Application and Development of Data Simulation and Mechanical Analysis in Civil Engineering

To analyse the merits of different reinforcement schemes for shear walls under varying steel substitution rules, specimens with different reinforcement configurations were designed. Finite element analysis was employed to analyse the peak displacement, shear capacity, and cost of each specimen. The results indicate that the reinforcement configuration under Rule 1 for Specimen 1 is superior. At a shear span ratio of 0.95, the peak displacement of the shear walls is 7.0 mm, and the shear capacities of all specimens are comparable. At a shear span ratio of 2.5, the peak displacement of the shear walls is 8.4 mm, and the shear capacities of Specimens 1 to 3 are increased by 1.7%, 3.5%, and 4.1%, respectively. Following steel substitution, Specimens 1 to 3 exhibit a cost increase of approximately 1.2 to 1.47 times compared to cast-in-place wall reinforcement costs.

Two special soil types, black soil (clayey) and brown soil (sandy loamy), are distributed in China. Succession cropping obstacle for corn (maize) and peanut occurs frequently in these areas. A soil layer displacing plough prototype was developed to diminish the injury. The prototype displaced the upper soil and subsoil. Test fields were conducted in October 2013. Soil conditions were investigated in June 2014. The results show that the soil temperature in the operated field was 1–3 ºC higher than CK. The soil-water permeability coefficient in the operated field was about 3.3 times greater than CK.

Advancing building energy efficiency represents a crucial pathway toward decarbonizing the construction industry. This study is based on the bibliometric method to analyse the quantitative analysis of academic literature related to building energy efficiency technology in China in web of science database from 2017 to 2024. By studying the publication trends, journal characteristics, number of article citations, research contributions from academic institutions, as well as the popular keywords of research and the future direction of theme evolution in this field, the study provides a reference value for researchers’ future research collaborations. The findings reveal that a rapid development in China’s building energy efficiency research, with CHEMICAL ENGINEERING JOURNAL emerging as one of the most influential journals in this field. The analysis identifies WANG Y, ZHANG Y, LIU Y, and WANG L as the most influential researchers in building energy efficiency technology. Institutionally, the Chinese Academy of Sciences lead in research output and impact. Emerging trends are reflected in the fastest growing keywords such as “energy efficiency”, “photocatalysis”, and “machine learning”. However, the application of advanced methodologies like “deep machine learning” is not yet common in China's building energy efficiency, highlighting a critical area for future exploration. This paper provides a comprehensive foundation for guiding collaborative efforts and deepening scholarly engagement in building energy efficiency technologies.

Prefabricated buildings, as an efficient and sustainable construction method, have garnered increasing attention in the industry. However, the complexity of engineering processes and human factors contribute to significant rework risks, which can adversely affect project schedules and quality. This study employs a system dynamics approach to analyze and optimize the prefabricated construction (PC) process, with a focus on mitigating rework risks. Through comprehensive modeling and empirical research, the study proposes several optimization strategies aimed at reducing rework and enhancing project outcomes. The findings indicate that addressing design module issues can significantly reduce production errors and quality defects in assembly components, thereby decreasing the likelihood of rework. Furthermore, optimizing construction techniques enhances efficiency and minimizes the need for adjustments during construction. Improved collaboration and communication within teams further enhance project management, reducing the potential for misunderstandings and errors. The implementation of these strategies not only accelerates project timelines and controls costs but also supports the sustainable development of the construction industry. This study underscores the critical importance of optimizing PC processes, offering innovative methodologies that effectively reduce rework risks, improve quality control, and elevate overall project performance. These insights provide valuable guidance for industry practitioners seeking to optimize construction outcomes and achieve greater efficiency and sustainability in their projects.

The tensile properties of ultra-high performance concrete (UHPC) with ceramic fiber volume fractions of 0%, 0.3%, 0.6%, 0.9%, and 1.2% were evaluated through splitting tensile tests at high temperatures (200–800 ℃). The effects of temperature and fiber content on the tensile strength of UHPC at elevated temperatures were investigated. Based on the tensile strength data after high-temperature exposure, the microstructure and phase composition of UHPC subjected to different temperature conditions were analyzed using scanning electron microscopy (SEM). The results indicate that the heating temperature is the primary factor influencing the tensile strength of UHPC, with the tensile strength being highly sensitive to temperature variations. As the temperature increases, the splitting tensile strength of UHPC exhibits a linear decline. The tensile properties of ceramic fiber reinforced UHPC at high temperatures are superior to those of unreinforced UHPC. Notably, when the ceramic fiber content is 0.9%, the loss in splitting tensile strength of the ceramic fiber reinforced UHPC after high-temperature exposure is the least.

The high-temperature properties and microstructure of ceramic fiber reinforced ultra-high performance concrete (UHPC) were evaluated through compressive strength and scanning electron microscope (SEM) tests at various temperatures. This research delved into how temperature and fiber content affect the visible appearance, mass loss rate, compressive strength, and microstructural alterations of UHPC. The findings demonstrated that incorporating ceramic fibers leads to a reduction in the concrete’s mass loss rate. When the heating temperature is less than 400 °C, ceramic fibers are effective in decelerating the decrease in compressive strength. But as the temperature rises further, the hydration products in the concrete start to decompose at a faster pace. Due to the concurrent influence of pore pressure, thermal stress, and the radial tensile stress emerging from the differences in thermal expansion coefficients, the compressive strength of the ceramic fiber - reinforced Ultra - High Performance Concrete (UHPC) plummets rapidly. Nevertheless, at any given temperature, the compressive strength of the fiber - reinforced UHPC remains significantly greater in comparison to that of the non - reinforced UHPC.

Alkali-activated sediment cementitious material was prepared using Zipingpu reservoir sediment as the main raw material, S95 slag powder as the admixture, and Ca(OH)2 as the activator. The samples were characterized by XRD, TG-DTA, SEM, and other analytical methods to explore the impacts of varying Ca(OH)₂ contents on both the macroscopic and microscopic properties of alkali-activated cementitious materials made from Zipingpu reservoir sediment. The results indicate that as the Ca(OH)₂ content rises, the compressive and flexural strengths of the Zipingpu reservoir sediment cement blocks initially display an upward trend and subsequently a downward trend. When the Ca(OH)2 content is 10%, the compressive and flexural strengths of the cement blocks in 28 days are the highest, which are 27.30 MPa and 5.47 MPa respectively. Microscopic analysis shows that with the increase of Ca(OH)2 content, the content of hydration products in the Zipingpu reservoir sediment cemented block gradually increases, and the cemented block structure becomes denser and denser. However, when the Ca(OH)2 content is 12%, excessive alkali activator causes the skeleton structure of the cemented block to be destroyed and the strength is reduced. The Comprehensive analysis of the mechanical properties and structural composition of cemented blocks with different Ca(OH)2 content shows that the optimal Ca(OH)2 content is 10%.

Reservoir sediment replaces clay and shale for the preparation of sintered bricks, which is of great significance to the country’s protection of cultivated land and mountains, exploration of new models of sediment utilization, and organic integration of high-quality regional social development. This paper systematically reveals the effects of different forming pressures, mix ratios, and sintering processes on the performance and microstructure of sintered bricks prepared from Zipingpu reservoir sediment. These results are capable of offering scientific backing for the multi-channel utilization of the sediment from Zipingpu reservoir. Research shows that a) For the Zipingpu reservoir sand sintered brick, the optimal preparation process parameters are as follows: the forming pressure is 600 kN, the sintering temperature is 925 °C, and the sintering time is 1 h. Under these conditions, the obtained sintered brick has a compressive strength of 29.64 MPa. b) The mineral components of the sintered products are quartz, plagioclase, potassium feldspar, pyroxene, and magnetite. Quartz and calcite in the sand decompose at high temperatures and react to form plagioclase and potassium feldspar. c) The infrared absorption peaks of sand and sintered bricks all appear near 3429 cm−1, 1632 cm−1, 1431 cm−1, 1023 cm−1, 767 cm−1, 530 cm−1, and 467 cm−1.

Large hydropower projects in the high mountainous and canyon regions of western China often encounter toppling slopes presenting significant challenges such as controlling large deformations, managing substantial movements caused by minor disturbances, and handling complex construction conditions. During blasting excavation, the vibration mechanism of toppling slopes with a layered structure differs markedly from that of conventional rock slopes, lead to distinctive dynamic responses. Consequently, establishing safety control standards related to slope stability is a critical research focus for such topping slopes. This paper examines these challenges at the Miaowei Hydropower Station on the Lancang River. By analyzing blasting vibration monitoring results collected during construction period, along with rockmass structure assessments, provides a comprehensive analysis of the blasting vibration mechanism from the perspectives of blasting excavation dynamics, excavation procedure, slope morphology, and rock mass discontinuity characteristics. Additionally, based on discrete element numerical methods for dynamic analysis, a feedback analysis of the slope blasting excavation process was conducted, leading to the proposal safety control standards based on two key parameters: blasting excavation charge and particle vibration velocity. Specifically, the single-shot charge should not exceed 30 kg, the total charge for per blast should not exceed 600 kg, and the particle velocity of the blasting vibration should not exceed 4 cm/s.

Large-diameter shield tunneling involves excavating a substantial section at significant depths and torques, which can disturb the surrounding rock and soil, particularly in regions characterized by intense karst development. Currently, research on the disturbance and deformation characteristics, stress mechanisms induced by tunneling, and deformation modes of karst caves and strata is limited. This paper investigates the stress mechanisms when large-diameter shield tunneling traverse karst-rich regions. To facilitate real-time monitoring of the surrounding rock pressure during shield tunneling, a novel monitoring method is proposed. By analyzing the real-time data, this study examines the stress patterns and mechanisms acting on the tunnel sidewall during shield tunneling. It is observed that the positive pressure on the tunnel sidewall typically increases and then decreases due to the soil chamber pressure exerted by the shield tunnel during excavation, resulting in a residual positive stress after tunneling is completed. Additionally, the lateral pressure on the tunnel sidewall experiences two distinct additional pressures. The first is due to the soil chamber pressure from the shield before the cutterhead reaches the area, and the second is induced by the synchronous grouting pressure during the assembly of tunnel segments. A residual lateral stress remains even after the shield tunnel has passed through. At a distance of 2.6 m from the tunnel sidewall, the additional total stress in the surrounding rock accounts for 39% of the initial horizontal geo-stress, while the residual additional total stress constitutes 30% of the initial horizontal geo-stress. This study provides a foundational understanding of the stability of karst cave sidewalls during large-diameter shield tunneling. Furthermore, it offers valuable data support for future large-diameter shield tunneling projects in areas with significant karst development and artificial structures.

For assessing the safety performance of a structure in service, the ultimate pile bearing capacity is an important parameter. The literature indicates that experimental data on pile bearing capacity can be utilized to make quick and accurate predictions. Random forest is employed for these predictions, while five distinct algorithms are utilized to optimize the process: PSO, SSA, WSO, GWO, and DBO are all optimization algorithms used in engineering and computer science. These algorithms are designed to solve complex optimization problems by mimicking the behavior of animals in their natural habitats. An unused subset is selected randomly and evaluated with appropriate metrics to assess the model. Based on the results, the R2 values for the five models are 0.9103, 0.8766, 0.9410, 0.9133, and 0.9687 for RF-PSO, RF-SSA, RF-WSO, RF-GWO and RF-DBO. As far as Mean Absolute Percentage (MAP) is concerned, the RF-DBO model has the lowest optimal MAP. The RF-DBO prediction model has the lowest RMSE (3.6232) and MAPE among all models, making it the most accurate, stable, and effective in predicting pile capacity. It outperforms the RF-PSO, RF-WSO, and RF-GWO models in these categories.

As a base, cement-stabilized macadam material offers high strength, which increases with curing age, good plate properties, low deflection and strong load diffusing capacity. However, the poor anti-shrinkage performance and self-healing ability of the semi-rigid base lead to the cracking of the base, which leads to cracks in the asphalt pavement. Crack disease has become the most prevalent disease impacting pavement structure. The fracture resistance of the cement-stabilized macadam base has a direct impact on the service life of asphalt pavement. Based on Yan-Chong expressway test segment, this article proposes laying basalt fiber belt in a cement-stabilized macadam base to construct reinforcement, employing the interface bonding friction force and mechanical biting force between the continuous fiber belt and cement to accomplish anti-crack properties. To investigate the effect of basalt fiber belt of varying width and curing age on the Unconfined Compressive Strength (UCS) index of a cement-stabilized macadam base, the compressive strength of a cement-stabilized mixture of varying width and curing age was measured under indoor experimental conditions. The test findings demonstrate that as the curing age increases, so does the UCS of the specimens without basalt fiber belt, 25 mm width and 50 mm width. Nevertheless, at 7 and 28 days of curing, the specimens laid with a laid with basalt fiber belt had a lower UCS than the unlaid specimens, and the difference was closing as the curing age increased. The UCS of reinforced cement-stabilized macadam with a 25 mm wide basalt fiber belt at the 90-day curing age is nearly identical to that of cement-stabilized macadam with standard mix ratio. Additionally, the strength difference of a 50 mm wide basalt fiber belt has also been cut in half.

The restaurant of a hotel in Shenzhou is an inner frame structure, with a total weight of more than 6000 tons. Due to the acceptance requirements of the fire passage and the safety control of the surrounding environment, the construction scheme of moving 9 m southward was adopted. Aiming at the problem of large volume of the mixed structure, the translation technology of steel rollers and incremental launching was adopted, making full use of the original structure foundation to lay the lower track, and the upper track underpinning beams were connected to form a truss, forming a stable tray structure system. The hydraulic control system was started for incremental launching, and finally the project goal was successfully achieved, providing a reference for the solution of similar projects.

The dam of Tuanzhouyuan in Yueyang City serves as the research subject. FLAC3D software is employed to develop an unsaturated seepage calculation program, which is then utilized to perform thermo-hydro-mechanical (THM) coupling calculations for the levee. The program enables a detailed analysis of the distribution patterns of the seepage field and temperature field within the levee body and its foundation. By doing so, the study aims to elucidate the correlation between the seepage field and the temperature field comprehensively. Moreover, through an in - depth analysis of the evolution characteristics of the backwater slope temperature and flow velocity, the feasibility of using infrared detection for identifying seepage - related hidden dangers is demonstrated. The research findings reveal a strong synchronicity between the variations in the seepage field of the levee foundation and the evolution of temperature. Specifically, when the flow velocity at the measurement points within the levee body and foundation increases, the temperature shows a sharp decline. By capturing the difference between the temperature at any given moment and the initial temperature at different positions on the backwater slope, it becomes possible to accurately locate the seepage center. This achievement can contribute significantly to realizing the objective of “early detection and effective response” in flood control and emergency rescue operations.

The surrounding rock experiences the combined impacts of elevated ground stress, high water pressure, and hot groundwater during the deep-buried tunnels with high water temperatures. The stress in the surrounding rock and groundwater flow significantly affects the temperature variations in the tunnel's construction environment. Therefore, studying heat insulation and cooling measures while constructing high-water temperature tunnels is significant. This study uses a numerical simulation method to analyze water plugging and cooling feasibility in high-water temperature tunnels through grouting measures under thermal-fluid-solid coupling conditions. The variation characteristics and laws of the tunnel's stress field, seepage field, and temperature field surrounding rock under different grouting parameters are discussed. The results show that underground hot water is significantly lost when tunnels are excavated without grouting, and the tunnel wall's cooling effect is inferior. After constructing a 5 m grouting ring, excavating the tunnel significantly affects the seepage and temperature fields within the grouting ring. The seepage flow of underground hot water in the tunnel is reduced to about 1/2942 of its original value before grouting, and the temperature of the tunnel wall is significantly reduced. Through orthogonal testing, the order of influence of different grouting parameters on the average temperature of the tunnel wall is determined as follows: grouting permeability k > grouting thickness d > solid thermal conductivity of the grouting ring λ > thermal expansion coefficient of the grouting ring β.

With the increasing demand for aggregate 1 in engineering, the shortage of natural river sand resources and the environmental protection requirements of the project itself are constantly improving. It is an inevitable trend to replace some natural river sand to artificial sand. This experiment is used the control variable method to adjust the mixed ratio of artificial sand and river sand in concrete. Concrete of C30 strength grade is prepared in accordance with specifications with other mix ratios constant. After 28 days, it will be took out from the concrete curing room and carried on the compressive strength test. And we use the XRD of the crushed concrete block and the SEM of the microscopic electron microscope scanning to analyze the concrete and record the influence of the different mixed ratio on the compressive strength of concrete.

Foamed mixture lightweight soils are a mixture of cement, water, foam and soil, which are largely used in civil engineering. Soils are skeleton support structure of foamed mixture lightweight soils and can greatly impact their physical and mechanical properties. This study investigated the effect of fine fraction and sand content on the physical and mechanical properties of sand-based foamed mixture lightweight soil (FMLS), including flowability, wet density and unconfined compressive strength (UCS). Three fine fractions of sand, 13.5%, 14.5% and 15% were selected for the test. These sands replaced the cement with different proportions (0%–80%), and then mixed with the foaming agent to prepare specimens. Experimental results showed that as the sand content increases, the flowability, wet density and unconfined compressive strength all show a decrease variation. Low fine fraction can provide better properties. At the same sand content, FMLS with 13.5% fine fraction has the highest strength. In terms of the experimental results, an empirical-analytical model taking into account the effect of fine fraction and sand content to predict the unconfined compressive strength value for sand-based foamed mixture lightweight soils was proposed. The developed model can be further used for strength evaluation of foamed mixture lightweight soils.

During the excavation of water-rich cave tunnels, it remains crucial to establish the safe rock pillar thickness at the excavation face to define the required reinforcement measures and guarantee operational security throughout engineering processes. Many factors, including geological conditions, the extent of karst development, and the water pressure within the karst cavity, influence the thickness of the safety rock pillar in a karst tunnel. Utilizing the displacement mutation criterion of the tunnel face, the safe rock pillar thickness for the karst tunnel is quantified through finite element modeling. The methodology commences with a test of the tunnel rock's geomechanical behavior, followed by parameter calibration for the tunnel's geological envelope. Based on the experimental correction parameters, the numerical simulation of the longitudinal deformation characteristics at the karst tunnel face is carried out, ultimately identifying the critical proximity range between solution cavities and working faces that triggers interfacial displacement instabilities. The thickness of the safe rock pillar is computationally determined through displacement mutation criterion at the tunnel face, with systematic investigation revealing the thickness of the safe rock pillar and its variation law across varying geostatic stresses and hydrostatic conditions. The results show that: (1) As submersion duration increases, the surrounding rock's cohesion and internal friction angle typically demonstrate a declining trend, resulting in reduced shear strength of the rock mass. (2) Under deeply buried conditions, the precision of the stratum structure method and its convergence limitations lead to reduced accuracy in determining safe rock pillar thickness when abrupt displacement occurs at the tunnel face, particularly when the karst cavity is positioned 1 m to 4 m from the tunnel face. (3) Integrating numerical modeling with displacement anomaly criteria enhances the accuracy of safe rock pillar thickness calculations during abrupt displacement events at the tunnel face. The required thickness of the protective rock barrier rises proportionally with increased hydraulic pressure within the cavity and the tunnel's burial depth.

Based on a sewage treatment plant (STP) in the Philippines, this article introduces the structural seismic design mainly under the control of U.S. codes. The comparison highlights the difference between U.S. codes and Chinese codes in terms of seismic load, which including dynamic water pressure, response spectrum, the two stage analysis method, etc. Through comparison, it can be seen that the U.S. codes are more detailed in seismic load definition than Chinese codes. The article also points out the critical points and difficulties in the seismic design of STP projects or water-retaining structure based on U.S. codes, providing valuable reference for similar STP oversea projects in the future.

Plenty of particle transport and sedimentation in arid and semi-arid areas are threatening the development of photovoltaic, wind power and other industries. However, the lack of basic experimental data has severely limited the understanding of particle motion processes and subsequent disaster prevention work. We carried out the dust diffusion and settlement in mountainous area experiment in environmental wind tunnel using 100 μm, 300 μm, 500 μm and 300 μm mixed with 500 μm sand particles. The wind speed profile changes dramatically at the mountain model position and the large wind velocity gradient provide significant aerodynamic forces to the sand particles and affect their trajectories. With the increase of sand particle size, the strength and probability of collision between particles and particles are greater, resulting in a larger gap between particles and particles. Sand particles at 500 μm are more affected by gravity and form flatter trajectories. Sedimentation distributions are all single-peak curves with different particle sizes, and the larger horizontal transport flux will result in an asymmetrical distribution of sand settlement. Large particles and small particles interact with each other and the result that the sedimentation peak location is averaged.

Significant progress has been made in the field of aeolian sand geomorphology and desert environment evolution in the past decades, but the understanding of dune development mechanism under the influence of power transmission towers is still insufficient. In this paper, Real-Space Cellular Automaton Laboratory (ReSCAL) dune model is used to simulate the evolution process of barchan dune around transmission tower under different wind velocities and dune sizes. Results show that transmission tower changes the local wind field and forms some small tail structures in the rear side of the tower due to the change of the wind field. The influence of the transmission tower on the height of the dune is most obvious, and the maximum height difference reached about 2 m. The height of the dune increases first and then decreases with time, and the time of this turning point increases with the decrease of wind velocity. The maximum height difference reached about 1 m in different wind velocity simulation cases. Small dune is more easily affected by the transmission tower, and dunes of different sizes eventually tend to form the same height.

The anchorage structure is subjected to the coupling effect of multiple corrosion factors in the process of long-term service, resulting in corrosion damage of the anchors. This paper reviews the research on the durability of anchorage structure in complex environments. Firstly, the main factors influencing the corrosion of anchorage structure are discussed, which includes stress, humidity, temperature, oxygen concentration, and the pH. Secondly, several commonly accelerated corrosion test methods, such as the salt spray test, electrochemical corrosion test, and immersion corrosion test, are introduced, and their applications in the durability study of anchorage structure are summarized. Finally, the corrosion assessment criteria and methods are summarized, and it is pointed out that future research should strengthen the exploration of corrosion mechanisms and introduce intelligent monitoring means and new material technologies to improve the assessment of the durability of anchorage structure.

A large number of deep fractures have formed on the bank slopes of the Jinping First-Tier Hydropower Station, particularly on the left bank slope. These fractures have a significant impact on slope stability, underground powerhouse safety, and dam construction. Despite numerous studies conducted on their formation mechanisms and evolutionary trends, a consensus has yet to be reached. This study attempts to simulate the dynamic evolution of deep fractures during the process of valley downcutting using a self-developed continuous-discontinuous deformation analysis method. The findings indicate that changes in boundary conditions resulting from valley downcutting lead to alterations in slope stability, which in turn induce deformation towards the outside of the slope and the formation of deep tensile (or tear) fractures. Notably, when the valley is incised to an elevation ranging from 1,650 m to 1,900 m, deep fractures not only expand but also generate new fractures that interconnect with each other. The evolution of high slope configurations and the self-dynamic adjustment process of high stresses are largely driven by the boundary condition changes brought about by valley downcutting, ultimately leading to the creation of deep fractures. The research findings have significant implications for the theoretical understanding and practical mitigation strategies for deep fractures in hydropower station engineering.

Large LNG storage tanks can be damaged easily when subjected to strong earthquakes. If the leakage occurs due to structural damage or excessive liquid shaking amplitude, it will lead to a series of secondary disasters, resulting in catastrophic economic losses and social impacts. The occurrence of ground motion is highly random. At present, most of the time-history analysis of LNG storage tanks adopts classical ground motion records, which cannot be guaranteed to match the focal mechanism and site characteristics. Deterministic ground motion records are adopted, and the consideration of non-stationary random characteristics of ground motion is not perfect. To study the failure mode of LNG storage tank under earthquake action, evaluate the ability of LNG storage tank to complete the predetermined function in a probabilistic sense, and study the seismic reliability of LNG storage tank have important theoretical significance and guiding value for engineering structure decision, design and evaluation.

Using Xixiayuan Reservoir sediment as the main raw material and S105 slag powder as the admixture, the influence of different Na2SiO3 content and different alkali excitators co-excitation on the compressive strength of Xixiayuan Reservoir sediment cemented blocks was investigated. The results show that the optimal doping amount of Na2SiO3 for single excitation is 8%. Double excitation can effectively improve the compressive strength of Xixiayuan sediment cemented blocks. With the increase of alkali activator content, excessive alkali appears in the cemented block, which affects the compressive strength.

Estimation of dielectric constants is crucial for locating underground cavities. A typical method for determining the dielectric constants of soil layers is the inverse analysis based on ground penetrating radar (GPR) data. This study proposes an efficient probabilistic inverse analysis method for multi-layer dielectric constants by integrating Bayesian inference and a Bidirectional Long Short-Term Memory (BiLSTM) model. The BiLSTM model serves as the forward model in the inverse analysis, which is trained based on a dataset generated from finite-difference time-domain (FDTD) simulations. The dielectric constants and thicknesses of soil layers are inferred by incorporating measured data, and their posterior distributions are obtained through Markov Chain Monte Carlo (MCMC) sampling. A three-layer soil case is used to illustrate and validate the proposed method. The results show that the proposed method can efficiently and accurately estimate the dielectric constants and thicknesses of multi-layer soils, while also effectively quantifying the associated uncertainties.

This study investigates at the influence of five Warm Mix Asphalt Chemical Additives (WMACAs)—Evotherm M1, Rediset RLQ1200, ZycoTherm, Fastac, and Ecogreen REJ—on the rheological and mechanical properties of asphalt mixtures, focusing on aging and aggregate interactions. Multiple Stress Creep Recovery (MSCR) and Linear Amplitude Sweep (LAS) were performed to assess deformation and fatigue resistance, while chemical oxidation was analyzed using Fourier Transform Infrared Spectroscopy (FTIR). Mechanical properties were examined through the Indirect Tensile Strength (ITS) test, Tensile Strength Ratio (TSR), and Hamburg Wheel Tracking Test (HWTT) on specimens compacted using Superpave gyratory compaction in accordance with AASHTO specifications. The results indicate that WMACAs do not significantly affect the asphalt binder itself. However, the type of aggregate plays a crucial role in performance. Nantou aggregates improved additive efficacy, resulting in enhanced tensile strength, rutting resistance, and durability, whereas Hualien aggregates were associated with reduced performance. Among the additives, ZycoTherm exhibited superior resistance to deformation, moisture, and aging, making it particularly suitable for high-stress applications. The study highlights the need for selecting effective WMACAs and compatible aggregates to optimize pavement durability.

Addressing the challenges of low sensitivity and inadequate spatial resolution in conventional deep displacement monitoring methods, a novel approach is introduced that involves the surface mounting of ultra-weak fiber Bragg grating (UW-FBG) fiber optic cables to the inclined tube for monitoring deep displacements of landslides. The UW-FBG strain sensing principle is theoretically analysed, and the calculation formula for wavelength shift in relation to deflection and displacement is derived. The strain characteristics of the UW-FBG fiber optic cable are calibrated in the laboratory, and the performance of the UW-FBG fiber optic cable, when applied to the surface of an inclinometer tube, is experimentally validated. This technology is then implemented for monitoring landslides on the banks of the Three Gorges region. The findings indicate that the deflection values obtained from the UW-FBG inclinometer structure closely align with the actual deflection values measured by a micrometer, with an error margin of approximately 0.5 μm and a transfer efficiency of 95.51%. This method accurately captures deep displacement during the rainy season in landslide monitoring, offering a highly promising solution for the surveillance of deep displacement.

Liaojiaxi railway bridge is the key node of Chongqing Rail Transit Line 15 in China. The concrete beam-steel arch composite rigid frame system is innovatively adopted, that is, the conventional prestressed concrete continuous rigid frame is combined with the deck type steel arch to form an open-web main girder composed of upper chord concrete beam and lower chord steel arch rib, which can overcome the disadvantages of long-term deflection and web cracking of conventional long-span concrete rigid frame bridge. The upper and lower chords of the main bridge are constructed by the hanging basket balanced cantilever method. Due to its small section size, the cable-stayed suspension system is used to assist the structural force during the construction period in order to better control the line shape. Based on the conventional diamond hanging basket, the crane system is added to form an integrated construction equipment, which realizes the synchronous operation of cantilever concrete pouring and arch rib assembling in the narrow space. A special temporary locking device for the upper and lower chord closure section is developed, which is well adapted to the deformation differences caused by temperature, shrinkage, creep, and other effects in steel-concrete structures. Practice has proven that this new bridge type has significant technical and economic advantages in the span range of 200–400 m, and has promotion and application value.

In practical engineering applications, structures typically exhibit a rigid-flexible coupled vibration effect, resulting in large nonlinearities in structural components and load identification accuracy being greatly affected. Since most load identification methods do not consider structural flexibility, this paper based on Simpack to establish a flexible beam to consider the multi-body coupling vibration effect of the beam structure, and simulate and experimentally study the load identification. Firstly, the multi-body dynamic model of flexible cantilever beam is established, and the coupling vibration response of the beam under concentrated dynamic load is obtained. Secondly, the truncated singular value decomposition (TSVD) regularization methodis selected to solve the flexible body load equation and find the optimal solution of the equation. Finally, through numerical simulation, the identification results of flexible beam structure under different loads are analyzed, and the effects of different noise levels and different response data on the identification results are discussed. The results show that for the flexible beam, the method can accurately identify various forms of loads on the structure by using the displacement response and velocity response, but the identification effect is not ideal for the sudden change load such as square wave load, and it is easy to be affected by noise. Additionally, it should be noted that using acceleration response data to reverse calculate the load results is poor.

In the process of installation of floating fish cages offshore, it is usually necessary to leave enough catenary tension for the mooring chain while fish cages are in position. However, due to the influence of construction cost and other factors, most floating fish cages in China often use fixed length mooring system connected by mooring chain and eye plate, and are not equipped with tightening ratchet and other forms of mooring chain tightening device, which is more difficult to connect. To solve this problem, based on the connection construction of one floating fish cage offshore, a connection technology was proposed to ensure catenary tension of fish cage in position. Based on catenary analysis equation, the connection tensioning force under different tide levels was solved, and the influence of environmental load on the connection process of the fish cage mooring chain was simulated by using CFD method. The feasibility of the connection technology was verified in the actual construction. The results show that the environmental force has a great influence on the cage connection, and the influence of flow load is much greater than that of wind load and tide level. Theoretically, the peak value of the tensioning force under Beaufort scale for wind speed level IV can reach to 94.22t, which is of reference significance for the future connection installation of such floating fish cages offshore.

This paper focuses on the water inrush issue in the fault fracture zone of Ankang Tunnel of Xikang High-Speed Railway and conducts research on the grouting reinforcement method. The tunnel traverses the complex geological area of Qinling Mountains, especially the intersection section with the Zaoshu Pian Fault, where the rock mass is severely fractured and the water inflow is large, posing challenges to the construction. Through a comprehensive analysis of the engineering geological characteristics of the tunnel, including topography, climate, stratigraphic lithology and hydrogeological conditions, the geological environment of the water inrush section is revealed. On this basis, this paper proposes an advanced grouting reinforcement scheme for the upper half section, using sulphoaluminate cement as the grouting material, with a grouting distance set at 25 m and the grouting pressure controlled within 5–7 MPa. To verify the grouting effect, three monitoring sections are set up in the reinforced tunnel section to monitor the rock stress and the vault displacement. The monitoring data show that the rock stress and the displacement after grouting are relatively concentrated in the middle area of the tunnel, with the maximum surrounding rock pressure reaching 382 kPa and the maximum vault displacement being 66.4 mm. The analysis points out that the seepage channels and cavities formed after water inrush in the middle area lead to uneven diffusion of the grouting slurry, poor combination effect between the slurry and the geotechnical body, and the formation of isolated coagulation bodies, which affect the reinforcement effect. Therefore, for shallow-buried tunnels in water-rich fault fracture zones, this paper suggests that advanced grouting be carried out before the occurrence of water inrush disasters to improve the uniformity of slurry diffusion and enhance the grouting reinforcement effect of the surrounding rock. This research provides technical reference and practical guidance for similar projects and has important engineering application value.

Affected by the cold and high-altitude climate environment, the slope rock body undergoes repeated cycle of freezing and thawing, and the deterioration of physical-mechanical performances may lead to collapse disasters. Relying on the approach road slope of a hydropower station in the western region, the physical model of three typical collapse failure modes of dumping, slipping and falling was studied, aiming to clarify the freeze thawing catastrophe mechanism of high and steep rock slope in the alpine region. The results show that: 1) The temp change rate of fractured rock body is different at different buried depths, and the temp change rate is faster at the position closer to the surface, and the slower the temp change rate at the farther position; 2) After the temp change in the fracture to 0 ℃, the temperature curve showed a temperature plateau, and the platform segment of the deep position curve of the fracture was longer than that of the superficial position curve. The length of the platform segment is inversely correlated with the temperature gradient of the surrounding environment. 3) When the surface temperature of the rock body drops below 0 ℃, the frost heave force begins to increase, and then rises in a fluctuating manner. When the frost heave force pushes the fracture deformation and opening, the pressure is released and the frost heave force is weakened. As the freezing depth continues to develop, the frost heave force will increase again, and so on repeatedly, the overall trend will fluctuate. 4) The frost heave force in the fracture is positively correlated with the freezing depth and the constraints of the rock body. The research results provide a key mechanical basis for the occurrence of freeze thawing collapse disasters on rock slopes, and are of great significance for guiding slope stability assessment and protection engineering design.

The combination of low-heat cement and fly ash is suitable as a cementitious material for dam concrete. In this work, the hydration heat release, hydration products and hydration mechanism was investigated by the experiments and model analysis. The results show that the incorporation of fly ash has a significant impact on the hydration process of cement, including delaying the hydration time and significantly reducing the hydration heat. Due to the volcanic ash effect of fly ash, the calcium hydroxide will be consumed. When the amount of fly ash increases, the volcanic ash effect becomes more pronounced. The amount of calcium hydroxide increases first and then decreases with time, and the largest is at 28d hydration. The proposed model were adopted to simulate the C-S-H, calcium hydroxide, ettringite, etc. The model results basically consistent with the experiment results. The combination model is an reliable analytical tools to study the hydration of low heat cement blended with fly ash.

Based on the underpinning and rectification project of a frame structure building with pile foundations, this paper studied the jacking technology of underpinning pile reinforcement and analyzed the issue of structural tilt distortion caused by the differential settlement. The reasons of differential settlement, such as climate, collapsibility, under-consolidation of soil, and other factors, were thoroughly examined, and appropriate reinforcement strategies were suggested. The project employed micro-piles for settlement relief and underpinning, performed rectification construction using underpinning piles, and used jacking technology to lower or locally jack the building in order to rectify the tilt. The PLC synchronous jacking control platform was used to precisely regulate the jack’s lifting capacity and guaranteed the structure’s safety during the jacking process. To improve the structural stability, grout wass used to fill the space beneath the foundation after jacking. The project had a good economic and social value, saving construction time and costs, and successfully meeting its objectives. In addition, this paper offered some recommendations that serve as a guide for the correlated projects, including pre-load inspection before jacking, consideration of stress concentration throughout the jacking operation, and construction quality of important connections.

Optimizing highway design can help reduce carbon emissions throughout the entire life cycle of highways. To analyze the carbon reduction benefits of highway design optimization, the carbon emission factor method was used to develop a model for calculating the carbon reduction benefits of design optimization. Using an expressway in the Guangdong-Hong Kong-Macao Greater Bay Area as a case study, the carbon reduction benefits from various design optimizations—such as shortening the route length, sharing traffic corridors with local roads, and optimizing interchange type—were calculated. The study results show that design optimization during the planning stage has a significant impact on carbon reduction. The case project achieved a total reduction of 1.88 × 108 kg of carbon emissions. The carbon reduction benefits of the three design optimizations, ranked from greatest to least, were: shortening the route length (1.43 × 108 kg) > optimizing the interchange design (4.47 × 107 kg) > sharing traffic corridors with local roads (5.92 × 105 kg). Material savings contributed the most to carbon reduction, with route shortening and interchanges type optimization accounting for 93.90% and 92.13% of the total carbon reductions, respectively, mainly due to the reduced use of steel bar and cement. The carbon reduction benefits from energy savings were greater than those from land-use savings, and the contribution of electricity savings exceeded that of fossil fuels such as diesel, gasoline, and fuel oil. Accordingly, efforts to reduce carbon emissions at the design stage of highways should be strengthened by evaluating design alternatives in terms of project scale, construction schemes, low-carbon materials, and construction conditions, thereby promoting the development of low-carbon highway infrastructure.

Semi diagenetic rocks refer to special rocks that have not been completely deposited and metamorphosed in the Neogene Period. They have both the characteristics of soil and rock in composition, structure, and construction. Semi diagenetic rock has weak cementation, low strength, and poor resistance to water. Serious water and mud inrushs occurred in semi diagenetic surrounding rock in Wangjiazhai Tunnel of Lincang-Qingshuihe Expressway, Yunnan Province, China during excavation which brought great difficulties to the project. A systematic case study on the water and mud inrush disaster was performed with Wangjiazhai Tunnel as an example. The basic laws of water and mud inrush were summarized based on observation and engineering geological analysis. Water and mud inrush mechanisms were revealed according to inrush phenomena. Comprehensive disposal methods were suggested to prevent and control the inrush disasters. The research results can provide reference basis for similar engineering construction and disaster control.

Relying on the project of Xiaolangdi Dam Yellow River Diversion Project, 500 groups of shield tunneling data are selected, and shield tunneling process is taken as the sequence of data sets. Based on BP, PSO-BP and LSTM neural network model, those prediction models of shield thrust are established respectively, and three models are used to predict shield thrust. The results of prediction are compared and analyzed in detail. It can be seen from the research results: (1) All the three neural network models can well predict shield thrust, and their prediction set R2 are biggger than 0.75, the LSTM neural network has the best prediction effect which the R2 is 0.86, and the error of most prediction data is less than 20%. (2) By comparing the prediction results of those models, it can be seen that the prediction results of BP and PSO-BP neural network are generally bigger than the true value, while the prediction value of LSTM neural network are generally smaller. (3) By comparing the prediction results of those models, it can be seen that PSO algorithm effectively optimizes BP neural network, and LSTM neural network has the best prediction effect.

At present, tunnel leakage is mainly discovered by manual inspection, which seriously affects the accuracy of leakage identification. The feasibility of using infrared thermal imaging to detect tunnel leakage is explored, with the Outer Ring Tunnel in Shanghai, China, chosen as a case study. The Outer Ring Tunnel belongs to an immersed tube tunnel. In site experiments are performed to detect leakage under operation environment. In summer, the groundwater temperature is lower than that of the concrete surface, causing the infrared images of the tunnel leakage area to show low-temperature zones surrounded by high-temperature regions. When the ambient temperature is low, the temperature difference between the tunnel defect leakage point (the lowest temperature point) and the intact wall (the highest temperature point) is 2.6 ℉ ~ 3.3 ℉. When the surrounding temperature is elevated, the temperature difference ranges from 3.6 ℉ to 5.1 ℉, which shows that infrared thermal imaging detection of tunnel leakage is feasible under natural conditions.

Primarily, the definition, predominant formation mechanisms, and taxonomical classifications of substantial deformation within tunnel surrounding strata are expounded. Subsequently, upon a profound and comprehensive scrutiny of a plenitude of engineering remediation exemplars pertaining to significant deformation of tunnel surrounding strata on both domestic and international fronts, the quintessential and cardinal role enacted by fully grouted bolts is accentuated and brought to the fore. Thereafter, the cardinal anchoring doctrines of fully grouted bolts and the nascent advancements in anchoring support paradigms within the domestic milieu are successively and meticulously explicated. Concurrently, a rigorous and incisive dissection of the merits and demerits of these theoretical constructs is effected, and sagacious and astute recommendations for the progression and refinement of the extant bolt support technologies are proffered.

This study investigates the Gushan Village Tunnel as a case study to systematically analyze the characteristics of karst development and its implications for tunnel construction and operational safety. By integrating ground-penetrating radar (GPR) and borehole drilling techniques, fifteen karst anomaly zones were identified. These zones were further examined through detailed drilling investigations to assess the scale, filling conditions, and spatial distribution of cavities and fissures. The findings reveal that karst predominantly develops around fault zones and fractured rock masses, posing significant threats to tunnel stability, including instability of surrounding rock masses, tunnel floor subsidence, and elevated risks of water inrush. To mitigate these challenges, a series of comprehensive control measures were proposed, including grouting reinforcement, cavity filling, and drainage management. The study highlights the high efficiency and reliability of combining GPR and drilling technologies for karst detection, offering robust theoretical support and practical insights for tunnel construction in similar geological settings.

3D concrete printing technology (3DCP) represents a significant advancement in the construction industry. However, the production process often encounters interface issues, which may arise between layers, strips, or between the 3D printing template and the post-cast concrete. The inadequate performance of these interfaces is a central challenge in 3DCP components. This paper analyses the formation mechanisms and existing problems of these three interfaces, focusing on the improvement of the interface performance using both physical and chemical means in the existing research. Physical methods include altering interface roughness and designing macro-interlocking features, while chemical methods involve the application of cement-based and polymer interfacial agents. This paper aims to provide researchers with a comprehensive understanding of these two critical approaches for improving 3DCP component interfaces and to propose more advanced enhancement strategies to facilitate the further development of the 3DCP industry.

In the eastern Tibetan Plateau, numerous landslides triggered by rainfall occur annually during the rainy season, posing serious threats to lives and properties in mountainous towns and cities. Quantitative evaluation of landslide risk is the focus of geological disaster prevention and control. Using the Deda ancient landslide on the right bank of the Baqu River in the upper Jinsha River as an example, on-site detailed investigations, drone aerial surveys, and numerical simulations were conducted to identify the deformation of the Deda ancient landslide, analyze landslide destabilization probabilities under different rainfall recurrence periods, determine the scope of landslide threats via numerical simulation, assess the vulnerability of affected structures within the impact area, and quantify risk values for buildings and people across various rainfall recurrence periods. The risk values of buildings and people under different rainfall return periods are quantitatively calculated. The results indicate that 28 buildings in the study area are at risk from landslides, with over 69% of structures having a susceptibility greater than 0.8 and a population susceptibility index of 0.596. The probability of destabilization gradually increases under natural, 20-year, 50-year, and 100-year rainfall conditions, with annual property losses estimated at 68,100 yuan, 532,000 yuan, 791,000 yuan, and 927,000 yuan, respectively, and estimated casualties of 3, 17, 25, and 30 people, respectively. The results of the study quantify the loss after the occurrence of landslides, which is an important reference for the prevention and control of this type of landslides, and can provide disaster prevention and mitigation suggestions for relevant departments.

Construction dust generates from construction sites and construction activities such as housing construction projects and municipal infrastructure projects, which is one of the main sources of atmospheric particulate matter. Its massive release and dust fall have significant harm to buildings, equipment, personnel and so on. At present, there are relatively few measurement data on the characteristics of dust emission on the surface of construction sites, and the attention on the dynamic change of dust concentration or emission amount during fluid release is far from enough. Therefore, based on the dust release mechanism and field wind tunnel structure, a new portable surface dust release measuring device is designed and developed in this paper. The instrument has the advantages of small size, easy transportation, easy operation and low cost, and the test results show that it has high accuracy, and can be applied to the complex terrain that is difficult to reach the wind tunnel. It is suitable for analyzing and studying the dust emission capacity of the surface of different construction sites and the corresponding physical mechanism.