Through the demand analysis of emergency power supply construction, waterfall noise reduction treatment, and utilization of residual pressure resources, combined with water resources and industrial infrastructure cond...Through the demand analysis of emergency power supply construction, waterfall noise reduction treatment, and utilization of residual pressure resources, combined with water resources and industrial infrastructure conditions, this paper proposes the significance of micro hydropower station construction. However, micro hydropower stations face issues such as insufficient construction standardization, prominent safety hazards, lack of specialized standards, and the need for improved planning and design. Therefore, this paper analyzes and discusses the constraints and improvement summaries in the entire construction process of micro hydropower stations from aspects including guidance of standard formulation, rationality of planning and design, and innovation of new product applications.展开更多
The upper Yangtze River region is one of the most frequent debris flow areas in China. The study area contains a cascade of six large hydropower stations located along the river with total capacity of more than 70 mil...The upper Yangtze River region is one of the most frequent debris flow areas in China. The study area contains a cascade of six large hydropower stations located along the river with total capacity of more than 70 million kilowatts. The purpose of the study was to determine potential and dynamic differences in debris flow susceptibility and intensity with regard to seasonal monsoon events. We analyzed this region's debris flow history by examining the effective peak acceleration of antecedent earthquakes,the impacts of antecedent droughts, the combined effects of earthquakes and droughts, with regard to topography, precipitation, and loose solid material conditions. Based on these factors, we developed a debris flow susceptibility map. Results indicate that the entire debris flow susceptibility area is 167,500 km^2, of which 26,800 km^2 falls within the high susceptibility area, with 60,900 km^2 in medium and 79,800 km^2 are in low susceptibility areas. Three of the six large hydropower stations are located within the areas with high risk of debris flows. The synthetic zonation map of debris flow susceptibility for the study area corresponds with both the investigation data and actual distribution of debris flows. The results of debris flow susceptibility provide base-line data for mitigating, assessing, controlling and monitoring of debris flows hazards.展开更多
Isolated operation of hydropower stations on Wujinag River was seen disadvantages of low rate of water utilization and much loss of electricity caused by abandoned water during low load periods. To tackle the problem,...Isolated operation of hydropower stations on Wujinag River was seen disadvantages of low rate of water utilization and much loss of electricity caused by abandoned water during low load periods. To tackle the problem, centralized control over cascade hydropower stations is practiced with a considerable economic benef it gained.展开更多
China is rich in hydropower resources,and mountain rivers have abundant water resources and huge development potential,which have a profound impact on the pattern of water resources allocation in China.As the main way...China is rich in hydropower resources,and mountain rivers have abundant water resources and huge development potential,which have a profound impact on the pattern of water resources allocation in China.As the main way of water resources and hydropower development,the construction of cascade hydropower stations,while meeting the requirements of water resources utilization for social development,has also brought adverse effects on river ecosystems.Therefore,the impact of the construction of cascade hydropower stations on mountainous river ecosystems,where the minimum ecological flow of rivers must be ensured and reviewed.In addition,this paper proposed the deficiencies and outlooks for cascade hydropower stations based on previous research results.展开更多
Large and medium-sized hydropower stations generally include multiple units, so the operation control is more complex. If the operation mode is not reasonable, it will not only fail to play the functions of large and ...Large and medium-sized hydropower stations generally include multiple units, so the operation control is more complex. If the operation mode is not reasonable, it will not only fail to play the functions of large and medium-sized hydropower stations, but also affect various regional regulation and control work. Therefore, it is necessary to find the most scientific operation mode to ensure the operation effect of hydropower stations. This paper summarizes the optimization methods commonly used in the operation of hydropower stations, then analyzes the common problems in the operation of hydropower stations, and finally discusses the specific methods to optimize the operation of hydropower stations. Through the research to help improve the operation of hydropower stations, to enhance the scientific operation of large and medium-sized hydropower stations.展开更多
Power generation dispatching is a large complex system problem with multi-dimensional and nonlinear characteristics. A mathematical model was established based on the principle of reservoir operation. A large quantity...Power generation dispatching is a large complex system problem with multi-dimensional and nonlinear characteristics. A mathematical model was established based on the principle of reservoir operation. A large quantity of optimal scheduling processes were obtained by calculating the daily runoff process within three typical years, and a large number of simulated daily runoff processes were obtained using the progressive optimality algorithm （POA） in combination with the genetic algorithm （GA）. After analyzing the optimal scheduling processes, the corresponding scheduling rules were determined, and the practical formulas were obtained. These rules can make full use of the rolling runoff forecast and carry out the rolling scheduling. Compared with the optimized results, the maximum relative difference of the annual power generation obtained by the scheduling rules is no more than 1%. The effectiveness and practical applicability of the scheduling rules are demonstrated by a case study. This study provides a new perspective for formulating the rules of power generation dispatching.展开更多
In a medium-term electricity market,in order to reduce the risks of price and inflow uncertainties, the cascade hydropower stations may use the options contract with electricity supply companies. A profit-based model ...In a medium-term electricity market,in order to reduce the risks of price and inflow uncertainties, the cascade hydropower stations may use the options contract with electricity supply companies. A profit-based model for risk management of cascade hydropower stations in the medium-term electricity market is presented. The objective function is profit maximization of cascade hydropower stations. In order to avoid the risks of price and inflow uncertainties, two different risk-aversion constraints: a minimum profit constraint and a minimum conditional value-at-risk, are introduced in the model. In addition, the model takes into account technology constraints of the generating units, which includes reservoir flow balance, reservoir capacity limits, water discharge constraints, etc. The model is formulated as a mixed integer nonlinear programming problem. Because the search space of the solution is very large, a genetic algorithm is used to deal with the problem.展开更多
Most of the hydropower projects in Southwest China and the adjacent foreign regions will be put into operation between 2015 and 2020, which will bring some difficulties for reasonable accommodation and delivery of ele...Most of the hydropower projects in Southwest China and the adjacent foreign regions will be put into operation between 2015 and 2020, which will bring some difficulties for reasonable accommodation and delivery of electric energy. In this paper the author studies the development scale, development schedule, accommodation and transmission schemes of the cascade hydropower stations along the Lancang River basin, one of the five large basins in China, based on the load characteristics of grids at both the sending end and the receiving end, the strategy of complementary utilization of thermal power and hydropower, the advanced transmission technologies, and the optimal economic performance. The study results show that, the cascade hydropower stations on the upper reaches of the Lancang River in Yunnan should mainly serve Guangdong Province, with proper planning of partly serving Yunnan Province during dry seasons. The transmission schemes should adopt UHVDC, UHVAC, and single-tower double-circuited HVDC transmission scheme according to the transmission capacity and distance.展开更多
According to site-specific environments such as high water pressures, high in-situ stresses and strong rockbursts, the design scheme of the long and deep diversion tunnels at Jinping II hydropower station was optimize...According to site-specific environments such as high water pressures, high in-situ stresses and strong rockbursts, the design scheme of the long and deep diversion tunnels at Jinping II hydropower station was optimized to ensure construction safety. New drainage tunnels were considered. Furthermore, lining structures and grouting pressures were modified during the excavation of tunnels. The construction scheme was updated dynamically based on the complex geological conditions. For instances, the diversion tunnels were first excavated by drilling and blasting method at the first stage of construction, and then by the combination method of tunnel boring machine （TBM） and drilling and blasting, and finally by drilling and blasting method. Through optimized scheme and updated construction scheme, the excavation of diversion tunnel #1 was successfully completed in June, 2011. This paper summarizes the key issues in rock mechanics associated with the construction of the long and deep diversion tunnels at Jinping II hydropower station. The experiences of design and construction obtained from this project could provide reference to similar projects.展开更多
The columnar jointed rock mass(CJR), composed of polygonal cross-sectional columns cut by several groups of joints in various directions, was exposed during the excavations of the Baihetan hydropower station, China. I...The columnar jointed rock mass(CJR), composed of polygonal cross-sectional columns cut by several groups of joints in various directions, was exposed during the excavations of the Baihetan hydropower station, China. In order to investigate the unloading performances and the stability conditions during excavation of the columns, an experimental field study was performed. Firstly, on-site investigations indicated that the geotechnical problems, including rock relaxation, cracking and collapse, were the most prominent for the CJR Class I that contains intensive joint network and the smallest column sizes.Comprehensive field tests, including deformation measurement by multi-point extensometers, ultrasonic wave testing, borehole television observation and stress monitoring of rock anchors, revealed that the time-dependent relaxation of the CJRs was marked. The practical excavation experiences for the Baihetan columnar jointed rock masses, such as blasting scheme, supporting time of shotcrete and rock bolts, were presented in the excavations of the diversion tunnels. These detailed investigations and practical construction experiences can provide helpful information for similar geotechnical works in jointed rock mass.展开更多
Toward solving the actual operation problems of cascade hydropower stations under hydrologic uncertainty, this paper presents the process of extraction of statistical characteristics from long-term optimal cascade ope...Toward solving the actual operation problems of cascade hydropower stations under hydrologic uncertainty, this paper presents the process of extraction of statistical characteristics from long-term optimal cascade operation, and proposes a monthly operation function algorithm for the actual operation of cascade hydropower stations through the identification, processing, and screening of available information during long-term optimal operation. Applying the operation function to the cascade hydropower stations on the Jinshajiang-Yangtze River system, the modeled long-term electric generation is shown to have high precision and provide benefits. Through comparison with optimal operation, the simulation results show that the operation function proposed retains the characteristics of optimal operation. Also, the inadequacies and attribution of the algorithm are discussed based on case study, providing decision support and reference information for research on large-scale cascade operation work.展开更多
The Jinping I hydropower station is a huge water conservancy project consisting of the highest concrete arch dam to date in the world and a highly complex and large underground powerhouse cavern. It is located on the ...The Jinping I hydropower station is a huge water conservancy project consisting of the highest concrete arch dam to date in the world and a highly complex and large underground powerhouse cavern. It is located on the right bank with extremely high in-situ stress and a few discontinuities observed in surrounding rock masses. The problems of rock mass deformation and failure result in considerable challenges related to project design and construction and have raised a wide range of concerns in the fields of rock mechanics and engineering. During the excavation of underground caverns, high in-situ stress and relatively low rock mass strength in combination with large excavation dimensions lead to large deformation of the surrounding rock mass and support. Existing experiences in excavation and support cannot deal with the large deformation of rock mass effectively, and further studies are needed. In this paper, the geological conditions, layout of caverns, and design of excavation and support are first introduced, and then detailed analyses of deformation and failure characteristics of rocks are presented. Based on this, the mechanisms of deformation and failure are discussed, and the support adjustments for controlling rock large deformation and subsequent excavation procedures are proposed. Finally, the effectiveness of support and excavation adjustments to maintain the stability of the rock mass is verified. The measures for controlling the large deformation of surrounding rocks enrich the practical experiences related to the design and construction of large underground openings, and the construction of caverns in the Jinping I hydropower station provides a good case study of large-scale excavation in highly stressed ground with complex geological structures, as well as a reference case for research on rock mechanics.展开更多
Irregular columnar jointed structure is a primary irregular columnar morphological tensile fracture. In order to study the geometric features of irregular columnar joints and the new problems in geotechnical engineeri...Irregular columnar jointed structure is a primary irregular columnar morphological tensile fracture. In order to study the geometric features of irregular columnar joints and the new problems in geotechnical engineering, hydraulic and hydropower engineering caused by columnar jointed basaltic mass, Voronoi graph from geometry was introduced to simulate the irregular columnar jointed basaltic mass at Baihetan hydraulic station. Discrete element software UDEC was used to simulate the whole process of rigid bearing plate test. Anisotropic constitutive of columnar joints was adopted to analyze the stress diffusion of rock mass at dam base of Baihetan. The results show that, the compaction property and hysteresis effect are well simulated based on discrete element simulation of Voronoi joint structure by UDEC. Four stages of cyclic loading and unloading process are imaged clearly. The results from in situ rigid bearing plate tests are explicated and the stress diffusion rule of anisotropic body is affected by structure surface. The elements in the stress state of 4-5 MPa are the most, about more than 35% of the total. Appropriate constitutive must be proposed to columnar jointed rock mass with different styles. It has important significance to realize the nonlinear mechanical behavior of irregular columnar jointed basaltic mass.展开更多
Jinping I hydropower station is one of the most challenging projects in China due to its highest arch dam and complex geological conditions for construction.After geological investigation into the dam foundation,a few...Jinping I hydropower station is one of the most challenging projects in China due to its highest arch dam and complex geological conditions for construction.After geological investigation into the dam foundation,a few large-scale weak discontinuities are observed.The rock masses in the left dam foundation are intensively unloaded,approximately to the depth of 150–300 m.These serious geological defects lead to a geological asymmetry on the left and right banks,and thus some major diffculties of dam construction are encountered.In this paper,the influences of geological defects on the project are analyzed,followed by the concepts and methods of treatment design.Based on the analysis,the treatment methods of the weak rock masses and discontinuities are carefully determined,including the concrete cushion,concrete replacement grids,and consolidation grouting.They work together to enhance the strength and integrity of the dam foundation.Evaluations and calibrations through geo-mechanical model tests in combination with feld monitoring results in early impoundment period show that the arch dam and its foundation are roughly stable,suggesting that the treatment designs are reasonable and effective.The proposed treatment methods and concepts in the context can be helpful for similar complex rock projects.展开更多
The excavated height of the left bank slope of the diversion power system intake in Jinchuan hydropower station is about 16o m. The stability and safety of the slope during construction and its operation/utilization b...The excavated height of the left bank slope of the diversion power system intake in Jinchuan hydropower station is about 16o m. The stability and safety of the slope during construction and its operation/utilization become one of the most important geological engineering problems. At the same time, it is also crucial to select a safe and economic excavation gradient for the construction. We studied the problem of how to select a safe and economic slope ratio by analyzing the geological condition of the high slope, including the lithology, slope structure, structural surface and their combinations, rock weathering and unloading, hydrology, and the natural gradient. The study results showed that the use of an excavation gradient larger than the gradient observed during site investigation and the gradient recommended in standards and field practice manuals is feasible. Then, we used the finite element method and rigid limit equilibrium method to evaluate the stability of the excavation slope under natural, rainstorm and earthquake conditions. The calculated results showed that the excavated slope only has limited failure, but its stability is greatly satisfactory. The research findings can be useful in excavation and slope stabilization projects.展开更多
To deal with the construction difficulties of Xiangjiaba underground hydropower station,such as complex geological conditions,narrow rock bench,high loading,high quality requirements and urgent time limit,the project ...To deal with the construction difficulties of Xiangjiaba underground hydropower station,such as complex geological conditions,narrow rock bench,high loading,high quality requirements and urgent time limit,the project adopted the concept of precision blasting.The explosive energy and rock mass fragmentation were well controlled by taking reasonable excavation sequence,designing steel pipe drilling frame,the additional techniques of double layer smooth blasting,evenly micro charge,staggered arrangement of boreholes and pre-stressed anchors.These technologies ensured the excavation quality of the rock face beam,achieving successful blasting results:Semi hole ratio was 100%in Ⅱ surrounding rock,99.2%in Ⅲ surrounding rock and 90%~ 97.3%in Ⅳ surrounding rock;underbreak was avoided and the average backbreak was only2.9 cm;the unevenness was 0 ~ 4 cm;the influence depth of blasting and unloading was 0.2 ~ 0.7 cm.展开更多
Considering the additional electric energy generated after the full operation of the underground hydropower station, the electric energy accommodation of the Three Gorges Project （TGP） is reviewed. It is .focused on...Considering the additional electric energy generated after the full operation of the underground hydropower station, the electric energy accommodation of the Three Gorges Project （TGP） is reviewed. It is .focused on the additional electricity accommodation, based on the research at the earl）, stage. The electric energ）, accommodation solutions ate recommended as that. based on the cost-benefit analysis of the power distribution area, the additional electric energy of the Three Gorges should be given ptqority to meet the needs at the supply end of Hubei and Chongqing. The results of this research has a reference value on the implementation of the Three Gorges electric power accommodation, after the further optimization of the transmission curves in both wet and dry seasons.展开更多
The simple gate control system which is made of traditional manual or proximity switch cannot meet the requirements of connecting with the computer monitoring system of hydropower station, it must be reformed. On the ...The simple gate control system which is made of traditional manual or proximity switch cannot meet the requirements of connecting with the computer monitoring system of hydropower station, it must be reformed. On the basis of the integrated analysis for small hydropower station, the paper discussed the singlechip as the core to realize the methods of gate automatic control system in small hydropower station. The designs for hardware and software of gate control system were introduced. And the control system was reformed from customary manual control to computer automatic control. The simulation experiment shows that this scheme is feasible.展开更多
文摘Through the demand analysis of emergency power supply construction, waterfall noise reduction treatment, and utilization of residual pressure resources, combined with water resources and industrial infrastructure conditions, this paper proposes the significance of micro hydropower station construction. However, micro hydropower stations face issues such as insufficient construction standardization, prominent safety hazards, lack of specialized standards, and the need for improved planning and design. Therefore, this paper analyzes and discusses the constraints and improvement summaries in the entire construction process of micro hydropower stations from aspects including guidance of standard formulation, rationality of planning and design, and innovation of new product applications.
基金supported by the National Natural Science Foundation of China (Grant No. 41661134012 and 41501012)the Taiwan Youth Visiting Scholar Fellowship of Chinese Academy of Sciences (Grant No. 2015TW2ZB0001)
文摘The upper Yangtze River region is one of the most frequent debris flow areas in China. The study area contains a cascade of six large hydropower stations located along the river with total capacity of more than 70 million kilowatts. The purpose of the study was to determine potential and dynamic differences in debris flow susceptibility and intensity with regard to seasonal monsoon events. We analyzed this region's debris flow history by examining the effective peak acceleration of antecedent earthquakes,the impacts of antecedent droughts, the combined effects of earthquakes and droughts, with regard to topography, precipitation, and loose solid material conditions. Based on these factors, we developed a debris flow susceptibility map. Results indicate that the entire debris flow susceptibility area is 167,500 km^2, of which 26,800 km^2 falls within the high susceptibility area, with 60,900 km^2 in medium and 79,800 km^2 are in low susceptibility areas. Three of the six large hydropower stations are located within the areas with high risk of debris flows. The synthetic zonation map of debris flow susceptibility for the study area corresponds with both the investigation data and actual distribution of debris flows. The results of debris flow susceptibility provide base-line data for mitigating, assessing, controlling and monitoring of debris flows hazards.
文摘Isolated operation of hydropower stations on Wujinag River was seen disadvantages of low rate of water utilization and much loss of electricity caused by abandoned water during low load periods. To tackle the problem, centralized control over cascade hydropower stations is practiced with a considerable economic benef it gained.
基金This research was funded by Guangxi key R&D program(Guike AB19259015)and Guangxi key R&D program(Guike AB20297017)Guangxi Key Laboratory of Water Engineering Materials and Structures fund program(GXHRI-WZMS-2020-07).
文摘China is rich in hydropower resources,and mountain rivers have abundant water resources and huge development potential,which have a profound impact on the pattern of water resources allocation in China.As the main way of water resources and hydropower development,the construction of cascade hydropower stations,while meeting the requirements of water resources utilization for social development,has also brought adverse effects on river ecosystems.Therefore,the impact of the construction of cascade hydropower stations on mountainous river ecosystems,where the minimum ecological flow of rivers must be ensured and reviewed.In addition,this paper proposed the deficiencies and outlooks for cascade hydropower stations based on previous research results.
文摘Large and medium-sized hydropower stations generally include multiple units, so the operation control is more complex. If the operation mode is not reasonable, it will not only fail to play the functions of large and medium-sized hydropower stations, but also affect various regional regulation and control work. Therefore, it is necessary to find the most scientific operation mode to ensure the operation effect of hydropower stations. This paper summarizes the optimization methods commonly used in the operation of hydropower stations, then analyzes the common problems in the operation of hydropower stations, and finally discusses the specific methods to optimize the operation of hydropower stations. Through the research to help improve the operation of hydropower stations, to enhance the scientific operation of large and medium-sized hydropower stations.
基金supported by the National Key Basic Research Development Program of China (Grant No. 2002CCA00700)
文摘Power generation dispatching is a large complex system problem with multi-dimensional and nonlinear characteristics. A mathematical model was established based on the principle of reservoir operation. A large quantity of optimal scheduling processes were obtained by calculating the daily runoff process within three typical years, and a large number of simulated daily runoff processes were obtained using the progressive optimality algorithm （POA） in combination with the genetic algorithm （GA）. After analyzing the optimal scheduling processes, the corresponding scheduling rules were determined, and the practical formulas were obtained. These rules can make full use of the rolling runoff forecast and carry out the rolling scheduling. Compared with the optimized results, the maximum relative difference of the annual power generation obtained by the scheduling rules is no more than 1%. The effectiveness and practical applicability of the scheduling rules are demonstrated by a case study. This study provides a new perspective for formulating the rules of power generation dispatching.
基金The National Natural Science Foundation of China (No.50579101)
文摘In a medium-term electricity market,in order to reduce the risks of price and inflow uncertainties, the cascade hydropower stations may use the options contract with electricity supply companies. A profit-based model for risk management of cascade hydropower stations in the medium-term electricity market is presented. The objective function is profit maximization of cascade hydropower stations. In order to avoid the risks of price and inflow uncertainties, two different risk-aversion constraints: a minimum profit constraint and a minimum conditional value-at-risk, are introduced in the model. In addition, the model takes into account technology constraints of the generating units, which includes reservoir flow balance, reservoir capacity limits, water discharge constraints, etc. The model is formulated as a mixed integer nonlinear programming problem. Because the search space of the solution is very large, a genetic algorithm is used to deal with the problem.
文摘Most of the hydropower projects in Southwest China and the adjacent foreign regions will be put into operation between 2015 and 2020, which will bring some difficulties for reasonable accommodation and delivery of electric energy. In this paper the author studies the development scale, development schedule, accommodation and transmission schemes of the cascade hydropower stations along the Lancang River basin, one of the five large basins in China, based on the load characteristics of grids at both the sending end and the receiving end, the strategy of complementary utilization of thermal power and hydropower, the advanced transmission technologies, and the optimal economic performance. The study results show that, the cascade hydropower stations on the upper reaches of the Lancang River in Yunnan should mainly serve Guangdong Province, with proper planning of partly serving Yunnan Province during dry seasons. The transmission schemes should adopt UHVDC, UHVAC, and single-tower double-circuited HVDC transmission scheme according to the transmission capacity and distance.
文摘According to site-specific environments such as high water pressures, high in-situ stresses and strong rockbursts, the design scheme of the long and deep diversion tunnels at Jinping II hydropower station was optimized to ensure construction safety. New drainage tunnels were considered. Furthermore, lining structures and grouting pressures were modified during the excavation of tunnels. The construction scheme was updated dynamically based on the complex geological conditions. For instances, the diversion tunnels were first excavated by drilling and blasting method at the first stage of construction, and then by the combination method of tunnel boring machine （TBM） and drilling and blasting, and finally by drilling and blasting method. Through optimized scheme and updated construction scheme, the excavation of diversion tunnel #1 was successfully completed in June, 2011. This paper summarizes the key issues in rock mechanics associated with the construction of the long and deep diversion tunnels at Jinping II hydropower station. The experiences of design and construction obtained from this project could provide reference to similar projects.
基金the financial support from the International Partnership Program of Chinese Academy of Sciences(Grant No.115242KYSB20160017)the Key Project of Natural Science Foundation of China(Grant No.11232014)National Natural Science Foundation of China(Grant No.51379202)
文摘The columnar jointed rock mass(CJR), composed of polygonal cross-sectional columns cut by several groups of joints in various directions, was exposed during the excavations of the Baihetan hydropower station, China. In order to investigate the unloading performances and the stability conditions during excavation of the columns, an experimental field study was performed. Firstly, on-site investigations indicated that the geotechnical problems, including rock relaxation, cracking and collapse, were the most prominent for the CJR Class I that contains intensive joint network and the smallest column sizes.Comprehensive field tests, including deformation measurement by multi-point extensometers, ultrasonic wave testing, borehole television observation and stress monitoring of rock anchors, revealed that the time-dependent relaxation of the CJRs was marked. The practical excavation experiences for the Baihetan columnar jointed rock masses, such as blasting scheme, supporting time of shotcrete and rock bolts, were presented in the excavations of the diversion tunnels. These detailed investigations and practical construction experiences can provide helpful information for similar geotechnical works in jointed rock mass.
基金supported by the National Natural Science Foundation of China (Grant No. 40971300)the Fundamental Research Funds for the Central Universities (Grant No.10QX43)
文摘Toward solving the actual operation problems of cascade hydropower stations under hydrologic uncertainty, this paper presents the process of extraction of statistical characteristics from long-term optimal cascade operation, and proposes a monthly operation function algorithm for the actual operation of cascade hydropower stations through the identification, processing, and screening of available information during long-term optimal operation. Applying the operation function to the cascade hydropower stations on the Jinshajiang-Yangtze River system, the modeled long-term electric generation is shown to have high precision and provide benefits. Through comparison with optimal operation, the simulation results show that the operation function proposed retains the characteristics of optimal operation. Also, the inadequacies and attribution of the algorithm are discussed based on case study, providing decision support and reference information for research on large-scale cascade operation work.
文摘The Jinping I hydropower station is a huge water conservancy project consisting of the highest concrete arch dam to date in the world and a highly complex and large underground powerhouse cavern. It is located on the right bank with extremely high in-situ stress and a few discontinuities observed in surrounding rock masses. The problems of rock mass deformation and failure result in considerable challenges related to project design and construction and have raised a wide range of concerns in the fields of rock mechanics and engineering. During the excavation of underground caverns, high in-situ stress and relatively low rock mass strength in combination with large excavation dimensions lead to large deformation of the surrounding rock mass and support. Existing experiences in excavation and support cannot deal with the large deformation of rock mass effectively, and further studies are needed. In this paper, the geological conditions, layout of caverns, and design of excavation and support are first introduced, and then detailed analyses of deformation and failure characteristics of rocks are presented. Based on this, the mechanisms of deformation and failure are discussed, and the support adjustments for controlling rock large deformation and subsequent excavation procedures are proposed. Finally, the effectiveness of support and excavation adjustments to maintain the stability of the rock mass is verified. The measures for controlling the large deformation of surrounding rocks enrich the practical experiences related to the design and construction of large underground openings, and the construction of caverns in the Jinping I hydropower station provides a good case study of large-scale excavation in highly stressed ground with complex geological structures, as well as a reference case for research on rock mechanics.
基金Projects(50979030, 50911130366) supported by the National Natural Science Foundation of ChinaProject(2009B14014) supported by the Fundamental Research Funds for the Central Universities in China
文摘Irregular columnar jointed structure is a primary irregular columnar morphological tensile fracture. In order to study the geometric features of irregular columnar joints and the new problems in geotechnical engineering, hydraulic and hydropower engineering caused by columnar jointed basaltic mass, Voronoi graph from geometry was introduced to simulate the irregular columnar jointed basaltic mass at Baihetan hydraulic station. Discrete element software UDEC was used to simulate the whole process of rigid bearing plate test. Anisotropic constitutive of columnar joints was adopted to analyze the stress diffusion of rock mass at dam base of Baihetan. The results show that, the compaction property and hysteresis effect are well simulated based on discrete element simulation of Voronoi joint structure by UDEC. Four stages of cyclic loading and unloading process are imaged clearly. The results from in situ rigid bearing plate tests are explicated and the stress diffusion rule of anisotropic body is affected by structure surface. The elements in the stress state of 4-5 MPa are the most, about more than 35% of the total. Appropriate constitutive must be proposed to columnar jointed rock mass with different styles. It has important significance to realize the nonlinear mechanical behavior of irregular columnar jointed basaltic mass.
文摘Jinping I hydropower station is one of the most challenging projects in China due to its highest arch dam and complex geological conditions for construction.After geological investigation into the dam foundation,a few large-scale weak discontinuities are observed.The rock masses in the left dam foundation are intensively unloaded,approximately to the depth of 150–300 m.These serious geological defects lead to a geological asymmetry on the left and right banks,and thus some major diffculties of dam construction are encountered.In this paper,the influences of geological defects on the project are analyzed,followed by the concepts and methods of treatment design.Based on the analysis,the treatment methods of the weak rock masses and discontinuities are carefully determined,including the concrete cushion,concrete replacement grids,and consolidation grouting.They work together to enhance the strength and integrity of the dam foundation.Evaluations and calibrations through geo-mechanical model tests in combination with feld monitoring results in early impoundment period show that the arch dam and its foundation are roughly stable,suggesting that the treatment designs are reasonable and effective.The proposed treatment methods and concepts in the context can be helpful for similar complex rock projects.
基金financially supported by Chinese National Natural Science Foundation (Grant No. 41072229)State Key Laboratory of Hydraulics and Mountain River Engineering (Sichuan University) open fund (Grant No. 201110)Key Laboratory of Hydraulic and Waterway Engineering of the Ministry of Education and National Engineering Research Center for Inland Waterway Regulation (Chongqing Jiaotong University) open fund (Grant No. SLK2011B04)
文摘The excavated height of the left bank slope of the diversion power system intake in Jinchuan hydropower station is about 16o m. The stability and safety of the slope during construction and its operation/utilization become one of the most important geological engineering problems. At the same time, it is also crucial to select a safe and economic excavation gradient for the construction. We studied the problem of how to select a safe and economic slope ratio by analyzing the geological condition of the high slope, including the lithology, slope structure, structural surface and their combinations, rock weathering and unloading, hydrology, and the natural gradient. The study results showed that the use of an excavation gradient larger than the gradient observed during site investigation and the gradient recommended in standards and field practice manuals is feasible. Then, we used the finite element method and rigid limit equilibrium method to evaluate the stability of the excavation slope under natural, rainstorm and earthquake conditions. The calculated results showed that the excavated slope only has limited failure, but its stability is greatly satisfactory. The research findings can be useful in excavation and slope stabilization projects.
文摘To deal with the construction difficulties of Xiangjiaba underground hydropower station,such as complex geological conditions,narrow rock bench,high loading,high quality requirements and urgent time limit,the project adopted the concept of precision blasting.The explosive energy and rock mass fragmentation were well controlled by taking reasonable excavation sequence,designing steel pipe drilling frame,the additional techniques of double layer smooth blasting,evenly micro charge,staggered arrangement of boreholes and pre-stressed anchors.These technologies ensured the excavation quality of the rock face beam,achieving successful blasting results:Semi hole ratio was 100%in Ⅱ surrounding rock,99.2%in Ⅲ surrounding rock and 90%~ 97.3%in Ⅳ surrounding rock;underbreak was avoided and the average backbreak was only2.9 cm;the unevenness was 0 ~ 4 cm;the influence depth of blasting and unloading was 0.2 ~ 0.7 cm.
文摘Considering the additional electric energy generated after the full operation of the underground hydropower station, the electric energy accommodation of the Three Gorges Project （TGP） is reviewed. It is .focused on the additional electricity accommodation, based on the research at the earl）, stage. The electric energ）, accommodation solutions ate recommended as that. based on the cost-benefit analysis of the power distribution area, the additional electric energy of the Three Gorges should be given ptqority to meet the needs at the supply end of Hubei and Chongqing. The results of this research has a reference value on the implementation of the Three Gorges electric power accommodation, after the further optimization of the transmission curves in both wet and dry seasons.
文摘The simple gate control system which is made of traditional manual or proximity switch cannot meet the requirements of connecting with the computer monitoring system of hydropower station, it must be reformed. On the basis of the integrated analysis for small hydropower station, the paper discussed the singlechip as the core to realize the methods of gate automatic control system in small hydropower station. The designs for hardware and software of gate control system were introduced. And the control system was reformed from customary manual control to computer automatic control. The simulation experiment shows that this scheme is feasible.
