All the dams of small reservoirs in Zhaoyuan City are earth-rock dams. This paper comprehensively describes the investigation methods used in the actual leakage investigation process, such as drilling, in-situ testing, geotechnical testing, geophysical prospecting and other methods, which have achieved a large number of application results in practical projects. The author summarizes the method of preliminarily judging reservoir seepage by using the changes in soil properties in practical work, and applies this method to engineering examples. Through on-site water injection tests, the seepage channels of the dam are finally determined, and the feasibility of this method in finding dam seepage is proved. This method is simple, effective, convenient and fast to use. It can quickly lock the causes of dam seepage and provide directions for further seepage analysis. It has certain reference value for future leakage investigation of earth-rock dams.

Relying on the project of “Dawukou Regulating Reservoir for Water Supply in the West Line of Yinchuan Metropolitan Area”, this paper makes a thorough study on gravel-soil admixture in dam filling of plain-type reservoir, and discusses its applicability in dam filling by means of its physical and mechanical characteristics. Through the particle test of different mixing ratio, the optimum mixing ratio of clayey soil to sand and gravel (volume ratio) is determined to be 7∶3, and the admixtures are compacted in the laboratory and rolled in the field. After reaching the designed compactness of 98%, the permeability test, direct shear test and compression test are carried out, and all the test results meet the design and specification requirements. Moreover, the shear strength index of the admixture is far greater than that of the clay soil, which is more conducive to the anti-sliding stability of the dam body. The research and application of gravel-soil admixture technology improves the construction quality, solves the problem of material source, saves the project investment, and ensures the safety of the project. The study shows that gravel-soil admixture has a good application prospect in the dam filling of plain reservoir, which can provide technical reference for similar projects.

For the situation where the liquid level of a mobile water tank in a port may fluctuate due to vibrations and liquid movement, and considering the existing problems such as insulation failure and insufficient liquid level monitoring accuracy of the water tank, this paper designs an intelligent water tank control system suitable for mobile scenarios. The system adds static wave tubes inside the water tank to suppress liquid movement, and combines multi-sensor fusion technology and compound filtering algorithms of radar, ultrasonic waves, and pressure sensors to effectively solve the problem of liquid level fluctuation interference during movement, achieving precise liquid level monitoring; at the same time, the temperature control system is mainly optimized, adopting a hierarchical heating and dynamic adjustment strategy, and stabilizing the water temperature within the target range under typical port environmental temperatures, with significantly reduced electricity heating energy consumption compared to traditional schemes. This system effectively ensures the stability of the water tank liquid level and the controllability of water temperature under mobile conditions, providing technical support for the precise control of mobile liquid storage equipment.

To solve the problem of systematic gain mismatch in power factor correction (PFC) circuit caused by nonlinear change of inductance with DC bias, a real-time inductance detection algorithm based on high frequency ripple slope method is proposed. First, a single-phase full-bridge PFC voltage-current double loop control model is established, and the influence of inductance variation on the current loop transfer function is deduced. The current loop bode diagram and simulation results show that the system stability will be affected when the inductance parameters change greatly. Secondly, by monitoring the slope of high frequency ripple current of PFC inductors, the instantaneous inductance value is calculated online, and the PI parameter of current loop is dynamically adjusted at 1 kHz frequency to achieve constant loop gain. The comparison simulation based on Simulink shows that the system can maintain stability under large inductance fluctuation under this algorithm. This algorithm can provide a theoretical reference for the design of high reliability PFC circuits.

The Critical Heat Flux (CHF) in microchannel flow boiling is a key parameter limiting the heat dissipation performance of high-heat-flux devices. Enhancing CHF is crucial for the safe operation of electronic devices, new energy batteries, and aerospace thermal management systems. This article reviews research progress on the influencing mechanisms of CHF in microchannel flow boiling. It focuses on analyzing four typical CHF enhancement techniques: surface modification (porous structures, microstructured surfaces), working fluid modification (nanofluids, zeotropic mixtures), microchannel structural optimization (grooved walls, bidirectional counter-flow designs), and flow control (microfluidic transistors, micropin-fin fences). A comparative analysis of the applicability characteristics of different methods is provided, offering valuable references for mechanistic research and technological development of CHF in microchannel flow boiling.

The prediction of photovoltaic power generation is influenced by many factors. To improve the accuracy of the prediction, statistical methods are first used to screen and statistically analyze experimental test data. In order to improve the accuracy of photovoltaic power generation prediction, environmental factors with high linear correlation with the power generation of the power station are selected and the SSA-LSTM neural network model are introduced for training and testing. By preprocessing historical data, the model firstly uses Singular Spectrum Analysis (SSA) to extract the main periodic components, and then utlizese Long Short Term Memory Networks (LSTM) for load prediction. The research results indicate that the model can effectively capture the dynamic changes in photovoltaic power generation, which has high accuracy in predicting photovoltaic power generation.

In order to solve the design problems of offshore photovoltaic power plants under complex working conditions, taking the 300 000 kW offshore photovoltaic project in Changli, Qinhuangdao as a case study, this paper focuses on the key technology of integrated design and installation of a fixed pile foundation type. By analyzing key parameters such as sea ice force, wave load, and sea current force in the Bohai Sea, multiple loads are combined, and the fixed pile foundation type scheme is modeled. The bearing characteristics of the pile foundation are analyzed, and the economic and reliability of the steel pipe pile and steel grid combination scheme considering sea ice effect are verified. The research results indicate that: 1) The results of limiting ice force by sea ice strength under different pile diameters show a linear positive correlation between pile diameter and ice force, and sea ice load is the controlling factor for the pile foundation design of this project. 2) Based on load combinations and modeling results, using steel pipe piles as the foundation of the photovoltaic platform, the bearing capacity of each section of the pile body meets the requirements. This study has verified the effectiveness of the method through engineering practice, providing a technical paradigm for large-scale development of offshore photovoltaics and a scientific basis for the design of photovoltaic power stations in high latitude sea areas.

To explore the feasibility of using rice husk, an agricultural waste, for preparing lightweight and high strength building materials, the original rice husk mortar was made by using the original rice husk instead of the engineering sand, mixed with polypropylene fiber with different blending ratio and length, and made with cement and water. We analyzed the influence of replacing part of engineering sand with original rice husk on the properties of mortar through experiments. The compressive strength, flexural strength and density of rice husk mortar were studied through macroscopic experimental studies. The results showed that the proper addition of rice husk could improve the compressive and flexural strength and reduce the density of the mortar compared with the original mortar. The 28 d compressive and folding strengths of rice husk mortar with a rice husk content of 40% and polypropylene(PP) fiber content of 0.1% and the PP fiber length of 6 mm were the highest, which were 9.61 MPa and 2.45 MPa, respectively. The order of the influence of each factor was as follows: rice husk content>fiber length>fiber volume.

In order to explore the distribution of soil pressure on the side of the pile, bending moment of pile shaft and horizontal displacement of the pile top during the excavation and pile loading stages of the H-shaped prestressed concrete piles,three groups of indoor scaled model tests with prestressed rectangular piles and with or without prestressed H-shaped piles are carried out. And the test results show that the lateral earth pressure on both sides of the sheet pile has the same trend as the static earth pressure calculation value when it is not excavated, but the measured earth pressure at different depths is always lower than the static earth pressure calculation value. In the excavation stage,the lateral earth pressure on the excavation side of prestressed H-shaped piles is smaller than that of rectangular sheet piles and non-prestressed H-shaped piles. The ultimate bearing capacity of H-shaped piles under prestressed condition is about 1.33 times of that of rectangular sheet piles,taking the stacking weight at the critical displacement value as the bearing capacity index. The results show that the prestressed H-type piles have the optimal comprehensive performance, which can effectively improve the mechanical behavior of the pile shaft and significantly enhance the bearing capacity, thus possessing great engineering application value.

Taking a high-speed railway three-span continuous beam bridge as an example, a three-dimensional finite element model of the bridge-soil-pile system is established using ABAQUS finite element software. Nonlinear spring elements combined with damping elements are used to simulate the pile-soil interaction, and nonlinear dynamic time-history analysis is conducted on the finite element model. The effects of three seismic waves and three types of site soil conditions on the structural seismic response are compared. Compared with the calculation model without considering pile-soil interaction, the research results indicate that the influence of pile-soil interaction cannot be ignored, and considering the pile-soil interaction will significantly increase the displacement and acceleration of the pier top, and pier base shear force. Different seismic waves and site soil conditions also have a large impact on the analysis results; the softer the soil conditions of the site, the more significant the impact of pile-soil interaction on the seismic response of the bridge.

This paper focuses on the longitudinal cracks that occur in the web of variable cross-section box beams during the cantilever construction of long-span prestressed concrete continuous girder bridges. Based on detailed on-site observation data and phased treatment practices, a systematic analysis of the causes and countermeasures is conducted. The crack characteristics are manifested as oblique extension along the direction of the prestressed ducts, with a length of approximately 2 meters, a width of up to 2 mm, and a depth of about 5 cm. The research reveals that the causes have distinct phased features: in the early stage, it is attributed to the non-uniform stress and material segregation during the concrete pouring period; in the later stage, it is mainly due to the improper prestress tension sequence and insufficient anti-crack reserve of the structure. Through the implementation of targeted measures (increasing the stiffness of the hanging basket, optimizing the concrete pouring process, enhancing the structural reinforcement, and adjusting the tension sequence), the crack defects are successfully eliminated. This study provides important theoretical basis and practical references for the quality control of similar bridge construction.

Aiming at the prevalent issues of information silos and the lack of fine-grained management in current urban governance, this research integrates “BIM＋GIS” technologies to construct an intelligent urban design management platform, with the objective of enhancing urban spatial quality and management efficiency. Based on an analysis of the professional, staged, and hierarchical management requirements of urban design, the study proposes a platform construction strategy centered on the establishment of a knowledge system and the formulation of control standards. A four-tier technical framework is designed, consisting of the foundation, data, application, and presentation layers. By establishing a structured knowledge system that covers four critical stages:scheme review, control standards, design conditions, and parcel schemes, the platform achieves precise regulation of five core elements: land layout, building morphology, transportation planning, environmental quality, and open space. Furthermore, it integrates core functional modules such as visual spatial modeling, information sharing and query, and auxiliary review. The findings demonstrate that the “BIM＋GIS” based urban design management platform offers significant advantages, including high data compatibility and robust spatial analysis capabilities. It enables data sharing throughout the full lifecycle of digital cities, providing a systematic support tool for promoting technological innovation in urban design and scientific governmental decision-making.

The tungsten deposit area in Kuimei Mountain is located at the composite zone formed by the eastern segment of Nanling E-W trending structural belt and the southern segment of NE-NNE trending structural belt in Wuyi Mountain. The mining area is characterized by the coexistence of quartz vein-type wolframite ores and skarn-type scheelite ores.This study determines the isotopes of hydrogen, oxygen and sulfur found in the wolframite,quartz and chalcopyrite ores from a quartz vein-type wolframite deposit.The results show that the δ¹⁸O values of wolframite range from 4.4‰ to 5.7‰. The δ¹⁸O values of quartz veins range from 12.3‰ to 13.4‰,and the calculated δ¹⁸O_H2O values of quartz veins range from 1.42‰ to 6.19‰.The δD values of quartz inclusions in ore-bearing quartz veins range from －49‰ to －67‰, and the δ³⁴S values of chalcopyrite concentrate between －3.2‰ and 0.3‰. The findings indicate that the metallogenic fluid for the main mineralization period of tungsten ores in Kuimei Mountain is not only originated primarily from magmatic water but also subject to influences from atmospheric precipitation. It is also found that the origin of the metallogenic fluid’s sulfur source is primarily magmatic.