The fan-shaped central revolving gate is a new type of gate with a significantly different flow pattern from the traditional gate. In order to study the hydrodynamic pressure characteristics of the fan-shaped central revolving gate, model experiment was conducted on the different opening coefficients of the gate based on the 60 m span gate of Wusongjiang regulation project and its energy dissipation design conditions, and the time-average pressure, average fluctuation amplitude, pulsation intensity and spectral characteristics under different opening coefficients were analyzed. The results show that the time-average pressure of the gate blade is positive pressure at each opening coefficient, and the overall pulsating pressure amplitude is relatively stable. The pulsating pressure of each measuring point is close to normal distribution under different opening coefficients. The pulsation intensity changes with the change of the opening and measuring point position. With the increase of the opening coefficient, the pulsation intensity presents a trend distribution of decreasing first and then increasing, and the pulsation intensity belongs to the low-frequency pulsation. The change of the measuring point position in the width direction will affect the pulsation intensity of the measuring point, and the center line pulsation intensity can be used instead of the whole gate pulsation intensity.

Considering the lack of research on the ventilation characteristics of open flow spillway tunnels under high flow velocity conditions, based on a 50 m/s high-speed jet test device, this paper investigated the effects of flow velocity, ventilation tunnel area, and relative height of spillway tunnels on the ventilation volume and wind speed distribution in ventilation tunnels. By analyzing 44 sets of prototype observation data and 28 sets of experimental data, an empirical formula for calculating ventilation at high flow rates was proposed. The results show that the measured value of ventilation is 2.1-9.6 times of the standard value when the water flow velocity is 18.0-37.2 m/s. As the area of the ventilation tunnel increases, the rate of increase in ventilation volume gradually decreases, and the distribution of wind speed inside the ventilation tunnel is related to the area of the ventilation tunnel. The ventilation volume first increases and then decreases with the increase of the height of the spillway tunnel, and the change in the relative height of the spillway does not change the wind speed distribution characteristics. The calculated ventilation value by the improved formula is relatively close to the actual measurement value, with 3/4 of the data within the 20% error line range. Research results can provide guidance for engineering practice.

In order to study the distribution of the annular gap flow field during the bend start of the pipeline vehicle under different loading conditions. Numerical simulation combined with physical model test verification was used to study the annular gap flow field during the horizontal bend start of duct trucks with different loads. The results show that the increase of load does not change the overall distribution of the gap flow field velocity, but only changes the magnitude of the gap flow field velocity; Under different loading conditions, the axial flow velocity of the gap flow field of the pipe vehicle in the horizontal bend has the law of increasing and then decreasing from the inner wall of the pipe to the outer wall of the pipe vehicle. The circumferential flow velocity is more uniformly distributed at the section of the pipe vehicle gap inflow port and the section in the vehicle, but the opposite distribution of flow velocity on both sides of the sealing cover appears at the section of the gap flow outlet. The radial flow velocity is more uniformly distributed as far away from the support body and the seal cover, and the flow velocity increases significantly at the support body in the slit flow outlet section of the pipeline vehicle. This study explains the reasons for the formation of annular gap flow field distribution law and obtains the flow velocity distribution law of the gap flow field when the pipe vehicle is started at the bend with different loads. While improving and enriching the theory of annular gap flow, it provides theoretical basis for the application of hydraulic conveying in cartridge loading pipeline.

Rock wall crane beam is a common bearing structure in underground powerhouse. Because it is directly supported on the surrounding rock, the stability of the rock crane beam is greatly affected by the geological conditions of the surrounding rock. Taking the rock wall crane beam of phase Ⅱ underground powerhouse of Fengning pumped storage power as an example, the distribution law of rock wall crane beam anchor stress and surrounding rock deformation were explained by analyzing the rock mass structural plane characteristics, the rock mass alteration effect as well as the in-situ observation data of the rock wall crane beam. Furthermore, the correlations between the bolt stress of the crane beam and the deformation of surrounding rock, the geological conditions as well as the construction process were deeply analyzed. The reasons for the large bolt stresses and the large deformations of surrounding rock of the crane beam were then explained, and the influence mechanism of rock mass structural plane and rock mass alteration on the stability of the crane beam was finally revealed. This research can provide technical support for the structural design, the construction organization and the safety demonstration of the rock wall crane beam, thus has practical engineering significance.

Based on the instability criterion proposed by the cusp catastrophe theory, the whole surrounding rock was judged, and the relevant tunnel excavation model was established by using the finite element software MIDAS GTS NX, and the changes in surrounding rock stress, displacement and maximum vibration velocity peak in the tunnel-fault system under the conditions of groundwater seepage and blasting were studied by taking No. 2 tunnel project of Daliangshan in Lexi Highway of Sichuan Province for an example. The results show that the comprehensive stiffness ratio of the surrounding rock k<1 and the bifurcation set equation Δ<0 are found by the calculation of the instability criterion, both of which indicate that the surrounding rock has the risk of instability. Under the seepage condition, the maximum principal stress of the fault surrounding rock is 27.71 MPa, and the displacement settlement of the vault is 307.83 mm. Compared with the non-fault area, the stress increases by about 20.64%, and the displacement increases by 105.21%. Influenced by blasting factors, the maximum vertical peak vibration velocity at the fault area is about 13 times that of the common surrounding rock, it is up to 162.97 cm/s. It can be seen that the existence of a fault will have an amplification effect on the dynamic response of surrounding rock. Both theoretical calculation and numerical simulation results show that the F3 fracture of the Daliangshan Tunnel has the risk of instability, and corresponding preventive measures should be taken in advance during construction.

In order to reduce the impact of bridge pier groups on the water flow at the intersection of the main rivers of Hangzhou Zhijiang New City, three shoreline optimization schemes were studied to improve the flow pattern based on a two-dimensional mathematical model. The optimal remediation plan was recommended based on multiple objectives such as water resistance ratio, land area, water area, bridge pier safety, and so on. The results show that the widening one side of the river channel to prevent bridge piers from being located in the main channel or changing the route to avoid bridge piers can effectively reduce the impact of bridge piers on the water level. The three optimization schemes have the same improvement effect on the backwater of the bridge piers. Scheme 2 and scheme 3 will affect the safety of bridge piers, with relatively small water area and large land acquisition area. Scheme 1 has little impact on the safety of bridge piers and is relatively easy to implement. Scheme 1 has high comprehensive advantages, and is recommended as the optimal option.

In order to understand the mechanism of crack formation in the RCC gravity dam body during operation, this paper takes the Shimantan reservoir dam as the research object, adopts a method of using the ESEL command in APDL language and the rotation of local coordinate system to complete the random aggregate delivery, and constructs a three-dimensional macro-micro finite element model of the No. 9 non-overflow dam section of the Shimantan dam. The simulation results of aggregate placement show that the method can quickly generate three-dimensional spherical and polyhedral aggregates, greatly improving the efficiency of aggregate generation. The results calculated by the macro-micro model are more consistent with the actual crack distribution of the dam, and the impact of the rapid rise in summer temperature and rapid drop in winter temperature on the cracking of concrete dams during operation cannot be ignored.

The arch dam deformation monitoring model is the most commonly used method for arch dam health monitoring. Aiming at the deformation monitoring problem of extra-high arch dams, this paper proposes an intelligent optimization support vector machine deformation monitoring model for concrete extra-high arch dams. Particle swarm optimization (PSO) was used to optimize the penalty factor, kernel function parameters of the support vector machine (SVM), and tolerate bias. The deformation monitoring model of concrete extra-high arch dam based on PSO-SVM was established, and the influence of aging factors on the model performance was analyzed. Engineering examples show that the PSO-SVM deformation monitoring model of concrete extra-high arch dam has good prediction accuracy and generalization ability, which is suitable for deformation monitoring of extra-high arch dam.

The calculation of maximum power supply capacity is an important issue in optimal operation of UHV complex large power grid. With the large-scale access of high-proportion renewable energy to the power grid, the problem of power and energy balance is becoming more and more prominent. Considering the stability spinning constraint, coupling section constraint and unit regulation capacity constraint, the calculation problem of maximum power supply capacity presents high-dimensional characteristics, which is difficult to model and solve. According to the limitation of transmission section and the characteristics of partition operation of UHV complex large power grid, an optimal dispatching model of maximum power supply capacity of UHV complex large power grid considering section coupling control was established. Then, the Simplex method (SM), Interior Point method (IP), Simulated Annealing (SA), Beluga Whale Optimization (BWO) and Artificial bee colony algorithm (ABC) were applied to solve the model respectively, and the maximum power supply capacity of the large power grid in the next 15 minutes was calculated. The coordinated optimization scheme of various types of power supply and reserve was proposed. Finally, a regional power grid was taken as an example to verify the model and the solution method. The simulation results show that because of the large scale of the power system and the complex coupling relationship between the sections, the heuristic intelligent optimization algorithm has a long running time, slow convergence speed and low search accuracy. The interior point method converges rapidly, has strong robustness, is insensitive to the selection of initial values, has better stability and computational efficiency, which can provide effective and practical support for power supply and power balance of complex UHV power.

In response to the inadequacies of traditional earthen and reinforced concrete flood walls that create barriers between urban areas and waterfront regions, which no longer meet the public's demands, the introduction of aluminum alloy flood walls in the Moon Bay flood control renovation project has been proposed. A transformation plan that combines modular flood walls with ecological embankments has been implemented. The post-renovation project has demonstrated excellent operational effectiveness, eliminating the oppressive feel of conventional flood defenses within the urban space. Furthermore, it seamlessly extends the urban landscape space to the water's edge, creating a unified and continuous landscape interface. This approach ensures flood safety while fostering a waterfront landscape with distinctive regional characteristics.