In recent years,digital twin technology has gained significant attention and application in the engineering construction field in China.Its real-time feedback function has brought more standardized construction operat...In recent years,digital twin technology has gained significant attention and application in the engineering construction field in China.Its real-time feedback function has brought more standardized construction operations to various engineering construction and maintenance processes.In this context,this paper analyzes the specific application of digital twin technology in hydraulic engineering based on its foundations.Taking the reinforcement and anti-seepage digital twin application of a certain embankment section as an example,it explores the reinforcement and anti-seepage construction effects of embankment engineering with the involvement of digital twin technology under complex hydrogeological conditions.The research shows that this technology can significantly improve the control accuracy of slurry diffusion,the identification ability of seepage risks,and the adaptability of engineering construction.Its application provides a replicable digital solution for the governance model of hydraulic engineering.展开更多
[Objective] The research aimed to study the application of chemical tracing experiment technique in leakage detection of hydraulic engineering.[Method] According to the current situation of Sanyuan Western Suburb Rese...[Objective] The research aimed to study the application of chemical tracing experiment technique in leakage detection of hydraulic engineering.[Method] According to the current situation of Sanyuan Western Suburb Reservoir in Xianyang City of Shaanxi Province,three sections （L1,L2 and L3） were set.KI was selected as the chemical tracer to carry out the tracing and detection research.[Result] There was no obvious leakage phenomenon in L1,L2 and L3 sections.The impermeability of rock in some dam abutments was bad.[Conclusion] The leakage reason of Western Suburb Reservoir was that the impermeability of rock in some dam abutments couldn’t satisfy seepage requirement.After the reservoir was put into operation,the water level in front of dam rose,and the ground water level of dam abutment also rose.The penetration water pressure correspondingly increased,and the water content of bank slope at the downstream of dam increased.展开更多
With the development of China's economy,the implementation scale and scope of hydraulic engineering projects are increasing,and the application of anti-seepage technology has an important influence on the construc...With the development of China's economy,the implementation scale and scope of hydraulic engineering projects are increasing,and the application of anti-seepage technology has an important influence on the construction quality of hydraulic engineering.In this paper,the significance and problems of the application of anti-seepage technology in the construction of hydraulic engineering projects were mainly analyzed,and specific application strategies were proposed.展开更多
China is a country with many mountains and hills, most of which are in subtropical areas, and are prone to floods and other natural disasters in summer. Water conservancy and hydropower projects are all over the count...China is a country with many mountains and hills, most of which are in subtropical areas, and are prone to floods and other natural disasters in summer. Water conservancy and hydropower projects are all over the country. Many terrain are relatively high and steep, involving high slope projects. Due to the complex topographic conditions, in the survey and design stage, it is necessary to consider various problems that may be encountered in the project construction, compare and select multiple schemes according to the project boundary conditions, analyze and demonstrate the design scheme from the aspects of investment, construction period and construction difficulty, and finally determine the design scheme. Focusing on the causes of high slope instability, this paper puts forward relevant suggestions on high slope protection, and analyzes the quality control of high slope survey and design of water conservancy and hydropower projects.展开更多
In this paper, the connotation and application status of hydraulic environmental geological exploration and remote sensing technology of hydraulic engineering environment are respectively studied, and then the applica...In this paper, the connotation and application status of hydraulic environmental geological exploration and remote sensing technology of hydraulic engineering environment are respectively studied, and then the application methods of relevant technologies are analyzed in the geological work practice. It is hoped that the efficiency and accuracy of geological work can be improved through the research.展开更多
The construction of fully closed check dam (CD) is a conventional flood prevention mechanism implemented on rivers. Fully closed CDs trap large amounts of sediments in rivers to stabilize the river slopes and control ...The construction of fully closed check dam (CD) is a conventional flood prevention mechanism implemented on rivers. Fully closed CDs trap large amounts of sediments in rivers to stabilize the river slopes and control erosion. However, fully closed CDs cannot selectively trap sediment and may easily overflow, causing them to losing their ability to mediate and hold sediments. Previous studies proposed the concept of “breathable CDs”. The researcher introduced metal slit dam (SD) that could be assembled and disassembled quickly and conveniently. Once a CD reaches maximum capacity, operators must ensure that the water channels of the dam are free from blockage. Moreover, they must inspect the internal accumulation conditions of the dam periodically or immediately following heavy typhoon rains. When necessary, either the sediment buildup in the upriver blockage must be cleared, or the transverse structure of the dam must be removed to allow fine particles to be discharged along with a moderate amount of water. These actions can free up the sediment-storing capacity of the dam for the next heavy typhoon rains. In addition, operators should also inspect the damages inflicted on the dam, such as erosion, wear and tear, and deformation conditions. Damaged components should be disassembled and repaired if possible, or recycled and reused. The present study performed channel tests to simulate closed CDs, SDs, steel pipe dam (SPDs), and steel pipe plus slit dam (SPSDs) for 50-year and 100-year frequency floods. Results were then analyzed to determine the sediment trapping (ST) effects of various CDs, the effects of “adjustable CDs”, and the changes of moderated riverbeds.展开更多
With the continuous development of China's social economy, the demand for water resources is increasing. Generally, water exists in natural form, and the water resources in natural form can not be fully utilized. ...With the continuous development of China's social economy, the demand for water resources is increasing. Generally, water exists in natural form, and the water resources in natural form can not be fully utilized. In order to effectively manage the natural water resources and give full play to the application value of water resources, we need to pay attention to the construction of water conservancy projects. Using scientific water conservancy projects can effectively prevent flood risk, ensure social harmony and stability, and ensure the life safety of residents. In the current process of water conservancy project construction, the use of scientific and effective embankment anti-seepage construction technology can improve the level of water conservancy project construction. However, it should be noted that there are still some problems in the application of embankment anti-seepage construction technology in water conservancy projects, which affect the application benefits of embankment anti-seepage construction technology in water conservancy projects. In this case, it is necessary to scientifically select the anti-seepage construction technology according to the specific construction needs of China's water conservancy projects, and comprehensively apply a variety of anti-seepage technologies based on the embankment permeability of water conservancy projects, so as to improve the anti-seepage effect and the embankment construction effect.展开更多
In China, the construction of water conservancy projects has brought great convenience to the development of agriculture in China, which not only reduces the occurrence of flood disasters, but also promotes the develo...In China, the construction of water conservancy projects has brought great convenience to the development of agriculture in China, which not only reduces the occurrence of flood disasters, but also promotes the development of agricultural production in China. Therefore, in the process of infrastructure construction of water conservancy projects, we should also pay attention to the regulation of river courses in water conservancy projects. River ecological slope protection technology has played a very important role in water conservancy projects. It not only reduces the problem of water and soil loss around the water conservancy project, but also improves the beauty of the river. In addition, landscape planning has been carried out around the river, forming a beautiful waterfront scenic spot. Therefore, ecological river slope protection technology should be reasonably applied in water conservancy projects, and scientific and reasonable engineering and ecological measures should be taken to promote the development of water conservancy project construction on the basis of ensuring the construction quality of ecological river slope protection.展开更多
The primary objective of this study was to design and size a sustainable sanitation solution for the Ndiebene Gandiol 1 school located in the eponymous commune in northern Senegal. Field investigations led to the coll...The primary objective of this study was to design and size a sustainable sanitation solution for the Ndiebene Gandiol 1 school located in the eponymous commune in northern Senegal. Field investigations led to the collection of wastewater samples. Their analysis revealed specific pollutant loads, including loads of BOD5 3.6966 kgO<sub>2</sub>/day and COD of 12.8775 kgO<sub>2</sub>/day, which were central to the design phase. Following a rigorous assessment of the existing sanitation infrastructure, constructed wetland (CWs) emerged as the most appropriate ecological solution. This system, valued for its ability to effectively remove contaminants, was tailored to the specific needs of the site. Consequently, the final design of the filter extends over 217.16 m<sup>2</sup>, divided into two cells of 108.58 m<sup>2</sup> each, with dimensions of 12.77 m in length and 8.5 m in width. The depth of the filtering medium is approximately 0.60 m, meeting the standards while ensuring maximized purification. Typha, an indigenous and prolific plant known for its purification abilities, was selected as the filtering agent. Concurrently, non-crushed gravel was chosen for its proven filtration capacity. This study is the result of a combination of scientific rigor and design expertise. It provides a holistic view of sanitation for Ndiebene Gandiol. The technical specifications and dimensions of the constructed wetland filter embody an approach that marries indepth analysis and practical application, all aimed at delivering an effective and long-lasting solution to the local sanitation challenges. By integrating precise scientific data with sanitation design expertise, this study delivers a holistic solution for Ndiebene Gandiol. The detailed dimensions and specifications of the constructed wetland filter reflect a methodology that combines meticulous analysis with practical adaptation, aiming to provide an effective and sustainable response to the challenges of rural and school sanitation in the northern region of Senegal.展开更多
Confronted with the challenge of wastewater management, particularly in the school environment of Senegal, our study set out to achieve multiple objectives. Following field surveys, laboratory analyses of wastewater s...Confronted with the challenge of wastewater management, particularly in the school environment of Senegal, our study set out to achieve multiple objectives. Following field surveys, laboratory analyses of wastewater samples were carried out, revealing a significant pollutant load. In the community of Gandiol, near Saint-Louis (Senegal), the school of Ndiebene Gandiol 1 faces significant sanitation challenges. Our study aimed to address this issue by using a constructed filter composed of two filtering bed cells measuring 12 × 8.5 m, preceded by a septic tank. We particularly focused on the influence of Vetiver;a plant chosen for its purification potential. Our analyses showed remarkable efficiency of the filter. Elimination rates reached 95% for 5-Day Biochemical Oxygen Demand (BOD5), 91% for Chemical Oxygen Demand (COD), and 92% for SS, far exceeding the Senegalese standards set at 50 mg/L, 200 mg/L, and 40 mg/L, respectively. Furthermore, the concentration of fecal coliforms was reduced to 176 FCU/100mL, well below the Senegalese threshold of 2000 FCU/100mL and close to the World Health Organization’s (WHO) recommendation of 1000 FCU/100mL. However, despite these promising results, some parameters, particularly the concentration of certain pollutants, approached the thresholds defined by European legislation. For example, for Suspended Solids (SS), the post-treatment level of 3 mg/L was well below the Senegalese standard but edged close to the European minimum of 10 mg/L. In conclusion, the Vetiver filter demonstrated a remarkable ability to treat school wastewater, offering high pollutant elimination percentages. These results suggest significant opportunities for the reuse of treated water, potentially in areas such as irrigation, though some adjustments may be necessary to meet the strictest standards such as those of the European union (EU).展开更多
The overarching goal of this study is to offer an effective and sustainable solution to the challenges of sanitation in rural and school settings in the northern region of Senegal. The study explores a wastewater trea...The overarching goal of this study is to offer an effective and sustainable solution to the challenges of sanitation in rural and school settings in the northern region of Senegal. The study explores a wastewater treatment approach based on phytoremediation, with a particular focus on the use of horizontally-flowing reed bed filters. Furthermore, it aims to adapt and optimize these systems for the specific needs of Senegal, focusing on wastewater in school environments. Thus, we constructed a horizontally-flowing reed bed filter, planted with Typha, at the Ndiébène Gandiol school in Senegal. We will investigate the efficiency of wastewater treatment by this horizontally-flowing reed bed filter, emphasizing the role of the plant used: Typha. The filter is described in detail, specifying its dimensions, its composition of flint gravel, and the choice of plants, namely Typha. The experimental protocol is detailed, describing the sampling at the entrance and exit of the filter to evaluate water quality. The parameters analyzed include Chemical Oxygen Demand (COD), Biochemical Oxygen Demand over 5 days (BOD5), suspended solids, ammonium, nitrates, phosphates, pH, conductivity, and fecal coliforms. The results indicate a significant improvement in water quality after treatment. COD, BOD5, suspended solids, and fecal coliforms are greatly reduced, thus demonstrating the efficacy of the Typha filter. However, nitrate concentrations remain relatively stable, suggesting room for improvement in their elimination. A perspective of reuse of the treated water is considered, showing that the effluents from the planted filter meet Senegalese and international standards for irrigation. The findings suggest that these waters could be used for a variety of crops, thereby reducing the pressure on freshwater resources. In conclusion, the Typha-based filtration system shows promising results for improving water quality in this region of Senegal. However, adjustments are necessary for more effective nitrate removal. This study paves the way for sustainable use of treated wastewater for irrigation, thus contributing to food security and the preservation of water resources.展开更多
In this paper,the metal hydraulic engine mount (HEM) with the orifice is presented,the construction of HEM is consist of hydraulic cylinder and the spring on the bottom,its mechanical model is given and dynamics equat...In this paper,the metal hydraulic engine mount (HEM) with the orifice is presented,the construction of HEM is consist of hydraulic cylinder and the spring on the bottom,its mechanical model is given and dynamics equations are set up with considering kinematics conditions and continuous of fluid,the dynamics behavior of HEM including dynamic stiffness of fluid and transferability of HEM are studied here.The example of hydraulic engine mount is calculated,it is shown that the vibration reduction performance of the hydraulic engine mount of this paper is better.The analysis method of vibration reduction behavior for HEM in this paper can be used in designing of the reduction vibration devices and the HEM in this paper can be used in the practical engineering for reduction vibration.展开更多
The structure and working principle of a two-cylinder four-stroke single-piston hydraulic free piston engine(HFPE) were introduced. The basic vibration equation of free piston assembly(FPA) was established based upon ...The structure and working principle of a two-cylinder four-stroke single-piston hydraulic free piston engine(HFPE) were introduced. The basic vibration equation of free piston assembly(FPA) was established based upon the energy conversion between the injected fuel and the friction together with the load. Both the theoretical and numerical results show that the vibration system of FPA is a nonlinear conservative autonomous system in one cycle. The FPA vibration is symmetric with constant amplitude when FPA is only driven by the compression pressure in the compression accumulator and that in the combustion chamber. When considering the friction and load, FPA could still achieve a stable vibration after a few cycles' adjustment whether the input energy is equal to the consumed energy or not. The vibration characteristics are different when FPA vibrates in the compression stroke and the expansion stroke, which is the unique feature of the single-piston HFPE.展开更多
Geometrical analyses of 3930 potholes （3565 fluvial potholes, 237 marine potholes and 128 hillside potholes） from 33 localities in the world reveal a consistent, linear relationship： D Nh ＋ M, where h and D are, r...Geometrical analyses of 3930 potholes （3565 fluvial potholes, 237 marine potholes and 128 hillside potholes） from 33 localities in the world reveal a consistent, linear relationship： D Nh ＋ M, where h and D are, respectively, the depth and mean diameter of pothole, M is a critical size of the initial concavities （seminal potholes） that subsequently underwent growth, and N is the ratio of diameter expanding （wall erosion） speed to deepening （floor abrasion） speed. For the stream potholes, N is generally less than 1 with an average value of 0.67, M varies from 5.3 cm to 40.5 cm with an average of 20 cm, and N decreases gently with increasing M. However, the marine and hillside potholes are generally characterized by N 〉 1 and M 〈 10-14 cm, and a power-law relationship N 4.24M o.78 （coefficient of determination R2 0.75, M is in cm） exists. The results indicate that depth increases faster than diameter for stream potholes due to the larger size of grinding stones （〉5-10 cm）, while depth increases slower than diameter for marine potholes and hillside potholes due to the smaller size of grinding stones （〈5-10 cm）. The pothole h-D relationship is nearly independent of rock type. Knowledge of the pothole depth-diameter relationship is useful in a number of contexts, including simulation of hydraulic dynamics, theoretical considerations of erosion, comprehension of channel incision and development of canyons and gorges, and accurate estimation of excavation volume and mechanical strength ofpotholed bedrock in the design and stability analysis of hydraulic and environmental engineering projects （e.g. dam construction and river dredging）.展开更多
To investigate the dynamic characteristics and damping theory of the passive hydraulic engine mount （PHEM）, numerical prediction is performed through lumped parameter model. System parameters, including volume compl...To investigate the dynamic characteristics and damping theory of the passive hydraulic engine mount （PHEM）, numerical prediction is performed through lumped parameter model. System parameters, including volume compliance of the decoupler chamber, effective piston area, fluid inertia and resistance of inertia track and direct-decoupler, are identified by means of experiments and finite element method （FEM）. Dynamic behaviors are tested with elastomer test system for purpose of validating PHEM. With incorporation of inertia track and direct-decoupler, PHEM behaves effective and efficient vibration isolation in range of both low and high frequencies. The comparison of the numerical results with the experimental observations shows that the present PHEM achieves fairly good performance for the engine vibration isolation.展开更多
The characteristics of a hybrid hydraulic vehicle driven by the hydraulic common rail propulsion system with a hydraulic free-piston engine and a hydraulic transformer were studied.A mathematical model of the propulsi...The characteristics of a hybrid hydraulic vehicle driven by the hydraulic common rail propulsion system with a hydraulic free-piston engine and a hydraulic transformer were studied.A mathematical model of the propulsion system was established and a control method of the propulsion system was proposed.Extensive simulation results of hybrid hydraulic vehicles with the hydraulic common rail propulsion system were presented.The hydraulic common rail propulsion system achieved the switch power control and the constant power propulsion.The control method based on the propulsion,break and speed limit requirement was verified.Our results showed that the hydraulic common rail propulsion system gained an ideal acceleration process.展开更多
Natural methane （CH4） oxidation that is carried out through the use of landfill covers （biocovers） is a promising method for reducing CH4 emissions from landfills. Previous studies on peat-based landfill covers ha...Natural methane （CH4） oxidation that is carried out through the use of landfill covers （biocovers） is a promising method for reducing CH4 emissions from landfills. Previous studies on peat-based landfill covers have mainly focused on their biochemical properties （e.g. CH4 oxidation capacity）. However, the utilization of peat as a cover material also requires a solid understanding of its geotechnical properties （thermal, hydraulic, and mechanical）, which are critical to the performance of any biocover. Therefore, the objective of this context is to investigate and assess the geotechnical properties of peat-based cover materials （peat, peat–sand mixture）, including compaction, consolidation, and hydraulic and thermal conductivities. The studied materials show high compressibility to the increase of vertical stress, with compression index （Cc） values ranging from 0.16 to 0.358. The compressibility is a function of sand content such that the peat–sand mixture （1：3） has the lowest Cc value. Both the thermal and hydraulic conductivities are functions of moisture content, dry density, and sand content. The hydraulic conductivity varies from 1.74 × 10^-9 m/s to 7.35 × 10^-9 m/s, and increases with the increase in sand content. The thermal conductivity of the studied samples varies between 0.54 W/（m K） and 1.41 W/（m K） and it increases with the increases in moisture and sand contents. Increases in sand content generally increase the mechanical behavior of peat-based covers; however, they also cause relatively high hydraulic and thermal conductivities which are not favored properties for biocovers.展开更多
Vulnerability to natural disasters falls into three categories： exposure, resistance, and resilience, where resilience mainly refers to the capability of a pressure-bearing system to recover by returning to its initi...Vulnerability to natural disasters falls into three categories： exposure, resistance, and resilience, where resilience mainly refers to the capability of a pressure-bearing system to recover by returning to its initial state, that is, the ability to adapt to disaster pressure. Resilience is a major subject of research on disaster prevention and mitigation. This research mainly focuses on the ability of the hydraulic structure to recover from the significant impacts of typhoons. According to the load/unload response ratio theory, the degree of instability by which nonlinear systems can be identified according to the difference between load and unload responses was analyzed. This analysis was used as a basis to study the resilience of a hydraulic structure. Taking the Yangtze River embankments under the impact of Typhoon Matsa as an example, the ability of the typical sections of different types of embankments to adapt to the significant impact of the typhoon, i.e., the resilience of the hydraulic structure, is described with the help of the load/unload response ratio （L）. The results of the calculated resilience reflect the actual conditions of the structure and can be used to determine the applicability of the embankment section. The load/unload response ratio theory is one of the effective tools for calculating the resilience of hydraulic structures under the significant impacts of typhoons.展开更多
In this study, we investigated the effect of compression on the micromechanical and the petro- physical properties of salted wellbore cement systems. The experiments were conducted using a customized bench scale model...In this study, we investigated the effect of compression on the micromechanical and the petro- physical properties of salted wellbore cement systems. The experiments were conducted using a customized bench scale model, which utilized an expandable tubulars simulating the compression of a previously cemented casing under field-like conditions. The “mini-wellbore model” sample consisted of a pipe inside pipe assembly with a cemented annulus. The cement samples were cured in a water bath for 28 days prior to the compression experiments to allow adequate hydration. The impact of compression on the cement’s petro-physical and mechanical properties was quantified by measuring the porosity, permeability and hardness of salt cement cores drilled parallel to the orientation of the pipe from the compacted cement sheath. Permeability (Core-flood) experiments were conducted at 21℃, 10,342 kPa confining pressure for a period of 120 minutes. During the core-flood experiments, conducted using Pulse-decay method, deionized water was flowed through cement cores to determine the permeability of the cores. The results obtained from these experiments confirmed that the compression of the cement positively impacted the cements ability to provide long term zonal isolation, shown by the effective reduction in porosity and permeability. Furthermore, the results confirm reduction in the detrimental effect of salt on the strength and stiffness in post-compression cement.展开更多
In recent years, the Water Affairs Bureau of Changfeng County, Anhui Province has closely adhered to the general tone of "making up for the shortcomings of water conservancy projects and strengthening the supervi...In recent years, the Water Affairs Bureau of Changfeng County, Anhui Province has closely adhered to the general tone of "making up for the shortcomings of water conservancy projects and strengthening the supervision of water conservancy industry", actively strengthened the supervision and management of water conservancy projects, insisted on the high-quality development of water conservancy projects, optimized the supervision system and mechanism of water conservancy projects, achieved positive results, but also had problems and put forward relevant countermeasures.展开更多
文摘In recent years,digital twin technology has gained significant attention and application in the engineering construction field in China.Its real-time feedback function has brought more standardized construction operations to various engineering construction and maintenance processes.In this context,this paper analyzes the specific application of digital twin technology in hydraulic engineering based on its foundations.Taking the reinforcement and anti-seepage digital twin application of a certain embankment section as an example,it explores the reinforcement and anti-seepage construction effects of embankment engineering with the involvement of digital twin technology under complex hydrogeological conditions.The research shows that this technology can significantly improve the control accuracy of slurry diffusion,the identification ability of seepage risks,and the adaptability of engineering construction.Its application provides a replicable digital solution for the governance model of hydraulic engineering.
文摘[Objective] The research aimed to study the application of chemical tracing experiment technique in leakage detection of hydraulic engineering.[Method] According to the current situation of Sanyuan Western Suburb Reservoir in Xianyang City of Shaanxi Province,three sections （L1,L2 and L3） were set.KI was selected as the chemical tracer to carry out the tracing and detection research.[Result] There was no obvious leakage phenomenon in L1,L2 and L3 sections.The impermeability of rock in some dam abutments was bad.[Conclusion] The leakage reason of Western Suburb Reservoir was that the impermeability of rock in some dam abutments couldn’t satisfy seepage requirement.After the reservoir was put into operation,the water level in front of dam rose,and the ground water level of dam abutment also rose.The penetration water pressure correspondingly increased,and the water content of bank slope at the downstream of dam increased.
文摘With the development of China's economy,the implementation scale and scope of hydraulic engineering projects are increasing,and the application of anti-seepage technology has an important influence on the construction quality of hydraulic engineering.In this paper,the significance and problems of the application of anti-seepage technology in the construction of hydraulic engineering projects were mainly analyzed,and specific application strategies were proposed.
文摘China is a country with many mountains and hills, most of which are in subtropical areas, and are prone to floods and other natural disasters in summer. Water conservancy and hydropower projects are all over the country. Many terrain are relatively high and steep, involving high slope projects. Due to the complex topographic conditions, in the survey and design stage, it is necessary to consider various problems that may be encountered in the project construction, compare and select multiple schemes according to the project boundary conditions, analyze and demonstrate the design scheme from the aspects of investment, construction period and construction difficulty, and finally determine the design scheme. Focusing on the causes of high slope instability, this paper puts forward relevant suggestions on high slope protection, and analyzes the quality control of high slope survey and design of water conservancy and hydropower projects.
文摘In this paper, the connotation and application status of hydraulic environmental geological exploration and remote sensing technology of hydraulic engineering environment are respectively studied, and then the application methods of relevant technologies are analyzed in the geological work practice. It is hoped that the efficiency and accuracy of geological work can be improved through the research.
文摘The construction of fully closed check dam (CD) is a conventional flood prevention mechanism implemented on rivers. Fully closed CDs trap large amounts of sediments in rivers to stabilize the river slopes and control erosion. However, fully closed CDs cannot selectively trap sediment and may easily overflow, causing them to losing their ability to mediate and hold sediments. Previous studies proposed the concept of “breathable CDs”. The researcher introduced metal slit dam (SD) that could be assembled and disassembled quickly and conveniently. Once a CD reaches maximum capacity, operators must ensure that the water channels of the dam are free from blockage. Moreover, they must inspect the internal accumulation conditions of the dam periodically or immediately following heavy typhoon rains. When necessary, either the sediment buildup in the upriver blockage must be cleared, or the transverse structure of the dam must be removed to allow fine particles to be discharged along with a moderate amount of water. These actions can free up the sediment-storing capacity of the dam for the next heavy typhoon rains. In addition, operators should also inspect the damages inflicted on the dam, such as erosion, wear and tear, and deformation conditions. Damaged components should be disassembled and repaired if possible, or recycled and reused. The present study performed channel tests to simulate closed CDs, SDs, steel pipe dam (SPDs), and steel pipe plus slit dam (SPSDs) for 50-year and 100-year frequency floods. Results were then analyzed to determine the sediment trapping (ST) effects of various CDs, the effects of “adjustable CDs”, and the changes of moderated riverbeds.
文摘With the continuous development of China's social economy, the demand for water resources is increasing. Generally, water exists in natural form, and the water resources in natural form can not be fully utilized. In order to effectively manage the natural water resources and give full play to the application value of water resources, we need to pay attention to the construction of water conservancy projects. Using scientific water conservancy projects can effectively prevent flood risk, ensure social harmony and stability, and ensure the life safety of residents. In the current process of water conservancy project construction, the use of scientific and effective embankment anti-seepage construction technology can improve the level of water conservancy project construction. However, it should be noted that there are still some problems in the application of embankment anti-seepage construction technology in water conservancy projects, which affect the application benefits of embankment anti-seepage construction technology in water conservancy projects. In this case, it is necessary to scientifically select the anti-seepage construction technology according to the specific construction needs of China's water conservancy projects, and comprehensively apply a variety of anti-seepage technologies based on the embankment permeability of water conservancy projects, so as to improve the anti-seepage effect and the embankment construction effect.
文摘In China, the construction of water conservancy projects has brought great convenience to the development of agriculture in China, which not only reduces the occurrence of flood disasters, but also promotes the development of agricultural production in China. Therefore, in the process of infrastructure construction of water conservancy projects, we should also pay attention to the regulation of river courses in water conservancy projects. River ecological slope protection technology has played a very important role in water conservancy projects. It not only reduces the problem of water and soil loss around the water conservancy project, but also improves the beauty of the river. In addition, landscape planning has been carried out around the river, forming a beautiful waterfront scenic spot. Therefore, ecological river slope protection technology should be reasonably applied in water conservancy projects, and scientific and reasonable engineering and ecological measures should be taken to promote the development of water conservancy project construction on the basis of ensuring the construction quality of ecological river slope protection.
文摘The primary objective of this study was to design and size a sustainable sanitation solution for the Ndiebene Gandiol 1 school located in the eponymous commune in northern Senegal. Field investigations led to the collection of wastewater samples. Their analysis revealed specific pollutant loads, including loads of BOD5 3.6966 kgO<sub>2</sub>/day and COD of 12.8775 kgO<sub>2</sub>/day, which were central to the design phase. Following a rigorous assessment of the existing sanitation infrastructure, constructed wetland (CWs) emerged as the most appropriate ecological solution. This system, valued for its ability to effectively remove contaminants, was tailored to the specific needs of the site. Consequently, the final design of the filter extends over 217.16 m<sup>2</sup>, divided into two cells of 108.58 m<sup>2</sup> each, with dimensions of 12.77 m in length and 8.5 m in width. The depth of the filtering medium is approximately 0.60 m, meeting the standards while ensuring maximized purification. Typha, an indigenous and prolific plant known for its purification abilities, was selected as the filtering agent. Concurrently, non-crushed gravel was chosen for its proven filtration capacity. This study is the result of a combination of scientific rigor and design expertise. It provides a holistic view of sanitation for Ndiebene Gandiol. The technical specifications and dimensions of the constructed wetland filter embody an approach that marries indepth analysis and practical application, all aimed at delivering an effective and long-lasting solution to the local sanitation challenges. By integrating precise scientific data with sanitation design expertise, this study delivers a holistic solution for Ndiebene Gandiol. The detailed dimensions and specifications of the constructed wetland filter reflect a methodology that combines meticulous analysis with practical adaptation, aiming to provide an effective and sustainable response to the challenges of rural and school sanitation in the northern region of Senegal.
文摘Confronted with the challenge of wastewater management, particularly in the school environment of Senegal, our study set out to achieve multiple objectives. Following field surveys, laboratory analyses of wastewater samples were carried out, revealing a significant pollutant load. In the community of Gandiol, near Saint-Louis (Senegal), the school of Ndiebene Gandiol 1 faces significant sanitation challenges. Our study aimed to address this issue by using a constructed filter composed of two filtering bed cells measuring 12 × 8.5 m, preceded by a septic tank. We particularly focused on the influence of Vetiver;a plant chosen for its purification potential. Our analyses showed remarkable efficiency of the filter. Elimination rates reached 95% for 5-Day Biochemical Oxygen Demand (BOD5), 91% for Chemical Oxygen Demand (COD), and 92% for SS, far exceeding the Senegalese standards set at 50 mg/L, 200 mg/L, and 40 mg/L, respectively. Furthermore, the concentration of fecal coliforms was reduced to 176 FCU/100mL, well below the Senegalese threshold of 2000 FCU/100mL and close to the World Health Organization’s (WHO) recommendation of 1000 FCU/100mL. However, despite these promising results, some parameters, particularly the concentration of certain pollutants, approached the thresholds defined by European legislation. For example, for Suspended Solids (SS), the post-treatment level of 3 mg/L was well below the Senegalese standard but edged close to the European minimum of 10 mg/L. In conclusion, the Vetiver filter demonstrated a remarkable ability to treat school wastewater, offering high pollutant elimination percentages. These results suggest significant opportunities for the reuse of treated water, potentially in areas such as irrigation, though some adjustments may be necessary to meet the strictest standards such as those of the European union (EU).
文摘The overarching goal of this study is to offer an effective and sustainable solution to the challenges of sanitation in rural and school settings in the northern region of Senegal. The study explores a wastewater treatment approach based on phytoremediation, with a particular focus on the use of horizontally-flowing reed bed filters. Furthermore, it aims to adapt and optimize these systems for the specific needs of Senegal, focusing on wastewater in school environments. Thus, we constructed a horizontally-flowing reed bed filter, planted with Typha, at the Ndiébène Gandiol school in Senegal. We will investigate the efficiency of wastewater treatment by this horizontally-flowing reed bed filter, emphasizing the role of the plant used: Typha. The filter is described in detail, specifying its dimensions, its composition of flint gravel, and the choice of plants, namely Typha. The experimental protocol is detailed, describing the sampling at the entrance and exit of the filter to evaluate water quality. The parameters analyzed include Chemical Oxygen Demand (COD), Biochemical Oxygen Demand over 5 days (BOD5), suspended solids, ammonium, nitrates, phosphates, pH, conductivity, and fecal coliforms. The results indicate a significant improvement in water quality after treatment. COD, BOD5, suspended solids, and fecal coliforms are greatly reduced, thus demonstrating the efficacy of the Typha filter. However, nitrate concentrations remain relatively stable, suggesting room for improvement in their elimination. A perspective of reuse of the treated water is considered, showing that the effluents from the planted filter meet Senegalese and international standards for irrigation. The findings suggest that these waters could be used for a variety of crops, thereby reducing the pressure on freshwater resources. In conclusion, the Typha-based filtration system shows promising results for improving water quality in this region of Senegal. However, adjustments are necessary for more effective nitrate removal. This study paves the way for sustainable use of treated wastewater for irrigation, thus contributing to food security and the preservation of water resources.
基金Supported by National Fund Committee for Study Abroad
文摘In this paper,the metal hydraulic engine mount (HEM) with the orifice is presented,the construction of HEM is consist of hydraulic cylinder and the spring on the bottom,its mechanical model is given and dynamics equations are set up with considering kinematics conditions and continuous of fluid,the dynamics behavior of HEM including dynamic stiffness of fluid and transferability of HEM are studied here.The example of hydraulic engine mount is calculated,it is shown that the vibration reduction performance of the hydraulic engine mount of this paper is better.The analysis method of vibration reduction behavior for HEM in this paper can be used in designing of the reduction vibration devices and the HEM in this paper can be used in the practical engineering for reduction vibration.
基金Project(51275451)supported by the National Natural Science Foundation of ChinaProject(51221004)supported by the Science Fund for Creative Research Groups of National Natural Science Foundation of China+1 种基金Project(2013CB035400)supported by the National Basic Research Program of ChinaProject(2011BAK03B09)supported by the National Key Technology R&D Program of China
文摘The structure and working principle of a two-cylinder four-stroke single-piston hydraulic free piston engine(HFPE) were introduced. The basic vibration equation of free piston assembly(FPA) was established based upon the energy conversion between the injected fuel and the friction together with the load. Both the theoretical and numerical results show that the vibration system of FPA is a nonlinear conservative autonomous system in one cycle. The FPA vibration is symmetric with constant amplitude when FPA is only driven by the compression pressure in the compression accumulator and that in the combustion chamber. When considering the friction and load, FPA could still achieve a stable vibration after a few cycles' adjustment whether the input energy is equal to the consumed energy or not. The vibration characteristics are different when FPA vibrates in the compression stroke and the expansion stroke, which is the unique feature of the single-piston HFPE.
基金Natural Sciences and Engineering Research Council of Canada for a discovery grant
文摘Geometrical analyses of 3930 potholes （3565 fluvial potholes, 237 marine potholes and 128 hillside potholes） from 33 localities in the world reveal a consistent, linear relationship： D Nh ＋ M, where h and D are, respectively, the depth and mean diameter of pothole, M is a critical size of the initial concavities （seminal potholes） that subsequently underwent growth, and N is the ratio of diameter expanding （wall erosion） speed to deepening （floor abrasion） speed. For the stream potholes, N is generally less than 1 with an average value of 0.67, M varies from 5.3 cm to 40.5 cm with an average of 20 cm, and N decreases gently with increasing M. However, the marine and hillside potholes are generally characterized by N 〉 1 and M 〈 10-14 cm, and a power-law relationship N 4.24M o.78 （coefficient of determination R2 0.75, M is in cm） exists. The results indicate that depth increases faster than diameter for stream potholes due to the larger size of grinding stones （〉5-10 cm）, while depth increases slower than diameter for marine potholes and hillside potholes due to the smaller size of grinding stones （〈5-10 cm）. The pothole h-D relationship is nearly independent of rock type. Knowledge of the pothole depth-diameter relationship is useful in a number of contexts, including simulation of hydraulic dynamics, theoretical considerations of erosion, comprehension of channel incision and development of canyons and gorges, and accurate estimation of excavation volume and mechanical strength ofpotholed bedrock in the design and stability analysis of hydraulic and environmental engineering projects （e.g. dam construction and river dredging）.
基金National Hi-tech Research Development Program of China(863 Program,No.2001AA505000-11)
文摘To investigate the dynamic characteristics and damping theory of the passive hydraulic engine mount （PHEM）, numerical prediction is performed through lumped parameter model. System parameters, including volume compliance of the decoupler chamber, effective piston area, fluid inertia and resistance of inertia track and direct-decoupler, are identified by means of experiments and finite element method （FEM）. Dynamic behaviors are tested with elastomer test system for purpose of validating PHEM. With incorporation of inertia track and direct-decoupler, PHEM behaves effective and efficient vibration isolation in range of both low and high frequencies. The comparison of the numerical results with the experimental observations shows that the present PHEM achieves fairly good performance for the engine vibration isolation.
基金Supported by the National Ministry Fundamental Research Foundation of China(A2220060053)
文摘The characteristics of a hybrid hydraulic vehicle driven by the hydraulic common rail propulsion system with a hydraulic free-piston engine and a hydraulic transformer were studied.A mathematical model of the propulsion system was established and a control method of the propulsion system was proposed.Extensive simulation results of hybrid hydraulic vehicles with the hydraulic common rail propulsion system were presented.The hydraulic common rail propulsion system achieved the switch power control and the constant power propulsion.The control method based on the propulsion,break and speed limit requirement was verified.Our results showed that the hydraulic common rail propulsion system gained an ideal acceleration process.
文摘Natural methane （CH4） oxidation that is carried out through the use of landfill covers （biocovers） is a promising method for reducing CH4 emissions from landfills. Previous studies on peat-based landfill covers have mainly focused on their biochemical properties （e.g. CH4 oxidation capacity）. However, the utilization of peat as a cover material also requires a solid understanding of its geotechnical properties （thermal, hydraulic, and mechanical）, which are critical to the performance of any biocover. Therefore, the objective of this context is to investigate and assess the geotechnical properties of peat-based cover materials （peat, peat–sand mixture）, including compaction, consolidation, and hydraulic and thermal conductivities. The studied materials show high compressibility to the increase of vertical stress, with compression index （Cc） values ranging from 0.16 to 0.358. The compressibility is a function of sand content such that the peat–sand mixture （1：3） has the lowest Cc value. Both the thermal and hydraulic conductivities are functions of moisture content, dry density, and sand content. The hydraulic conductivity varies from 1.74 × 10^-9 m/s to 7.35 × 10^-9 m/s, and increases with the increase in sand content. The thermal conductivity of the studied samples varies between 0.54 W/（m K） and 1.41 W/（m K） and it increases with the increases in moisture and sand contents. Increases in sand content generally increase the mechanical behavior of peat-based covers; however, they also cause relatively high hydraulic and thermal conductivities which are not favored properties for biocovers.
基金supported by the National Natural Science Foundation of China (Grants No.50909066 and51179108)
文摘Vulnerability to natural disasters falls into three categories： exposure, resistance, and resilience, where resilience mainly refers to the capability of a pressure-bearing system to recover by returning to its initial state, that is, the ability to adapt to disaster pressure. Resilience is a major subject of research on disaster prevention and mitigation. This research mainly focuses on the ability of the hydraulic structure to recover from the significant impacts of typhoons. According to the load/unload response ratio theory, the degree of instability by which nonlinear systems can be identified according to the difference between load and unload responses was analyzed. This analysis was used as a basis to study the resilience of a hydraulic structure. Taking the Yangtze River embankments under the impact of Typhoon Matsa as an example, the ability of the typical sections of different types of embankments to adapt to the significant impact of the typhoon, i.e., the resilience of the hydraulic structure, is described with the help of the load/unload response ratio （L）. The results of the calculated resilience reflect the actual conditions of the structure and can be used to determine the applicability of the embankment section. The load/unload response ratio theory is one of the effective tools for calculating the resilience of hydraulic structures under the significant impacts of typhoons.
文摘In this study, we investigated the effect of compression on the micromechanical and the petro- physical properties of salted wellbore cement systems. The experiments were conducted using a customized bench scale model, which utilized an expandable tubulars simulating the compression of a previously cemented casing under field-like conditions. The “mini-wellbore model” sample consisted of a pipe inside pipe assembly with a cemented annulus. The cement samples were cured in a water bath for 28 days prior to the compression experiments to allow adequate hydration. The impact of compression on the cement’s petro-physical and mechanical properties was quantified by measuring the porosity, permeability and hardness of salt cement cores drilled parallel to the orientation of the pipe from the compacted cement sheath. Permeability (Core-flood) experiments were conducted at 21℃, 10,342 kPa confining pressure for a period of 120 minutes. During the core-flood experiments, conducted using Pulse-decay method, deionized water was flowed through cement cores to determine the permeability of the cores. The results obtained from these experiments confirmed that the compression of the cement positively impacted the cements ability to provide long term zonal isolation, shown by the effective reduction in porosity and permeability. Furthermore, the results confirm reduction in the detrimental effect of salt on the strength and stiffness in post-compression cement.
文摘In recent years, the Water Affairs Bureau of Changfeng County, Anhui Province has closely adhered to the general tone of "making up for the shortcomings of water conservancy projects and strengthening the supervision of water conservancy industry", actively strengthened the supervision and management of water conservancy projects, insisted on the high-quality development of water conservancy projects, optimized the supervision system and mechanism of water conservancy projects, achieved positive results, but also had problems and put forward relevant countermeasures.
