Hydraulic Structure and Hydrodynamics

In order to study the mechanical properties of the upper loosely-paved gravelly soil used to protect the compacted dam material under the freeze–thaw cycle during winter construction on the engineering site, the gravelly soil with the soil-rock ratio of 7:3 was mixed evenly and sealed under the corresponding dry density and moisture content, and then subjected to freeze–thaw cycles. After reaching the corresponding freeze–thaw times, the compaction samples were taken out. The direct shear tests were conducted on gravelly soil after freeze–thaw cycles under different vertical pressures and the change pattern of mechanical properties were analyzed. The experimental results show that freeze–thaw cycles have no significant effect on the shear strength of soil samples under the lower vertical pressure. Under the higher vertical pressure, the shear strength of soil samples decreases with the number of freeze–thaw cycles and then stabilizes. The effect of freeze–thaw cycles on the shear strength parameters of the gravelly soil is more obvious. As the number of freeze–thaw cycles increases, the cohesive force tends to increase, while the internal friction angle decreases, tending to stabilization after 10 freeze–thaw cycles.

There are numerous cascade reservoirs in China’s small and medium-sized river basins. Once the cascade reservoirs break, the disastrous consequences will result in extreme economic, social, and ecological losses. According to the hidden danger investigation results of cascade reservoirs, a risk assessment method and standard for cascade reservoirs were proposed and established based on the risk matrix method, which provides a foundation for the risk assessment of cascade reservoirs. Taking the D, C, and H cascade reservoirs as the case study, according to the hidden danger investigation results and dam break consequences of the reservoirs, it was concluded that the risk levels of the three reservoirs were in order of extremely high risk, high risk, and high risk. Therefore, it is suggested that engineering and non-engineering measures should be taken to reduce the cascade reservoir’s risk to ensure the high-quality and safe operation of the cascade reservoir group in China.

The clearwell has the dual function of hydraulic regulation and disinfection contact. Improving hydraulic efficiency is an important measure to reduce the amount of disinfection by-products. The example of the clearwell was modeled as a whole. Then the influence of the main geometric dimensions on the hydraulic efficiency of the clearwell were studied by two-dimensional numerical simulation method, and the rationality of the design scheme was verified. The results showed that the length–width ratio had the most obvious influence on hydraulic efficiency, but the trend of t10/T increasing was slowing down. The t10/T value could be increased by reducing the number and width of bends and increasing the diameter of inlet pipe. The Pe under each working condition was greater than one, so the particle translation with the water flow was the main factor of mass transfer. The length–width ratio of the clearwell was 38 and the t10/T was 0.54 which would meet the design requirement of not less than 0.5.

Reservoir-induced earthquakes have the characteristics of shallow focal depth, small magnitude, high frequency and density in the Baitan-Zhilixincun section of the lower reaches of the Jinsha River. The rock mass of the shallow strata is mostly carbonate rock, which is widely distributed. The shallow metamorphic rocks are mainly distributed at the depth of 10 km. In the concentrated area of reservoir-induced earthquakes, the number of secondary faults is relatively large, and they are mainly reverse faults. The stress and strain patterns of the shallow cracks are mainly unloading cracks in the rock mass on the left and right banks of the Baitan-Jiaopingdu section. The main storage characteristics of groundwater are bedrock fissure water and karst fissure water. The rapid impoundment of the reservoir makes the bedrock fissure.

Reservoir sedimentation profoundly impacts riverbed dynamics and engineering applications, posing a dual challenge by compromising riverbed evolution and critical water storage infrastructure. The escalating loss of reservoir capacity due to sediment accumulation imperils lives, properties, and global water sustainability, undermining the reservoir’s safety role. Using the Three Gorges Reservoir (TGR) as a case study, we analyze extensive hydrological data from Cuntan, Qingxichang, Wanxian, and Miaohe stations (2002–2020). Our findings reveal: (1) Pre-impoundment, Qingxichang and Wanxian exhibit high sediment carrying capacities, which reduce noticeably during early impoundment. Subsequently, with the changes of pre-dam water levels, an overall decreasing trend of sediment-carrying capacity is observed, characterized by annual fluctuations, while Miaohe consistently maintains a lower level due to its proximity. (2) Wanxian experiences significant sediment carrying capacity reduction during constant water level periods of various operational stage, with up to 99.4% decrease post-impoundment. (3) Sediment carrying capacity varies annually primarily due to changes of reservoir pre-dam water levels, and secondarily, owing to incoming water and sediment fluctuations. Increased influx raises sediment carrying capacity, while reduced influx decreases it. Morphological cross-section configuration emerges as a dominant factor in sediment carrying capacity, outweighing dam proximity. Wide, shallow sections have lower capacity than narrow, deep ones. For narrow, deep sections, dam proximity’s influence exceeds cross-sectional morphology.

In the construction and operation of cascaded reservoir groups, higher requirements have been put forward for multi-objective optimization scheduling of cascaded reservoir groups, aiming to promote benefits and eliminate hazards through joint scheduling, leverage comprehensive benefits, ensure basin safety, and meet the needs of digital transformation of hydropower and water conservancy. Based on the research of integrated methods for hydrological forecasting, multi-objective scheduling, and decision-making of basin cascade reservoirs, this study constructs a multi-objective intelligent control system that serves hydrological forecasting, cascade scheduling, flood control, and risk assessment of cascade reservoirs, and applies it to the development of cascade hydropower in the southern European river basin of Laos.

In order to study the influence of subway foundation pit on the displacement of surrounding strata under the condition of dewatering. Based on the finite element modeling of a subway foundation pit project under construction in Nanjing, this paper discusses the influence of excavation only on the ground settlement around the subway foundation pit and the influence of dewatering foundation pit on the ground settlement around the subway foundation pit. Through the comparison of the two cases, the influence law of the horizontal and vertical displacement of the surrounding strata caused by the precipitation is analyzed. It is concluded that the vertical displacement of the surrounding strata caused by the foundation pit is larger in the case of the dewatering, and only the horizontal displacement of the excavation foundation pit is considered to be smaller.

3D dynamic finite element calculation is carried out for a 161 m high geomembrane faced soft rockfill dam on overburden in a strong earthquake area. The dynamic response of the dam is obtained. The horizontal dynamic displacement is relatively more significant. The maximum vertical permanent deformation and deflection of geomembrane occur at the dam crest near the maximum dam cross section. The tensile strain of geomembrane increases significantly at the dig-fill junction and the reverse arc section. The maximum tensile strain of geomembrane is 1.52%, and the safety factor of geomembrane tensile strain is greater than the allowable value. Even subjected to the strong earthquake, the geomembrane slab can effectively coordinate the deformation with the dam body and deep overburden and the dam can be in a safe operation state.

Through the analysis of seepage monitoring data of Anhua reservoir dam, the anti-seepage effect of dam reinforcement project is evaluated. The analysis of monitoring data shows that the osmometer water level behind the inclined clay wall of the dam is relatively stable and has little correlation with the reservoir water level. Compared with the upstream reservoir water level, the water level of osmometer in each section falls between 7.31 and 9.30 m at high water level, which indicates that the anti-seepage effect of clay inclined core wall of dam body is better. The water head of the concrete cut-off wall in the connection section between the right dam head and the wing wall of the spillway gate is reduced by 6.65 m, and the potential difference between the front and rear of the wall is 74.7%, which indicates that the anti-seepage effect of the connection between the dam and the wing wall of the spillway gate is good. There is no obvious correlation between the water level of the pressure gauge pipe around the dam on the left bank and the water level of the reservoir, which is mainly affected by rainfall infiltration and mountain groundwater, indicating that there is no seepage around the dam.

Due to the special landform, complex river system and rapid development of urban agglomerations in the Guangdong-Hong Kong-Macao Greater Bay Area, the task of flood and waterlogging prevention in the Greater Bay Area is heavy and its responsibility is important. In order to effectively improve the effectiveness of flood and waterlogging prevention, this paper analyzes current problems facing flood and waterlogging prevention in the Greater Bay Area, and proposes building an intelligent sensing IoT network of Flood and Waterlogging Prevention based on IPv6 and IoT technology, making the flood warning’s response time be reduced from 60 ms to less than 30 ms, to provide more efficient, more precise and more secure network support and data protection for flood and waterlogging prevention.

Accurate and reasonable cement take prediction is of great significance for effective control of dam foundation grouting quality and cost. This article combined the previous research results and engineering practice to explore the different influencing factors of cement take, and conducted parameter correlation analysis to determine the input parameters for prediction. Then, an intelligent prediction model for cement take based on improved extreme learning machine (ELM) is proposed, which uses the grasshopper optimization algorithm (GOA) to optimize its input weights w and hidden layer thresholds b. Finally, taking sets of cement take data from a real dam foundation project as an example to verify the performance of the proposed prediction model, the results illustrates that the proposed model has good prediction accuracy and can assist grouting engineers in adjusting grouting construction design and controlling grouting quality, which has a wide application prospect.

This article comprehensively considers hydrogeological and meteorological conditions, including topography, tides, runoff, and wind. Integrating factors such as ship lock operation rules and tidal dynamic parameters, a two-dimensional tidal salinity model is established. The study further conducts computational analyses on the desalination effects of various pump operation processes in the newly constructed ship lock on the estuary. The results show that during the ship lock operation, saltwater plumes can enter inland rivers through tidal dynamics and accumulate on one side of the ship lock, leading to upstream propagation. In addition, high saltwater backflow and rapid upstream propagation of saltwater accumulation were observed during high tides. This study also studied the model calculation and analysis of anti-salt pump stations of different scales and operating processes, providing theoretical basis and technical support for engineering design plans.

This research paper focuses on the development of a groundwater classification and grading method specifically tailored for underground space development projects. The study aims to provide a systematic approach to assess the groundwater conditions and associated risks. Based on the principle of multi-objective optimization, groundwater classification and grading method is proposed in this paper. According to the types of confined water in different foundation pits, this method accurately evaluates the impact of the changes in the confined water on the surrounding environment, and comprehensively analyzes other limiting factors such as project investment, project safety, surrounding buildings, and ecological environment, and then controls the confined water.

Rainfall infiltration is a major cause of slope instability, and many researchers have conducted extensive studies on the mechanism of slope instability under the influence of rainfall infiltration. The design of slope support currently faces several challenges, including a shortage of appropriate design basis, dependence on imprecise, experience-based, or analogy-based designs, and the absence of focused and optimized design methods. Using numerical simulation, this study aimed to find the impact of various anchor reinforcement schemes on slope stability during heavy rainfall. Several anchoring reinforcement schemes have been proposed, the impact of anchoring angle, anchoring distance, anchoring length, and other parameters on the slope’s safety factor has been analyzed and compared, and the optimal solution has been suggested.

The safety of subsea tunnels during earthquakes is a crucial factor in the design process. It is appropriate to consider the impact of the seawater above when assessing the seismic resistance of a subsea tunnel. In this paper, finite element models of the seawater-seabed-tunnel structure system are established using ABAQUS software to investigate the fluid–structure interaction and plastic damage of the lining. The seismic response and damage characteristics of the subsea tunnel are compared at various seawater depths. The study found that the overlying seawater inhibits the vertical movement of the seabed surface, but has minimal effect on the horizontal movement. With the increase in seawater depth, the stress on the tunnel structure will noticeably increase, with the spandrel and arch foot becoming the weak points in seismic design. Overlying seawater will increase the dissipation energy of the tunnel system, leading to tunnel damage. When the seawater depth exceeds 20 m, the tunnel system’s dissipation energy at varying depths of seawater will significantly increase.

In order to study the effect of seepage and stress coupling on excavation deformation of foundation pit, finite element numerical analysis method is used in this paper, taking a hanging water curtain foundation pit project under construction in the rich water stratum area of the Yangtze River floodplain as an example. By comparing the deformation index of the surrounding surface settlement foundation pit with different models, the law of the influence of seepage on the deformation of foundation pit excavation is obtained. The results show that when there is no foundation pit dewatering requirement and the support stiffness is large enough, the settlement caused by the release of ground loss stress is small, and the surface settlement curve around the foundation pit is parabolic. When there is precipitation in the pit and considering the support stiffness is large enough, the surrounding surface settlement caused by foundation pit construction is triangular in distribution. The calculation and analysis of foundation pit excavation considering the coupling of seepage and stress in actual excavation construction show that the surrounding surface settlement curve is a combination of the above two settlement characteristics, and the numerical and curve characteristics are coupled.

The valley plain has the characteristics of both mountainous hills and plains, with special terrain conditions and frequent floods. In order to improve the drainage capacity of the river valley plain, this article takes the Bihu Plain in the Oujiang River Basin as an example, uses MIKE11 one-dimensional hydrodynamic software to establish a mathematical model of the river network, analyzed the flood and drainage in the river valley plain, studied the impact of Traditional Flood control mode and Flood control mode based on sponge cities concept in regional drainage, analyzes the advantages and disadvantages of different flood control strategies in practical cases, and provides solutions for regional flood control, Summarized and clarified the relationship between urban flood control and watershed flood control.

This paper summarizes the typical landslide characteristics and main triggering factors by statistically analyzing the detailed investigation data of 51 landslides in Hebei Province, among which rainfall-induced cover-type landslides are the most typical form of landslides. In order to study the destabilizing and destructive mechanism of high steep cover type slope under the action of rainfall infiltration, taking a cover type slope as an example, based on the theory of unsaturated seepage and shear strength, the changing rules of seepage field, displacement field, plasticity zone, and sliding cracking surface of the cover type slope under the condition of intermittent rainfall were analyzed by using the slip surface stress method, and the safety coefficient of the slope under the action of rainfall was calculated. The results show that: after the rainfall starts, because the shallow soil layer of the slope is mainly coarse gravel soil and gravel soil, with relatively strong permeability, the rainwater on the slope surface infiltrates into the interior of the slope body and softens the soil body along the soil-rock interface, and the soil body of the slope body produces displacement at the leading and trailing edges, and shallow sliding is formed in the slope; with the continuation of the rainfall, the slope produces a through plastic zone, and the soil body of the leading edge pulls the central pile body to produce traction slip, and the trailing edge of the soil body produces traction slip, and the trailing edge of the soil body produces traction slip. As the rainfall continues, the slope produces through plastic zone, the leading edge soil body pulls the central pile body to produce traction slip, the trailing edge soil body pushes the central pile body to produce nudging slip, and the deformation gradually develops from the surface to the depth, from the leading edge to the trailing edge.

There is independence and integration between water supply and sediment reduction in sediment-laden river reservoirs. How to maintain effective storage capacity and meet water supply requirements for a long time is one of the problems to be solved in the efficient operation of sediment-laden river reservoirs. In this paper, Dongzhuang Reservoir of Jinghe River is taken as the research object. Through the analysis of measured data and mathematical model calculation, the measured hydrological sediment and cross-section erosion and deposition in the lower reaches of Jinghe River and Weihe River are analyzed. The reservoir sediment discharge flow index which is beneficial to reduce the sediment deposition in the lower reaches of Weihe River and maintain the effective reservoir capacity for a long time is studied, and the joint regulation mode of reservoir runoff and sediment is put forward. The results show that the sediment regulation of Dongzhuang Reservoir during the sediment retention period is mainly to reduce the deposition of the lower reaches of the Weihe River, and the sediment regulation during the normal operation period of the reservoir is mainly to maintain the effective storage capacity of the reservoir for a long time. The joint regulation of the Dongzhuang Reservoir and the surrounding four storage reservoirs, such as the Ganhe Reservoir, the Xijiao Reservoir, the Longtan Reservoir, and the Helan Reservoir, can reduce the deposition of the lower reaches of the Weihe River by 11 million tons per year, increase the guarantee rate of agricultural irrigation from 30 to 50%, and increase the guarantee rate of industrial water supply from 57 to 95%. And the outflow of the reservoir meets the requirements of the ecological base flow of the river. The research results provide technical support for the optimal operation of reservoirs in sediment-laden rivers.

To study the development and collapse mechanism of karst collapse in Jingquan Water Source Area of Tengzhou City, a two-dimensional fluid solid coupling model was established using the finite element software ABAQUS. A comprehensive analysis was conducted on the development process of karst collapse, and the mechanism of soil cave collapse under the effects of rainfall and excessive groundwater exploitation in the study area was summarized. The results indicate that the periodic fluctuation of groundwater level caused by rainfall and excessive groundwater exploitation is manifested as a decrease in soil strength, ultimately leading to karst collapse. The use of strength reduction method can effectively conduct quantitative analysis of karst cave collapse stability.

The curved weir, as an innovative weir design, offers an extended upstream edge compared to orthogonal weirs, enhancing discharge capacity across its width and ensuring river flow safety. However, for rivers of fixed width, the effects of the curved configurations, partically the central angles, on hydraulic performance, warrant further investigation. This research uses FLOW-3D software to numerically simulate curved weir and orthogonal weir with different central angles (120°, 150° and 180°), and comparatively analyses the hydraulic characteristics of the two types of weirs under different upstream head conditions in terms of flow pattern, flow velocity, discharge coefficient and so on. The results show that under the condition of low upstream head, the discharge capacity of curved weir is obviously stronger than that of orthogonal weir, and when the degree of central angle α = 120°, which provides the necessary theoretical basis for the practical popularization of curved weir.

Estuary wetland, as an independent “living body”, has the process of geographical evolution, i.e. juvenile stages (juvenile), maturation stage (adult) and aging stage (later). Taking the Yellow River estuary wetland as a case study, this paper calculates the evolution stages of the estuary wetland by using the area-elevation integral curve and fractal theory. The following conclusions are obtained. (1) In the juvenile stage, the basin erosion are strong, estuary wetland develops quickly due to high sediment transport into the estuary area. When the basin geomorphology develops to the adult stage, the river sediment transport is stable, the estuary wetland area continues to expand at a stable speed. In the later stage, erosion from the river basin weakens, the river sediment transport decreases, the sediment transport to the estuary wetland decreases, and the wetland begins to shrink gradually. (2) Human activities directly affect the ecological environment of estuary wetlands and shorten the evolution process of estuary wetlands. (3) According to the temporal and spatial variation trend calculation on Yellow River estuary wetland, the total area of wetland in 2025 will be 2518.4 km2, of which natural wetland accounts for 1252.8 km2, the area of constructed wetland accounts for 1265.6 km2. Natural wetland begins to shrink. Therefore, it is necessary to take measures to protect the natural wetland in the Yellow River Delta, to control the development of constructed wetland reasonably, and to realize the sustainable development of wetland ecological environment in the Yellow River Delta.

Seepage is an important factor affecting the safety of embankment engineering. It is of great significance to strengthen seepage monitoring, obtain hidden danger information in time and deal with it scientifically for ensuring the safety of the whole embankment. Guided by the heating optical fiber sensing theory, a large scale embankment model optical fiber testing platform was designed and built. With this platform, model tests of large scale embankment are carried out under three typical conditions, including variable water level, different tangential flow velocity and different rainfall patterns. The sensing efficiency of heating fiber to seepage behavior of embankment model driven by different hydraulic conditions is compared and analyzed, and the key results are summarized. The heating fiber method has little effect on expanding the monitoring range, but it can improve the sensitivity. The optical fiber in the infiltrated area has a stronger sensing ability to frequency and amplitude of fluctuations. Tangential flow velocity was positively correlated with temperature variation only in the infiltration zone. The cumulative effect of rainfall on the seepage field can be monitored.

To study the variation law of internal seepage and stability of purple silty cohesive unsaturated soil slope under different rain patterns, we use GeoStudio to calculate and analyze the changes of pore water pressure and safety factor of the slope after undergoing three rain patterns, namely, front peak pattern, back peak pattern and step pattern, under the action of moderate rain, heavy rain and rainstorm. Research has found that under the same conditions, it takes the longest time for the pore water pressure under the back peak type to reach stability, and the slope safety factor decreases the most. Therefore, it is necessary to strengthen the management of slope stability protection after rainfall in the back peak type.

Study on risk assessment of urban flood is the key to ensure the operation safety of city. In existing researches, the dynamic impact factors were not taken into account, and the evaluation method based on heuristic algorithm depends on a large number of training samples. To solve the above deficiencies, dynamic risk assessment of urban flood based on improved genetic algorithm was proposed in this paper. In this assessment index system, disaster-inducing factors, hazard-inducing environment, hazard-affected body, disaster prevention and reduction ability are taken into considered. The dynamic assessment of urban flood risk for small sample is realized by using genetic algorithm improved by date augmentation, also the consistency and superiority of the method are verified by case study. The research results of this paper provide a new idea and a technical mean for the dynamic management of urban flood risk assessment, and have very important value of application and promotion.

In order to analyze the influence of the siphon effect in the pipeline on the actual operation of the head cover drainage system in different working conditions of a hydropower station, a reasonable and effective siphon failure device is set up. Based on PIPENET, the fluid calculation and analysis software of pipe network, this paper aims at the overall modeling of the head cover drainage system of the hydropower station, and then conducts hydraulic calculation and analysis on it, and studies the design scheme of damage siphon effect, which provides strong support for the optimal design of the head cover drainage system.

Traditional monopile foundations cannot support the greater lateral loads and horizontal displacement needs required by offshore wind turbines due to their increasingly large size. Popularity has increased for a recently created hybrid pile foundation that combines a traditional monopile with a wide-shallow bucket. In this paper, 1-g model tests in soft clay are used to analyze the lateral behavior of hybrid pile foundation under static load. As a standard, the monopile with the same pile diameter and embedded length is employed. According to the experiment’s findings, the pile-bucket hybrid foundation’s lateral ultimate bearing capacity is more than 70% higher and its initial stiffness is nearly twice as good as that of a monopile foundation under the same lateral load. In addition, this paper compares the pile displacement, pile bending moment, and p-y curve of monopile foundation and hybrid pile-bucket foundation.

The urbanization process leads to many problems with resources and environment, and the problem of urban flooding is particularly prominent. The permeable floor can solve the problem of urban flooding from the perspective of ecology. Based on simulated rainfall, load test, freeze–thaw cycle test and so on, a comprehensive evaluation of permeable floor is carried out from the aspects of functional application, ecological effect and economy by means of gray analysis and AHP. It is showed that the permeable floor can reduce surface runoff and meet the functional requirements of floor. The evaluation of permeable floor mainly needs considering functional application and ecological effect index. The major factor of functional application is bearing capacity. The major factor of ecological effect is capability of conserving water. The major factor of economy is maintenance cost and durability. The gray evaluation result is between excellent and good when 4 level evaluation gray class which includes excellent, good, medium and poor is used. This study provides a reference for the solution of urban flooding and the evaluation of ecological floor.

In order to identify the hydrodynamic load of a new type of permeable structure for the offshore oilfield, a physical simulation test is performed using a scale model. The variation of hydrodynamic load parameters of the new permeable structure under different working conditions is compared. The results can provide basic data for optimization of structural parameters of the new permeable structure for offshore oilfields. The relevant experimental results can provide basic data for optimizing the structural parameters of permeable structures in tidal flats, and provide a basis for the engineering design and construction of permeable structures.

The emergence of digital twin technology has facilitated the assessment of the level of water ecological civilization in the Yangtze River basin. In recent years, the digital twin technology in the Yangtze River basin has led to a gradual improvement in the efficiency of water quality and environment monitoring. In this context, how to flexibly apply digital twin technology to measure the development level of ecological civilization in the Yangtze River basin? In order to solve this problem, this paper firstly builds the evaluation index system of water ecological civilization level in Yangtze River basin based on DPSIRM model, and introduces Entropy weighting technique. Then analyzes the impact of digital twin technology on each index dimension, and finally designs how digital twin construction can better promote the construction of water ecological civilization in Yangtze River basin.

The construction of a reservoir on the river can meet the social requirements for irrigation, navigation, water supply, and power generation in the area. However, reservoir development also disrupts the natural flow continuity of the river, leading to fundamental changes in important water environmental factors such as water temperature, water quality, morphology, and water level. In this study, the Shihutang navigation-power junction project mainly affects the middle reaches of the Ganjiang River, the Wan’an to Xiajiang section is taken as the study area, and a one-dimensional hydrodynamic mathematical model of the middle reach of the Ganjiang River is established. The model is calibrated and validated based on measured water level and discharge data in order to study the influence of the Shihutang navigation-power junction project operation on the hydrodynamic characteristics of the middle reach of the Ganjiang River. The results show that the changes in water level, discharge, and velocity in the upstream and downstream areas are generally consistent before and after the operation of the Shihutang navigation-power junction project. The operation of the Shihutang navigation-power junction project has a significant influence on the hydrodynamic characteristics at the dam site, with the influence decreasing as the distance from the dam site increases.

When alarming the abnormal state of the construction site, due to the lack of systematicness in the composition analysis of specific construction safety influencing factors at different stages, the accuracy of linkage alarm is relatively high. Therefore, the study on linkage alarm of abnormal state of large pumped storage power station under video monitoring is put forward. Combined with different stages of construction, the existing factors affecting construction safety are comprehensively analyzed from three aspects: construction preparation, foundation and main structure. Based on the image information collected by video surveillance, the existence state of safety influencing factors in the video surveillance picture is identified through the convolution layer including the upper and lower layers, and the operation content that needs to be alarmed at the construction site is determined by combining the correlation between safety influencing factors. In the test results, the design of linkage alarm method not only has high stability for the overall accuracy of alarm in different test conditions, but also keeps above 90.0% all the time.

Strong transverse flows and fluctuations often occur in the downstream approach channel and entrance area during flood discharge at high dam hubs. This study takes a power station as a research sample. Flow velocities, transverse flow intensities, fluctuation characteristics and ship navigation status are analyzed and studied through field observations. The results show that during flood discharge the entrance area experiences transverse short-wave fluctuations and significant transverse currents. The oscillation of hydraulic jumps is the direct factor causing fluctuations in the downstream entrance area. The fluctuation amplitude of the center and edge of the entrance area was generally large, and the fluctuation spread to the approach channel and continuous attenuation. The main fluctuation attenuation occurs at the transition from the broad riverway to the downstream restricted approach channel. As the flood discharge increases, the lateral rolling of the ships becomes more pronounced. The change in power station discharge has a relatively small effect on the ships’ heeling and trim.

In view of the uneven distribution of water resources in the multi-lock and dam plains, the insufficient connection and layout of river systems such as isolated wetlands and pond barriers in floodplains, resulting in insufficient water resources allocation capacity, poor flood storage and drainage, and serious water ecological damage. Taking Langfang City as an example, based on graph theory and complex network theory, considering the flow capacity of DAMS and gates and human demand for water landscape, the importance of rivers and canals in river network—optimizing river network layout—establishing comprehensive evaluation index system of river network layout—comprehensive evaluation is taken as the main line to evaluate and determine the importance of rivers and canals in river network. The overall layout of river network connectivity in the north, middle and south regions of Langfang is optimized and evaluated. The results show that there are large differences in the current layout of waterways in the three regions, with poor river network connectivity in the southern part of the Langfang. The overall layout of the optimized river network was improved by 13.0%, 3.0% and 12.4% compared to the overall layout in Langfang. The optimized scheme provides technical support and theoretical basis for the optimal implementation of the regional river and lake connectivity project in Langfang.

Research on full life cycle management in water conservancy engineering is currently limited, resulting in issues like improper project siting, high construction costs, and insufficient risk management capabilities. To address these challenges, this paper proposes an innovative management approach using the K-means clustering algorithm. This method leverages the K-means algorithm's simplicity and fast convergence to cluster and analyze diverse data from different stages of water conservancy projects. It then presents these clustering results visually to assist project managers in making informed decisions. Using the K-means algorithm in the planning and design stage of water conservancy projects as an example, we demonstrate its feasibility, efficiency, and scientific rigor in managing the entire project life cycle. The research findings indicate the following: The research results show that (1) In the planning and design stage, the K-means algorithm aids in making informed decisions about engineering construction sites by clustering and analyzing relevant data. (2) The improved K-means clustering algorithm exhibits high processing efficiency and accuracy when handling various types of water conservancy project data. (3) The K-means algorithm's application can span the construction, operation, and maintenance stages. It can cluster and analyze data related to material consumption, equipment usage, construction efficiency, and quality, ensuring compliance with quality standards, cost control, and project optimization. Additionally, it can be used to cluster and analyze data akin to water conservancy projects, like historical risk factors, aiding in risk evaluation and prediction.

By considering factors such as topography, meteorology, and hydrology, this paper examines the causes of flood and drought disasters in Binzhou City, located in Shandong Province, which serves as the central city of the Yellow River Delta, and summarizes recent flood and drought events. The analysis highlights weaknesses in the current flood and drought prevention system, particularly regarding systematic river management and flood control informatization. To address these issues effectively, this study proposes a set of measures to enhance Binzhou's flood and drought disaster prevention system, including prioritizing improvements in flood control and drainage standards, expediting key flood control projects’ implementation, strengthening river management, investigating potential risks of water conservancy projects, improving sea embankment construction while developing an intelligent platform for water affairs. These countermeasures aim to bolster Binzhou's comprehensive disaster prevention and mitigation capacity while reinforcing its water security.

In order to ensure the safety of urban drainage and alleviate urban waterlogging, this study focuses on the impact of dynamic river water levels on pipeline drainage. The region south of Yiwu River in Yiwu City was selected as the study area. Utilizing the Mike modeling platform, simulations were conducted to assess pipeline drainage outlets under heavy rainfall conditions with return periods of 2-year, 3-year, and 5-year. These simulations considered connections to both the river's normal water level and various flood scenarios based on different design frequencies. The study also analyzed the influence of changes in river water levels on the drainage capacity of the pipeline network and their impact on urban waterlogging. This research provides a reference basis for understanding the causes of urban waterlogging in the study area and its mitigation.

Hydraulic characteristics of rock plug blasting are the key to successful construction of rock plug inlet/outlet. In this paper, the hydraulic characteristics of rock plug blasting at the inlet/outlet of the lower reservoir of a pumped storage power station are studied by means of physical model test. The characteristic laws of water hammer pressure, surge of gate shaft and accumulation effect during blasting are obtained. The results verify the rationality of the design type of rock plug inlet, and demonstrate the feasibility of using gate direct water blocking scheme and high water level blasting during rock plug blasting. The research results can provide technical support for the design and construction of this project, and provide reference for similar projects.

Aiming at the optimal arrangement of pressure monitoring points in urban water supply network, with the goal of maximizing the monitoring range, an optimal arrangement model of monitoring points is constructed, considering the pressure correlation, node flow sensitivity and the effectiveness of the water flow path in the pipe network. Taking an urban water supply pipe network in East China as an example, the model is solved by three kinds of population intelligent algorithms: Krill Harvesting Algorithm (KHA), Bat Algorithm (BA), and Particle Swarm Algorithm (PSO). The optimization results of the three algorithms are compared in various aspects, and it is found that the KHA algorithm shows the most excellent search accuracy and efficiency in the problem of optimal arrangement of monitoring points, because of the strong global optimization ability and not easy to fall into local optimal solutions.

On the basis of 30-year observed ERA5 wind field analysis data, the wave changes around Hangzhou Bay are generated based on SWAN model. The wave rose diagrams of different locations in Hangzhou Bay have been drawn, the seasonal and interannual variation characteristics of wave height are analyzed. Several results are followed. (1) The direction of dominate wave located in the Hangzhou Bay head are NE and ENE, whereas the strongest wave direction is NE; Meanwhile, in the middle of Bay, the dominate wave direction, which on the northern side are E and ESE, in middle are ENE and E, and on the southern side are NE and ENE. The strongest wave direction from north to south are ESE, E and ENE respectively. In the inlet, the dominate wave direction, which on the northern side are ENE and E, in middle are NE and ENE, and on the southern side is NNE. The strongest wave direction from north to south are ESE, E and NE respectively. (2) The trend of mean significant wave height distribution is consistent all year round. It is diffused from the inlet to the top of Hangzhou Bay. The inlet is larger than the top, and the middle is larger than both sides. The quarterly average significant wave height varies from 0.36 to 0.40 m, while the mean value in autumn is slightly higher than those in other seasons. (3) In Hangzhou Bay, there is no vertical difference on annual mean wind speed of the latest 30 years, and the general trend is relatively stable. The variation tendency of annual mean significant wave height is consistent with that of annual mean wind speed. Also it is found that the correlation between them is good with the correlation coefficient of 0.77.

In this manuscript, a methodology for three-dimensional geological modeling and visualization in dredging engineering was proposed to understand and analyze the spatial distribution of soil conditions in complex underwater geological settings for dredging engineering comprehensive and enhance the operational efficiency of dredgers. A three-dimensional digitized platform for dredging engineering was established by using computer technology, database management, visualization techniques and 3D geological modeling. The intelligent system of dredging engineering geological database is mainly developed using the .NET as the program development platform and C# and C++ as language. This system realizes the functions of engineering geological data storage and management, 3D geological modeling, dredging engineering analysis, and so on. The practical application showed that the system boasts not only fast 3D modeling speed, strong operability and high conformity with the actual geological situation, but also the dredging engineering analysis module, which greatly improves the quality and efficiency of construction. It can meet the actual needs of dredging engineering well and has broad promotion and application prospects.