Flow and sediment problem is one of the key factors which affect the dispatching operation and life of the Three Gorges Project(TGP).Many approaches have been employed to research the flow and sediment problems of the...Flow and sediment problem is one of the key factors which affect the dispatching operation and life of the Three Gorges Project(TGP).Many approaches have been employed to research the flow and sediment problems of the TGP during its demonstration,planning,design,construction and operation,and many important results have been obtained.To understand the progress of flow and sediment measurement in China's representative projects and the experience of sediment observation in super large reservoirs,the flow and sediment measurement of the TGP is mainly introduced in this paper.It includes the general situation of the TGP,the distribution of the hydrological station network,the measurement factors,the new measurement technology,and the sediment changes in the reservoir and downstream after the impoundment of the TGP.The sediment measurement results show that the basic situation of sediment problems is good,and these sediment problems may probably accumulate,develop,and transform over time,so they should be paid continuous attention.展开更多
The Yangtze River has nurtured the fertile land on both its banks and hundreds of millions of Chinese people. but its raging waters have also wreaked havoc on the people living in its reaches. Since the founding of Ne...The Yangtze River has nurtured the fertile land on both its banks and hundreds of millions of Chinese people. but its raging waters have also wreaked havoc on the people living in its reaches. Since the founding of New China, large-scale surveys, planning, scientific research and feasibility studies have been carried out in an effort to harness the展开更多
Based on the measured hydrological data from 1951 to 2008, the chain hydrological effect between Jingjiang River and Dongting Lake is analyzed by comparative method after the Three Gorges Project operation. The result...Based on the measured hydrological data from 1951 to 2008, the chain hydrological effect between Jingjiang River and Dongting Lake is analyzed by comparative method after the Three Gorges Project operation. The result indicates that 1） the scouring amount in Jing- jiang River made up 78.9% of the total from Yichang to Chenglingji, and its average scouring intensity was higher than the latter; 2） the water and sand diversion rates at the three outlets of the Jingjiang River were reduced by 2.33% and 2.78% separately; 3） the proportion of multi-year average runoff and sediment through the three outlets in the total into the Dongting Lake decreased by 7.7% and 24.4% respectively; 4） in Dongting Lake, the speed of sediment accumulation was lowered by 26.7%, in flood season, the runoff amount was 20.2% less than the multi-year average value, leading to seasonal scarcity of water year by year. The former prolonged the lake life, while the latter induced droughts in summer and fall in successive years, shortage of drinking and industrial water, shipping insecurity, as well as ecological problems such as decrease of birds and quick increase of Microtus fortis; 5） The multi-year average values of sediment and flood transporting capacity at the lake outlet were respec- tively increased by 26.6% and 3.7%, the adapt to the new change of the river-lake embankments were protected effectively. Then, to relation, some suggestions were put forward, such as optimizing further operation program of the Three Gorges Reservoir, reexamining the idea of river and lake regulation, and maintaining connection of the river and the lake.展开更多
This paper reviewed existing literatures on land use change since the demonstration phase of the Three Gorges Project and found that reservoir inundation, migration resettlement, urban relocation, and post-supporting ...This paper reviewed existing literatures on land use change since the demonstration phase of the Three Gorges Project and found that reservoir inundation, migration resettlement, urban relocation, and post-supporting construction were first paid more attention to, when analyzing the driving forces of land use change in the migration area. However, at the post-migration period （the end of migration resettlement）, above-mentioned drivers had not obviously driven land use change, but the evolutions of ＂migration demands＂ replacing them increasingly became the major drivers of land use change in the migration area. Therefore, the future priority fields of land use explanations in the mi- gration area, Three Gorges Project were （1） identifying the corresponding relationships between the spatial distributions of land use change and migration resettlement and indigenous inhabitants; （2） un- derstanding the change of ＂migration demands＂ and their causing ＂indigenous inhabitants＇ demands＂ being how to drive land use transforms; （3） finding the driving processes of the conflict and exclusion between immigrants and indigenous inhabitants, and the transfer of immigrants and indigenous in- habitants on land use change; and （4） measuring the dynamic feedback of ＂migration demands＂ at dif- ferent stages on the processes, directions and their corresponding impacts of land use change in order to building the coupling framework among ＂migration demands＂, driver behaviors, and land use. This paper presents a new access for the explanation of land use change and also supplies scientific proofs to obtain adaptive decision-making to optimize land use patterns in the migration area, Three Gorges Project.展开更多
To date,the Three Gorges Project is the largest hydro junction in the world.It is the key project for the integrated water resource management and development of the Changjiang River.The technology of the project,with...To date,the Three Gorges Project is the largest hydro junction in the world.It is the key project for the integrated water resource management and development of the Changjiang River.The technology of the project,with its huge scale and comprehensive benefits,is extremely complicated,and the design difficulty is greater than that of any other hydro project in the world.A series of new design theories and methods have been proposed and applied in the design and research process.Many key technological problems regarding hydraulic structures have been overcome,such as a gravity dam with multi-layer large discharge orifices,a hydropower station of giant generating units,and a giant continual multi-step ship lock with a high water head.展开更多
The Three Gorges Project(TGP)has changed the flow-sediment process in the middle Yangtze River.For navigation purposes,there is an urgent need to study the changes of the river regime over a long-term period and the s...The Three Gorges Project(TGP)has changed the flow-sediment process in the middle Yangtze River.For navigation purposes,there is an urgent need to study the changes of the river regime over a long-term period and the shoal-channel evolution over different seasons since the completion of the TGP.Based on analysis of the measured data and the results of a two-dimensional mathematical model,the changes of the river regime and river bed evolution in the Yaojian reach downstream of the TGP were studied.Results show that a high sediment transport flux helps to keep the main flow in the North Branch,while a low sediment transport flux helps to keep the main flow in the South Branch.Thus,the main branch will not change in the near future because of the low sediment transport load.In this study,the flow-sediment process adjusted by the TGP was restored to the conditions before the TGP,and the river bed evolution under the adjusted and non-adjusted flow-sediment conditions was calculated.After the completion of the TGP,the reservoir storage accelerated the flood recession process and decreased the erosion by 11.9%under the flow-sediment conditions in 2010,and the deposition in the flood season decreased by 56.4%.展开更多
The construction of the double-lane five-step ship lock of the Three Gorges Project （TGP） wascommenced in 1994, the excavation of the ship lock was completed by the end of 1999, and the ship lockwas put in operation...The construction of the double-lane five-step ship lock of the Three Gorges Project （TGP） wascommenced in 1994, the excavation of the ship lock was completed by the end of 1999, and the ship lockwas put in operation in June 2003. The side slopes of the ship lock are characterized by great height（170 m）, steepness （70 m in height of upright slope）, and great length （over 7000 m in total length）. Inassociation with the ship lock, the surrounding rocks in slope have a high potential to deform, withwhich the magnitude of deformation is restricted. Monitoring results show that the deformation of thefive-step ship lock high slopes of the TGP primarily occurred in excavation period, and deformationtended to be stable and convergent during operation period, suggesting the allowable ranges of deformation.At present, the slopes and lock chambers are stable, and the ship lock works well under normaloperation condition, enabling the social and economic benefits of the TGP. 2015 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved.展开更多
Geomorphic dynamics of alluvial rivers in response to upstream damming have substantial impacts on navigation, habitat protection, and channel stability. The purpose of this study was to determine how flow and sedimen...Geomorphic dynamics of alluvial rivers in response to upstream damming have substantial impacts on navigation, habitat protection, and channel stability. The purpose of this study was to determine how flow and sediment regimes, and meander characteristics affect the morphological adjustment of bends in the Lower Jingjiang Reach(LJR) before and after the Three Gorges Project(TGP). Based on detailed field measurements and hydrological and topographic datasets from 1991 to 2016, banks and point bars morphodynamics of 12continuous bends in the LJR were comprehensively analyzed. Point bars in the LJR mainly experienced a net deposition before the TGP operation, but substantially deteriorated with a net erosion rate of 4.6 million m^(3) yr^(-1) in the post-TGP periods(2003–2016), and erosion on heads and upstream margins of point bars was a general adjustment pattern in the 12 bends.The most significant morphological changes of point bars and banks occurred in 2006–2011,indicating a delayed response of the channel evolution of the LJR to damming. Detailed observations suggested that the medium discharges(16,000–18,000 m^(3) s^(-1)) were the most contributive discharges in shaping the morphology of point bars and banks in the LJR after damming. In addition, we revealed the importance of sediment supply on meander deformation of the LJR, driven by sediment exchange over point bars, and more upstream planform deformation tended to occur in bends with high sinuosity(>2.0) in the LJR after damming.The relationship between meander deformation and sinuosity was manifested through the geometric adjustment range of point bars. The morphological adjustments of point bars in the highly curved or compound bends of the LJR were more conducive to cause flow deflections,leading to form concave-bank bars after the TGP operation.展开更多
Seismic monitoring data for the past 50 years in the Three Gorges Reservoir area show that the reservoir head area is a typical weak seismic region with low seismieity before impoundment and that the epicenters were c...Seismic monitoring data for the past 50 years in the Three Gorges Reservoir area show that the reservoir head area is a typical weak seismic region with low seismieity before impoundment and that the epicenters were concentrated in the east and west sides of the Zigui Basin, most of which were natural tectonic earth- quakes. After impoundment, the seismic activity shifted to the segment between Badong and Zigui along the Yangtze River, mainly within 5 km of the reservoir bank. The seismogenesis was categorized into four types： Karst collapse earthquakes, earthquakes caused by Karst gas explosion, mining tunnel collapse earthquakes, and rock （terrane） slip earthquakes, all of which are related to the lithology, structure, and tectonics of near- surface geological bodies of the area. Compared with the seismicity before impoundment, the seismic frequency increase was remarkable, with most of the magnitudes below Ms2.0. Therefore, the intensity of the earth- quakes remained at a low level. On November 22, 2008, a magnitude 4.1 earthquake, the largest earthquake recorded since impoundment, occurred in Quyuan Town, Zigui County. The intensity and PGA of reservoir-in- duced earthquakes are higher than those of tectonic earthquakes with equal magnitude, but the peak intensity of reservoir-induced earthquakes is not likely to go beyond that of the estimated range from earlier studies.展开更多
The Three Gorges Project is one of the essential key projects for flood controlling and water resources regulation in the Yangtze River. The project includes a river-crossing dam, underground powerhouses, and navigati...The Three Gorges Project is one of the essential key projects for flood controlling and water resources regulation in the Yangtze River. The project includes a river-crossing dam, underground powerhouses, and navigation structures. Because of the huge size and complicated construction technologies, the project faced a series of challenging engineering issues. In terms of rock mechanics, there are many key technical issues, including the sliding resistance and stability of the dam section along the foundations of powerhouses No.l-5, the ,,;lope stability of the double-line five-stage shiplock, excavation of large-scale underground powerhouses, and curtain grouting under the dam. With decades of scientific research and 16 years of practical construction experiences and reservoir operations, these key technical issues in construction of the Three Gorges Project are successfully resolved, which will attribute to the development of hydropower technology. On the basis of the monitoring data during construction and normal operation periods of the Three Gorges Project, this paper presents a systematic analysis of these key rock mechanical issues in terms of behaviors, solutions, dynamic controlling, monitoring arrangement and integrated assessment.展开更多
The general design and layout of the double-line five-step ship-lock,the water delivery technique for high head ship-lock,the key technical problems of fully lined ship-lock and the monitoring techniques for large-sca...The general design and layout of the double-line five-step ship-lock,the water delivery technique for high head ship-lock,the key technical problems of fully lined ship-lock and the monitoring techniques for large-scale miter gates and hoisting equipment under complicated operation conditions of Three Gorges Project (TGP) are introduced.Since the operation of ship-lock in 2003,the operation practice has proved that the design techniques are advanced,rational and reliable.The design and construction of the fully lined ship-lock promotes the development of design theory and practice of ship-lock projects,which makes the construction technology of ship-lock in the world reach a new level.展开更多
This paper establishes a 3D numerical model for 15# hydropower house of the Three Gorges Project (TGP) and performs a nonlinear static and dynamic damage analysis. In this numerical model, a coupling model of finite a...This paper establishes a 3D numerical model for 15# hydropower house of the Three Gorges Project (TGP) and performs a nonlinear static and dynamic damage analysis. In this numerical model, a coupling model of finite and infinite elements for simulating infinite foundation of hydropower station is adopted. A plastic-damage model based on continuum damage mechanics, which includes the softening and damage behavior under tension is considered for the concrete material. The dynamic equilibrium equations of moti...展开更多
The Three Gorges Project attracts worldwide attention because of the Three Gorges migrants, and the agriculture of the Three Gorges Reservoir Area is a foundation for the development of the Three Gorges migrants. The ...The Three Gorges Project attracts worldwide attention because of the Three Gorges migrants, and the agriculture of the Three Gorges Reservoir Area is a foundation for the development of the Three Gorges migrants. The Three Gorges Reservoir Area is situated at the mountainous area with bad agricultural development conditions and relatively low levels of development. As a result, the large-scale migration fias special influence on its agricultural development, which has attracted much attention. The paper analyzes influence that the migrants have forced on its agricultural development based on the scientific data, and makes some explorations on the models that are suitable for the development of mountainous agriculture in the Three Gorges Reservoir Area.展开更多
The construction of Three Gorges Project (TGP) is characterized by large construction scale,high construction intensity and complexity in technology.In view of various technical difficulties such as navigation in cons...The construction of Three Gorges Project (TGP) is characterized by large construction scale,high construction intensity and complexity in technology.In view of various technical difficulties such as navigation in construction period,two river closures,high-intensity concrete and earth-rock construction,high-intensity construction and demolition of RCC (roller compacted concrete) cofferdam in stage III and immediate navigation of double-line five-step shiplock after impoundment of reservoir,the scheme of river diversion during construction is adopted,namely "diversion in 3 stages,open channel navigation and cofferdam power generation".The practice and innovation achievements in river diversion during construction as well as earth-rock and concrete construction are presented emphatically.展开更多
The pinion bracket-assembly(PBA) is a major part of three gorges project(TGP) ship lift drive system. The static strength,fatigue strength and stress distribution of hinge pin of PBA were analyzed by ANSYS, and the st...The pinion bracket-assembly(PBA) is a major part of three gorges project(TGP) ship lift drive system. The static strength,fatigue strength and stress distribution of hinge pin of PBA were analyzed by ANSYS, and the structure of PBA was optimized. The results show that after the optimization, the maximum comprehensive stress is 259.59 MPa, the maximum fatigue cumulative damage of weld joints is 0.94 and the maximum vertical deformation of hinge pin is 0.14 mm. The elastic deformation, hydropneumatic spring cylinder(HSC) load response and the vibration characteristics of PBA were studied by the bearing test when PBA bore the load caused by different water level errors. The results indicate that when the water level of ship chamber ranges from 3.4 m to 3.6 m,the vertical elastic deformation of the pinion shaft is between-8.58 and 10.50 mm. When upward outage-load(1580 k N) is imposed by the test-rack, the vertical elastic deformation of the pinion shaft is 13.42 and 14.07 mm and HSC load response is 795.80-800.80 k N. In the process of imposing load on the pinion by the test-rack, the maximum vibration amplitude and acceleration of PBA internal components are 0.37° and 2.67 rad/s2, respectively; the maximum impact on the pin caused by vibration is 19.89 k N; the pinion shaft vertical displacement and HSC load response do not fluctuate. There is a great difference between the frequency of meshing force of the pinion and the rack(1.06 Hz) and first-order natural frequency of PBA(8.41 Hz), thus PBA will not resonate.From all above, PBA meets the static strength and fatigue strength requirements. The vibration of PBA internal components has no effect on the vertical displacement of the pinion shaft, HSC load response and smooth operation of PBA. There is a liner relationship in the ratio of 2:1 between the thrust imposed by the test-rack and HSC load, thus HSC can limit the load imposed on the pinion.展开更多
Three Gorges Project (TGP),the largest water resources and hydropower project in the world with huge scale and complex techniques,has great comprehensive benefits mainly in flood control,power generation and navigatio...Three Gorges Project (TGP),the largest water resources and hydropower project in the world with huge scale and complex techniques,has great comprehensive benefits mainly in flood control,power generation and navigation improvement.Through 17-year construction and practice,the project has been successfully completed.Some valuable experience from the successful construction of TGP has been gained for the management system and mechanism of hydropower project construction in China.Its construction management mode produces important influences on the management system of domestic capital construction.With combination of the construction management practice of TGP,the characteristics of management system and mechanism are summarized,and the suggestions on current hydropower development system and construction management mode are put forward.展开更多
Climate change and human activities have profoundly changed the evolutionary processes and developmental trends of the hydrology and geomorphology of rivers and lakes.Such changes have affected the evolution of bars a...Climate change and human activities have profoundly changed the evolutionary processes and developmental trends of the hydrology and geomorphology of rivers and lakes.Such changes have affected the evolution of bars and channels at the intersections of rivers and lakes and the utilization of water depth resources in waterways,which,in turn,have affected the sustainable development of waterways,such as the“Golden Waterway”of the Yangtze River.Considering the confluence of Dongting Lake and the Yangtze River as the present study area,we analyzed the effect of the hydrology of Dongting Lake and the evolution of bars and channels in the Jingjiang reach of the Yangtze River on the depth of the waterways.Our results indicated that from before the operation of the Three Gorges Project(1960–2002)to after its operation(2003–2021),the flow and sediment volume of the three inlets of Dongting Lake demonstrated a continuous decreasing trend.Furthermore,the relative increase in the runoff of the Jingjiang reach increased channel erosion.Channel erosion at the river–lake confluence from 2003 to 2021 created favorable conditions for increasing the dimensions of the waterways.The total length of the river–lake confluence that did not meet the requirements for safe navigation[4.5×200m(water depth×width)]was 12.6 km,accounting for 68.35%of the total length of the Jingjiang reach with obstructed navigation.We observed that a decrease in the low‐water level and“steep slope and rapid flow”were the major factors hindering the navigation of the reach(from Zhicheng to Dabujie)affected by the Songzikou diversion of Dongting Lake.This was mostly reflected by the width of the 4.5m waterway being less than 200 m.A declining water level,shrinking sandbanks and tidal flats,and alternating branches that destabilize the low‐water route were the major factors hindering navigation in the reach(from Taipingkou)affected by the Taipingkou diversion of Dongting Lake.Consequently,alternative waterways were implemented during low‐water periods with the water depth decreasing below 4.5 m.The obvious collapse of sandbanks and tidal flats and their erosion and migration were the major factors hindering navigation of the Ouchikou diversion of Dongting Lake.In addition,the scattered submerged shoals in the navigation channel restricted the width of the 4.5m channel to less than 200 m.The reach affected by the Dongting Lake confluence(from Xiongjiazhou–Chenglingji reach)was subject to the erosion and silting of bends and the jacking effect of lake outflow,causing shoals with a water depth of less than 4.5m in the channel.However,the jacking effect slowed the current,thereby assisting in improving channel conditions.展开更多
This paper studies current policies in compensation for land lost due to construction of the Three Gorges project (TGP), China. In the case study of Kaixian County, the value of land in the peri-urban areas is underes...This paper studies current policies in compensation for land lost due to construction of the Three Gorges project (TGP), China. In the case study of Kaixian County, the value of land in the peri-urban areas is underestimated. Some losses in land are tangible and thus measurable, but some losses are intangible and thus immeasurable. The land available in the resettlement areas is scarce and rarely of equivalent quality. This study suggests that the loss of agricultural land be compensated with alternative land and/or non-land-based livelihood strategies, including part compensation in monetary terms and preferential policies.展开更多
In this paper we have analyzed precise gravity survey and gravity effects resulted from water loading, crustal deformation, ground water level change and precipitation before and after the water impoundment in the Thr...In this paper we have analyzed precise gravity survey and gravity effects resulted from water loading, crustal deformation, ground water level change and precipitation before and after the water impoundment in the Three Gorges Reservoir. We found that： ① In dam area of the reservoir, gravity effect resulted from water load increase is the most significant, maximum gravity change is 200×10^-8 m/s^2, but this effect is limited in amplitude and range. Gravity change can be observed about 5 km offshore. The gravity change caused by ground water level change is regional; and the impact of precipitation on it should not be neglected. ② At head area of the reservoir, the maximum gravity change is near Xiangxi. Monitoring the variation of gravity field and further study should continue in the future.展开更多
基金National Key Research and Development Program of China,Grant/Award Number:2022YFC3201801。
文摘Flow and sediment problem is one of the key factors which affect the dispatching operation and life of the Three Gorges Project(TGP).Many approaches have been employed to research the flow and sediment problems of the TGP during its demonstration,planning,design,construction and operation,and many important results have been obtained.To understand the progress of flow and sediment measurement in China's representative projects and the experience of sediment observation in super large reservoirs,the flow and sediment measurement of the TGP is mainly introduced in this paper.It includes the general situation of the TGP,the distribution of the hydrological station network,the measurement factors,the new measurement technology,and the sediment changes in the reservoir and downstream after the impoundment of the TGP.The sediment measurement results show that the basic situation of sediment problems is good,and these sediment problems may probably accumulate,develop,and transform over time,so they should be paid continuous attention.
文摘The Yangtze River has nurtured the fertile land on both its banks and hundreds of millions of Chinese people. but its raging waters have also wreaked havoc on the people living in its reaches. Since the founding of New China, large-scale surveys, planning, scientific research and feasibility studies have been carried out in an effort to harness the
基金Construction Program of the Key Discipline in Hunan Province,No.2008001The Construction Program of the Key Discipline in Hunan Normal University
文摘Based on the measured hydrological data from 1951 to 2008, the chain hydrological effect between Jingjiang River and Dongting Lake is analyzed by comparative method after the Three Gorges Project operation. The result indicates that 1） the scouring amount in Jing- jiang River made up 78.9% of the total from Yichang to Chenglingji, and its average scouring intensity was higher than the latter; 2） the water and sand diversion rates at the three outlets of the Jingjiang River were reduced by 2.33% and 2.78% separately; 3） the proportion of multi-year average runoff and sediment through the three outlets in the total into the Dongting Lake decreased by 7.7% and 24.4% respectively; 4） in Dongting Lake, the speed of sediment accumulation was lowered by 26.7%, in flood season, the runoff amount was 20.2% less than the multi-year average value, leading to seasonal scarcity of water year by year. The former prolonged the lake life, while the latter induced droughts in summer and fall in successive years, shortage of drinking and industrial water, shipping insecurity, as well as ecological problems such as decrease of birds and quick increase of Microtus fortis; 5） The multi-year average values of sediment and flood transporting capacity at the lake outlet were respec- tively increased by 26.6% and 3.7%, the adapt to the new change of the river-lake embankments were protected effectively. Then, to relation, some suggestions were put forward, such as optimizing further operation program of the Three Gorges Reservoir, reexamining the idea of river and lake regulation, and maintaining connection of the river and the lake.
基金supported by the Key Project of Science and Technology of Ministry of Education,China(No.210181)the Foundation of Application Basic Research Project of Chongqing Municipal Commission of Education,China(No.KJ090805)
文摘This paper reviewed existing literatures on land use change since the demonstration phase of the Three Gorges Project and found that reservoir inundation, migration resettlement, urban relocation, and post-supporting construction were first paid more attention to, when analyzing the driving forces of land use change in the migration area. However, at the post-migration period （the end of migration resettlement）, above-mentioned drivers had not obviously driven land use change, but the evolutions of ＂migration demands＂ replacing them increasingly became the major drivers of land use change in the migration area. Therefore, the future priority fields of land use explanations in the mi- gration area, Three Gorges Project were （1） identifying the corresponding relationships between the spatial distributions of land use change and migration resettlement and indigenous inhabitants; （2） un- derstanding the change of ＂migration demands＂ and their causing ＂indigenous inhabitants＇ demands＂ being how to drive land use transforms; （3） finding the driving processes of the conflict and exclusion between immigrants and indigenous inhabitants, and the transfer of immigrants and indigenous in- habitants on land use change; and （4） measuring the dynamic feedback of ＂migration demands＂ at dif- ferent stages on the processes, directions and their corresponding impacts of land use change in order to building the coupling framework among ＂migration demands＂, driver behaviors, and land use. This paper presents a new access for the explanation of land use change and also supplies scientific proofs to obtain adaptive decision-making to optimize land use patterns in the migration area, Three Gorges Project.
文摘To date,the Three Gorges Project is the largest hydro junction in the world.It is the key project for the integrated water resource management and development of the Changjiang River.The technology of the project,with its huge scale and comprehensive benefits,is extremely complicated,and the design difficulty is greater than that of any other hydro project in the world.A series of new design theories and methods have been proposed and applied in the design and research process.Many key technological problems regarding hydraulic structures have been overcome,such as a gravity dam with multi-layer large discharge orifices,a hydropower station of giant generating units,and a giant continual multi-step ship lock with a high water head.
基金supported by the National Key Research and Development Program of China(Grants No.2016YFC0402307 and 2016YFC0402103)the National Natural Science Foundation of China(Grant No.51520105014).
文摘The Three Gorges Project(TGP)has changed the flow-sediment process in the middle Yangtze River.For navigation purposes,there is an urgent need to study the changes of the river regime over a long-term period and the shoal-channel evolution over different seasons since the completion of the TGP.Based on analysis of the measured data and the results of a two-dimensional mathematical model,the changes of the river regime and river bed evolution in the Yaojian reach downstream of the TGP were studied.Results show that a high sediment transport flux helps to keep the main flow in the North Branch,while a low sediment transport flux helps to keep the main flow in the South Branch.Thus,the main branch will not change in the near future because of the low sediment transport load.In this study,the flow-sediment process adjusted by the TGP was restored to the conditions before the TGP,and the river bed evolution under the adjusted and non-adjusted flow-sediment conditions was calculated.After the completion of the TGP,the reservoir storage accelerated the flood recession process and decreased the erosion by 11.9%under the flow-sediment conditions in 2010,and the deposition in the flood season decreased by 56.4%.
文摘The construction of the double-lane five-step ship lock of the Three Gorges Project （TGP） wascommenced in 1994, the excavation of the ship lock was completed by the end of 1999, and the ship lockwas put in operation in June 2003. The side slopes of the ship lock are characterized by great height（170 m）, steepness （70 m in height of upright slope）, and great length （over 7000 m in total length）. Inassociation with the ship lock, the surrounding rocks in slope have a high potential to deform, withwhich the magnitude of deformation is restricted. Monitoring results show that the deformation of thefive-step ship lock high slopes of the TGP primarily occurred in excavation period, and deformationtended to be stable and convergent during operation period, suggesting the allowable ranges of deformation.At present, the slopes and lock chambers are stable, and the ship lock works well under normaloperation condition, enabling the social and economic benefits of the TGP. 2015 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved.
基金Key Program of National Natural Science Foundation of China,No.U2040219National Natural Science Foundation of China,No.51579015Program of National Key Research and Development Plan of China,No.2016YFC0402108, No.2016YFC0402103。
文摘Geomorphic dynamics of alluvial rivers in response to upstream damming have substantial impacts on navigation, habitat protection, and channel stability. The purpose of this study was to determine how flow and sediment regimes, and meander characteristics affect the morphological adjustment of bends in the Lower Jingjiang Reach(LJR) before and after the Three Gorges Project(TGP). Based on detailed field measurements and hydrological and topographic datasets from 1991 to 2016, banks and point bars morphodynamics of 12continuous bends in the LJR were comprehensively analyzed. Point bars in the LJR mainly experienced a net deposition before the TGP operation, but substantially deteriorated with a net erosion rate of 4.6 million m^(3) yr^(-1) in the post-TGP periods(2003–2016), and erosion on heads and upstream margins of point bars was a general adjustment pattern in the 12 bends.The most significant morphological changes of point bars and banks occurred in 2006–2011,indicating a delayed response of the channel evolution of the LJR to damming. Detailed observations suggested that the medium discharges(16,000–18,000 m^(3) s^(-1)) were the most contributive discharges in shaping the morphology of point bars and banks in the LJR after damming. In addition, we revealed the importance of sediment supply on meander deformation of the LJR, driven by sediment exchange over point bars, and more upstream planform deformation tended to occur in bends with high sinuosity(>2.0) in the LJR after damming.The relationship between meander deformation and sinuosity was manifested through the geometric adjustment range of point bars. The morphological adjustments of point bars in the highly curved or compound bends of the LJR were more conducive to cause flow deflections,leading to form concave-bank bars after the TGP operation.
基金supported by the China Three Gorges Corporation(SXSN/2377)
文摘Seismic monitoring data for the past 50 years in the Three Gorges Reservoir area show that the reservoir head area is a typical weak seismic region with low seismieity before impoundment and that the epicenters were concentrated in the east and west sides of the Zigui Basin, most of which were natural tectonic earth- quakes. After impoundment, the seismic activity shifted to the segment between Badong and Zigui along the Yangtze River, mainly within 5 km of the reservoir bank. The seismogenesis was categorized into four types： Karst collapse earthquakes, earthquakes caused by Karst gas explosion, mining tunnel collapse earthquakes, and rock （terrane） slip earthquakes, all of which are related to the lithology, structure, and tectonics of near- surface geological bodies of the area. Compared with the seismicity before impoundment, the seismic frequency increase was remarkable, with most of the magnitudes below Ms2.0. Therefore, the intensity of the earth- quakes remained at a low level. On November 22, 2008, a magnitude 4.1 earthquake, the largest earthquake recorded since impoundment, occurred in Quyuan Town, Zigui County. The intensity and PGA of reservoir-in- duced earthquakes are higher than those of tectonic earthquakes with equal magnitude, but the peak intensity of reservoir-induced earthquakes is not likely to go beyond that of the estimated range from earlier studies.
文摘The Three Gorges Project is one of the essential key projects for flood controlling and water resources regulation in the Yangtze River. The project includes a river-crossing dam, underground powerhouses, and navigation structures. Because of the huge size and complicated construction technologies, the project faced a series of challenging engineering issues. In terms of rock mechanics, there are many key technical issues, including the sliding resistance and stability of the dam section along the foundations of powerhouses No.l-5, the ,,;lope stability of the double-line five-stage shiplock, excavation of large-scale underground powerhouses, and curtain grouting under the dam. With decades of scientific research and 16 years of practical construction experiences and reservoir operations, these key technical issues in construction of the Three Gorges Project are successfully resolved, which will attribute to the development of hydropower technology. On the basis of the monitoring data during construction and normal operation periods of the Three Gorges Project, this paper presents a systematic analysis of these key rock mechanical issues in terms of behaviors, solutions, dynamic controlling, monitoring arrangement and integrated assessment.
文摘The general design and layout of the double-line five-step ship-lock,the water delivery technique for high head ship-lock,the key technical problems of fully lined ship-lock and the monitoring techniques for large-scale miter gates and hoisting equipment under complicated operation conditions of Three Gorges Project (TGP) are introduced.Since the operation of ship-lock in 2003,the operation practice has proved that the design techniques are advanced,rational and reliable.The design and construction of the fully lined ship-lock promotes the development of design theory and practice of ship-lock projects,which makes the construction technology of ship-lock in the world reach a new level.
基金Supported by National Natural Science Foundation of China (No.50679009)Key Laboratory for Scientific Research of Department of Education in Liaoning Province (No.2008S045)
文摘This paper establishes a 3D numerical model for 15# hydropower house of the Three Gorges Project (TGP) and performs a nonlinear static and dynamic damage analysis. In this numerical model, a coupling model of finite and infinite elements for simulating infinite foundation of hydropower station is adopted. A plastic-damage model based on continuum damage mechanics, which includes the softening and damage behavior under tension is considered for the concrete material. The dynamic equilibrium equations of moti...
基金the Project of Construction Committee of Three Gorges Reservoir (Grant No. SX[2002]00401)Chinese Academy of Science (Grant No. KZCX2-SW-319-01).
文摘The Three Gorges Project attracts worldwide attention because of the Three Gorges migrants, and the agriculture of the Three Gorges Reservoir Area is a foundation for the development of the Three Gorges migrants. The Three Gorges Reservoir Area is situated at the mountainous area with bad agricultural development conditions and relatively low levels of development. As a result, the large-scale migration fias special influence on its agricultural development, which has attracted much attention. The paper analyzes influence that the migrants have forced on its agricultural development based on the scientific data, and makes some explorations on the models that are suitable for the development of mountainous agriculture in the Three Gorges Reservoir Area.
文摘The construction of Three Gorges Project (TGP) is characterized by large construction scale,high construction intensity and complexity in technology.In view of various technical difficulties such as navigation in construction period,two river closures,high-intensity concrete and earth-rock construction,high-intensity construction and demolition of RCC (roller compacted concrete) cofferdam in stage III and immediate navigation of double-line five-step shiplock after impoundment of reservoir,the scheme of river diversion during construction is adopted,namely "diversion in 3 stages,open channel navigation and cofferdam power generation".The practice and innovation achievements in river diversion during construction as well as earth-rock and concrete construction are presented emphatically.
基金Project(SPKJ016-06)supported by the Key Research Project of State Power Corporation,ChinaProject(2004AC1O1D31)supported by the Key Scientific Research Project of Hubei Province,ChinaProject(0722018)supported by the China Three Gorges Corporation
文摘The pinion bracket-assembly(PBA) is a major part of three gorges project(TGP) ship lift drive system. The static strength,fatigue strength and stress distribution of hinge pin of PBA were analyzed by ANSYS, and the structure of PBA was optimized. The results show that after the optimization, the maximum comprehensive stress is 259.59 MPa, the maximum fatigue cumulative damage of weld joints is 0.94 and the maximum vertical deformation of hinge pin is 0.14 mm. The elastic deformation, hydropneumatic spring cylinder(HSC) load response and the vibration characteristics of PBA were studied by the bearing test when PBA bore the load caused by different water level errors. The results indicate that when the water level of ship chamber ranges from 3.4 m to 3.6 m,the vertical elastic deformation of the pinion shaft is between-8.58 and 10.50 mm. When upward outage-load(1580 k N) is imposed by the test-rack, the vertical elastic deformation of the pinion shaft is 13.42 and 14.07 mm and HSC load response is 795.80-800.80 k N. In the process of imposing load on the pinion by the test-rack, the maximum vibration amplitude and acceleration of PBA internal components are 0.37° and 2.67 rad/s2, respectively; the maximum impact on the pin caused by vibration is 19.89 k N; the pinion shaft vertical displacement and HSC load response do not fluctuate. There is a great difference between the frequency of meshing force of the pinion and the rack(1.06 Hz) and first-order natural frequency of PBA(8.41 Hz), thus PBA will not resonate.From all above, PBA meets the static strength and fatigue strength requirements. The vibration of PBA internal components has no effect on the vertical displacement of the pinion shaft, HSC load response and smooth operation of PBA. There is a liner relationship in the ratio of 2:1 between the thrust imposed by the test-rack and HSC load, thus HSC can limit the load imposed on the pinion.
文摘Three Gorges Project (TGP),the largest water resources and hydropower project in the world with huge scale and complex techniques,has great comprehensive benefits mainly in flood control,power generation and navigation improvement.Through 17-year construction and practice,the project has been successfully completed.Some valuable experience from the successful construction of TGP has been gained for the management system and mechanism of hydropower project construction in China.Its construction management mode produces important influences on the management system of domestic capital construction.With combination of the construction management practice of TGP,the characteristics of management system and mechanism are summarized,and the suggestions on current hydropower development system and construction management mode are put forward.
基金National Key Research and Development Program of China,Grant/Award Number:2021YFB2600500Fundamental Research Funds for Central Welfare Research Institutes,Grant/Award Number:TKS20200404Special Scientific Research Project of Changjiang Waterway Regulation,Grant/Award Number:SXHXGZ‐2022‐1。
文摘Climate change and human activities have profoundly changed the evolutionary processes and developmental trends of the hydrology and geomorphology of rivers and lakes.Such changes have affected the evolution of bars and channels at the intersections of rivers and lakes and the utilization of water depth resources in waterways,which,in turn,have affected the sustainable development of waterways,such as the“Golden Waterway”of the Yangtze River.Considering the confluence of Dongting Lake and the Yangtze River as the present study area,we analyzed the effect of the hydrology of Dongting Lake and the evolution of bars and channels in the Jingjiang reach of the Yangtze River on the depth of the waterways.Our results indicated that from before the operation of the Three Gorges Project(1960–2002)to after its operation(2003–2021),the flow and sediment volume of the three inlets of Dongting Lake demonstrated a continuous decreasing trend.Furthermore,the relative increase in the runoff of the Jingjiang reach increased channel erosion.Channel erosion at the river–lake confluence from 2003 to 2021 created favorable conditions for increasing the dimensions of the waterways.The total length of the river–lake confluence that did not meet the requirements for safe navigation[4.5×200m(water depth×width)]was 12.6 km,accounting for 68.35%of the total length of the Jingjiang reach with obstructed navigation.We observed that a decrease in the low‐water level and“steep slope and rapid flow”were the major factors hindering the navigation of the reach(from Zhicheng to Dabujie)affected by the Songzikou diversion of Dongting Lake.This was mostly reflected by the width of the 4.5m waterway being less than 200 m.A declining water level,shrinking sandbanks and tidal flats,and alternating branches that destabilize the low‐water route were the major factors hindering navigation in the reach(from Taipingkou)affected by the Taipingkou diversion of Dongting Lake.Consequently,alternative waterways were implemented during low‐water periods with the water depth decreasing below 4.5 m.The obvious collapse of sandbanks and tidal flats and their erosion and migration were the major factors hindering navigation of the Ouchikou diversion of Dongting Lake.In addition,the scattered submerged shoals in the navigation channel restricted the width of the 4.5m channel to less than 200 m.The reach affected by the Dongting Lake confluence(from Xiongjiazhou–Chenglingji reach)was subject to the erosion and silting of bends and the jacking effect of lake outflow,causing shoals with a water depth of less than 4.5m in the channel.However,the jacking effect slowed the current,thereby assisting in improving channel conditions.
文摘This paper studies current policies in compensation for land lost due to construction of the Three Gorges project (TGP), China. In the case study of Kaixian County, the value of land in the peri-urban areas is underestimated. Some losses in land are tangible and thus measurable, but some losses are intangible and thus immeasurable. The land available in the resettlement areas is scarce and rarely of equivalent quality. This study suggests that the loss of agricultural land be compensated with alternative land and/or non-land-based livelihood strategies, including part compensation in monetary terms and preferential policies.
基金Social Welfare Research Special Project of Ministry of Science and Technology (2004DIB3J131).
文摘In this paper we have analyzed precise gravity survey and gravity effects resulted from water loading, crustal deformation, ground water level change and precipitation before and after the water impoundment in the Three Gorges Reservoir. We found that： ① In dam area of the reservoir, gravity effect resulted from water load increase is the most significant, maximum gravity change is 200×10^-8 m/s^2, but this effect is limited in amplitude and range. Gravity change can be observed about 5 km offshore. The gravity change caused by ground water level change is regional; and the impact of precipitation on it should not be neglected. ② At head area of the reservoir, the maximum gravity change is near Xiangxi. Monitoring the variation of gravity field and further study should continue in the future.
