC and current velocity during the semidiurnal tides.And the remarkable onshore net sediment flux could occur on the high marsh and mudflat close to the marsh fringe during the short period under the rough weather condition.
