Search Results (15)

This study explores the design and construction methods for auxiliary workings for the deepening of Shaft II at the Borynia Mine. The shaft, an essential intake structure for personnel and material transport, is being extended from 980 m to 1150 m to provide access to a new mining level at 1120 m. Given the challenging geological and operational conditions, a top-to-bottom deepening method was adopted, with excavation from a sub-level accessed via an auxiliary incline. The study details the planning and implementation of key auxiliary workings, including hoisting machine chamber and technological shaft inset. A comprehensive geotechnical analysis was conducted to assess rock mass properties, classify geological formations, and estimate mechanical parameters affecting excavation stability. The support system design was carried out using both analytical and numerical methods, ensuring safe and efficient construction. The applied primary and secondary support structures have successfully maintained excavation stability. The findings demonstrate the reliability of the adopted engineering solutions and their applicability in deep mining environments. Full article

Prefabricated staircases are crucial components in modern architectural structures, but traditional concrete staircases are too heavy for efficient prefabrication, transportation, and construction. Therefore, this paper proposes a novel lightweight hollow slab prefabricated staircase (referred to as the KXB staircase). The staircase achieves hollow designs for steps and the baseplate by incorporating hollow tubes in the steps and adding polyethylene foam boards in the baseplate. Additionally, a standard prefabricated slab staircase (referred to as the CG staircase) was subjected to static loading tests to analyze failure characteristics, load-deflection curves, and strain distribution. A finite element model was created using ABAQUS (2020) and validated for accuracy through a comparison with experimental results. The results indicate that the novel lightweight hollow-slab prefabricated staircase surpasses conventional slab staircases in load capacity, deflection, and crack control. Furthermore, it achieves a 16% reduction in weight, a 28.6% improvement in load capacity, and a maximum error of 9.9% between the model and experimental results. The novel lightweight prefabricated staircase satisfies engineering requirements, minimizes transportation and hoisting costs, and demonstrates strong application potential. Full article

In the domain of bridge I-beam joint construction, conventional approaches such as cast-in-place concrete with suspended formwork and ordinary reinforced concrete precast slabs entail numerous limitations. The former features complex procedures, elevated costs, and significant safety risks, while the latter is hindered by the heavy weight of precast slabs, which causes difficulties in transportation and hoisting, inconvenient installation, and high costs. Reactive powder concrete ultra-thin precast slab (RPCUPS) is regarded as a potential solution due to its superior properties. Nevertheless, at present, there is an acute paucity of experience and research regarding the application of RPCUPS in bridge I-beam joints, particularly on a large scale. In a certain actual engineering project, a scheme was proposed to employ RPCUPS with a mere thickness of 20 mm in the bridge I-beam joints. In this scheme, the quantity of slabs is substantial, amounting to over 600,000. This constitutes the research gap and impetus of this study, with the aim of filling the existing knowledge void and providing technical support for engineering endeavors. This research carried out an extensive experimental test to systematically investigate the mechanical properties and safety of RPCUPS. Firstly, the material performance experiments were conducted to determine the manufacturing process of RPCUPS that meets the performance requirements. Subsequently, loading experiments on specimens under multiple working conditions were performed to disclose the cracking load and ultimate load of the two main types of RPCUPS and to analyze the influences of fiber type, mixing type, steel mesh, and slab thickness on the mechanical properties of RPCUPS (keeps the same volume rate of steel in a slab). Key findings encompass the outstanding mechanical properties and high safety factors of RPCUPS under diverse working conditions. Finally, in light of the actual construction environment, safety verification of temporary loading during actual construction was executed to furnish solid technical support for the practical engineering application of RPCUPS. The experimental results indicate that RPCUPS has been successfully applied on a large scale in actual engineering projects, not only without augmenting the cost but also significantly reducing the construction period by approximately five months, conspicuously enhancing the construction efficiency. These discoveries not only validate the feasibility of RPCUPS in bridge I-beam joint construction but also offer valuable references and guidance for similar future projects. Full article

The rapid development of artificial intelligence technology is driving the intelligentization process across various fields, particularly in knowledge graph construction, where significant achievements have been made. However, research on hyper-relational knowledge graphs in the industrial domain remains relatively weak. Traditional construction methods suffer from low automation, high cost, and poor reproducibility and portability. To address these challenges, this paper proposes an optimized construction process for a hyper-relational knowledge graph for mine hoist faults based on large language models. This process leverages the strengths of large language models and the logical connections of fault knowledge, employing GPT’s powerful reasoning abilities. A combined strategy of template-based and template-free prompts is designed to generate fault entities and relationships. To address potential data incompleteness caused by prompt engineering, link prediction is used to optimize the initial data generated by GPT o1-preview. We integrated the graph’s topological structure with domain-specific logical rules and applied the Variational EM algorithm for alternating optimization while also incorporating text embeddings to comprehensively enhance data optimization. Experimental results show that compared to the unoptimized MHSD, the optimized MHSD achieved a 0.008 improvement in MRR. Additionally, compared to the latest KICGPT, the optimized MHSD showed a 0.002 improvement in MRR. Finally, the optimized data were successfully imported into Neo4j for visualization. Full article

The floating hoisting of floating production storage and offloading (FPSO) production modules introduces substantial challenges due to the propensity for excessive deformation within the typical tubular truss structures during operations. This research proposes a temporary reinforcement scheme, leveraging finite element method simulations under wind, wave, and current loads, to mitigate deformation concerns. Utilizing DNV GeniE software, this study establishes a finite element model, simulating the floating lifting process and conducting a comparative analysis between pre- and post-reinforcement scenarios. The results demonstrate a significant reduction in maximum stress and deformation, substantiating the efficacy of the reinforcement strategy and underscoring the safety and reliability of such operations. The successful execution of this methodology heralds a promising avenue for marine engineering practices, advocating for the optimization of large-scale offshore module installation. Full article

Accurate identification of lithology in petroleum engineering is very important for oil and gas reservoir evaluation, drilling decisions, and petroleum geological exploration. Using a cross-plot to identify lithology only considers two logging parameters, causing the accuracy of lithology identification to be insufficient. With the continuous development of artificial intelligence technology, machine learning has become an important means to identify lithology. In this study, the cutting logging data of the Junggar Basin were collected as lithologic samples, and the identification of argillaceous siltstone, mudstone, gravel mudstone, silty mudstone, and siltstone was established by logging and logging parameters at corresponding depths. Aiming at the non-equilibrium problem of lithologic data, this paper proposes using equilibrium accuracy to evaluate the model. In this study, manifold learning is used to reduce logging and logging parameters to three dimensions. Based on balance accuracy, four dimensionality reductions including isometric feature mapping (ISOMAP), principal component (PCA), independent component (ICA), and non-negative matrix factorization (NMF) are compared. It is found that ISOMAP improves the balance accuracy of the LightGBM model to 0.829, which can effectively deal with unbalanced lithologic data. In addition, the particle swarm optimization (PSO) algorithm is used to automatically optimize the super-parameters of the lightweight gradient hoist (LightGBM) model, which effectively improves the balance accuracy and generalization ability of the lithology identification model and provides strong support for fast and accurate lithology identification. Full article

Rail transit is an important part of the urban transportation system, while the noise generated during construction seriously affects the engineering personnel and surrounding residents. To investigate the noise emissions and characteristics during the construction of the enclosure structures in the rail transit engineering project, an empirical study is conducted through on-site surveys, semi-structured interviews, and experimental monitoring. The results indicate that during enclosure structure construction, there are nine key noise-emitting machines and four key noise-generating construction processes. Among them, the equivalent average sound levels of six machines, including pneumatic hammers, pneumatic drills, concrete pump trucks, construction drills, rotary drilling rigs, and grooving machines, exceed 80 dB(A). The energy contribution rate curves of machine spectra peak at 63 Hz, 500 Hz, 1000 Hz, and 4000 Hz, which have certain effects on construction personnel and nearby residents. Meanwhile, guide wall construction, groove construction, reinforcement cage fabrication and hoisting, and concrete pouring are identified as key noise-generating construction processes. This empirical investigation helps to establish a theoretical basis for noise control during the construction of enclosure structures in urban rail transit engineering projects, and the results provide valuable references for the formulation of auxiliary noise reduction measures. Full article

As important load-bearing structures, suspension cables have been widely used in suspension bridges, engineering ropeways, cable suspension systems and other special equipment. Their dynamic problems have always been a research hotspot. Especially for complex cable systems such as engineering ropeways and cable lifting equipment, there will be moving loads acting on multi-span continuous friction-slip cable structures, resulting in nonlinear coupled vibration. Therefore, few scholars have studied how to calculate the nonlinear coupling vibration effect between such moving loads and multi-span continuous cables considering friction slip. Therefore, this paper proposes the use of the combination of the direct stiffness method and the Newmark-β integration method to solve the nonlinear system of equations of motion, which can be derived from the coupled vibration response between the moving load and the main cable. The corresponding calculation program is prepared. Combined with the dynamic load test and simulation results of engineering cases, the correctness and reasonableness of the coupled vibration equations and the program can be verified through comparative analysis. The results show that the calculation results of the self-programmed program are in good agreement with the dynamic load test results, in which the maximum error of the vertical displacement in the span is −4.40% and 0.86%, and the error of the static calculation reaches −13.90%. The impact effect is more obvious when hoisting the weight out of the pulling cable, in which the impact coefficient of the main cable can be up to 2.0. The impact coefficient of the deviation of the cable tower is 4.0. During the traveling process of the moving load, the vertical downward deflection of the main cable at the action point is the largest, and the upward deflection is in the region of 0.2~0.8L from the action point. Full article

The paper aims to study the geometrical quality and opportunities of the state-of-the-art 3D camera Matterport Pro and examine its potential for industrial archaeology applications. The presented study consisted of two steps. In the first step, the geometrical quality of the camera-generated point cloud was investigated on the calibration test field. The geometrical quality was checked in two ways: (1) with distance comparison between reference targets and (2) with point cloud comparison. The coordinates of the reference targets were determined using a high-precision total station, while the FARO Scanner generated the reference point cloud. The study established that Matterport Pro has a scale systematic error that must be accounted for in 3D modeling and the inventory of archaeological objects. In the second step, the geometrical quality of the camera was checked for the actual archaeological object. As such an object, the historical copper-shaft Quincy Mine in Michigan State Upper Peninsula was considered. The specific subject of the study was one of the largest hoist engines in the world. The Matterport Pro camera scanned the indoor environment of the hoist engine house. The accuracy of the 3D model of the hoist engine was checked using additional linear measurements on-site. It was found that the accuracy of 1% showed that the camera specification can be improved through calibration. As an output of the second step, the accurately refined 3D model of the hoist engine’s interior was built. That model was embedded into a 3D model of the hoist engine’s house for usage in virtual tours of the Quincy Mine Museum. Finally, a virtual tour was created of the Quincy Mine house with exterior and interior models referenced to the geographical frame. Full article

The large-segment hoisting construction technology for bridges is increasingly widely used due to its flexibility and efficiency, although it also poses challenges to construction monitoring. Traditional monitoring technology is unitary with low data processing efficiency, making it difficult to meet the accuracy requirements of large-segment hoisting. The application of digital technology has brought about an opportunity for innovation in bridge construction monitoring technology. To address existing challenges and explore digital applications, this paper takes the integral hoisting construction control of the large-segment steel box girder in a large cross-sea bridge as an example, developing an alignment, stress, and temperature monitoring scheme by taking the key points of hoisting construction control into consideration. A monitoring platform was developed, and the workflow of large-segment hoisting construction monitoring is systematically summarized from the viewpoint of practical engineering, which provides a valuable reference for achieving precise and efficient construction monitoring and control in similar projects. Full article

Prefabricated buildings have the advantages of high efficiency and saving resources. However, China’s prefabricated buildings were built relatively late, and there are problems in terms of their low standardization, integration, and industrialization. The purpose of this study was to evaluate the risk of constructing prefabricated buildings under the engineering, procurement, and construction (EPC) general contracting mode from the perspective of general contractors and to propose countermeasures for the key risks. Firstly, a risk evaluation index system was established via a literature analysis, and a questionnaire survey was used to collect the data. SPSS was used to conduct the data factor analysis to finally identify 4 first-level indicators and 14 second-level indicators. Then, a structural equation model (SEM) was developed to further evaluate the impact of each indicator on the risk of constructing prefabricated buildings under the EPC general contracting mode. The results showed that the construction and design risk had the greatest impact. Among them, the technical level of the construction personnel while conducting the hoisting, stacking, and protection of on-site materials and the lack of integrated design experience among the designers were the key points for risk control. On the one hand, this study explored the whole life cycle of a project, which makes up for the lack of risk analyses and the control being limited to a single engineering stage that has been presented in previous studies. On the other hand, in terms of the design, procurement, and construction as a whole research object, we found that the fuzzy evaluation method and analytic hierarchy process (AHP) used in previous risk analyses and evaluation methods have defects. They cannot verify the rationality of the logical relationship between the evaluation indices. In contrast, this study used the SEM method to fill this research gap. This ensures the scientific nature of our research to the greatest extent. Additionally, we also found some problems with this type of research: the selection of the evaluation indicators and data collection vary with the region, project characteristics, project contracting mode, and risk management subject, which influence the results of studies. Overall, the SEM method established in this study provides a reference and can help us conduct similar research and model evaluations in other regions. This method can guide project implementers to make the best risk-management decisions, so it is of great significance for practitioners in this field. Full article

In this work, a test bed and stand structure were designed for the thrust test of an aircraft. The engine test rig consists of a thrust stand, test bed, transport system, and hoisting device. In this study, structural design and analysis of the stand and bed for engine thrust test equipment were performed. The stand structure supported the engine, and the test bed moved the thrust test equipment and the engine. Structural design loads were defined by analyzing the operating conditions. Structural analysis was performed based on the structural design results. As a result of analyzing the structural safety against thrust, which is the main design load, it was considered to be sufficiently safe. Finally, the target structure was manufactured to verify the design result. Full article

An anti-swaying or swaying-reduction effect for a container crane is key for improving the rapidity and safety of container handling operations. By analyzing the structure of a container crane hydraulic anti-swaying system, a dynamic system model was developed in the time domain, and the changing law of the load swaying angle was studied. In order to study the attenuation effect of the load swaying angle and the different working states of the anti-swaying system, the frequency domain equation of the load swaying angle was developed in the frequency domain. A time domain study on the dynamic model shows that the structure parameter is the key parameter that affects the load anti-swaying effect, and a larger structure parameter produces a better anti-swaying effect. A study regarding the load swaying angle in the frequency domain shows that the container crane hydraulic anti-swaying system works in a critical-damping state when the structure parameter load ratio is equal to twice the system frequency, and in this case, the hydraulic anti-swaying system has good load swaying-reduction effect and a small dependence on changes in the hoisting rope length. The longitudinal and transverse installation distances of the anti-swaying fixed pulleys jointly affect the structure parameter. In engineering applications, the longitudinal and transverse distances can be selected according to size near that of a standard container. To obtain a good swaying-reduction effect, data such as the hoisting load mass, the hoisting rope length, and the hoisting load swaying speed can be obtained in real-time and used to calculate the required pressure adjustments for the relief valve of the hydraulic anti-swaying system. Full article

In the process of using a long-span converter station steel structure, engineering disasters can easily occur. Structural monitoring is an important method to reduce hoisting risk. In previous engineering cases, the structural monitoring of long-span converter station steel structure hoisting is rare. Thus, no relevant hoisting experience can be referenced. Traditional monitoring methods have a small scope of application, making it difficult to coordinate monitoring and construction control. In the monitoring process, many problems arise, such as complicated installation processes, large-scale data processing, and large-scale installation errors. With a real-time structural monitoring system, the mechanical changes in the long-span converter station steel structure during the hoisting process can be monitored in real-time in order to achieve real-time warning of engineering disasters, timely identification of engineering issues, and allow for rapid decision-making, thus avoiding the occurrence of engineering disasters. Based on this concept, automatic monitoring and manual measurement of the mechanical changes in the longest long-span converter station steel structure in the world is carried out, and the monitoring results were compared with the corresponding numerical simulation results in order to develop a real-time structural monitoring system for the whole long-span converter station steel structure’s multi-point lifting process. This approach collects the monitoring data and outputs the deflection, stress, strain, wind force, and temperature of the long-span converter station steel structure in real-time, enabling real-time monitoring to ensure the safety of the lifting process. This research offers a new method and basis for the structural monitoring of the multi-point hoisting of a long-span converter station steel structure. Full article

The friction wear and thermal fatigue cracking of the brake shoe and friction-induced self-excited vibration (frictional flutter) of the disc brake can easily occur during emergency braking of a deep coal mine hoist with at high speed and with a heavy load. Therefore, tribo-brake characteristics between the brake disc and brake shoe during emergency braking of a deep coal mine hoist are investigated in the present study. Scaled parameters of the disc brake of a deep coal mine hoist are determined by employing the similarity principle. Friction tests between friction disc and brake shoe are carried out to obtain the coefficient of friction in the case of high speed and large specific pressure between the friction disc and brake shoe. Coupled thermo-mechanical finite element analyses of the brake disc and brake shoe are established to investigate temperature and stress fields of the brake disc and brake shoe during emergency braking, which is validated by the engineering failure case. Effects of braking parameters on flutter characteristics between the brake disc and brake shoe are explored by employing a double-degrees-of-freedom vibration mechanism model. The results show that the maximum temperature, equivalent Von Mises stress and contact pressure are all located at the average friction radii of contact surfaces of the brake disc and brake shoe during emergency braking. The cage crashing accident in the case of high speed and heavy load in a typical coal mine shows crack marks and discontinuous burn marks at central locations of brake shoe and brake disc surfaces, respectively, which indicates frictional flutter characteristics between brake disc and brake shoe. During emergency braking, flutter time duration decreases with increasing initial braking speed and damping parameter; the flutter amplitude and frequency of the disc brake increases with increasing normal braking load and stiffness, respectively. Full article