The method of machine learning (ML) is introduced to predict the velocity distribution in the section of channel containing vegetation, and the interaction mechanism between water flow and vegetation is analyzed. Based on the physical relationship between variables, input and output terms of the ML have been obtained. Combined with the experimental data of non-submerged rigid vegetation model, four ML methods, namely BP neural network, RBF neural network, support vector regression SVR and random forest RF are used to learn and model the pre-processed data set. Finally, through the Borda number in fuzzy opinion centralization decision-making method, the four models are evaluated. The results show that the ML model can carry out adaptive modeling according to specific data, and has a good engineering application prospect. The simulation results of ML are in good agreement with the experimental results, indicating that the ML method can effectively predict the flow velocity distribution structure with vegetation. The BP neural network has the best overall performance, and the accuracy of the results can be improved by using four models comprehensively.

Based on the principle and method of MIKE series model and taking Yangzhuang-detetion Basin for example, and combined with the operation plan, the MIKE11 model of Xiao-Hong-he for the flood fall, the MIKE21 model of flood simulation for Yangzhuang-detetion Basin, and the MIKE FLOOD model are constructed. The model parameters are tested and verified by “6.26”&“7.13” flood in 2000. Three schemes of Yangzhuang-detetion are simulated, and three aspects are analyzed, which includes the situation of flood routing, flood discharge process and comparison with the original design dispatching scheme. The results show that the simulation is accurate and reasonable. The operation process of detention basin and the flood routing in it can be simulated effectively by using models based on MIKE, which serves as an important basis for relevant applied research of detention area.

The flood season segmentation is an important basis for dynamic control of water level during flood season. However, there are complex hydraulic connections between the upstream and downstream reservoirs for the cascade reservoirs. The results of flood season segmentation based on the natural inflow may not be objective. In this paper, a method of flood season segmentation for cascade reservoirs considering the influence of reservoir operations are proposed, in which the inflow of downstream reservoirs are recalculated by considering the operations of upstream reservoirs, and are used to derive the flood season segmentation. In the case study of the cascade reservoirs which consist of Tianshengqiao first class, Guangzhao, Longtan and Yantan reservoirs in the upper Xijiang River Basin, the natural inflow and regulated inflow are used to calculate the flood season segmentation respectively. The results show that: ① for the Longtan Reservoir, the start time of main flood season is delayed by 16 days, and the start time of late flood season is delayed by 1 day, ② for the Yantan Reservoir, the start time of main flood season is delayed by 18 days, and the start time of late flood season is advanced by 1 day.

Based on historical observation data and CMIP5 simulation data, the trend evolution and multi-dimensional attributes of meteorological drought in the upper and middle regions of Huai River Basin are studied by using humid index, Mann-Kendall and run-length theory under historical and future climate scenarios. The results show that: ①the drought frequency increased gradually from 1970s to 1990s, and the drought in the future would be concentrated in the middle and late 21st century; the annual drought frequency would be higher but the four seasons would be generally lower than the historical level; the drought frequency in the coming January-April would be higher than the historical level, and the drought frequency in May-December would be closer to the historical level. ② Only the spring and autumn seasons in history showed a slight trend of drought, but not significant; however, annual and seasonal drought indices in the future showing a general drought trend, especially in winter. ③ The order of drought intensity and drought months would be RCP 8.5 future. ④The drought intensity, the number of drought months and the maximum drought intensity of RCP 4.5 would fluctuate greatly, but the average drought intensity would relatively stable. The multi-dimensional drought characteristics under RCP 8.5 would show relative stability, and the four drought characteristic values would increase slowly in the future. The results would be of great significance for water resources strategic planning, flood and drought disaster prevention and management under climate changes.

In this study, the Changbei Industrial Park in Nanchang City is taken as an example to construct the SWMM model. According to the land nature, rainwater system distribution and regional area of the study area, it is divided into four different research areas for digital modeling. The waterlogging analysis and technical optimization of Changbei Industrial Park are carried out by means of a whole-local-integral system theory method to improve the standard of drainage and waterlogging control. The hydrological situation of different scale area is analyzed, and the waterlogging area of different degree is found out, and LID is added to improve the drainage and waterlogging control ability. Finally, the whole area is verified and simulated. The results show that there are different space scales under traditional conditions. The drainage standards of 1 year drainage, 5 years' drainage, and 5 years of LID increase to 5 years' drainage standards, and 5~20 a unequal drainage standards are improved to 5 years of drainage standards in all the degree areas. Through the overall regional verification simulation, the drainage standard of the whole study area is raised from 1 a to 3 a, and waterlogging control can be raised from 5 a to 20 a. At the same time, the research shows that the existence of the storage tank in the scale II can significantly improve the drainage standards, alleviate the load of urban pipes and canals, and provide reliable technical support for solving the urban waterlogging problem in Nanchang City.

In order to assess the impact of wetland on flooding in Zhangli River and offer guidance for project construction, a two-dimensional mathematical model is established to calculate the flow procession of wetlands combined with culverts after reasonable calibration by one-dimensional mathematical model. The results show that the wetland has an obvious effect on flooding control, and the culverts in wetland can obviously reduce circulation, which can reduce water level and flow velocity effectively. The research findings provide an effective way for river regulation and flood control for river regulation.

This paper takes Yinma River (below the dam site of Shitoukoumen Reservoir) as the research object. The numerical simulation of flood evolution is carried out by using MIKE 11, Mike 21 and Mike floor model coupling. Through the simulation of historical flood, as well as the calibration and verification of parameters in the model, further analysis of flood evolution and inundation in Yinma River flood protection area. The results show that the flood zoning space in the study area is reasonable, high simulation accuracy and good effects with Mike software. The results can provide important basis and support for the flood control department's risk assessment, risk avoidance transfer and flood risk map drawing and other disaster prevention and mitigation work.

In order to understand the characteristics of urban rainfall runoff pollution, a research is done to take samples and monitor several rainfall runoffs on five different underlying surface in Hanyang District, Wuhan City. The research results show that the pollution levels of COD and TN of urban main roads, branches and green spaces in Hanyang District are inferior to the water quality standards of Class Ⅲ, and the SS concentration is inferior to the first grade A standards of Urban Sewage Disposal. Plant Contamination Integrated Discharge Standard. Rainfall characteristics have a significant influence on rainfall runoff pollution: for specific sampling points, the greater the rainfall intensity and the longer the dry period before the rain, the higher the pollutant concentration of rainfall runoff (EMC). The scour effect is significant in the early stage when the rainfall intensity at a higher level with an early rainfall front and the rain peak is long before the rain dry period, and at the same time, the FF30 value of the rain event before the rain peak is larger.

By using natural disaster risk assessment theory and methods and based on meteorological data, geographic information data and socio-economic data, the index system for evaluation of flood risk in Zhejiang is established. By using the AHP method and weighted synthesis, flood risk evaluation model is worked out. With GIS technology, the sensitivity of the disaster environment, the risk factors of flood disaster, the exposure of disaster bearing body and the ability of disaster prevention and resilience and integrated risk index in Zhejiang are calculated and flood risk in Zhejiang is zoned. By using correlation analysis method, the consequence of flood disasters and historical data of flood disasters in Zhejiang are compared and verified. The results show that the distribution of results of flood risk is basically consistent with spatial distribution of flood disaster losses, the risk in the eastern coastal areas and parts of the west of Zhejiang is higher, while the risk in the northwest of Zhejiang is lower.

Water and soil resources are the core of sustainable agricultural development. The rational use of water resources affects the way of land use. In order to analyze the matching situation of agricultural water and soil resources in Xinjiang, this study uses the matching coefficient method to reveal the spatio-temporal variation of water and soil resources coupling in 14 cities, states and cities of Xinjiang from 2008 to 2017. The results indicated that the matching coefficient of agricultural water and soil resources in Xinjiang increased from 2008 to 2017. The amount of water resources per unit area in northern Xinjiang is greater than that in southern and eastern Xinjiang. The matching coefficients of agricultural soil and water resources in Kizilsu Kirghiz Autonomous Prefecture, Altay region, Ili Kazakh Autonomous region, Urumqi City and Hetian region are increased significantly, while that in Bortala Autonomous Prefectureand Kashgar decreased significantly from 2008 to 2017.

In order to analyze the temporal and spatial variation characteristics of water environment quality in Qinhuangdao City, the monitoring data of COD, NH+4-N, TP and permanganate index of 17 monitoring sections in Qinhuangdao City were collected monthly in 2017. The water environment quality is evaluated by single factor evaluation and principal component analysis, and the causes of pollution are analyzed by combining the land use structure. The results show that: ①In time, TP and NH+4-N pollution is serious in spring and winter, but relatively low in summer and autumn, and the water quality in flood season is better than that in non-flood season on the whole. ②In space, 64.7% of the monitoring sections' water quality are inferior type Ⅴ. The pollution of Jian River, Yinma River and Tang River are relatively serious, and the pollution degree of downstream coastal rivers is greater than that of upstream rivers. ③The correlation between pollutant concentration and land use structure shows that human land use is the main cause of water pollution in the study area, and the increase in natural land area such as woodland and grassland is helpful to alleviating water pollution.

The Yanjin River is the main source of water supply and pollution receiving water in Renhuai City, Guizhou Province. At present, the pollution of the Yanjin River is serious, and the water quality is far from its target requirements, which, to a certain extent, brings hidden dangers to the safety of local industry, agriculture and residents. This paper takes the Yanjin River as the calculation object, collects and analyzes the local hydrological data, and conducts the investigation and analysis of the pollution sources along the river, and determines the indicators for calculating the allowable assimilative capacity as COD, NH3-N and TP. According to the characteristics of the water function area, the division of the control units are carried out, and on this basis, the pollution source prediction is carried out for the planning level year (2030). The allowable assimilative capacity of all control units are calculated by using the one dimensional water quality model and the allowable assimilative capacity model. The calculation results show that the values of allowable assimilative capacity of the Yanjin River are negative. According to the current situation of Yanjin River pollution, the corresponding water pollution prevention and control suggestions are proposed in the planning level year. After the implementation, the COD reduction is 722.3 t/a, the NH3-N reduction is 97.2 t/a, and the TP reduction is 9.3 t/a. The Yanjin River has reached its ecological goal. This paper can provide reference and scientific basis for the local water environment management.

Based on the long-term observation data and related statistical data of groundwater depth in Pingluo County from 2007 to 2017, the temporal and spatial variation characteristics and driving factors of groundwater depth in Pingluo County are analyzed by using the methods of trend analysis, geo-statistical analysis, principal component analysis and multiple linear regression analysis. The results show that: ①the groundwater depth in Pingluo County has been declining in the past 11 years on the whole, and that in Helan Mountains has been declining more obviously. The groundwater depth in the butterfly depression of the West Beach and the low-lying area of the North has slightly declined, while the inter-annual variation in other shallow groundwater areas is not obvious. ②The groundwater depth fluctuates in a two-peak pattern within a year, and the fluctuation range is obvious. Between 0.51~1.19 m, there is obvious seasonality. ③The groundwater depth varies greatly from east to west in spatial distribution, with little difference between north and south, and there are shallow buried areas in some low-lying areas. ④The change of groundwater depth in Pingluo County is mainly influenced by the anthropogenic factors such as the water diversion from the Yellow River and the area of crop cultivation. Rainfall, temperature and other environmental factors have little influence on groundwater depth.

In order to solve the problem of poor removal of phosphorus and ammonia nitrogen in runoff by bioretention facilities, four groups of filling layer improvement devices are installed. The ratios of gravel, red loam, steel slag and rice husk carbon in the packing layer of the device are: 1#, 80%∶10%∶10%; 2#, 80%∶3%∶17%; 3#, 90%∶3%∶7%; 4#, 85%∶5%∶10%. By using the laboratory simulation of rainfall runoff, the phosphorus and ammonia nitrogen concentration, pH and the permeability coefficient of the four devices are measured to determine the best removal rate of phosphorus and ammonia nitrogen in the modified bioretention devices, and the optimal ratio of the filler layer. The results show that the combination of steel slag and rice hull carbon has an effect on the removal of phosphorus and ammonia nitrogen. The removal of phosphorus and ammonia nitrogen in the 4# device is stable, the average removal rate of phosphorus and ammonia nitrogen is more than 85%, and the effluent pH and permeability coefficients are in compliance with relevant regulations. The proportions of gravel, red loam and combined filler are selected as 85% and 5%. 10% is the optimum filler ratio of modified bioretention facilities.

In order to study the characteristics of the production and discharge coefficient of rural domestic water pollutants in Yan'an area, 30 households in 3 typical towns in Luochuan County, Yan'an City are selected to conduct three investigations and analysis on rural domestic water pollutants in high flow period, level period and dry period. Abnormal values are removed from the survey data by using the Grubbs test. The survey results show that the types of toilet for farmers in the survey area are all aqua privies. The discharge of domestic sewage in the investigated area is 12.25 L/(person?d). The ratio coefficient of water consumption to discharge obtained is 0.73, and the discharge coefficients of CODCr, BOD5, ammonia nitrogen, total nitrogen, total phosphorus, animal and vegetable oils are 21.03, 10.71, 0.06, 0.29, 0.04, 0.07 g/(person?d), respectively. SPSS analysis shows that water consumption is positively correlated with BOD5, ammonia nitrogen, total nitrogen, total phosphorus, animal and vegetable oil discharge coefficient, and economic status is positively correlated with the ratio coefficient of consumption to discharge and CODCr discharge coefficient. This survey provides data support for the first general survey of pollutants in rural domestic water in Shaanxi Province.

In order to explore the effects of biochar on soil structure and fertility, five biochar additions, 10, 30, 50, 70, 90 t/hm2, were selected with a 0 t/hm2 as the control treatment. The soil structure and the status of potassium are analyzed from the perspective of soil aggregates combination and different kinds of soil potassium contents. The results show that the biochar affects the structure of soil mechanical stability agglomeration of Yangling, and significantly changes the mechanical stability aggregate combinations whose sizes are 0.5~0.25, 5~3 and 7~5 mm. Biochar increases the stability of soil mechanical agglomerates. However, biochar has no significant effect on the stability of water-stable aggregates. Available potassium ions, effective potassium, exchangeable potassium ions and water-soluble potassium ions are exponentially related to biochar additions. Biochar increases lettuce yield significantly, with every plant added 0.33 to 2.23 g. Considering the cost of biochar, it is wise to use 30 or 50 t/hm2 biochar in Yangling area in Shaanxi.

Because the impeller passage of low specific speed centrifugal pump is long and narrow, there is strong vibration in the process of operation due to the high head. In this paper, based on the steady-state analysis of impellers with different deflection angles, six measuring points are added to the volute of centrifugal pumps by using the signal processing method of unsteady calculation, and the time-domain and frequency-domain curves of impellers with - 10 °, - 5 °, 0,5 °, 10 ° deflection are obtained. By comparing the time-domain and frequency-domain curves, the way to reduce the pressure fluctuation of centrifugal pump is obtained. The results show that the fluctuating pressure distribution is related to the passing frequency of the blades, and the variation of the pressure fluctuation of each section caused by the offset of the splitter blades in different directions is different. In the case of counter clockwise offset, the pressure changes in the time domain of each section are mainly concentrated on the wave valley, and the addition of short splitter blade does not reduce the pressure fluctuation amplitude. In the case of clockwise offset, the pressure fluctuation amplitude of each section in the time domain decreases, and the overall optimization of the pressure fluctuation is the most stable under the scheme of clockwise offset of short splitter blade of 5 °.

In order to explore the effects of integrated water and fertilizer on soil moisture and apple growth in the arid regions of central Ningxia, the apple irrigation system suitable for the region is obtained. The experiment sets low water (W1) 2700 m3/hm2, medium water (W2) 3 450 mm3/hm2 and high water (W3) 4 200 m3/hm2, and three fertilizer treatments: low fertilizer (F1) 555 kg/hm2, medium fertilizer (F2) 675 kg/hm2 and high fertilizer (F3) 795 kg/hm2, a total of 9 treatments. The results show that the soil moisture changes significantly after each irrigation. With the increase in irrigation amount, the soil moisture of each layer increases correspondingly, and the soil moisture of each layer changes around 60% of field capacity. The soil moisture of the 20~60 cm soil layer is the largest, and the maximum soil moisture varies from 8.6% to 28.7%. With the advancement of the growth period, when the amount of fertilizer is the same and the irrigation amount is different, the chlorophyll content differs slightly. When the same irrigation amount and fertilization amount are different, the chlorophyll contents of each treatment increase with the increase in fertilizer application amount. The yield of apples increases with the increase in irrigation water and fertilizer, and the amount of fertilizer has a greater effect on the yield of apples than the irrigation amount. Based on the yield and quality of apples, it is concluded that in the Pingshui type (P=50%), the optimal irrigation scheme of 5~6 years new red star apple of integrated water and fertilizer is T5. Under this treatment, the yield of new red star apple is 6 237~8 318.85 kg/hm2, water production efficiency is 1.21~1.60 kg/m3.

Keeping constant of the gap between back cover plate and pump shell，and four different impeller schemes of centrifugal pump are designed by changing the width of back-blade. CFD simulation is used to calculate the full flow passage of the pump under various schemes，and the influence law of the width of the back-blade on the external characteristics of the centrifugal pump and the flow field distribution of the rear pump cavity is obtained. The results show that the area and value of the low pressure in the back-blade passage decrease first, and then increase with the increase in its width. The pressure gradient in the rear pump cavity is uniform. At 0.85 times the impeller radius, the pressure reaches the minimum. When the back-blade width is small, the streamline in the passage of back-blade is basically annular, and the liquid flow is relatively smooth. There are low-speed vortices in the flow passage of back blades, and vortexes that rotate in the opposite direction to the impeller. The larger the back-blade width is, the more obvious the vortexes are. Back-blade not only increases the pump head and shaft power consumption, but also reduces the efficiency of the pump. Its width has a great influence on the change of efficiency and shaft power, but the variation of head is not obvious. The research can provide a reference for controlling back-blade width in practical projects.

The calculation expression of the normal depth of the cubic parabola-shaped channel is a transcendental equation and contains an integrable function, which cannot be directly solved. The Gauss-Legendre qua-drature is used to establish the three-point format and four-point format expression for calculating the wet period. By introducing the concept of characteristic water depth, the basic equation of the normal depth of the cubic parabola-shaped channel is mathematically transformed to obtain the implicit function equation of the characteristic water depth. Based on the concept of quasi-quadratic function and regression analysis under logarithmic form, two sets of explicit calculation formulas for normal depth are proposed. Compared with other calculation formulas and error analysis, the absolute relative errors of the two explicit formulas are 0.41% and 0.36%, respectively, which is higher than the accuracy of the existing calculation formula, and the formula is simple in structure, clear in physical concept and wide in scope of application. When the calculation accuracy requirement is high, it is recommended to use the explicit formula 1 calculation; when simplicity is high, this paper suggests using the explicit formula 2 calculation.

In order to study the erosion of the pressure surface of the double-suction centrifugal pump, the Euler-Lagrange multiphase flow model is used to simulate the water and sand movement in the flow path of the centrifugal pump, and the discrete phase model is used to simulate the wear of the particles on the flow parts. In the case, CFD is used to simulate the full flow channel of the 800S-76 pump. By analyzing the characteristics and distribution of solid particles in the impeller flow passage, we know that the erosion at the end of the pressure surface of the blade is due to the high solid particle accumulation rate and the relative velocity of the solid particles, thus increasing the interaction between the solid particles and the blade. Secondly, through the tracking of the solid particle trajectory in the impeller flow channel and the analysis of the vortex in the flow channel, the influence of the flow vortex on the trajectory of the sediment particle and the structural characteristics of the flow vortex are studied. The results show that the distribution of solid particles and the relative velocity are important factors affecting the wear of the end of the pressure surface of the blade and that the flow vortex affects the particle trajectory in the flow channel, which indirectly affects the distribution of the impeller wear area. The research findings can provide a guidance for the optimization and transformation of the double suction centrifugal pump impeller, and have some reference significance for the wear research.

In order to investigate the changes of stem flow rate and the relationship with meteorological factors under different fertilization treatments, the “Hutai 8” grape is used as the research object to monitor the stem flow rate and meteorological factors simultaneously. The results show that the stem flow of the grape shows an obvious diurnal variation, and the daily variation curve shows several shapes. The stem flow rate and daily accumulation under different fertilization treatments are: medium fertilizer> low fertilizer> high fertilizer. On a cloudy day, the stem flow starts and the peak is later than that on a sunny day. The stem flow rate is positively correlated with net radiation, saturated water vapor pressure difference and temperature in different climates, but negatively correlated with relative humidity. Different fertilization amount would change the response of stem flow rate to meteorological factors. Net radiation is the main meteorological flow rate under different treatments. The impact facto and the coefficient of determination are all above 0.791.

In order to clarify the photosynthetic characteristics，yield and water use efficiency of winter wheat in response to drought and rewatering， “ZhouMai 22” is selected as the test material by controlling the water of the wheat in bucket under a rainout shelter. On the basis of safely wintering different water control conditions are applied for the jointing stage and the heading period，which are 70%~80% of the water holding capacity of the field (complete irrigation)，60%~70% (light drought)，50%~60% ( medium drought)，40%~50% (heavy drought). The photosynthetic characteristics，yield and water use efficiency (WUE) of winter wheat are investigated to explore the mechanism of drought and rehydration of crops so as to provide theoretical and technical support for drought resistance，high yield and stable yield of winter wheat. The main results are as follows: ①The trend of net photosynthetic rate (Pn) and stomatal conductance (Gs) remains highly consistent，both of which decrease significantly with the increase in drought and the increase in drought time. The effects of drought on different growth stages are as follows: continuous drought> heading stage> jointing stage. After rehydration，only single-stage light drought treatment can return to normal levels，and the degree of recovery at the heading stage is the highest. ② The threshold of drought degree for non-stomatal limiting factors under short-term drought conditions is heavy drought，and the threshold for long-term drought conditions is moderate drought. ③ In contrast，short-term light drought and yield reduction are not significant，and the yield decreases significantly with the increase in drought degree and drought time. The drought at the heading stage is higher than that at the jointing stage. After experiencing light drought and re-watering，the water use efficiency of winter wheat is significantly improved. According to the comprehensive study，short-term light drought in winter wheat can increase water use efficiency without significantly reducing yield，and the compensation effect is higher after drought rehydration at the heading stage，and continuous drought should be avoided.

To quantify the effects of different salinity irrigation water on the growth process of summer squash, the logistic, Mitscherlich, Gompertz, Korf and Richards models are used to simulate the growth process of summer squash, and the model simulation effect is analyzed and evaluated, and the influence of irrigation water salinity on the phenological parameters and growth parameters of summer squash is further revealed. The accuracy of dynamic process simulation is as follows: Logistic > Gompertz > Richards > Korf > Mitscherlich. Logistic model should be adopted in the quantitative description of the growth dynamic process of summer squash. The starting and ending time of linear growth phase of summer squash under different irrigation water salinity treatments are as follows: K5.1>K3.5>K1.7, and the length of linear growth period is as follows: K1.7>K3.5>K5. The average linear growth rate and maximum linear growth rate of zucchini after different salinity treatments are as follows: K3.5>K5.1>K1.7, and the linear growth amount is written as K3.5>K1.7>K5.1.

In order to study the water flow characteristics in the urban storm water pumping station with slanted intake, this paper improves the adverse flow pattern and the water distribution uniformity of the diversion structure. Based on the VOF model in multiphase flow theory of ANSYS CFX software and the RNG k-ε turbulence model, the flow pattern of the diversion structure and its water distribution uniformity are simulated. Both rectification measures applied to the diversion structure and numerical results are verified by physical model test. The results show that there are flow mal-distribution and some adverse flow patterns in the diversion structure, e.g. backflow, vortex flow, which is caused by the inflow from oblique culverts, affecting the security of station. The rectification measures, including splitting-flow pier, beam and expanding angle piers, improve the flow pattern and the uniformity of the flow distribution. Furthermore, physical model tests verify effectiveness of rectification measures and reliability of numerical method.

Reasonable water pricing and water charge collection mechanism is the key to the management of rural water supply projects. Through the investigation of 1 262 projects located in 6 areas of the country, the characteristics of water pricing and water charge collection situation is compared in different regions, different scales and different management subjects. Based on the analysis of the advantages and disadvantages of the current projects in scale development, water price calculation and professional management, Some suggestions are put forward, such as establishing water price calculation method, determining water charge collection method, improving management level, perfecting supervision and compensation mechanism.

This paper adopts TAW-3000 three-axis servo multi-field coupling test system, triaxial compression test of fine-grained marble samples subjected to different thermal cycles under different confining pressures，then compares the variation of peak strength, peak strain and elastic modulus of marble under different conditions. Thermal cycle is heated from room temperature to 400 ℃ at a rate of 10 ℃/min and then kept at a constant temperature for 4 h, and then room temperature is regained slowly. The number of thermal cycles is set to 0, 1, 2, 4, and 8 times, and the confining pressure is set to 0, 5, 10, 15, 20, 25 and 30 MPa. The results show that the physical and mechanical properties of the rock samples undergoing thermal cycling are significantly degraded, and the peak stress and elastic modulus are reduced to varying degrees, and the higher the number of thermal cycles is, the greater the reduction is. The peak strain increases as the number of thermal cycles increases, but the rate of increase gradually decreases. After the confining pressure is set, the mechanical properties of the rock sample are obviously improved. The peak stress, peak strain and elastic modulus increase with the increase in confining pressure.

The 3d numerical simulation of static penetration process of concrete sheet pile structure is carried out based on the CEL method (coupled Euler-Lagrange) in ABAQUS, the failure mode and the development law of resistance in the process of sheet pile penetration are studied, and quantitative analysis of resistance reduction effect is made from two aspects: presetting edge foot of pile bottom and soil drilling. The results show that there is a great difference between the soil failure modes of flat bottom pile and sheet pile with edge in the penetration process, the former obvious plastic penetration zone during penetration, the latter is mainly impingement failure, but there is no plastic through zone connecting the ground.The total penetration resistance can reach 2.3MN without resistance reduction measures, and for sheet pile structure, pile side friction resistance occupies an absolute proportion at the later penetration stage. The reduction effect of preset edge foot is limited，under the circumstances of 60 degree edge foot, 50 degree edge foot and 40 degree edge foot, the total penetration resistance decreases by 13.04%, 17.39% and 26.09% respectively. The resistance reduction effect of soil drilling is obviously better than that of preset edge foot, in which the total resistance decreases by 26.09%, 34.78%, 43.48% and 56.52% respectively when drilling ratios are 31.4%, 47.1%, 62.8% and 78.5% (corresponding to drilling 2, 3, 4 and 5 holes). Considering the amount of work and some projects requiring the use of friction, 47.1% and 62.8% drilling ratios are recommended. At the initial stage of penetration, the resistance reduction effect is obvious. With the increase in penetration depth, the drag reduction effect generally presents a law of first decline, then rise, and then stability.

In combination with the engineering practice of a bulb tubular turbine hydropower station, a finite element model of the ground powerhouse structure including bed rock is established in this paper. Considering contact nonlinearity, the bearing characteristics of the first and second stage concrete of the powerhouse flow channel under different interface treatments are analyzed. The results show that it is beneficial to improve concrete integrity by implanting steel bars on the first and second stage concrete joint surfaces or embedding the second stage concrete in the first stage concrete. These treatments are effective in reducing the tensile stress and the displacement of the second stage concrete. This paper suggests adopting the embedded scheme for the joint surface of the first and second phases of concrete, and considering planting reinforcement to fully exert the bearing capacity of the first stage concrete and ensuring the safe and stable operation of the unit.

In recent years, PS-InSAR and SBAS-InSAR time series analysis techniques have been widely used by effectively overcoming the shortcomings of traditional D-InSAR technology, such as loss of coherence and serious influence by the atmosphere. The InSAR time series analysis approach has improved the accuracy for surface deformation monitoring (up to mm level) and its reliability greatly, but the monitoring results are still limited by the quantity and spatial distribution of persistent scatters on the ground. In order to fully express the deformation information of the study region, this paper intends to exploit 27 scenes Sentine1-1A satellite C-band SAR data covering the Xiaolangdi dam site area during the period between October 2017 and October 2018. With efficient DS-InSAR technique, the high-space coverage and high-density time series deformation monitoring results of the Xiaolangdi dam has been obtained. The result shows that the deformation of Xiaolangdi dam has the obvious spatial heterogeneity. Besides, there is a certain correlation between deformation and the water level elevation change in the reservoir area. Among them, the displacement characteristics in the middle-upper part of the dam are the most significant, which can reach -10 mm/a in LOS. With the continuous improvement of the spatial and temporal resolution of SAR imagery and InSAR time-series technology, InSAR approach would have widespread application value and the prospects for dam safety monitoring.

Hydraulic interference occurs in a power plant with one pipe and multiple machines, which is a special transition process between large fluctuation and small fluctuation. In order to study the influence of the parameters of surge tank on the regulating quality of the unit under the condition of hydraulic interference, two typical hydraulic interference conditions are selected, and numerical calculation and analysis are carried out for different combinations of parameters of surge tank and two different regulating modes. The results show that the area of impedance hole has a great influence on the regulating quality of the unit under the condition of hydraulic interference. When d=2.7 m is selected, the unit can be operated normally. When the maximum output swing of the unit is small, it can also regain the stable state in a short time. When the large well area of the surge chamber is large, the disturbed unit can regain the stable operation state in a short time. The flow coefficient of the impedance hole has little influence on the regulating quality of the normal unit under the hydraulic interference condition.

The deformation of the concrete face rockfill dam (CFRD) mainly occurs during the construction stage and the reservoir impounding process. The dam deformation caused by the reservoir impoundment affects the deformation of the concrete face directly after the completion of the construction of concrete face. In order to avoid or reduce the adverse effect of impoundment on the concrete face, this paper analyzes the impact of reservoir impoundment on the dam deformation. According to the monitoring data of the Shuibuya concrete face rockfill dam, the deformation increment caused by reservoir impoundment is analyzed, and the spatial distribution rule of deformation increment is discussed. The results indicate that the influence degree of dam deformation affected by water impoundment gradually decreases along the river direction, and the higher the dam body, the lower decrease in the level of influence. The deformation of dam above about 1/2 height is more susceptible to impoundment. The distribution characteristics affected by impoundment of the horizontal displacement and the settlement are similar, but the settlement is more affected. In addition, the influence area of the initial impoundment is preliminary investigated. The result of the work can provide a useful reference and guidance for the optimization study of dam partition and dam deformation control.

This paper considers the technical characteristics of the main types of ship lift structure and the construction conditions as well as technical requirements of the shiplift of Langshitan Hydropower Station and proposes a post-dam dry transport vertical ship lift that combines the main technical features of dry transport vertical ship lift and wet transport vertical ship lift. The utility model has the advantages that the vertical ship lifter and the dam top traffic do not interfere with each other, the metal structure equipment is simple and the operation and maintenance difficulty and the workload are small. It also has broad application prospects in the construction of low-head water conservancy hubs with large water-level differences in floods and normal water storage levels and the construction of existing water conservancy projects that need to restore or renovate navigable buildings.

Fishway is an artificial passageway to help fish migrate and lay eggs. However, at present, owing to bad flow patterns, undesirable results of inducing fish at the intake and so on, the rate of fish passing through the completed fishhway is low. Therefore, it is of great significance to study the hydraulic characteristics of fishway. The fluent software is used to establish the mathematical model of double vertical seam fishway, and the hydraulic characteristics for the fishway with 10 sets of different slot widths is carried out. The results show that the width of vertical seam has an great effect on the structure distribution of flow field in the pool, the shape of mainstream and velocity characteristics of vertical slit section of double vertical seam fishway. When the relative width of the vertical seam is between 0.06 and 0.125, the flow field structure of the fishway is reasonable, the effective utilization rate of the main stream is high, the attenuation of the main stream is good, and the velocity distribution of the vertical seam section is relatively uniform.

Parameter estimation is an important part of system identification, and the final accuracy of modeling is determined by the effectiveness of its method. Hydraulic turbine regulating system is a complex non-linear system, and its parameters will change with the operating conditions. At the same time, the actual measurement signal is affected by the environment and is mixed with irrelevant information such as noise, which will increase the difficulty of parameter identification. Therefore, the applicability and accuracy of the parameter identification method for different operating and testing conditions, and the identifiability of the parameters are worthy of a further study. Based on a variety of intelligent optimization algorithms and two experimental conditions, the effectiveness and accuracy of each identification algorithm under various identification scenarios as well as the identifiability of parameters are compared and studied in this paper. The results show that the biogeography-based optimization algorithm has high and stable performance under various identification conditions.

Rockfill, soil and sediment are common granular materials in reservoir and dam engineering. Discrete element method (DEM) is used to simulate accumulation process of granular materials. Fractal theory is employed to analyze how particle size and friction coefficient of particles affect lateral force distribution. The lateral force distributions obtained from DEM and Rankine's earth pressure theory are compared. The results show that differences exist between lateral force distributions obtained from DEM and theory. As particle size and friction coefficient of particles increase, the differences become more obvious. However, the locations of resultant lateral forces obtained from DEM and theory are almost the same. Due to the inner arch structure effect in the accumulation of particles, the lateral force distributions obtained from DEM are zigzag and discontinuous. Some lateral forces increase rapidly compared with their neighbor forces, which should be considered for the engineering design. The distributions of lateral forces and force locations obtained from DEM are fractal. The fractal dimension of lateral forces is not affected significantly by the particle size and friction coefficient of particles, the values of which are 1.17~1.29. With the increase in particle size and friction coefficient of particles, the fractal dimension of force locations decreases, which means that the force locations tend to be more intensive and more forces will intensively act on some parts of the lateral wall.

How to identify the resource points with gentle terrain, low available water head, more inundated immigrants and slightly poor development conditions through 1~2 surveys, and how to do a good job in the early stage of analysis and demonstration, and how to choose the appropriate development mode are more complex issues, and also the key for central enterprises investing in the overseas hydropower market. Combined with the experience and lessons of individual preliminary investigation and identification of multiple hydropower resources, the surveyor systematically introduces the investigation and identification of overseas hydropower resources and the analysis and demonstration of its exploitability.