In response to the complex mechanism of runoff yield and concentration, insufficient groundwater monitoring data, and low accuracy of runoff prediction in Karst areas, a similarity prediction method that integrates physical mechanisms and data-driven approaches has been proposed. The optimal combination prediction scheme has been established for different flow magnitudes, prediction factors, and preceding affected lag-time, which can achieve adaptive matching and intelligent switching of multiple modes under different water and rain conditions. It can generate interpretable runoff prediction results. This method is applied to the runoff prediction of Longtan Hydropower Station. The results indicate that this method improves the accuracy and effective prediction period of runoff in Karst areas, which has scientific significance and practical value for ensuring the scientific scheduling and safe operation of large power plants.

The water intake mode of pumping station under the condition of large variable water level of water source has great impact on the reliability of water intake, project cost and safety of water intake building, so the reasonable evaluation of different water intake mode is one of the key problems in engineering design. In this paper, a two-level evaluation index system consisting of 3 quantitative indicators and 14 qualitative indicators was constructed. The analytic hierarchy process (AHP), entropy weight method and least square method were used to assign the combination of subjective and objective weights. The method of membership degree and fuzzy comprehensive evaluation was used to evaluate and rank different water intake schemes, and an engineering example was analyzed. The results show that the proposed index system is comprehensive, the weighting method is reasonable, and the evaluation method can better reflect the uncertainty of the scheme selection. The practical engineering example verified the feasibility of the evaluation method.

The resistivity method can reflect the soil physical index and structural properties, and it has the characteristics of high efficiency, convenience and non-destructive. In this study, the resistivity characteristics and the resistivity model of laterite had been analyzed using the pore water, water content and porosity as the key factors. A correction formula of contact resistance was proposed considering the influence of electrode area, and the resistivity prediction model of laterite had been established by introducing the structural factors to reflect the influence of pore water on the resistivity of laterite. The results show that the proposed contact resistivity correction formula can effectively reduce the test error, the laterite resistivity and structure factors decrease with the increasing water content and porosity with a power function relationship. The correlation of influencing factors of laterite resistivity is sorted as: pore water>water content>porosity. The resistivity prediction model of laterite was constructed with the variables of contact resistance, pore water, water content and porosity, which has high fitting accuracy. Thus, it can provide a reference for evaluating the physical indicators and structural properties of laterite.

In order to study the impacts of aggregate size and fiber length on the mechanical properties of basalt fiber concrete, three aggregate sizes and basalt fiber lengths have been taken into account, and 108 concrete test blocks (including 72 cubic test blocks and 36 prism test blocks) have been designed and made. Furthermore, axial compression test, splitting tensile test as well as bending test have been carried out to analyze each parameter influence on compression strength, splitting tensile strength and bending strength. On the basis of random fiber script, ABAQUS finite element modeling analysis is carried out, and the corresponding strength calculation has been proposed. The results show that with the increase of aggregate size, the mechanical properties of matrix concrete are improved. While with the adding of basalt fibers, the concrete mechanical properties rise higher than aggregate size increase. The concrete mechanical properties present good performance when 30mm aggregate size mixes with 18 mm and 24 mm basalt fibers. The result of designed random fiber script in ABAQUS finite element modeling matches with the experiment well, and the calculation method considering two-parameter influence of aggregate size and basalt fiber length has good applicability.

The characteristics and distribution of in-situ stress field have an important influence on the stability and engineering design of the surrounding rock of underground power house. According to the deep surface drilling hole and engineering geological conditions of the underground power house of a pumped storage power station, a three-dimensional numerical analysis model was established, and the inversion reconstruction of the initial in-situ stress field was realized through multiple linear regression analysis. The results show that the maximum horizontal principal stress measured in deep holes is 6.7-17.6 MPa. The magnitude and direction of the inversion model are in good agreement with the measured value, and the horizontal stress in the underground workshop area is dominant, and the maximum horizontal principal stress is 16.2-17.4 MPa. The maximum principal stress azimuth of the stress field in the plant area is less than 30°, and the stress distribution and azimuth angle meet the design requirements. The research results provide a reference for similar large-scale underground projects.

Factors such as climate change have increased the spatial-temporal distribution heterogeneity of rainfall, it is thus important to study the response of hydrograph to the influence of the spatial heterogeneity of rainfall, which is of great importance to provide guidance to the hydrologic simulation of the flooding under conditions that the rainfall of the mainstream and tributary streams have different occurrence frequencies. The watershed above Linyi station of the Yihe River in Shandong Province was selected as an example. The watershed hydrological model was established using the Xinanjiang model. Hourly rainfall data from June to September from 1980 to 2020 were used for frequency analysis to obtain the design storms with different return periods in the Yihe river basin with a duration of 72 h. The flood process at Linyi station was analyzed by considering combined design scenarios of design storms with different return periods. Simulations were run using the established hydrologic model to obtain the response of flood process to the spatial heterogeneity of rainfall. The results show that the spatial distribution of rainfall has a significant impact on peak flows, with rainfall in areas close to the basin outlet being the determining factor for peak flood flows, and that smaller amounts of rainfall can produce larger peak flows in scenarios with high spatial heterogeneity of rainfall. The results can provide reference for the flood forecasting of downstream cross-sections under conditions that the mainstream and tributary floods have different occurrence frequencies due to spatial heterogeneity of rainfall.

Currently, the researchers have not yet conducted a detailed analysis of the anchor block stability and there exist shortcomings in the discriminatory formula for the slip length. On the basis of the existing computational formulas, the axial force formula for the pipeline was optimized considering expansion joints, and the axial force formula was proposed for downstream elbow pipe without considering the expansion joints. Furthermore, by analyzing axial thrust on pipelines in the context of considering or not considering the expansion joints and comparing the concrete amount of the anchor block under all conditions, the anchor block of the buried steel pipe was found to have the minimum amount of concrete used in the context of not considering the expansion joints and under certain condition, which can provide a reference for future research and design work.

The proposed Longweizhou junction is a low-head hydro-junction project that focuses on navigation, flood control, water resources, and protection of the aquatic ecological environment. There are two continuous bends upstream and downstream of the dam site, and the straight section where the dam site is located is also short, so the river boundary conditions are not conducive to smooth flood discharge after the project. To demonstrate and optimize the general layout of the proposed hydro-junction, an integrated hydraulic-physical model with a scale of 1∶80 was adopted. On the basis of hydrodynamic similarity verification, a detailed experimental study was conducted on the discharge capacity of the hydro-junction, revealing the characteristics of flow velocity distribution and flow distribution in the original design scheme under typical flood conditions, clarifying the shortcomings of the original scheme and corresponding optimization ideas, putting forward the measure of cutting the side beach to improve discharge capacity. The optimized scheme test verified that the discharge capacity could meet the design requirements. The research results may serve as reference for the design of this project and other similar projects.

Aiming at analyzing the mechanism of slope failure and evolution propagation induced by typhoon and rainstorm, a numerical simulation of the safety state of a slope was carried out based on the measured rainfall data during various typhoons in Fujian Province of China. For the slope before instability, Monte Carlo method was used to calculate the real-time failure probability and reliability index and reveal the transient change characteristics of the seepage field and plastic zone of the slope. For the slope after instability, Herschel-Bulkley-Papanastasiou (HBP) model was used to describe the rheological characteristics of the slope using the SPH method. The propagation process of landslides was analyzed in terms of velocity and accumulation characteristics. The results show that the rainfall is the key factor to induce slope instability. When the slope failure occurs, the sliding speed of the leading edge can reach 15 m/s. This study provides a reference for the early warning and disaster prevention and mitigation of slope engineering under extreme conditions.

In order to study the water logging risk in lakeshore urban caused by the blocking drainage effect (BDE) of Poyang Lake, the "regulation and storage model" was used to elucidate the BDE of Poyang Lake on inner river drainage in Changnan District and to explore the impact of Poyang Lake on waterlogging risk of lakeshore urban. By defining the Index of Blocking Drainage (IBD) which quantifies the BDE, the main controlling factors that affect the IBD was explored and the response relationship between them was quantified. The results show that the main controlling factors affecting the IBD include rainfall intensity, water level of outer river, drainage capacity and storage space. There is an obvious quadric curve relationship between rainfall intensity and the IBD, and 11.67 mm/h is the inflection point of the curve. There is a four-quadrant risk diagram relationship between the IBD and the water level of outer river. The decrease frequency of the IBD increases with the increase of drainage capacity. The effect of reducing the IBD by improving the drainage capacity of Changnan District is obviously reduced when the rainfall intensity exceeds 11.67 mm/h. The IBD of the same rain intensity decreases gradually with the increase of storage space. The effect of reducing the IBD of Qingshanhu District by increasing the storage space is obviously reduced when the rainfall intensity exceeds 15.83 mm/h. The water logging risk in lakeshore urban caused by the DBE of Poyang Lake can be effectively reduced by appropriately improving the drainage capacity, reducing the proportion of impervious ground and increasing the adjustable storage space, but the ability to deal with extreme rainstorm events remains limited.