Abstract:In order to explore a new method for solving the problem of optimal operation of hydropower station, a new swarm intelligent optimization algorithm, i.e., wolf pack search algorithm, and its application to optimal operation of hydropower station were studied. The siege algorithm of the wolf pack search algorithm was improved. Design and solving steps of the wolf pack search algorithm for solving the problem in optimal operation of hydropower station were proposed. Based on the simulation test and analysis of the example of optimal operation of hydropower station, the effective range of the step on the raid of the wolf pack search algorithm was proposed. Simulation results show that the wolf pack search algorithm is new effective method for optimizing the operation of hydropower station.

Abstract:To analyze water use efficiency and water saving potential in China, based on the water conservancy inputoccupancyoutput tables of China and Haihe River basin in 1999, 2002 and 2007, we proposed a model to calculate water saving potential by sector compared with Haihe River basin, and a model to calculated the water conservation potential by sector. We applied the model in China compared with Haihe River basin and we found that the total water conservation potential of the national economy, compared with Haihe River basin, expanded from 1999 to 2007. Water conservation potential in the primary industry and the secondary industry was relatively large while water conservation potential in the tertiary industry and construction industry was small. In comparison with urban residents, rural residents showed more water conservation potential. Besides the agricultural sector, sectors, such as electricity, steam, hot water production and supply industry(without water electricity), chemical industry, metal smelting and rolling processing industry, paper printing and stationery manufacturing industry, food production and tobacco processing industry, among others, also showed great water conservation potential.

Abstract:Fecal Coliform (FC) concentration in surface waters, such as, rivers, lakes, reservoirs and coastal areas, of China was surveyed based on literatures published since 1980s. From the survey, the temporal variation and the spatial distribution of FC concentration is analyzed, and then influencing factors on distribution characteristics of FC are systematically discussed. The results demonstrate that FC concentration is generally high throughout the surface waters in China, which indicates that the waters suffer a severe microbial contamination. Rivers are most severely contaminated among different water bodies while reservoirs are cleanest. The concentration of FC shows significant inter-annual and intra-annual fluctuations, with the concentration in wet seasons being much greater than that in dry seasons. There is no obvious distribution pattern of FC concentration between southern and northern waters, while the FC concentration in eastern areas is obviously greater than that in western areas. The FC concentration in lower reaches of rivers is greater than that in the upper reaches, and the FC concentration near shore is greater than offshore. These indicate that human actions significantly increase the concentration of FC. Rainfall-runoff has a significant impact on the temporal variation and spatial distribution of FC. Besides, many other physical-chemical factors, including organic content, trophic level, salinity, and temperature of water are also responsible for the spatial distribution and temporal variation of concentration of FC.

Abstract:For existing problems in cooperation and development of international rivers, for example, insufficient information and poor communication within a river basin, in this paper it is explored the implication of transboundary monitoring mechanism. Furthermore, it is proposed a general mode of transboundary monitoring mechanism in terms of international river monitoring agreed framework, monitoring and management coordination organization, monitoring plan, execution, and feedback. Then it is presented the study cases of the transboundary monitoring mechanism for Rhine River, Danube River and other international rivers, it is also analyzed the present transboundary monitoring situation of main rivers in Southeast, Northwest and Southwest China. Finally, based on the joint monitoring experience of Rhine and Danube River basins as well as the joint monitoring situation between China and its neighboring countries, it is proposed several suggestions for China transboundary monitoring mechanism, i.e. establishing regional joint monitoring framework, improving the level of standardization and informatization of monitoring, and forming the multi-agent, diversified joint monitoring organization mode.

Abstract:By Combining the variation of meteorological factors, it is analyzed the impact of climate change on water requirement of main crops in Nanjing, China and it is presented some measures to address the impacts of climate change. For achieving this goal, water requirement of crops in Nanjing from 1951 to 2005 is calculated with the method of Mann-Kendall. Combining the variation of meteorological factors, the paper analyzes the impact of climate change on water requirement of main crops in Nanjing and put forward some measures to address climate change. The data show that the decrease of water requirement of summer crops, such as rice, cotton and corn, is related with the insignificant increase of summer temperature, increase of rainfall, drop of sunshine hours, and slowdown of wind speed. While the increase of water requirement of winter wheat and canola is mainly related to the highest growth rate of winter and spring temperatures, the effect of drop in sunshine hours and slowdown in wind speed is not enough to offset that of the increase in temperature and the reduction in humidity. The cropping system is affected by temperature, which may bring the increase of total crop water requirement. Thus, water-saving irrigation, especially water impoundment for controlling irrigation is necessary to reduce irrigation and drainage quota, weaken greenhouse effect and reduce the impact of climate change on the rice production.

Abstract:Based on maximum entropy distribution of the highest water level in weir, in this paper we present a simulation method of construction diversion risk that intuitively describes the diversion risk rate function of operational cofferdam and accurately assess construction diversion risk. In our method, the highest water level distribution density function is derived by using the distribution of flood peak and flood volume with the maximum entropy principle. Meanwhile, combining the discharge uncertainty of diversion buildings, the method stochastically simulates the highest water level sequence in weir. Then the method is employed to calculate diversion risk rate. The analysis shows that the simulated construction flood can well reflect the measured flood series. Moreover, the derived distribution density function of the highest water level in weir is reasonable, which can fully reflect true situation of recent measured flood in weir compared with traditional methods. On the premise of accuracy, this method improves risk calculation efficiency and applicability. Therefore, the method provides support for risk analysis and program decisions of construction diversion.

Abstract:A modal experimental study has been carried out on a new water and sediment separation device-circular rings desilting and sediment ejection basin. In this study it has been tested the velocity distribution of eight redial test sections respectively in radial, vertical and circular direction. The results indicate that the distribution of velocity and velocity gradient in the ring direction of circular rings is uneven and the largest numerical value emerges in 180° radial test section. Additionally, velocity and velocity gradient are inversely proportional to the radius in the radial direction, and surface water velocity is inversely proportional to water depth in the vertical direction. Besides, flow turbulence in the distance less than 1/2 radius is strong, while in other distance is weak. Furthermore, velocity in the central outflow ring reaches the maximum value of 7.3 times that of overflow weir inside, and the overflow weir length is 15 times that of central outflow ring. Overall, the experiment shows that the circular rings have better desilting conditions for the long overflow weir length.

Abstract:The load reducing method of the culvert with surrounding grouting and reinforcement is introduced to reduce the earth pressures and internal forces of highway culverts under high fills. Earth pressures and internal forces of the culvert with grouting and grouting covered with reinforcement are calculated by numerical simulations using finite element method, and the load reducing effects with different lateral grouting areas are compared. Additionally, the effects of geogrid stiffness, and the modulus of grouting on the earth pressures as well as internal forces of culvert are studied on the basis of parameter analysis. The results show that the grouting width surrounding the culvert wall is half of the culvert width, while the installation of geogrid reinforcement on the top of grouting area can further reduce earth pressures and internal forces. The increase of the geogrid stiffness makes very little effect on load reduction and the modulus in grouting area has a massive impact on earth pressures and internal forces. When the modulus is close to 100 MPa, earth pressures and internal forces reach at the lower values, which insignificantly decline as the increase of modulus.

Abstract:A modified four-parameter multi-axis equivalent strain damage model is presented based on a typical uniaxial tensile stress-strain curve model and four-parameter equivalent strain. To verify the concrete damage model, test results under six kinds of stress states, including uniaxial tension, uniaxial compression, biaxial tension, biaxial compression, biaxaial tension-compression, triaxial compression are compared with experimental results. With the concrete damage model, this paper numerically analyzed combined force situations of concrete shear tests and working performances of concrete gravity dams and concrete arch dams. The damage and stress distribution of these structures under static loadings are obtained and analyzed. The results showed that the numerical simulation results of shear tests coincide with experimental results. Therefore, the model can analyze the combined force situation with the shear as the main force and the model is suitable for the calculation under complex stress states. In addition, the reasonable damage and stress distribution rules of typical gravity dams and arch dams indicated that the model could analyze the working performance and safety of concrete dams.

Abstract:The computing model of Dynamic Watershed Simulation Model(DWSM) has some limitations, such as low robustness, long computing time, and inability to realize failure in a multicore computer. Therefore, in this paper, we improved the algorithms and storing rules. Based on the computational logic sequence of DWSM, we suggest to use the concept of basin subarea to design the tree structure model of river network instead of the hypothesis on virtual channel of the original calculation unit sequence table model. Also, we introduce the dynamic hierarchical parallel computing technology according to parallel computation of leaf nodes to improve the calculation model. Taking the Yellow River basin between Ningxia and Neimenggu as an example, the results show that the optimization of algorithm greatly improves the computational efficiency of DWSM as well as increases the applicability of calculation on water and sediment rules in the basins with large scale and complex structure of river network.

Abstract:Considering cyclic softening effect of soft soil foundation, cyclic strength of soft soil was embedded in the framework of the general finite element software ABAQUS by secondary development. Then, taking into account the pseudo-static analysis, it has been formulated a calculation model about the structural stability of the inverse T-type breakwater with jackets and pile foundations. Cyclic bearing capacities of the structures under action of wave load have been analyzed with the finite element method, and the influence of cyclic-softening effect of soft soil foundation on structural failure mode as well as the influence of structure size parameters on cyclic bearing capacity has been discussed. The results show that the cyclic bearing capacity of the inverse T-type breakwater with jackets and pile foundations is clearly lower than the ultimate bearing capacity without considering cyclic-softening effect of soft soil, and the rate of reduction is between 28.72％ and 41.20％ for the structure model. In consideration of the cyclic softening effect of soft soil, the failure mode of the structure may change from structure displacement for piles body yielding to structural failure caused by soil strength insufficient.

Abstract:In soft soil area, the large displacement usually occurs between the sluice pier and the wing, which results in seal failure and endangers the sluice's safe operation. Thus, in this paper, the whole sluice model was established with finite element method, and for the soil body, using the Drucker-Prager constitutive model considering soil body creep law. Thus, the reason of the displacement and the influence of connecting empty container in gate side on wings and pile foundation were explored. The results indicate that the groundsill linking empty container transition sluice and sea wall has improved the stress conditions of the pile foundation and effectively controlled displacement of the wing. Further, a reasonable empty container size can not only effectively control displacement, but also avoid project investment waste due to excessive size.

Abstract:In order to study changes in engineering properties of impervious soil with salt and to determine the critical value of salt content that conforms to design criterion, experiments were performed for testing physical, chemical, and mechanical properties of samples. These impervious soil samples were taken from river embankment and reservoir dam, and then they were mixed with various kinds and amounts of salt. The results show that the salt contents, in low liquid limit clay, all conform to the criterion with refined salt no more than 3.29％ and mixed salt no more than 2.99％. Within the tested salt content range, the permeability coefficients are all between 1×10^-7cm/s and 7.9×10^-7cm/s, which satisfy the criterion. Moreover, other indicators in experiments do change, but not much.

Abstract:The simulation of temperature control and crack prevention of large sluice under cold wave strike has low accuracy due to huge volume. To overcome this shortcoming, it is proposed a sub-master model correction algorithm. During the process of finite element calculation, the model was encrypted in space and time, and the results could be fed back to master model when the sub model finished the computations. The result of engineering example in Yucao Sluice showed that the influence on temperature of surface concrete is greater than internal concrete under cold wave of 5°C and 10°C, which leads to concrete crack; thus, taking appropriate measures can prevent crack. The result satisfied the need of construction and improved the speed of computations, which implies that the algorithm is reasonable.

Abstract:The storm drainage system model of Xincheng Park in Guangming New District of Shenzhen was set up based on InfoWorks ICM model. In this study the catchment area was divided respectively according to manhole and gully, and its effect on flow simulation results of park outlet was analyzed. The results showed that the selection of node-type had no obvious effect on peak flow simulation result in the condition of light or medium rainfall, while for storm or heavy rainfall the selection of node-type had great influence on peak flow. Compared to catchment division based on manhole, runoff-yielding time producing was delayed by dividing the catchment area based on gully. Therefore, research goal, regional scale and rainfall characteristics should be considered in the process of modeling to reasonably divide the catchment area.

Abstract:In this paper, it is proposed a new type of water-sediment separation device named sediment concentrated spiral tube (SCST), which is used in hydraulic fill. To confirm layout form of clear liquid discharge port—key components of the device, several tentative of clear liquid discharge port of SCST were investigated by numerical simulation and physical experiment. Considering the engineering applicability and efficiency of concentration, this paper selected the outside discharge port, whose discharge pipe was perpendicular to the main pipe, as the recommended clear liquid discharge port for SCST. Overall, the results showed: SCST, with the selected layout form, not only could improve sediment concentration for hydraulic fill, but also reduced the content of fine particles, as well as improved the engineering properties of fill sediment.

Abstract:In this study it is introduced the general packet radio service(GPRS) information communication method, which combining fiber sensors and common sensors, for the long transmission distance of safety monitoring engineering data in super long distance water delivery tunnel and different data formats(resulted from multiple sensors). And it is compared with the common information communication methods about safety monitoring system in hydraulic engineering practice. Besides, it is discussed the applicability and feasibility of the information communication method for super long distance water delivery tunnel as well as tested in an engineering practice in the Southwest China. Due to the fact that alternating current is not available for outdoor projects of super long distance water delivery tunnel, it is proposed the power supply mode of solar, wind, and electrical energy, which are able to meet the power supply demand of monitoring system for a long time.

Abstract:Landslide surge is a complex fluid-solid coupling problem that involves landslide kinetics, rock-soil mechanics, hydromechanics and other disciplines, and it has an important value in geological disaster research. Therefore, in this paper data of twenty typical landslide surges were collected and analyzed. Additionally, it is presented an evaluation of the large numbers of landslide surge forecast methods at home and abroad. The forecast evaluation methods of landslide surge are generally grouped into four categories, they are: empirical formula method, numerical analysis method, physical simulation method, and other method. Then the applicability, advantages and disadvantages of each method were discussed and analyzed. Further, based on the research status, limitations and development tendency, the outlooks of landslide surge research are proposed.

Abstract:This paper summarized geo-spatial interface for water erosion prediction project (GeoWEPP) model’s development process, technical framework, applicability and limitations, and then respectively described current research development of GeoWEPP from the standpoints of dynamic effect model (DEM) data, land use/cover change, management factors and soil factors. For the advantages and disadvantages combining with the research status of water erosion prediction model, this paper proposed development directions of the model and pointed out possibilities of development about GeoWEPP in five aspects：definition of the accuracy of DEM, transform of spatial scale, application in human activities center, combination with ecological process, and integrated development of WEPP and geographic information system (GIS).

Abstract:The basic theory and application value of extended finite element method(XFEM) are introduced briefly. The level set method for describing crack, the enrichment strategy of discontinuous displacement field, and the integration scheme of XFEM are presented with an example of crack problem(strong discontinuity) of reinforced concrete(RC), and recent achievements in these fields are exposed. Thereby, a summary of the situation of applications of XFEM in fracture machanics is given. On the basis of the foregoing, the research and application development of XFEM for the analysis of reinforced concrete structure crack are presented from two aspects: concrete cracking, and bond-slip between reinforcement and concrete. It is pointed out that element models, crack treatment, steel stress at crack section and other issues have to be further investigated in order to meet the requirements of characteristics of practical projects(e.g., hydraulic reinforced concrete structures), such as large scale, complex reinforcement, and multi-axial force state.

Abstract:The existing problems of hump air lock and water hammer in the projects of submarine water supply pipeline are harmful to the water supply target. Therefore, bubble theory and flow method are used to analyze the cause of hump air lock. By using method of characteristics, we establish a water hammer model caused by pump power failure in water supply pipeline, and introduce the protective measures against water hammer in submarine water supply pipeline. In addition, we point out that the integration of air tank and pipeline is possible for the special advantage of air tank in submarine water supply system. Furthermore, we introduce the mathematical model of air tank. Likewise, we observe that it is mandatory to ensure the submarine pipeline layouts on smooth terrain and pay full attention to the air tank protect technology, which are the keys to achieve safe operation of submarine water supply pipeline.