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Numerical simulation of flow field deposition and erosion characteristics around bridge-road transition section
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作者 ZHANG Kai WANG Zhenghui +3 位作者 WANG Tao TIAN Jianjin ZHANG Hailong LIU Yonghe 《Journal of Mountain Science》 SCIE CSCD 2024年第5期1491-1508,共18页
Wind-sand flow generates erosion and deposition around obstacles such as bridges and roadbeds, resulting in sand damage and endangering railway systems in sandy regions. Previous studies have mainly focused on the flo... Wind-sand flow generates erosion and deposition around obstacles such as bridges and roadbeds, resulting in sand damage and endangering railway systems in sandy regions. Previous studies have mainly focused on the flow field around roadbeds, overlooking detailed examinations of sand particle erosion and deposition patterns near bridges and roadbeds. This study employs numerical simulations to analyze the influence of varying heights and wind speeds on sand deposition and erosion characteristics at different locations: the bridge-road transition section(side piers), middle piers, and roadbeds. The results show that the side piers, experience greater accumulation than the middle piers. Similarly, the leeward side of the roadbed witnesses more deposition compared to the windward side. Another finding reveals a reduced sand deposition length as the vertical profile, in alignment with the wind direction, moves further from the bridge abutments at the same clearance height. As wind speeds rise, there’s a decline in sand deposition and a marked increase in erosion around the side piers, middle piers and roadbeds. In conclusion, a bridge clearance that’s too low can cause intense sand damage near the side piers, while an extremely high roadbed may lead to extensive surface sand deposition. Hence, railway bridges in areas prone to sandy winds should strike a balance in clearance height. This research provides valuable guidelines for determining the most suitable bridge and roadbed heights in regions affected by wind and sand. 展开更多
关键词 SANDSTORM Flow field Bridge-road transition section sedimentation erosion Numerical simulation
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Sediment yield and erosion–deposition distribution characteristics in ephemeral gullies in black soil areas under geocell protection 被引量:1
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作者 WANG Xinyu SU Yu +4 位作者 SUN Yiqiu ZHANG Yan GUAN Yinghui WANG Zhirong WU Hailong 《Journal of Arid Land》 SCIE CSCD 2023年第2期180-190,共11页
Investigating the effect of geocells on the erosion and deposition distribution of ephemeral gullies in the black soil area of Northeast China can provide a scientific basis for the allocation of soil and water conser... Investigating the effect of geocells on the erosion and deposition distribution of ephemeral gullies in the black soil area of Northeast China can provide a scientific basis for the allocation of soil and water conservation measures in ephemeral gullies.In this study,an artificial simulated confluence test and stereoscopic photogrammetry were used to analyze the distribution characteristics of erosion and deposition in ephemeral gullies protected by geocells and the effect of different confluence flows on the erosion process of ephemeral gullies.Results showed that when the confluence flow was larger,the effect of geocell was more evident,and the protection against ephemeral gully erosion was stronger.When the confluence flow rates were 0.6,1.8,2.4,and 3.0 m^(3)/h,ephemeral gully erosion decreased by 37.84%,26.09%,21.40%,and 35.45%.When the confluence flow rates were 2.4 and 3.0 m^(3)/h,the average sediment yield rate of the ephemeral gully was close to 2.14 kg/(m^(2)•min),and the protective effect of ephemeral gully erosion was enhanced.When the flow rate was higher,the surface fracture of the ephemeral gully was more serious.With an increase in confluence flow rate,the ratio of erosion to deposition increased gradually,the erosion area of ephemeral gullies was expanded,and erosion depth changed minimally.In conclusion,geocell measures changed erosion patterns by altering the rill erosion/deposition ratio,converting erosion from rill erosion to sheet erosion. 展开更多
关键词 GEOCELL erosion and deposition distribution runoff and sediment production ephemeral gully soil conservation
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Effects of soil crust on the collapsing erosion of colluvial deposits with granite residual soil
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作者 LIU Weiping ZENG Bohan +1 位作者 WANG Tianhuan DUAN Junyi 《Journal of Mountain Science》 SCIE CSCD 2024年第8期2579-2591,共13页
Collapsing erosion is a unique phenomenon commonly observed on the granite residue hillslopes in the tropical and subtropical regions of southern China,characterized by its abrupt occurrence and significant erosion vo... Collapsing erosion is a unique phenomenon commonly observed on the granite residue hillslopes in the tropical and subtropical regions of southern China,characterized by its abrupt occurrence and significant erosion volumes.However,the impacts of soil crust conditions on the erosion of colluvial deposits with granite residual soils have only been studied to a limited extent.To address this issue,this study investigates the impacts of three soil crust conditions(i.e.,without crust,10-minute crust,and 20-minute crust)on gully morphology,rainfall infiltration,and runoff and sediment yield during slope erosion of colluvial deposits with granite residues(classified as Acrisols)in Yudu County,Ganzhou City,Jiangxi Province,China,using simulated rainfall tests and photographic methods.The results showed that as the strength of the soil crust increased,the capacity of moisture infiltration and the width and depth of the gully as well as the sediment concentration and yield ratio decreased;at the same time,the runoff ratio increased.The sediment yield in the without-crust test was found to be 1.24 and 1.43 times higher than that observed in the 10-minute crust and 20-minute crust tests,respectively.These results indicate that soil crusts can effectively prevent slope erosion and moisture infiltration,while providing valuable insights for the management of soil erosion in natural environments. 展开更多
关键词 Granite residual soil Colluvial deposits Slope erosion Soil crust sediment yield
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Numerical simulation on sand sedimentation and erosion characteristics around HDPE sheet sand barrier under different wind angles
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作者 ZHANG Kai ZHANG Peili +3 位作者 ZHANG Hailong TIAN Jianjin WANG Zhenghui XIAO Jianhua 《Journal of Mountain Science》 SCIE CSCD 2024年第2期538-554,共17页
For the safety of railroad operations,sand barriers are utilized to mitigate wind-sand disaster effects.These disasters,characterized by multi-directional wind patterns,result in diverse angles among the barriers.In t... For the safety of railroad operations,sand barriers are utilized to mitigate wind-sand disaster effects.These disasters,characterized by multi-directional wind patterns,result in diverse angles among the barriers.In this study,using numerical simulations,we examined the behavior of High Density Polyethylene(HDPE)sheet sand barriers under different wind angles,focusing on flow field distribution,windproof efficiency,and sedimentation erosion dynamics.This study discovered that at a steady wind speed,airflow velocity varies as the angle between the airflow and the HDPE barrier changes.Specifically,a 90°angle results in the widest low-speed airflow area on the barrier’s downwind side.If the airflow is not perpendicular to the barrier,it prompts a lateral airflow movement which decreases as the angle expands.The windproof efficiency correlates directly with this angle but inversely with the wind’s speed.Notably,with a wind angle of 90°,wind speed drops by 81%.The minimum wind speed is found at 5.1H(the sand barrier height)on the barrier’s downwind side.As the angle grows,the barrier’s windproof efficiency improves,extending its protective reach.Sedimentation is most prominent on the barrier’s downwind side,as the wind angle shifts from 30°to 90°,the sand sedimentation area on the barrier’s downwind side enlarges by 14.8H.As the angle grows,sedimentation intensifies,eventually overtakes the forward erosion and enlarges the sedimentation area. 展开更多
关键词 Multi-wind direction HDPE sheet sand barrier Numerical simulation Windproof efficiency sedimentation erosion
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Utilizing sediment grain size characteristics to assess the effectiveness of clay–sand barriers in reducing aeolian erosion in Minqin desert area,China
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作者 SONG Dacheng ZHAO Wenzhi +5 位作者 LI Guangyu WEI Lemin WANG Lide YANG Jingyi WU Hao MA Quanlin 《Journal of Arid Land》 SCIE CSCD 2024年第5期668-684,共17页
The clay–sand barriers in Minqin desert area,China,represent a pioneering windbreak and sand fixation project with a venerable history of 60 a.However,studies on evaluating the long-term effectiveness of clay–sand b... The clay–sand barriers in Minqin desert area,China,represent a pioneering windbreak and sand fixation project with a venerable history of 60 a.However,studies on evaluating the long-term effectiveness of clay–sand barriers against aeolian erosion,particularly from the perspective of surface sediment grain size,are limited and thus insufficient to ascertain the protective impact of these barriers on regional aeolian activities.This study focused on the surface sediments(topsoil of 0–3 cm depth)of clay–sand barriers in Minqin desert area to explain their erosion resistance from the perspective of surface sediment grain size.In March 2023,six clay–sand barrier sampling plots with clay–sand barriers of different deployment durations(1,5,10,20,40,and 60 a)were selected as experimental plots,and one control sampling plot was set in an adjacent mobile sandy area without sand barriers.Surface sediment samples were collected from the topsoil of each sampling plot in the study area in April 2023 and sediment grain size characteristics were analyzed.Results indicated a predominance of fine and medium sands in the surface sediments of the study area.The deployment of clay–sand barriers cultivated a fine quality in grain size composition of the regional surface sediments,increasing the average contents of very fine sand,silt,and clay by 30.82%,417.38%,and 381.52%,respectively.This trend became markedly pronounced a decade after the deployment of clay–sand barriers.The effectiveness of clay–sand barriers in erosion resistance was manifested through reduced wind velocity,the interception of sand flow,and the promotion of fine surface sediment particles.Coarser particles such as medium,coarse,and very coarse sands predominantly accumulated on the external side of the barriers,while finer particles such as fine and very fine sands concentrated in the upwind(northwest)region of the barriers.By contrast,the contents of finest particles such as silt and clay were higher in the downwind(southeast)region of the sampling plots.For the study area,the deployment of clay–sand barriers remains one of the most cost-effective engineering solutions for aeolian erosion control,with sediment grain size parameters serving as quantitative indicators for the assessment of these barriers in combating desertification.The results of this study provide a theoretical foundation for the construction of windbreak and sand fixation systems and the optimization of artificial sand control projects in arid desert areas. 展开更多
关键词 clay-sand barriers sediment grain size grain size distribution aeolian erosion windbreak and sand fixation Minqin desert area
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Wind dynamic environment and wind-sand erosion and deposition processes on different surfaces along the Dunhuang–Golmud railway,China 被引量:1
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作者 ZHANG Hongxue ZHANG Kecun +1 位作者 AN Zhishan YU Yanping 《Journal of Arid Land》 SCIE CSCD 2023年第4期393-406,共14页
The Dunhuang–Golmud railway passes through different deserts in arid areas,especially drifting-sand desert and sandy-gravel Gobi.The near-surface wind environment and wind-sand transport process vary due to different... The Dunhuang–Golmud railway passes through different deserts in arid areas,especially drifting-sand desert and sandy-gravel Gobi.The near-surface wind environment and wind-sand transport process vary due to different external factors,such as topography,vegetation,and regional climate,resulting in evident spatial differences in surface erosion and deposition.Consequently,the measures for preventing wind-sand hazards will differ.However,the mechanism and control theory of sand damage remain poorly understood.In this study,we used meteorological observation,three-dimensional(3D)laser scanning,and grain-size analysis to compare and evaluate the spatial distribution of wind conditions,sand erosion and deposition patterns,and grain composition in the drifting-sand desert and sandy-gravel Gobi along the Dunhuang–Golmud railway in China.Results show that the annual mean wind speed,the frequency of sand-driving wind,and the drift potential of sandy-gravel Gobi are higher than those of drifting-sand desert,indicating a greater wind strength in the sandy-gravel Gobi,which exhibits spatial heterogeneity in wind conditions.The major sediment components in sandy-gravel Gobi are very fine sand,fine sand,and medium sand,and that in drifting-sand desert are very fine sand and fine sand.We found that the sediment in the sandy-gravel Gobi is coarser than that in the drifting-sand desert based on mean grain size and sediment component.The spatial distributions of sand erosion and deposition in the sandy-gravel Gobi and drifting-sand desert are consistent,with sand deposition mainly on the west side of the railway and sand erosion on the east side of the railway.The area of sand deposition in the drifting-sand desert accounts for 75.83%of the total area,with a mean deposition thickness of 0.032 m;while the area of sand deposition in the sandy-gravel Gobi accounts for 65.31%of the total area,with a mean deposition thickness of 0.028 m,indicating greater deposition amounts in the drifting-sand desert due to the presence of more fine sediment components.However,the sand deposition is more concentrated with a greater thickness on the embankment and track in the sandy-gravel Gobi and is dispersed with a uniform thickness in the drifting-sand desert.The sand deposition on the track of the sandy-gravel Gobi mainly comes from the east side of the railway.The results of this study are helpful in developing the preventive measures and determining appropriate selection and layout measures for sand control. 展开更多
关键词 surface erosion and deposition wind environment three-dimensional(3D)laser scanner drift potential grain-size characteristic Dunhuang–Golmud railway
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Effects of sand sedimentation and wind erosion around sand barrier:Numerical simulation and wind tunnel test studies 被引量:4
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作者 ZHANG Kai ZHANG Hai-long +3 位作者 DENG Yu-hui QU Jian-jun WANG Zheng-hui LI Sheng 《Journal of Mountain Science》 SCIE CSCD 2023年第4期962-978,共17页
Based on numerical simulations,this study highlights the sedimentation and erosion problems around a sand barrier through the relationship between the shear stress of the surface around the sand barrier and the critic... Based on numerical simulations,this study highlights the sedimentation and erosion problems around a sand barrier through the relationship between the shear stress of the surface around the sand barrier and the critical shear stress of sand grains.The numerical simulation results were verified using data measured by the wind tunnel test.The results showed that when the porosity was the same,the size and position of the vortex on the leeward side of the sand barrier were related to the inlet wind speed.As the wind speed increased,the vortex volume increased and the positions of the separation and reattachment points moved toward the leeward side.When the porosity of the sand barrier was 30%,the strength of the acceleration zone above the sand barrier was the highest,and the strength of the acceleration zone was negatively correlated with the porosity.Sand erosion and sedimentation distance were related to wind speed.With an increase in wind speed,the sand grain forward erosion or reverse erosion areas on the leeward side of the sand barrier gradually replaced the sedimentation area.With an increase in porosity,the sand sedimentation distance on the leeward side of the sand barrier gradually shortened,and the sand erosion area gradually disappeared.The sand sedimentation distance on the leeward side of the sand barrier with 30%porosity was the longest.The numerical simulation results were in good agreement with the wind tunnel test results.Based on the sand erosion and sedimentation results of the numerical simulation and wind tunnel test,when the porosity was 30%,the protection effect of the High Density Polyethylene(HDPE)board sand barrier was best. 展开更多
关键词 Sand sedimentation Wind erosion Numerical simulation Wind tunnel test
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Deep bed filtration model for cake filtration and erosion
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作者 L.I.KUZMINA Y.V.OSIPOV A.R.PESTEREV 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第2期355-372,共18页
Many phenomena in nature and technology are associated with the filtration of suspensions and colloids in porous media. Two main types of particle deposition,namely, cake filtration at the inlet and deep bed filtratio... Many phenomena in nature and technology are associated with the filtration of suspensions and colloids in porous media. Two main types of particle deposition,namely, cake filtration at the inlet and deep bed filtration throughout the entire porous medium, are studied by different models. A unified approach for the transport and deposition of particles based on the deep bed filtration model is proposed. A variable suspension flow rate, proportional to the number of free pores at the inlet of the porous medium, is considered. To model cake filtration, this flow rate is introduced into the mass balance equation of deep bed filtration. For the cake filtration without deposit erosion,the suspension flow rate decreases to zero, and the suspension does not penetrate deep into the porous medium. In the case of the cake filtration with erosion, the suspension flow rate is nonzero, and the deposit is distributed throughout the entire porous medium. An exact solution is obtained for a constant filtration function. The method of characteristics is used to construct the asymptotics of the concentration front of suspended and retained particles for a filtration function in a general form. Explicit formulae are obtained for a linear filtration function. The properties of these solutions are studied in detail. 展开更多
关键词 deep bed filtration cake filtration porous medium particle deposition and erosion analytical solution concentration front
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Sediment Erosion on Pelton Turbines:A Review 被引量:1
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作者 Xinfeng Ge Jie Sun +8 位作者 Dongdong Chu Juan Liu Ye Zhou Hui Zhang Lei Zhang Huixiang Chen Kan Kan Maxime Binama Yuan Zheng 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2023年第3期36-62,共27页
The Pelton turbine has been widely used to develop high-head water resources with sediments because of its advantages in life cycle costs.When a flood or monsoon season occurs,the sediment concentration in the river i... The Pelton turbine has been widely used to develop high-head water resources with sediments because of its advantages in life cycle costs.When a flood or monsoon season occurs,the sediment concentration in the river increases suddenly,causing severe erosion to the nozzle,needle,and runner of Pelton turbines.After decades of development,researchers have developed practical engineering experience to reduce the sediment concentration of the flow through the turbine and ensure the safety and efficiency of power generation.Research on the mechanism of sediment erosion,development of anti-erosion materials,and establishment of erosion prediction models have attracted scholarly interest in recent years.Extensive research has been conducted to determine a complete and valuable syndication erosion model.However,owing to the complexity of the flow and wear mechanisms,the influence of specific parameters of erosion and the syndication effect is still difficult to determine.Computational fluid dynamics and erosion monitoring technology have also been evaluated and applied.This paper presents a comprehensive review of the erosion of Pelton turbines,some of the latest technical methods,and possible future development directions. 展开更多
关键词 Pelton turbine sediment erosion sediment erosion mechanism CFD The experimental method
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Erosion Rates in Dam Catchments in Jordan—Effects of Topography, Geology, and Urbanizations
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作者 Elias Salameh Hakam Al-Alami Ibraheem Hamdan 《Open Journal of Soil Science》 2024年第5期319-331,共13页
Erosion as a natural process produces soils, which are very important natural resources for the fest land plant- and animal kingdoms. Loss of the soil cover reduces agricultural production, biodiversity, and the role ... Erosion as a natural process produces soils, which are very important natural resources for the fest land plant- and animal kingdoms. Loss of the soil cover reduces agricultural production, biodiversity, and the role of soil as a filter for infiltrating water to replenish the groundwater. It also threatens the food supplies. The knowledge of erosion rates of rocks and terrains is important for developing proactive measures to protect soils from erosion and loss. In this study, erosion rates of catchment areas were calculated based on dams’ catchment extensions and the sediment loads transported by flood flows into dams’ lakes. The study results show that the chemically, via floodwater, transported quantities of materials are negligible compared to the solid materials transported by the water. It calculates erosion rates ranging from 0.013 to 0.212 mm/yr (13 - 212 m/10<sup>6</sup> yr) for the different catchment areas. Erosion rates in Jordan are, generally, higher than those calculated for the different parts of the world ranging from 2.5 to 60 m/10<sup>6</sup> yr. This fact can be explained by the very steep topography, calcareous rock cover of the catchment areas and the barren rock exposures. 展开更多
关键词 erosion Rates JORDAN DAMS sediment Load
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Exploration of the Mechanisms for the Low Sensitivity of Deposition Flux to Upstream Sediment Reduction in the North Passage, Yangtze Estuary
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作者 WANG Xiao-guang ZHANG Wei +4 位作者 TONG Chao-feng LEI Zhi-yi QIN Jie JI Xiao-mei HUANG Rui 《China Ocean Engineering》 SCIE EI CSCD 2023年第4期533-546,共14页
Deltas are densely populated industrialized regions,and home to important ports and navigation channels.Due to human interferences,the Yangtze Estuary has experienced a significant reduction in sediment load caused by... Deltas are densely populated industrialized regions,and home to important ports and navigation channels.Due to human interferences,the Yangtze Estuary has experienced a significant reduction in sediment load caused by the Three Gorges Dam(TGD),as well as adjustment to local morphodynamics by the Deep-water Navigation Channel(DNC).While the dramatic reduction in sediment triggers the increased channel erosion,the deposition flux of the DNC located at the estuary mouth has little change.To explore the physical mechanism of this phenomenon,a two-dimensional model is used to establish the relationship between sediment load and the sediment budget of channels based on the bathymetry in 2016.Model results show that the tidal reach and the inner estuary have a negative sediment budget.And the seasonal characteristics of water and sediment fluxes become less obvious downstream.Sensitivity analysis shows that the influence of upstream sediment load on deposition flux decreases along the channel,with a transition from deposition to erosion occurring in the tidal reach.For the last-level bifurcation,the annual siltation of sediment in the North Passage(NP)decreases by 4.5%with low sensitivity.This is attributed to the reduction of sediment load partially mitigated by riverbed erosion and cascade bifurcations.In addition,the lateral sediment supply,which accounts for 68%of the sediment input in the NP,is stable.Overall,this study strengthens the understanding of the relationship between sediment load and artificially deepened systems,thus allowing for better management of estuarine sediment and navigation channel. 展开更多
关键词 DELTA navigation channel sediment load erosion and deposition sediment budget Yangtze Estuary
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Seabed deposition and erosion change and influence factors in the Yangshan Deepwater Port over the years 被引量:2
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作者 Shuhua Zuo Hualiang Xie +4 位作者 Xiaoming Ying Cheng Cui Yuxin Huang Huaiyuan Li Mingxiao Xie 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2019年第7期96-106,共11页
The seabed scouring and silting are very important to the construction of port and waterway engineering.Seabed deposition and erosion change is complicated due to the influence of sediment supply,human activities and ... The seabed scouring and silting are very important to the construction of port and waterway engineering.Seabed deposition and erosion change is complicated due to the influence of sediment supply,human activities and other factors.The Yangshan Deepwater Port is the new deep water harbor,which is an important part of the Shanghai International Shipping Service Center.Its construction has received much attention.At present,the water depth from the 1st to the 3rd harbor district is currently suitable under regular dredging and tidal current action.The fourth harbor district will be built in the world’s largest fully-automated deep water wharf.In the study,bathymetry change of the entire sea area of the Yangshan Deepwater Port and the 4th harbor district(i.e.,PhaseⅣproject)waters were analyzed quantitatively using multiyear bathymetric,hydrological and sediment data.The results show that from 1998 to 2010,seabed changes are characterized by large volumes of erosion and sedimentation,which the southern part was deposited and the northern part was eroded in the inner harbor waters,but the seabed of the Kezhushan inlet was eroded.Seabed changes of PhaseⅣproject waters generally show a scour tendency in recent few years with the annual scour rate about 0.7 m.Among the many factors,the existence of Kezhushan inlet and its influence of the western water flow play an important positive role in water depth changes under the ebb tide action. 展开更多
关键词 Yangshan Deepwater Port phaseⅣproject water and sediment environment SEABED deposition and erosion CHANGE DIVERSION DIKE
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Analysis of deposition and erosion of Dongting Lake by GIS 被引量:1
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作者 Gao Jun-feng Zhang Chen +1 位作者 Jiang Jia-hu Huang Qun 《Journal of Geographical Sciences》 SCIE CSCD 2001年第4期22-30,共9页
The sediments of the Dongting Lake come from four channels (one of them was closed in 1959), connected with the Yangtze River, four tributaries (Lishui, Yuanjiang, Zishui and Xiangjiang) and local area, and some of th... The sediments of the Dongting Lake come from four channels (one of them was closed in 1959), connected with the Yangtze River, four tributaries (Lishui, Yuanjiang, Zishui and Xiangjiang) and local area, and some of them are transported into the Yangtze River in Chenglingji, which is located at the exit of the Dongting Lake, some of them deposit into drainage system in the lake region and the rest deposit into the lake. The annual mean sediment is 166,555x104 t, of which 80% come from the four channels, 18% from the four tributaries and 2% from local area, whereas 26% of the total sediments are transported into the Yangtze River and 74% deposited into the lake and the lake drainage system. Based on topographic maps of 1974, 1988 and 1998, and the spatial analysis method with geographic information system (GIS), changes in sediment deposition and erosion are studied in this paper. By overlay analysis of 1974 and 1988, 1988 and 1998, erosion and sediments deposition areas are defined. The main conclusions are: (1) sediment rate in the lake is larger than erosion rate from 1974 to 1998. The mean deposition in the lake is 0.43 m; (2) annual sediment deposition is the same between 1974-1988 and 1988-1998, but the annual volume of deposition and erosion of 1988-1998 is bigger than that in 1974-1988; (3) before the completion of the Three Gorges Reservoir, there will be 7.82x108 m3 of sediments deposited in the lake, which would make the lake silted up by 0.33 m; (4) in the lake, the deposition area is found in the north of the east Dongting Lake, the south-west of the south Dongting Lake, and the east of the west Dongting Lake; while the eroded area is in the south of the east Dongting Lake, the middle of the south Dongting Lake, the west of the west Dongting Lake, as well as Xiangjiang and Lishui river flood channels. 展开更多
关键词 Dongting Lake sediment deposition and erosion spatial distribution GIS
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Characteristics of Wind Erosion and Deposition in Oasis-desert Ecotone in Southern Margin of Tarim Basin,China 被引量:7
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作者 MAO Donglei LEI Jiaqiang +3 位作者 ZENG Fanjiang RAHMUTULLA Zaynulla WANG Cui ZHOU Jie 《Chinese Geographical Science》 SCIE CSCD 2014年第6期658-673,共16页
The oasis-desert ecotone is a fragile ecological zone that is affected both by oasis and desert conditions. To understand the impact of the differences in wind power, and the influence of wind erosion and deposition o... The oasis-desert ecotone is a fragile ecological zone that is affected both by oasis and desert conditions. To understand the impact of the differences in wind power, and the influence of wind erosion and deposition on the ecotone, meteorological data and contemporaneous wind erosion and deposition data were collected on the southern margin of Tarim Basin with serious sand-blown hazards. The wind velocity, average wind velocity, sand drift potential(DP), resultant sand drift potential(RDP), and sand transportation rate decrease significantly and successively across four landscape types with increasing vegetation coverage(VC). Flat surfaces and areas of shifting sandy ground experience intense wind erosion with fast movement of mobile sand dunes; semi-fixed sand areas experience extensive wind deposition but only slight wind erosion; and fixed sand areas experience only slight wind erosion and deposition. Volume of wind erosion on bare newly reclaimed farmland is up to 6.96 times that of bare shifting sandy ground. Wind erosion volume per unit area and VC follow an exponential function relationship in natural conditions, while wind deposition volume per unit area does not conform to any functions which has close relationship with vary topography and arrangement patterns of vegetation besides for VC. The results indicate that the volume of wind erosion has a close correlation with VC, and different types and distribution patterns of topography and vegetation also profoundly influence the wind deposition volume in the field, and underground water tables in different landscape types control the plant community distribution. 展开更多
关键词 塔里木盆地南缘 风力侵蚀 沉积量 交错带 绿洲 荒漠 植被覆盖度 中国
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Influence of Erosion and Deposition on Metallic First Mirror in HT-7 Tokamak
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作者 陈聚 鄢容 陈俊凌 《Plasma Science and Technology》 SCIE EI CAS CSCD 2012年第8期708-711,共4页
Abstract Dedicated experiments in the HT-7 tokamak were performed to investigate the in- fluence of erosion and deposition on the mirror samples. The first mirror (FM) samples made of polyerystalline (PC) stainles... Abstract Dedicated experiments in the HT-7 tokamak were performed to investigate the in- fluence of erosion and deposition on the mirror samples. The first mirror (FM) samples made of polyerystalline (PC) stainless steel (SS), molybdenum (Mo) and tungsten (W) were fixed on a holder at an angle of 45° with respect to the horizontal plane and set at different locations with different connection lengths along the magnetic field. The optical reflectivity of the first mirror was measured by a spectrophotometer before and after plasma exposure. It was found that the surface morphology and specular reflectivity of the mirror samples after the exposure were different with respect to the different distances from the mirror surface to the last closed flux surface (LCFS) of the plasma in the tokamak. It was also found that shortening the connection length before the mirror surface would weaken the influence of the plasma erosion and impurity deposition on the mirror surface. In order to maintain the optical characteristics of the mirror surface, it is necessary to adopt the in-situ cleaning and mirror protection techniques. 展开更多
关键词 first mirror erosion deposition REFLECTIVITY surface morphology
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Modelling of carbon erosion and re-deposition for the EAST movable limiter
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作者 谢海 丁锐 +1 位作者 陈俊凌 孙继忠 《Plasma Science and Technology》 SCIE EI CAS CSCD 2017年第4期112-119,共8页
e movable limiter at the mid-plane of the Experimental Advanced Superconducting Tokamak (EAST) with carbon coatings on the surface was exposed to edge plasma to study the material erosion and re-deposition.After the... e movable limiter at the mid-plane of the Experimental Advanced Superconducting Tokamak (EAST) with carbon coatings on the surface was exposed to edge plasma to study the material erosion and re-deposition.After the experiments,the carbon erosion and re-deposition is modelled using the 3D Monte Carlo code ERO.The geometry of the movable limiter,3D configuration of the plasma parameters and electromagnetic fields under both limiter and divertor configurations have been implemented into the code.In the simulations,the main uncertain parameters such as carbon concentration ρc in the background plasma and cross-field transport coefficient D⊥ in the vicinity of surface according to the ‘funneling model',have been studied in comparison with experiments.The parameter ρc mainly influences the net erosion and deposition profiles of the two sides of the movable limiter,while D ⊥ mostly changes the profiles on the top surface. 展开更多
关键词 MODELLING EAST LIMITER erosion and deposition
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Analyses on Temporal and Spatial Variation Characteristics of Erosion and Deposition in the Front Edge of Salt Marsh Wetland
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作者 Wenjin Zhu Xue Li +1 位作者 Mei Zhang Xiaotian Dong 《Journal of Environmental Science and Engineering(B)》 2022年第5期213-224,共12页
Taking Yancheng Nature Reserve Salt Marsh as the research object,the remote sensing images from 2005 to 2020 were interpreted by using remote sensing and geographic information system technology.In this paper,the temp... Taking Yancheng Nature Reserve Salt Marsh as the research object,the remote sensing images from 2005 to 2020 were interpreted by using remote sensing and geographic information system technology.In this paper,the temporal and spatial variation characteristics of erosion and deposition in the front edge of salt marsh wetland were analyzed.The influence of sea level rise on the annual change of salt marsh area was analyzed.The characteristics of flow and sediment movement in salt marsh and the causes of erosion and deposition in front of salt marsh were analyzed.The results showed that:(1)During 2005-2007,the sea level was relatively low,and Spartina alterniflora in salt marsh expanded to the sea.Since 2007,the front edge of salt marsh wetland has coexisted with erosion and deposition.From 2008 to 2010,the front edge of salt marsh wetland once again showed a trend of comprehensive deposition to the sea side.From 2010 to 2012,the erosion of salt marsh wetland was serious.From 2012 to 2020,the front edge of salt marsh wetland in the range of 9 km south of Xinyang estuary was eroded.(2)The correlation analysis was carried out between the area of salt marsh wetland and sea level rise.Spartina alterniflora is easily affected by sea level change,owing to it having a low ecological niche.With the rise of sea level,the area of salt marsh has been decreasing since 2013.(3)In the front sea area of salt marsh wetland,the maximum velocity of the ebb and flood can reach the threshold velocity during the spring tide.The sediment starts to move at water depth of 10 m under wave actions.Owing to wave stirs up sediment and current transports the sediment,resuspended sediment causes the erosion of marsh-edge scarps. 展开更多
关键词 Salt marsh wetland remote sensing deposition erosion sea level rise wave-current action
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Dated deposition couplets link catchment erosion flux with storm discharge on the Chinese Loess Plateau
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作者 Zhangdong Jin Xiaqing Wang Xinbao Zhang 《Acta Geochimica》 EI CAS CSCD 2017年第3期548-551,共4页
Tracing erosion flux within a single catchment is one of the major targets for the Earth's Critical Zone science. The sedimentary succession in landslide-dammed reservoirs within the Chinese Loess Plateau(CLP) ser... Tracing erosion flux within a single catchment is one of the major targets for the Earth's Critical Zone science. The sedimentary succession in landslide-dammed reservoirs within the Chinese Loess Plateau(CLP) serves as a valuable archive of past erosion history. Deposition couplets and annual freeze–thaw layers were firstly identified for the sedimentary succession of the Jingbian reservoir on the northern CLP with high-resolution XRF core scanning. The deposition couplets in the reservoir since 1963 A.D. were further dated with ^(137) Cs activity. We found consistent one-to-one correspondence between couplet specific sediment yield and storm intensity. The reconstructed soil erosion history highlights the control of storm intensity and frequency on loess erosion on the northern CLP in the past hundreds of years. 展开更多
关键词 中国黄土高原 侵蚀通量 暴雨径流 流域 沉积序列 降雨 暴雨强度 华北平原
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Regulation of vegetation pattern on the hydrodynamic processes of erosion on hillslope in Loess Plateau,China 被引量:1
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作者 Guo-Qiang Yu Qian Wang +1 位作者 Li-Feng Zhu Xia Zhang 《Journal of Groundwater Science and Engineering》 2023年第1期4-19,共16页
As vegetation are closely related to soil erosion,hydrodynamic parameter changes under various vegetation pattern conditions can be used as an important basis for the research of the soil erosion mechanism.Through ups... As vegetation are closely related to soil erosion,hydrodynamic parameter changes under various vegetation pattern conditions can be used as an important basis for the research of the soil erosion mechanism.Through upstream water inflow experiments conducted on a loess hillslope,how the vegetation pattern influences the hydrodynamic processes of sediment transport was analyzed.The results show that the placement of a grass strip on the lower upslope can effectively reduce runoff erosion by 69%,relying on the efficiency of regulated hydrodynamic process.The effective location of grass strip for hillslope alleviating erosion is on the lower part of the upslope,mainly due to the grass strip measure used to regulate the hydrodynamic system.As a result,the underlying surface runoff resistance is increased by 5 times,runoff shear stress is decreased by more than 90%,and runoff power decreased by over 92%.The measure greatly separates the scouring energy of surface runoff that acts on the slope soil.Therefore,the use of grass strips effectively decreases the energy of runoff flowing along the slope,eliminating soil erosion to a great extent and thereby achieving a better regulation of hydrodynamic processe. 展开更多
关键词 Soil erosion Grass strip Scouring experiment sediment transport Regulating mechanism Loess Plateau
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Effects of freeze-thaw on soil erosion processes and sediment selectivity under simulated rainfall 被引量:9
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作者 WANG Tian LI Peng +5 位作者 REN Zongping XU Guoce LI Zhanbin YANG Yuanyuan TANG Shanshan YAO Jingwei 《Journal of Arid Land》 SCIE CSCD 2017年第2期234-243,共10页
The freeze-thaw (FT) processes affect an area of 46.3% in China. It is essential for soil and water conservation and ecological construction to elucidate the mechanisms of the FF processes and its associated soil er... The freeze-thaw (FT) processes affect an area of 46.3% in China. It is essential for soil and water conservation and ecological construction to elucidate the mechanisms of the FF processes and its associated soil erosion processes. In this research, we designed the control simulation experiments to promote the understanding of FT-water combined erosion processes. The results showed that the runoff of freeze-thaw slope (FTS) decreased by 8% compared to the control slope (CS), and the total sediment yield of the FTS was 1.10 times that of the CS. The sediment yield rate from the FTS was significantly greater than that from the CS after 9 min of runoff (P〈0.01). Both in FTS and CS treatments, the relationships between cumulative runoff and sediment yield can be fitted well with power functions (R2〉0.98, P〈0.01). Significant differences in the mean weight diameter (MWD) values of particles were between the CS and the FTS treatments in the erosion were smaller than those under FTS for both washed and observed for washed particles and splashed particles process (P〈0.05). The mean MWD values under CS splashed particles. The ratio of the absolute value of a regression coefficient between the CS and the FTS was 1.15, being roughly correspondent with the ratio of K between the two treatments. Therefore, the parameter a of the power function between cumulative runoff and sediment yield could be an acceptable indicator for expressing the soil erodibility. In conclusion, the FTS exhibited an increase in soil erosion compared to the CS. 展开更多
关键词 freeze-thaw erosion loess soil soil erodibility RUNOFF sediment size-selectivity rainfall simulation
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