Engineering Construction Research Articles

Teaching Reform and Practice of Soil Mechanics Course in the Context of Emerging Engineering Science

With the accelerated development of scientific and technological progress and industrial upgrading, Emerging Engineering Education has become the key to cultivate high-quality and innovative talents, and the teaching reform of the Soil Mechanics course, as a core basic course of civil engineering, is particularly important for adapting to the engineering needs of the new era. This paper discusses the teaching reform and practice of Soil Mechanics courses in the context of emerging engineering science, and puts forward the introduction of cutting-edge technology, updating course content, innovative teaching methods, the teaching quality of Soil Mechanics courses and the comprehensive quality of students, and other strategies, and seeks to promote the significant improvement of the quality of teaching and the quality of talents. Among them, the application of virtual reality and project-driven learning mode enhances students' practical ability and innovative thinking. The strengthening of practical teaching links and industry-university-research cooperation has enhanced the opportunities for students to participate in actual engineering projects, while the integration of Civic and Political Education has fostered students' professional ethics and sense of social responsibility. In the future, the course of Soil Mechanics will continue to adjust and optimise the teaching mode, cultivate high-quality civil engineering talents adapted to the needs of emerging engineering science, and provide powerful support for modern engineering construction.

Design, preparation, and performance of marine resource-based alkali-activated cementitious materials

The construction of islands and reefs and marine engineering cannot depend on cementitious materials, and how to utilize marine resources to prepare cementitious materials is the key to realizing the convenient construction of marine engineering. In this paper, starting from the necessary composition for the formation of gels, the effects of different activation methods on their activities were investigated by utilizing coral and diatomite as calcium and silicon sources, respectively. The study results show that using calcined coral to activate calcined diatomite resulted in a 28 days strength of up to 2.89 MPa, but it was not processable. The precursor with volcanic ash can be prepared by co-calcining coral and diatomite under lower temperature conditions, and its calcination temperature needs to be no less than 800 °C. In addition, characterization by XRD, FTIR, SEM and BET showed that increasing the calcination temperature helps to form more active substances with volcanic ash, such as CaO, CaSiO3, and Ca2SiO4, which can improve the compressive strength of alkali-activated materials prepared from them. The highest strength growth rate of 3.03 % and 28 days compressive strength of 10.80 MPa were obtained when the co-calcined temperature was 850 °C. The results of this study can provide some reference for the development of marine resource-based cementitious materials.

Eccentric compression performance of coral concrete-filled aluminum alloy tube (CCFAT) circular short columns

Coral concrete, utilizing coral reef bodies in place of traditional aggregates, shows promising prospects use in island projects. The use of aluminum alloy-reinforced coral concrete columns effectively enhances the load-bearing capacity of these structures. This study aims to investigate the performance of aluminum alloy circular tube-reinforced coral concrete short columns under eccentric compression. The study involved designing fifteen short columns for eccentric compression experiments, focusing on key parameters such as aluminum content (α), eccentricity (e0), and coral concrete strength (fc). The study obtained failure modes, bearing capacities, and load-deformation relationships, and analyzed the impacts of aluminum content, eccentricity, coral concrete strength, and hoop coefficient (ξa) on the columns’ strength, stiffness, and ductility. Subsequently, a finite element parameter expansion analysis using Abaqus was performed. Ultimately, a correction coefficient model was developed, compared with existing international specifications, and used to establish a suitable calculation model for the bearing capacity of CCFAT eccentric short columns. The results indicated that CCFAT eccentric short columns predominantly experienced bending failure. The stresses in the aluminum alloy round tube can reach the conditional yield strength, effectively collaborating with the concrete. The load-deformation relationship did not exhibit an intensification stage, and the lateral deflection curves tended to follow sinusoidal half-wave patterns. During the initial loading stage, adherence to the plane-section assumption was observed, with the hoop effect primarily manifesting in the compression zone. The strength index showed an approximately quadratic relationship with ξa, the stiffness index showed a positive correlation with ξa, and the ductility index demonstrated a strong positive association with ξa. The correction coefficient model, along with AIJ (2001), can be employed for calculating the bearing capacity of CCFAT eccentric short columns. This study introduces the novel concept of aluminum alloy tube-reinforced coral concrete columns as a composite structure for island civil engineering construction. Beyond the benefits of traditional steel tube concrete, these composite columns are expected to reduce engineering costs, shorten construction timelines, and address durability concerns through the incorporation of marine coral stones and fragments as concrete aggregates.

Bridging theory and practice: Stakeholder insights on circular economy in the building life cycle

The world strives for sustainable development to minimize environmental impact and resource consumption, where circular economy (CE) is emerging as a promising approach to address environmental, economic and social challenges associated with the Architecture Engineering Construction (AEC) industry. This study focuses on the implementation of circular economy principles in the End-of-Life (EoL) phase of existing buildings, aiming to identify gaps between theory and practice, specifically for reuse and recycle processes in AEC. The focal point are business models, processes and the regulatory framework in Austria. The research methodology employs semi-structured interviews with different stakeholders involved in activities within the EoL value chain, including architects, contractors, material suppliers, waste management organizations, demolition companies and regulatory authorities. Based on a literature review which addresses seminal issues for the implementation of CE in the building life cycle, this study compares findings from 12 interviews and the results from literature research, identifying gaps between theory and practice, with recommendations for a path forward.

Investigating the Energy Dissipation Mechanism of Piano Key Weir: An Integrated Approach Using Physical and Numerical Modeling

The enormous energy carried by discharged water poses a serious threat to the Piano Key Weir (PKW) and its downstream hydraulic structures. However, previous research on energy dissipation in PKWs has mainly focused downstream effects, and the research methods have been largely limited to physical model experiments. To deeply investigate the discharge capacity and hydraulic characteristics of PKW, this study established a PKW model with universally applicable geometric parameters. By combining physical model experiments and numerical simulations, the flow pattern of the PKW, the discharge at the overflow edges, and the variation in the energy dissipation were revealed for different water heads. The results showed that the discharge of the side wall constitutes the majority of the total discharge at low water heads, resulting in a relatively high overall discharge efficiency. As the water head increases, the proportion of discharge from the inlet and outlet keys increases, while the proportion from the side wall decreases. This change results in less discharge from the side wall and a consequent reduction in the overall discharge efficiency. The PKW exhibits superior energy dissipation efficiency under low water heads. However, this efficiency exhibits an inverse relationship with an increasing water head. The overall energy dissipation efficiency can reach 40% to 70%. Additionally, the collision of the water flows inside the outlet chamber and the mixing of the overflow jet play a primary role in energy dissipation. The findings of this study have significant implications for hydraulic engineering construction and PKW operational safety.

Long-term study on the mechanical properties of the ITZ in coral aggregate concrete and its impact on material durability

The rich coral reef resources on the island make coral aggregate concrete (CAC) widely applied in marine engineering construction. This study extensively investigates the mechanical properties of the interfacial transition zone (ITZ) within CAC and its consequential influence on the overall mechanical performance of concrete. This article uses the interface bonding strength method, microscopic hardness technology, and X -ray diffraction (XRD) test. It is found that the performance of ITZ is critical to the overall performance of CAC. Optimizing the formation of cement paste and regulating the generation of hydrophilic products can significantly enhance the interface strength and durability of concrete. Our findings demonstrate a clear mathematical correlation between the splitting tensile strength of interface bonding and the microhardness value of the ITZ, offering a novel theoretical framework and practical approach for concrete structure design. The characteristics of hydrophilic products within the ITZ, such as the orientation and dimensions of CH crystals, directly influence the intricate properties of concrete. Therefore, in the process of concrete preparation and construction, attention should be paid to the control and optimization of these micro-structural parameters.

Performance evaluation of bamboo species for structural applications using TOPSIS and VIKOR: A comparative study

This study focuses on and investigates bamboo as a workable building material for civil engineering projects. The various bamboo species suitable for the building are identified and their intrinsic mechanical and physical properties are investigated to get a thorough understanding. A detailed methodology is proposed that presents all the steps performed from sample size collection to investigating the characteristics of the bamboo species and demonstrating bamboo's structural capabilities. The study provides insightful and technical knowledge that will be extremely helpful in advancing the sustainable incorporation of bamboo into civil engineering construction methods. The findings have proven that varieties of bamboo with higher density and lower shrinkage rates, such as Thyrsostachys Oliveri (Oliveri), perform superior in structural applications. Multi-criteria decision-making techniques (TOPSIS and VIKOR) revealed Dendrocalamus strictus (Manvel) and Thyrsostachys Oliveri (Oliveri) as top-performing species, making them suitable for structural applications.

Experimental study on the in-plane behavior of mud brick walls strengthened with bamboo strip mesh and dried jute thread

Despite advancements in modern structural engineering, adobe and mud brick constructions persisted as important housing options for a significant percentage of the world's population. However, because of their low strength and brittle nature, they are susceptible to natural disasters, especially earthquakes, which is a concern for many mud-brick buildings found in seismically active areas. To address this issue, this research investigated the in-plane behavior of 4 ft x 4 ft mud-brick walls strengthened with locally available materials i.e. Bamboo Strips and Dried Jute Thread in mesh format with various spacing. The specimens were subjected to compressive and diagonal shear loading separately. The data collected was analyzed to determine the important mechanical properties such as compressive strength, modulus of elasticity, shear strength, modulus of rigidity, and energy absorption. Notably, the bamboo strips technique improved these properties by 30 %, 19 %, 96 %, 82 %, and 195 %, respectively. The dried jute thread wrapping technique, on the other hand, demonstrated even greater improvements with increases of 40 %, 69 %, 102 %, 110 %, and 314 % for the same properties. Based on the experimental results, the proposed technique can be applied to mud-brick wall in seismically active areas.

Experimental study on eccentric compression of the prefabricated columns with a new type of column-column connection node

An assembled building is defined by a construction methodology wherein prefabricated components are fabricated off-site and subsequently assembled at the construction site. This methodology confers cost efficiency, expedites construction timelines, and enhances the quality of the prefabricated components. Furthermore, it mitigates a range of environmental concerns inherent to conventional poured-in-place construction methods. This paper introduces a novel assembled column-column connection node that utilizes a new adhesive potted rebar lap joint. The research was divided into two principal components. Firstly, 18 specimens of adhesive potted rebar lap joints were tested under tension, with the lap length being the variable parameter. Secondly, eccentric compression experiments were conducted on one poured-in-place column and six assembled columns, varying parameters such as stirrup configuration and the length of the post-poured section. The failure modes of the columns, as well as their bearing capacities, deflection, rebar strains, and concrete strains, were analyzed and recorded. The test results revealed the existence of two different failure modes in the tensile tests of adhesive potted rebar lap joints. It was found that the reasonable lap length of the specimen should be no less than 14 times the diameter of the rebar (d). Eq. (15) was employed to estimate the suitable lap length for specimens with different sleeve and rebar diameters. In the failure sections of the prefabricated columns, all failures occurred outside the nodes. Moreover, the mechanical properties of small eccentrically compressed columns were comparable to those of the poured-in-place column. The use of spiral stirrups enhances the bearing capacity of the specimen, and an increase in the length of the post-poured section corresponds to a greater bearing capacity. The lateral deflection of the poured-in-place column generally follows a sinusoidal curve, while the lateral deflection of prefabricated columns in the later stages of loading does not exhibit a sinusoidal pattern. Both align with the assumption of a flat section. The stress performance of adhesive potted rebar lap joints in eccentric columns meets the strength requirements. The inclusion of tenons minimally affects the stress distribution in the node, fulfilling construction specifications. The stress performance of the assembled column nodes is reliable. The proposed adhesive potted rebar lap joint technology, along with the novel prefabricated column-column node, provides significant insights into engineering design and construction applications.

Grain-based coupled thermo-mechanical modeling for stressed heterogeneous granite under thermal shock

Microscopic damage and macroscopic mechanical properties of granite under the coupling effect of thermal load and initial stress are crucial considerations for the safe construction of underground geo-energy engineering. However, visualizing real-time micro-crack processes in rocks under high-temperature and high-pressure conditions using the current experimental techniques remains challenging. In this study, a numerical method is developed to analyze the thermally induced damage in heterogeneous granite under the coupled influence of initial stress and thermal loading. A biaxial thermo-mechanical grain-based model considering real mineral distribution is established based on digital image processing technology, the grain-based modeling method, and heat conduction theory. The microscopic parameters are calibrated and the effectiveness of the model is verified based on thermal shock and uniaxial compression experiments. The thermal destruction mechanism of granite under initial stress from a microscopic perspective was unveiled for the first time. During the thermal shock process, the stress within the rock does not remain constant at the initial stress value. Instead, it changes continuously with the progression of heat conduction. The impact of the initial stress on the thermally induced cracks is relatively minor. Cooling causes more damage to the rock than heating during thermal shock. The intragranular cracks of quartz consistently outnumber other intragranular or intergranular cracks during thermal shock. The initial stress and thermal shock damage enhance and weaken the biaxial peak strength of granite, respectively. The weakening effect of thermal shock on the peak strength becomes more pronounced at a higher initial stress. These research findings and proposed research techniques contribute to the management and optimization of underground geo-energy engineering.

Research on Outlier Detection Methods for Dam Monitoring Data Based on Post-Data Classification

Safety monitoring of hydraulic structures is a critical task in the field of hydraulic engineering construction. This study developed a method for preprocessing and classifying monitoring data for the identification of gross errors in hydraulic structures. By utilizing linear regression and wavelet analysis techniques, it effectively differentiated various waveform characteristics in data sets, such as Sinusoidal Wave Cyclical, Triangular Wave Cyclical, Seasonal Cyclical, and Weakly Cyclical growth types. In the experiments for gross error identification, the 3σ algorithm, K-medoids algorithm, and Isolation Forest algorithm were applied to test the data. The results showed that the K-medoids algorithm excelled in processing Sinusoidal Wave Cyclical Data Sets; the 3σ algorithm adapted better to Triangular Wave Cyclical Data Sets; the Isolation Forest algorithm performed well in handling data sets with significant anomalies or atypical fluctuations and excelled in scenarios with strong seasonality and large data fluctuations; and for complex Weakly Cyclical Growth Data Sets, all three algorithms were less effective, indicating the potential need for more advanced analysis methods or a combination of multiple techniques. Testing on actual engineering data further confirmed the importance of using specific gross error identification techniques for special data types after data set pre-classification, providing a more effective technical solution for the safety monitoring of hydraulic structures.

COMBINED SUPERCHARGING SYSTEM OF DOMESTIC HIGH-PRESSURE TWO-STROKE SPECIAL PURPOSE DIESEL

Modern trends in engine construction are inextricably linked to the improvement of power units by modernizing existing models. The introduction of a forced to 1100 kW diesel engine of the DN type allows to increase the efficiency and bring the equipment in line with modern requirements in a short time and with lower costs. The key method of improvement is the modernization of the supercharging system, which increases power without increasing the dimensions and weight of the engine, as well as improves technical and economic characteristics. A combined supercharging system with a low-pressure turbocharger (LPT) and a high-pressure drive compressor (HPT) is proposed, which work together or separately depending on the operating mode. The use of a mathematical model of the workflow made it possible to carry out a computational and experimental study of the proposed system in the modes of maximum power and maximum torque, confirming its high efficiency. The use of modern technologies and materials, as well as the introduction of innovative design and modeling methods, allows to create more reliable and durable power units. Modernization of the supercharging system is one of the most important directions in the development of modern engine construction, which allows to achieve an increase in the level of specific power, improvement of fuel economy and environmental characteristics of engines by ensuring optimal conditions for their operation in various operating conditions and in a wide range of operating modes. The paper presents the research results of the proposed two-stage supercharging scheme of the DN type diesel engine, which makes it possible to achieve a power of 1100 kW. It is shown that this scheme has advantages over the traditional one, as it makes it possible to provide a higher boost pressure in a wider range of crankshaft RPM, as well as to reduce power consumption from the crankshaft to drive the compressor at modes close to the nominal ones. These factors collectively lead to a significant improvement in the characteristics of the diesel due to the introduction of the two-stage supercharging system.

Fractional-order burgers model for coral concrete creep

With the rapid development of marine engineering construction, coral aggregate has been widely applied in practical engineering. Its creep characteristics must be emphasized, but only a few experimental studies have been conducted, and theoretical research has not yet been reported. In this study, based on the traditional Burgers rheological model and using the fractional order software components Able dashpot, constructs a fractional order creep model for coral concrete and provides a calculation method. Comparison shows that the traditional Burgers rheological model cannot adjust the creep rate and development degree in calculations, resulting in a large deviation between its predicted results and experimental values. However, the fractional order model established in this paper aligns with the creep development law of coral concrete, and its calculated values match well with experimental values, making it suitable for predicting the creep characteristics of coral concrete under different water-cement ratios. Sensitivity analysis of the fractional order can achieve effective control over the prediction of creep development in coral concrete in practical engineering. The fractional order creep model established in this paper can provide a basis for predicting and evaluating the long-term performance of coral concrete in practical engineering.

Brief analysis of the innovation work in civil engineering technology

Under the new situation, the development process of urbanization is accelerating, the construction industry is developing well, the number and scale of civil engineering projects are gradually expanding, and the construction technology, as the core of the project construction, has always been the focus of people's attention. Because the construction quality will directly affect the safety of personnel, it is necessary to clarify the characteristics of construction technology and improve the existing civil engineering construction technology. Realize the technical innovation of foundation pit construction, prestressed construction, reinforced concrete construction and other links, improve the technical content of engineering construction under the premise of ensuring the construction quality, and extend the service life of the building as far as possible.

Advanced informatic technologies for intelligent construction: A review

Since there is a growing interest in driving the digital transformation of the construction industry, the goal of this paper is to provide a full picture and understanding of the emerging research front on intelligent construction. Through the quantitative and qualitative analysis, relevant pieces of literature are thoroughly reviewed to extract useful knowledge to raise awareness of intelligent construction, resulting in the summary of research status and the determination of future needs. In light of the research findings, the rapid development of intelligent construction follows the strategies of standardization, digitization, intellectualization, collaboration, greenization, and customization, which mainly support “4S” technologies. The popular research topics covering intelligent engineering services for the project's full lifecycle (i.e., design, construction, operation, and maintenance) and even the city level have been deeply explored, which are proven to dramatically improve project efficiency, safety, and automation. Moreover, challenges exist in three potential paths for future research, including the digital twin-enabled engineering cloud platform, man-machine-environment interaction, great sustainability under carbon peaking and carbon neutrality goals. As for the practical value, a synthesized point of up-to-date reference is created to guide managers to promote intelligent construction in real-world engineering.

Supply–Demand Matching of Engineering Construction Materials in Complex Mountainous Areas Based on Complex Environment Two-Stage Stochastic Programing

Supply–Demand Matching of Engineering Construction Materials in Complex Mountainous Areas Based on Complex Environment Two-Stage Stochastic Programing

Research Progress on the Microstructure Evolution Mechanisms of Al-Mg Alloys by Severe Plastic Deformation.

Al-Mg alloys are widely used as important engineering structural materials in aerospace engineering, transportation systems, and structural constructions due to their low density, high specific strength, corrosion resistance, welding capability, fatigue strength, and cost-effectiveness. However, the conventional Al-Mg alloys can no longer fully satisfy the demands of practical production due to difficulties caused by many defects. The high strength of Al-Mg alloys as non-heat treatment precipitation-strengthened alloys is achieved primarily by solid solution strengthening along with work hardening rather than precipitation strengthening. Therefore, severe plastic deformation (SPD) techniques can be often used to produce ultrafine-grained structures to fabricate ultra-high strength aluminum alloys. However, this approach often achieves the strengthening of material at the cost of reduced ductility. This paper comprehensively summarizes the various approaches of ultrafine/nanocrystalline materials for enhancing their plasticity, elaborates on the creation of a bimodal microstructure within the alloy, and discusses the formation of a nanotwin microstructure within the alloy and the incorporation of dispersed nanoparticles. The mechanisms underlying both the strengthening and toughening during large plastic deformation in aluminum alloys are summarized, and the future research direction of high-performance ultrafine crystalline and nanocrystalline Al-Mg aluminum alloys is prospected.

A Novel Dataset Replenishment Strategy Integrating Time-Series InSAR for Refined Landslide Susceptibility Mapping in Karst Regions

The accuracy of landslide susceptibility mapping is influenced by the quality of sample data, factor systems, and assessment methods. This study aims to enhance the representativeness and overall quality of the sample dataset through an effective sample expansion strategy, achieving greater precision and reliability in the landslide susceptibility model. An integrated interpretative framework for landslide susceptibility assessment is developed using the XGBoost-SHAP-PDP algorithm to deeply investigate the key contributing factors of landslides in karst areas. Firstly, 17 conditioning factors (e.g., surface deformation rate, land surface temperature, slope, lithology, and NDVI) were introduced based on field surveys, satellite imagery, and literature reviews, to construct a landslide susceptibility conditioning factor system in line with karst geomorphology characteristics. Secondly, a sample expansion strategy combining the frequency ratio (FR) with SBAS-InSAR interpretation results was proposed to optimize the landslide susceptibility assessment dataset. The XGBoost algorithm was then utilized to build the assessment model. Finally, the SHAP and PDP algorithms were applied to interpret the model, examining the primary contributing factors and their influence on landslides in karst areas from both global and single-factor perspectives. Results showed a significant improvement in model accuracy after sample expansion, with AUC values of 0.9579 and 0.9790 for the training and testing sets, respectively. The top three important factors were distance from mining sites, lithology, and NDVI, while land surface temperature, soil erosion modulus, and surface deformation rate also significantly contributed to landslide susceptibility. In summary, this paper provides an in-depth discussion of the effectiveness of LSM in predicting landslide occurrence in complex terrain environments. The reliability and accuracy of the landslide susceptibility assessment model were significantly improved by optimizing the sample dataset within the karst landscape region. In addition, the research results not only provide an essential reference for landslide prevention and control in the karst region of Southwest China and regional central engineering construction planning but also provide a scientific basis for the prevention and control of geologic hazards globally, showing a wide range of application prospects and practical significance.

A study on the response of waterbird diversity to habitat changes caused by ecological engineering construction

Wetland degradation is a major factor in the decline of biodiversity. Ecological engineering construction efforts, such as water diversion, have been the main method of wetland restoration. To reveal the effects of biodiversity conservation and ecological engineering construction in the semiarid regions of China, waterbird surveys were carried out 2 years before and 8 years after the construction of the ecological engineering project discussed in this study. The relationships among waterbirds and habitat landscape patterns, hydrology and vegetation conditions were analyzed. The impacts of ecological engineering on habitats and waterbird diversity were revealed. The results showed that (1) there were significant changes in land use, hydrological distributions and vegetation cover in the study area before and after the construction of the ecological project. The quality of waterbird habitats after the construction project was better than that before construction. However, there were fluctuating conditions. (2) The areas of water bodies and marshes were positively correlated with the number and diversity of waterbirds. However, increases in arable land, forestland, grassland and saline land can stress rare waterbirds. Changes in water levels, water body areas and vegetation cover in the conservation area all directly affect the availability of waterbird habitats, which can affect waterbird diversity. The wetland water level is the most important impact factor. (3) The annual water diversion volume in the study area is 5.00 × 107 m3. When the water level is maintained at approximately 1.5-2.5m, the number of waterbirds remains stable. This study can provide scientific guidance and a methodological basis for the construction of ecological projects with waterbirds as protected targets.

Research on the diffusion plugging mechanism of flowing water grouting slurry in karst pipelines

Among the many adverse geological disasters, the surge water disaster in karst areas causes the greatest loss to underground engineering construction, so it is necessary to carry out relevant research on the management of surge water disaster in karst pipelines. This study presents the creation of an oily epoxy resin magnetic convergence grouting material (OEMS) specifically developed to prevent water infiltration in pipelines. A self-designed visual karst pipeline grouting simulation system was used to conduct an experimental study on the diffusion and plugging behavior of magnetic slurry grouting. A model was constructed to simulate the migration of a magnetic slurry in water inrush circumstances. The model is based on the theory of slurry diffusion and the concept of magnetic adsorption. The results suggest that:(i) The best performance in grouting sealing is achieved when the ratio of new OEMS epoxy resin A liquid to B liquid is 2:1, and the blending ratio of flyash and Fe3O4 powder falls between 25 and 55%. (ii) The primary and secondary correlations among the parameters that affect the rate of change in flow rate, plugging pressure, and slurry retention rate are as follows: Hydrodynamic velocity has the greatest correlation, followed by plugging length, Fe3O4 power ratio, and flyash mixture ratio. (iii) The validity of the model is verified by comparing empirical observations with calculated theoretical values.