To study the diversion risk of pumped storage power station construction under extreme rainfall, based on the idea of system risk analysis, the Copula-Monte Carlo method for diversion risk prediction was proposed by considering the correlation between upper and lower reservoir inflow. Joint distribution of the upper reservoir extreme rainfall and the lower reservoir flood volume was constructed to simulate the construction flood process caused by extreme rainfall. According to the characteristics of the upper and lower reservoirs diversion engineering, the risk model of the diversion system in the pumped storage power station was established to simulate the risk rate by considering hydrological and hydraulic uncertainty. Finally, a pumped storage power station under construction in southwest China was taken as an example, the results show Gumbel-Copula joint distribution fits the construction flood well in extreme rainfall cases, the diversion system risk rate is higher and more realistic when considering the correlation. It provides a reference for pumped storage power station construction diversion scheme selection and flood standard design under extreme rainfall.

Scientific evaluation of flood resource utilization potential is an important prerequisite for carrying out flood resource utilization in the basin and alleviating the contradiction between supply and demand of water resources. To evaluate the potential of flood resource utilization in different sections of the Xizhijiang River Basin, the SWAT model was constructed to simulate the natural runoff process of Xizhijiang River Basin, and the flood resources of the basin were quantified by combining the limit analysis theory. The potential of flood resources utilization in the upper, middle and lower reaches of the basin was evaluated, and the feasibility of flood resources utilization in Xizhijiang River Basin was discussed based on the water quality conditions. The results show that the SWAT model has good applicability in runoff simulation of Xizhijiang River Basin; The inter-annual distribution of flood resources is uneven, and there are great differences in inter-annual flood resources utilization potentiality. The utilization condition of flood resources in the lower reaches is better than that in the upper reaches, while the utilization rate of flood resources in the lower reaches is lower. The average annual current and theoretical utilization potential of flood resources in the lower reaches are 3.48×10⁸m³ and 7.97×10⁸m³, respectively. The water quality indexes of the main stream of Xizhijiang River Basin are not lower than the class Ⅲ standard, and the utilization of flood resources in Xizhijiang River is feasible. This study can provide support for the optimal allocation of flood resources in Xizhijiang River Basin, and it has an important reference value for achievement of high quality development of the basin.

Regarding the impact of the construction of the Guotan Hub of the Tanghe Navigation Project on the flood control safety of the river channel, the design flood of Guotan Hub was calculated through measured flood data of hydrological stations and linear interpolation method. According to the measured cross sections and thalwegs over the years, the river channel scouring and silting evolution and evolution trend prediction were analyzed. The water surface profile of a river was calculated using the energy equation of a constant non-uniform gradient flow equation. The second-order RungeKutta method of a two-dimensional model was used to simulate the impact of construction projects on the flow field during river flood discharge. The results indicate that the Guotan Hub of the Tanghe Navigation Project has a relatively small impact on river flooding so that solved the technical problem of flood impact assessment for Guotan Shipping Hub, which provided reference for relevant departments.

To accurately obtain the health performance level of a pumped storage unit (PSU), a health performance tendency prediction method based on convolution neural network-long short-term memory neural network (CNN-LSTM) is proposed. Firstly, a unit health state model based on Gaussian process regression was constructed to effectively characterize the operating characteristics of the PSU. Then, an index that can quantify the health performance of the PSU was proposed. Finally, by integrating the good local feature extraction ability of the CNN and the advantage of the LSTM in time series prediction, a prediction model based on CNN-LSTM was proposed. The experiments were conducted using monitoring data from a pumped storage station in China. The results show that the proposed method can betterly predict the future evolution of the PSU's health performance.

Based on elasto-viscoplastic theory of Perzyna and strain energy theory and 3D yield criterion considering the effect of intermediate principal stress, a mesoscopic coupled elasto-viscoplastic-damage model is developed in order to explore the intermediate principal stress effect on the time-dependent behavior of deep hard rock in excavation damage zone. The model is implemented in a software for engineering rockmass fracturing process (CASRock). By comparing modeling results with experimental results, the model and the code are validated. Furthermore, the time-dependent behaviour of ^#1 laboratory of CJPL-II project is simulated, and the time-dependent fracture process of hard rock in excavation damage zones under different intermediate principal stresses are investigated. The results show that the time-dependent fracture behavior of hard rock exhibits an obvious interval effect of intermediate principal stress. It is found that the interval effect of the intermediate principal stress is affected by time through the isochronous curve clusters of the total viscoplastic strain and the intermediate principal stress. Finally, the existence of the excavation damage zone can promote the development of time-dependent fracture of its internal surrounding rock, thereby expanding the scope of the plastic zone.

In the case that hydrological data only include rainfall station data and measured water level data of river monitoring section, it is always a major challenge to improve the accuracy of flood forecasting in small and medium-sized basins. In this paper, flood automatic coding was realized according to data characteristics, and historical floods were classified by using decision tree model, thus the candidate flood groups and eliminated flood groups were obtained and the calculation efficiency was improved. On this basis, a flood forecasting model was established based on the similarity measurement of spatio-temporal hydrological data. Taking the hydrological data of Dafenshui Basin in Jiangxi Province as an example, a case analysis of hydrological data was carried out, and four floods were randomly selected for verification. The results show that the qualification rate of flood peak water level is 100%, and the qualification rate of flood peak time is 75%, the accuracy is high, which has important theoretical value and practical significance in hydrological data research.

In order to explore the microcrack initiation, propagation and damage evolution of rock samples with different crack types (opening and closed), inclination and crack length, based on PFC2D, the fractured rock sample model was constructed and the uniaxial compression numerical tests were carried out. The initial crack and failure characteristics of rock sample under different crack obliquity and type were explained from the perspective of mesoscopics. The damage analysis of rock samples was carried out from the perspective of energy. The results are as follows. With the increase of crack inclination angle, the peak strength of the open type is positively correlated, while that of the closed type decreases first and then increases. The elastic modulus is consistent with the change of peak strength. When 30°≤α≤60°, the microcrack initiation characteristics of the two kinds of fractured rock samples are consistent. When 60°≤α≤90°, the failure paths of the two rock samples are similar. The damage variable and correction coefficient were defined based on the energy of cementation failure, and the evolution model was established. The rationality of the model was verified from the perspectives of fracture type, inclination angle and length. The research results can provide a theoretical basis for further understanding the damage evolution process of fractured rock mass after loading.

The Lhasa River Basin is a typical arid and semi-arid basin in the Qinghai-Tibet Plateau, where the ecosystem is extremely fragile. It is of great significance to study the spatio-temporal variation of vegetation index (NDVI) in response to the changes of meteorological factors, and to explore the adaptability of vegetation on the Qinghai-Tibet Plateau to the meteorological factors under the background of climate change. Based on the monthly NDVI, precipitation (P), and average temperature (T) time series dataset in the Lhasa River Basin from 1982 to 2017, using Pettitt, Mann-Kendall trend test and Pearson correlation analysis, this paper analyzed the spatio-temporal variation characteristics of growing period NDVI (G-NDVI) and meteorological factors, and identified responses patterns of G-NDVI to climate factors. The results show that the G-NDVI changed abruptly in 1997, and there was a trend shift from increasing to decreasing. The climate of the watershed changed from “wetting-colding” before the abrupt point to “drying-warming” after the abrupt point, and its effect on vegetation growth changed from promoting to inhibiting. There are two zones in the watershed where the responses patterns of G-NDVI to meteorological factors changed before and after the abrupt point. In the western permafrost areas, G-NDVI shows significant correlation with P and T in the second phase after 1997, i.e., emerging the “responding” function on meteorological factors variation. In the southern seasonal frozen zone, after the abrupt point, time lags of G-NDVI to P were elongated, and meanwhile the “responding” of G-NDVI to T has been triggered. The latency of NDVI response to P in the western permafrost region is longer than that in the southern seasonal frozen zone. In the second phase after 1997, the response area of NDVI to meteorological factors increased compared with that before the abrupt point, and the effect of meteorological factors on vegetation growth in the Lhasa River basin was enhanced.

To improve the accuracy of areal mean rainfall data and solve the problems of instability of least square estimation in runoff error correction based on dynamic system response curve, ridge estimation of rainfall error based on differential response was introduced based on least square ridge estimation. The calculation of the Xin’anjiang model was generalized a system. The method was applied in flood forecast error correction in Jianyang basin with 37 historical floods chosen as test samples. The results indicate that the ridge estimation of rainfall error based on differential response has obvious correction effects in Jianyang basin, which can improve the accuracy and stability of flood forecasting.

In recent years, urban rainstorm disasters have occurred frequently in China. The community, as an important component of the city, is exposed to urban flooding. In view of the imperfection of the waterlogging prevention and control system, this paper briefly analyzes the characteristics and prevention methods of urban flooding, and summarizes the limitations of the current system. A waterlogging prevention system based on micro system, minor system and major system is constructed from a drainage perspective. The waterlogging prevention and control methods based on site elevation, terrain slope, and water-retaining measure is established. A design method system including design points, design process, design diagram, and key design parameters is formed, which provides reference for the planning and design of sponge communities in new era.