Aiming at the complicated law of specific energy along stepped chute and the low accuracy and limited application scope of current calculation method of water surface profile, a reliable method of calculating water surface profile was proposed. Based on hydraulic model test, this paper introduced the relative specific energy and made dimensional analysis. Then the dimensionless relative specific energy was systematically studied qualitatively and quantitatively. The results show that the dimensionless relative specific energy is related to the relative critical water depth, spillway slope and dimensionless position. The dimensionless relative specific energy has a good linear correlation along the stepped spillway. Based on the quantitative research results, the empirical formula of dimensionless relative specific energy calculation was given, and a new method of water surface profile calculation was obtained. The analysis of numerical example shows that the calculation method of water surface profile has high accuracy and wide application range, which can provide theoretical reference and technical support for the design of stepped chute.

In order to study the uniaxial tensile behavior of autoclaved aerated concrete blocks (AACB) in static state, the uniaxial tensile test of AACB with different densities was carried out. The tensile failure characteristics and failure mechanism of AACB were analyzed. The change rules of its tensile strength and elastic modulus under different densities were discussed, as well as the relevant formulas of the relationship between uniaxial tensile strength and porosity, compressive strength and splitting tensile strength. The experimental results show that the tensile yield strength and elastic modulus of AACB increase with the increase of density, but the tensile yield strain decreases gradually. The macroscopic failure of AACB under uniaxial tension is mainly controlled by the tensile damage mechanism of the material. It shows obvious brittle failure characteristics. Based on the ideal prediction model of porous materials and the regression analysis of test results, the semi-empirical formula and correction coefficient of AACB uniaxial tensile strength and porosity under the test conditions were fitted. The conversion relationship between AACB tensile strength and its compressive strength and splitting tensile strength was proposed.

The ecological and economic value of water resources is the unity of economic value, social value and ecological environmental value. It is of great significance to analyze the change rule of its value for rationally optimizing the allocation of water resources, promoting the sustainable development of the ecological and economic system of water resources. The emergy theory analysis method was used to calculate the ecological and economic value of water resources in Zhengzhou City from 2009 to 2020. Its time evolution law and influencing factors were discussed, and its future development trend was analyzed by R/S analysis method. The results show that there is a growing trend for water ecological economic value in Zhengzhou City on the whole. The value change is mainly affected by GDP, per capita disposable income, sewage wastewater emissions and other factors. The results show that the future trend in the past time series characteristics were positively related, namely, water ecological economic value in Zhengzhou City still showed a trend of growth in the future.

For underground powerhouse in high geostress area, the excavation of the lower powerhouse cavern after the completion of the pouring of the rock-anchored crane beam may have an adverse impact on the crane beam. Aiming at this problem, three-dimensional elastoplastic finite element method was used to analyze the stress and deformation, the stress of the anchor and the stability of the crane beam of an underground powerhouse during construction and operation period. The results show that in the high geostress field, the rock-anchored crane beam will have large deformation, and the joint surface between the beam and the surrounding rock will have large tensile stress. After the crane beam is poured, the stress and deformation of the beam will increase greatly in three stages. As the excavated part is far away from the beam, the stress and deformation of the beam will become gentle, and the safety factor of the joint surface between the beam and the wall will be large, which can provide a reference for the crane beam pouring and cavern construction in similar projects.

Accident pump-stopping water hammer is a technical problem that needs to be highly valued in long-distance pressurized water diversion projects. This paper carried out calculation and analysis of hydraulic transition process on the Oujiang River Diversion Project. The loss of power accident of four pumps under maximum lift was taken as control condition, and the loss of power accident of single pump was taken as verification conditions. The optimization of pump outlet valve closing law was taken as the main water hammer protection measure. The research shows that when the butterfly valve at the outlet of the pump refuses to operate, the pressure and flow in the pipeline fluctuate more violently than that of the single pump during pump trip accident, and the reverse speed of the pump does not meet the specification requirements. By adopting the two-stage broken line closing law of the pump outlet butterfly valve, a better water hammer protection effect can be obtained.

In order to study the deformation and internal force of concrete lining structure of expansive soil trapezoidal channel in northern Xinjiang, indoor test and numerical simulation were used to calculate expansive deformation of foundation soil. Based on the beam theory of elastic foundation, a mechanical model was established to calculate the deformation and internal force of concrete lining slab. The deformation and internal force of concrete lining slabs were calculated and analyzed after the operation of the channel with the initial moisture content of the foundation soil being 6%, 9%, 12% and 15%. The results show that the deformation and internal force of the concrete lining plate increase with the decrease of the initial moisture content of the foundation soil. When the moisture content of the foundation soil is 6%, the maximum expansive deformation of the channel floor and slope plate can reach 3.48 cm and 3.94 cm. When the initial water content is constant, the expansion reaction force is the largest at the foot of the slope, and the displacement and bending moment are the largest at the middle of the bottom plate. The displacement of channel slope plate is the largest at one third of the slope foot, and the bending moment is the largest at one sixth of the slope foot. Finally, according to the research results, two engineering measures of "anti-seepage and moisturizing" were proposed.

Carrying out quantitative assessment of regional water security is an important basis for water security diagnosis and scientific decision-making. To analyze temporal-spatial characteristics of water security in Gansu Province, an index system of 2 system layers, 6 criteria layers and 25 evaluation indexes was constructed. Based on the combination weighting method of improved AHP and entropy weight method, the weight of each index was calculated. The water security status of 14 cities (states) in Gansu Province in 2010, 2015 and 2020 was comprehensively evaluated by cloud model. The results show that the water security of each city (state) is on the rise in 2010, 2015 and 2020, and it is generally in the basic and relatively security level. The shortage of water resources and flood and drought disasters are the main restrictive factors that affect the water security in Gansu Province. Improving water resources conditions and modern water management level are the important measures to improve the water security in Gansu Province.

In order to investigate the influence of the bottom dip angle of contraction section of the dustpan-shaped inlet on the hydraulic performance of the passage, the physical model and hydrodynamic model of the inlet structure of the dustpan-shaped inlet were established. The Reynolds N-S equation and RNG κ-ε turbulence model were adopted to simulate the flow field of the passage with 5 different underside inclinations in the inlet contraction section. The results show that the bottom dip angle increases has a great influence on the velocity distribution of the inlet contraction section and the throat of the winnowed dustpan-shaped inlet passage, and the scheme of the bottom dip angle increases the density of the srteamline distribution and the curvature of the throat, with the increase of flow velocity, the hydraulic loss of the passage is large, and the velocity distribution uniformity of the outlet section of the passage is low; The scheme with small bottom dip angle makes the streamline distribution smooth and the throat streamline curvature becomes slow, the velocity decreases, the hydraulic loss of the passage reduces, and the velocity distribution uniformity of the outlet section of the passage increases; The magnitude of the inclination of the bottom surface of the intake contraction section has no obvious influence on the weighted average angle of the flow velocity of the outlet section of the passage. Hydraulic performance of passage with different bottom dip angles was analyzed. When the bottom dip angle of the inlet contraction section of the dustpan-shaped inlet passage is less than 3°, the water flow in the inlet passage is smooth, the hydraulic loss is small, and the flow pattern at the outlet of the passage meets the water inlet conditions of the pump impeller chamber.

In order to study the hydraulic characteristics of staggered stepped energy dissipaters with different slopes, the flow pattern, flow field, pressure field and energy dissipation characteristics of staggered stepped and rectangular stepped energy dissipaters with slope of 1:2.0 and 1:2.5 under different flow rates were compared and studied by using the method of numerical simulation and model test. The results show that with the increase of the slope of the staggered step dissipator, the three-dimensional vortex scale formed at the step groove increases, the water flow is violent and the water depth is large. The absolute value of the vertical pressure of the step is larger, and the range of negative pressure zone increases. The horizontal pressure distribution of the step under the two slopes is similar, and the closer the step is, the smaller the pressure is. The energy dissipation rate of stepped energy dissipaters with a slope of 1:2.0 is larger. The energy dissipation rate of energy dissipaters with the same slope has a nonlinear relationship with the flow rate. The larger the flow rate is, the slower the energy dissipation rate changes. The staggered stepped energy dissipater is more fully aerated and has higher energy dissipation rate than the rectangular stepped spillway. The conclusions can provide a theoretical basis for the structural optimization of staggered stepped energy dissipater.

Rainfall observations derived from 76 ground rainfall gauges from January 1, 2018 to December 31, 2020 were used to evaluate the accuracy of IMERG Final Run (IMERG_FR) and IMERG Early Run (IMERG_ER) in IMERG (Integrated Multi-satellitE Retrievals for GPM) products over the small Sancha River basin in Guizhou Province. This study aimed to explore the precipitation detection capacity of IMERG_FR and IMERG_ER on different time scales. Metrics for assessment include correlation coefficient (C_CC), relative bias (R_RB), root-mean-squared error (R_RMSE), probability of detection (P_POD), false alarm ratio (F_FAR), critical success index (C_CSI). The performance of IMERG was assessed at different time scale with different precipitation thresholds. The results show that the IMERG_FR and IMERG_ER have a certain precipitation detection ability in the small basin on the whole, and it still needs to improve the accuracy of IMERG products in estimating precipitation intensity.