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Marine propellers operate under severe service conditions and experience various corrosion forms. Electrochemical, mechanical, and biological corrosion are the three main common types of corrosion that occur on marine propellers. Electrolysis (electrolytic corrosion), being one of the electrochemical corrosion forms, has been extensively observed on marine propellers. It is the forced introduction of an external current in metals when submerged in seawater. However, it has rarely been studied for marine propellers, mostly on underground pipelines. This paper investigates the effect of electrolysis on a chromium-containing coating on copper substrate by studying the surface and cross-sectional microstructure of the substrate. It is likely that cathodic disbondment caused by high alkalinity and hydrogen evolution at the defect location were the primary reasons contributing to the failure of the coating, and the silver-colored layer deposition around the delaminated area is the corrosion product of copper–chromium oxide. The purpose of this study is to understand the electrolysis corrosion mechanism on Cu substrate and to develop a highly effective anticorrosion coating for marine propellers. [ABSTRACT FROM AUTHOR]

Magnetic induction (MI)-operated wireless sensor networks (WSNs), due to their similar performance in air, underwater, and underground mediums, are rapidly emerging networks that offer a wide range of applications, including mine prevention, power grid maintenance, underground pipeline monitoring, and upstream oil monitoring. MI-based wireless underground sensor networks (WUSNs), utilizing small antenna coils, offer a viable solution by providing consistent channel conditions. The cross-layer protocols address the specific challenges of WUSNs, leading to improved network performance and enhanced operational capabilities in real-world applications. This work proposes a distributed cross-layer solution, leveraging the hybrid marine predator naked mole rat algorithm (MPNMRA) for MI-operated WUSNs. The solution, called DECMN (distributed energy-throughput efficient cross-layer network using MPNMRA), is designed to optimize the MI communication channels, MI relay coils (MI waveguide), and MI waveguide with 3D coils to fulfill quality of service (QoS) parameters, while achieving energy savings and throughput gains. DECMN utilizes the interactions between various layers to develop cross-layer protocols based on MPNMRA. Simulation results demonstrate the effectiveness of DECMN, offering energy savings, increased throughput, and reliable transmissions within the performance limits. [ABSTRACT FROM AUTHOR]

The underground pipeline is a critical component of urban water supply and drainage infrastructure. However, the absence of accurate pipe information frequently leads to construction delays and cost overruns, adversely impacting urban management and economic development. To address these challenges, the digital management of underground pipelines has become essential. Despite its importance, research on the structural analysis and reconstruction of underground pipelines remains limited, primarily due to the complexity of underground environments and the technical constraints of LiDAR technology. This study proposes a framework for reconstructing underground pipelines based on unstructured point cloud data, aiming to accurately identify and reconstruct pipe structures from complex scenes. The Random Sample Consensus (RANSAC) algorithm, enhanced with parameter-adaptive adjustments and subset-independent fitting strategies, is employed to fit centerline segments from the set of center points. These segments were used to reconstruct topological connections, and a Building Information Model (BIM) of the underground pipeline was generated based on the structural analysis. Experiments on actual underground scenes evaluated the method using recall rate, radius error, and deviation between point clouds and models. Results showed an 88.8% recall rate, an average relative radius error below 3%, and a deviation of 3.79 cm, demonstrating the framework's accuracy. This research provides crucial support for pipeline management and planning in smart city development. [ABSTRACT FROM AUTHOR]

Drainage pipelines face significant threats to underground safety due to external defects. Ground Penetrating Radar (GPR) is a primary tool for detecting such defects from within the pipeline. However, existing methods are limited to single or multiple axial scan lines, which cannot provide the precise spatial coordinates of the defects. To address this limitation, this study introduces a novel GPR-based drainage pipeline inspection robot system integrated with multiple sensors. The system incorporates MEMS-IMU, encoder modules, and ultrasonic ranging modules to control the GPR antenna for axial and circumferential scanning. A novel Cross-Line Fusion of GPR (CLF-GPR) method is introduced to integrate axial and circumferential scan data for the precise localization of external pipeline defects. Laboratory simulations were performed to assess the effectiveness of the proposed technology and method, while its practical applicability was further validated through real-world drainage pipeline inspections. The results demonstrate that the proposed approach achieves axial positioning errors of less than 2.0 cm, spatial angular positioning errors below 2°, and depth coordinate errors within 2.3 cm. These findings indicate that the proposed approach is reliable and has the potential to support the transparency and digitalization of urban underground drainage networks. [ABSTRACT FROM AUTHOR]

Water pipelines in water diversion projects can leak, leading to soil deformation and ground subsidence, necessitating research into soil deformation monitoring technology. This study conducted model tests to monitor soil deformation around leaking buried water pipelines using distributed fiber optic strain sensing (DFOSS) technology based on optical frequency domain reflectometry (OFDR). By arranging strain measurement fibers in a pipe–soil model, we investigated how leak location, leak size, pipe burial depth, and water flow velocity affect soil strain field monitoring results. The results showed that pipeline leakage creates a "saddle-shaped" spatial distribution of soil strain above the pipeline, effectively indicating ground subsidence locations. When only one survey line is arranged, it is preferable to place the optical fiber directly above the pipeline. Surface monitoring fibers primarily detected tensile strain, with more pronounced peak values observed under conditions of larger leak size, higher flow velocity, shallow burial depth, and top-pipe leakage location. Monitoring fibers below the pipeline showed mainly unimodal distribution, with peak strain coinciding with the leak location. The sequential timing of strain changes at different fiber positions enabled the determination of soil seepage direction. This study demonstrates that DFOSS technology can provide important support for the early warning of such geological disasters. [ABSTRACT FROM AUTHOR]

The underground pipeline network is an important infrastructure for urban development and also serves as a "lifeline" project for cities. However, due to various factors such as pipeline aging, construction activities, uneven sand settlement, and external loads, underground pipelines often experience leak, leading to water loss. Studying the leakage characteristics can help evaluate the actual degree of leakage loss within the pipeline network. This article considers the influence of three media—sand, water, and air—on the leakage characteristics of pipelines. Initially, leakage simulation experiments were conducted on three different types of leaking pipelines, each exhibiting different leak shapes. Second, the experimental results were compared and analyzed based on existing theoretical models. Subsequently, the Fluent module of ANSYS software was utilized for finite element analysis, ultimately deriving the theoretical formula for the leakage flow rate. The results showed that pipeline leakage led to the formation of an "inverted-cone" sand-water mixing zone and a "semi-elliptical" erosion pit with cracks in sandy media, causing surface oscillations in water media and the formation of water columns spraying outward in air media. The leakage flow rate increases with increasing pressure, and the order of its values under different leakage forms is axial crack > circular hole > circumferential crack. The International Water Association (IWA) model and the fixed and variable area discharges (FAVADs) model can be used to approximate the calculation of the leakage flow rate. Under identical conditions, the leakage flow rate increases on the order of S1, S2, S3, W, and A with changes in the medium and decreases with an increase in burial depth H. The final deformation of each leakage port in the pipeline is approximately elliptical. The value of m increases approximately linearly with the increase in pipeline outer diameter, approximately exponentially with the increase in leakage port size, and approximately exponentially decreases with the increase in pipeline wall thickness and elastic modulus. The FAVAD model is more consistent with finite element results than both the Torricelli (TOR) model and the IWA model. The improved FAVAD model and the S.S.A model provide ideal and reliable calculation results, which can be applied to calculate the leakage flow rate in buried pipelines. [ABSTRACT FROM AUTHOR]

Detection of underground natural gas pipeline micro-leakage based on unmanned aerial vehicle (UAV) hyperspectral remote sensing and GIS. Hyperspectral images can indirectly detect underground natural gas pipeline micro-leakage through spectral and spatial variation characteristics of surface vegetation. However, most of existing studies were based on ground-mounted platforms, which could only perform small-range single-point detection and might occur misidentifications. UAV hyperspectral remote sensing can allow wide-range detection of surface vegetation. Moreover, underground pipeline distribution GIS data can provide prior knowledge about leakage points to exclude misidentifications. Therefore, a natural gas pipeline micro-leakage experiment was set up. UAV hyperspectral images of grasslands and pipeline distribution vector data were obtained, which led to a proposed new wide-range multi-points detection methodology of underground natural gas micro-leakage. Firstly, the vegetation identification index (WVI) $\left({{R_{470}} + {R_{674}}} \right)/\left({{R_{555}} + {R_{750}}} \right)$ R 470 + R 674 / R 555 + R 750 was designed based on WOA–VMD (whale optimization algorithm – variational modal decomposition) to segment and extract the vegetation stress zones. Then, UAV- and GIS-based natural gas micro-leakage vegetation stress identification model was constructed to obtain the leak points of natural gas micro-leakage. Finally, the recognition ability was evaluated by comparing with three stress vegetation identification indices proposed in previous studies. The result showed that there was no missing or false detection in identification results; the identification and positioning effect was better than other indices, which could meet the practical application requirements. [ABSTRACT FROM AUTHOR]

Copyright of Journal of South-Central Minzu University (Natural Science Edition) is the property of Journal of South-Central Minzu University (Natural Science Edition) Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article discusses the construction and conversion of infrastructure for hydrogen distribution, highlighting the increasing demand for hydrogen in municipalities and industries. Various experts emphasize the need to accelerate the transition to hydrogen and focus on developing distribution networks. Gas network operators are working on implementing scenarios for transforming gas distribution grids towards climate neutrality, with a majority of municipalities and industrial customers planning to use climate-neutral gases in the long term. The article also mentions successful pilot projects and the importance of a hydrogen-capable distribution network for supplying industrial sites with process heat. [Extracted from the article]

The paper introduces a new algorithm that can determine the location of the compromised pipeline and its path while also examining the impact of the sensor array's parameters on imaging outcomes. Results show that the sensor array rotates at a specific angle relative to the pipeline, and the pipeline's path remains visible. Experimental trials using a vibration sensor to capture vibrational data indicate that at an acceleration of water reaching 9 m/s2, the maximum output analog voltage (corresponding to the leakage point) reaches 35.6 mv, with the analog voltage decreasing as one moves away from the main leakage point, thereby validating the viability of the new algorithm. Rotating the pipeline at a certain angle can result in an output analog voltage of up to 37.4 mv, and the presence of the leaking pipe and its path continues to be observable. [ABSTRACT FROM AUTHOR]

Urban and offshore subterranean comprehensive pipelines are currently utilized frequently as infrastructure for fitting different engineering pipelines used for electricity, signal transmission, natural gas, petroleum, heating, water supply, and drainage systems. This study utilizes the finite element limit analysis (FELA) and artificial neural network (ANN) to evaluate the pull-out capacity factor of the buried rectangular box carrying the pipelines with internal inclined force in cohesive soil. In FELA, rigorous upper bound and lower bound solutions are performed to achieve the exact result. In this study, a dimensionless parametric analysis is carried out by considering the effect of five parameters viz. buried depth ratio, width-depth ratio, overburden factor, internal inclination angles, and interface factor on the pull-out capacity factor of a buried rectangular box, which can be called as a rectangular pipeline. Two significant samples of the investigated parameters are selected to evaluate the soil failure pattern (failure envelope) using the shear dissipation of soil failure for the buried rectangular pipeline subjected to inclined loading. Using the FELA results, the predictive equations are proposed using ANN, and then sensitivity analysis is performed to examine the sensitivity of each investigated essential parameter on the stability of the underground rectangular pipeline. The predictive ANN model for the buried rectangular pipe subjected to inclined loading is presented as design charts for practice and further investigation. [ABSTRACT FROM AUTHOR]

The failure state of the natural gas pipelines in underground space may cause explosions, and an explosion flow field is affected by the structure of the venting duct. Based on FLACS software v9.0, the influence of the explosion vent and venting duct on temperature and pressure fields is studied. The results show that when the area of the explosion vent increases from 0 to 100 cm2, the peak overpressure decreases by half, and the overpressure drops to zero within 0.3 s. For different L-type venting ducts, when the structural coefficient is less than 5, the peak overpressures and pressure variations are similar. When the structural coefficient is equal to 5, the peak overpressure significantly decreases, and the time to reach the peak value is extended by 50%. From the perspective of achieving a safe and efficient venting effect, the optimal structural coefficient is 5 for the L-type venting duct. [ABSTRACT FROM AUTHOR]

This study addresses the challenge of accurately predicting corrosion rates and estimating the remaining life of underground gas pipelines, which is complicated by the complex interaction of physical factors and environmental conditions. Traditional models are inadequate in capturing these variables, leading to less reliable predictions, which this study aims to address by developing a more accurate and optimized artificial neural network (ANN) model. This study focuses on predicting corrosion rates and estimating the remaining life of underground gas pipelines using ANNs implemented in MATLAB. It incorporates both physical factors, such as maximum corrosion depth and pipe thickness, and environmental variables such as moisture, soil resistivity, and chloride concentration. The analysis identified corrosion depth and wall thickness as significant contributors, influencing material integrity by 20% and 16%, respectively. The optimal ANN model, with a Levenberg-Marquardt structure and one hidden layer of 10 neurons, achieved superior accuracy, with an MSE of 0.038 and R² of 0.9998. The study addresses the challenge of accurately predicting corrosion rates and remaining life in underground gas pipelines by developing an optimised ANN model. Its contribution lies in creating a highly accurate prediction tool that outperforms traditional models and enables more informed decisions for pipeline maintenance and safety. [ABSTRACT FROM AUTHOR]

To enhance the corrosion resistance of underground pipelines made of low carbon steel, nano-TiO2-modified polyurea was applied to their surface. The anti-corrosion performance of these nano-TiO2-modified coatings was tested by immersing them in a NACE (5 wt.% NaCl + 0.5 wt.% CH3COOH) solution under high temperatures and high CO2 pressures. The mass variation, SEM morphology, and open-circuit potential were determined. EIS tests, neutral salt spray tests, and contact angle measurements were carried out to analyze the effect of nanoparticles on corrosion resistance. Within the same pressure range, the polyurea coating shows the highest corrosion resistance when 5% TiO2 nanoparticles were added compared to that of polyurea coatings with 0%, 10%, and 15% TiO2 added. Coatings with 5% TiO2 nanoparticles showed rapid diffusion after being immersed for 96 h, indicating that the anti-corrosion performance of the coating weakened. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Measurement Science & Instrumentation is the property of Journal of Measurement Science & Instrumentation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In advancing “smart city” initiatives, multi‐functional sensing devices are crucial for the structural health monitoring (SHM) of key infrastructures. This study presents a self‐sensing sealing electronic gasket (e‐gasket) featuring multi‐modal interdigitated‐electrode‐based sensors for underground pipeline damage assessments, via simultaneously detected distribution information of contact pressure and relative humidity (RH). Detecting performance is enhanced through functional surface coatings and optimized pore size of the porous foam layer. An equivalent decoupling model for precise detection is established by analyzing the electrical responses of capacitance and impedance, and a rough estimation method relying on relative response is investigated to reduce the energy consumption and enhance monitoring efficiency. It demonstrates excellent multi‐modal sensing capabilities, repeatability, and stability over the long term. Experimental results verify the effectiveness in condition detection, fault classification, damage severity assessment, and early warning functions of the e‐gasket, enabling comprehensive SHM. [ABSTRACT FROM AUTHOR]

The pipeline leakage detection and leak localization trouble is a highly demanding and dangerous issue. Underground pipelines are critical for transporting enormous fluid volumes (e.g., water) across extended distances. Not only would solving this issue save the nation a great deal of money and resources, but it will also save the environment. However, because of the harsh climatic conditions below earth, current leak detection systems are not enough for monitoring subterranean pipelines. To address these issues, this study suggests a hybrid wireless sensor network for monitoring subterranean pipelines that is based on magnetic induction and time domain reflectometry (TDR). TDR is installed in this instance below a wireless sensor network that is based on MI. TDR significantly reduces the time needed for inspection while accurately locating the leak. Based on MI technology, we provide a wireless sensor network for inexpensive, real-time leak detection in subterranean pipelines. Through the integration of data from several sensor types located within and around subterranean pipes, MISE-PIPE detects leaks. Ad-hoc WSNs are employed in pressure measurement. (WDNs) is a popular subject that has drawn attention from scholars lately. Since leak localisation has a significant influence on the human population and the economy, time and accuracy are essential components. A broad leak localisation technique is proposed using statistical classifiers operating in the residual space. Classifiers are trained using leak data from every node in the network, accounting for demand uncertainty, noise from sensor preservatives, and leak size. After localising and identifying leaks, all monitoring data is sent to the CH using the K-means clustering technique, which performs two vital tasks: optimum clustering, extending the Network Lifetime, and maintaining Quality of Service. The K-Means technique is used to optimise the clustering process. The K-means clustering technique is used to transfer all monitoring data to the CH for the purpose of pipeline leak identification and localisation. Unlike the current underground pipeline monitoring system, our proposed Hybrid TDR-MI-based wireless sensor network allows precise real-time leak identification and localisation. [ABSTRACT FROM AUTHOR]

To address low detection accuracy and speed due to the multisolvability of the ground‐penetrating radar signal, we proposed a novel centralized feature pyramid‐YOLOv6l–based model to enhance detection precision and speed in road damage and pipeline detection. The centralized feature pyramid was used to obtain rich intra‐layer features and improve the network performance. Our proposed model achieves higher accuracy compared with the existing detection models. We also built two new evaluating indexes, relative average precision and relative mean average precision, to fully evaluate the detection accuracy. To verify the applicability of our model, we conducted a road field detection experiment on a ground‐penetrating radar dataset we collected and found that the proposed model had good performance in increasing detection precision, achieving the highest mean average precision compared with YOLOv7, YOLOv5 and YOLOx models, with relative mean average precision and frame rate per second at 16.38% and 30.5%, respectively. The detection information for the road damage and pipeline were used to conduct three‐dimensional imaging. Our model is suitable for object detection in ground‐penetrating radar images, thereby providing technical support for road damage and underground pipeline detection. [ABSTRACT FROM AUTHOR]

The mathematical modeling of the dynamics of a two-layer shallow pipeline under the influence of transport load (the load created by an object moving along the pipeline) has been successfully resolved. The pipeline is represented as an extended circular cylindrical two-layer shell with a thin inner (bearing) layer and a thick outer (enclosing) layer situated in an elastic half-space. Dynamic equations of elasticity theory using Lamé potentials are utilized to describe the motion of the half-space and the enclosing layer of the shell. The vibrations of the bearing layer of the shell are described by the classical equations of the theory of shells. Numerical experiments have considered the case of a moving axisymmetric cylindrical normal load applied to a pipeline (without an enclosing layer and with an enclosing layer of varying thickness and material stiffness). It was demonstrated that if the material of the enclosing layer of the pipeline is more rigid than that of the rock mass, the dynamic effect of the moving load on the rock mass is reduced. [ABSTRACT FROM AUTHOR]

Purpose. The purpose of the work is to establish the dependences of the levels of the protective potential of the system of protection of underground steel pipelines when approaching and/or crossing overhead power lines. Methodology. To achieve the goal, the methods of the theory of equivalent electric circuits and the theory of the electromagnetic field, implemented in the packages of applied computer programs Matlab/Simulink and COMSOL Multiphysics, were used. Findings. The spatial distribution in the soil of the induced electric field of the overhead power line in the direct location of the pipeline, which varies with a frequency of 50 Hz, was determined. The distribution of both constant and alternating voltage on the pipeline relative to the soil is given. An analysis of corrosion processes in the pipeline was carried out, on the basis of which the relatively safe flow of corrosion processes in the pipeline under the action of simultaneously occurring alternating current with a frequency of 50 Hz and direct current was investigated. Originality. The scientific novelty of the work consists in determining the regularities of the influence of overhead lines on the nature of the distribution of the protective potential of cathodic protection stations with variable changes in the configuration of pipelines and laying conditions. The existence of significant deviations of the levels of the protective potential in the presence of a variable polyharmonic component of the signal is proven. On the basis of the study, it was established that under the accepted initial conditions, both criteria are unsatisfactory in some sections of the pipeline near the power transmission line. Practical value. The practical significance of the research results is in determining the set of technical characteristics of the electrotechnical complex of protection against electrochemical corrosion, which allows ensuring the necessary levels of protective potential in the presence of a source of stray currents (overhead power lines). [ABSTRACT FROM AUTHOR]

This paper presents a calculation method that evaluates the extent of disturbance based on structural safety limits. Additionally, it summarizes the assessment methods for construction disturbance zones in shield tunneling near pile foundations, urban ground structures, and underground structures. Furthermore, taking the construction of the Chengdu Jinxiu Tunnel under bridges and urban pipelines as the engineering background, a study on the disturbance zoning of adjacent structures was conducted. The most intense disturbance occurs within one week of the tunnel underpass process, and it has a significant impact within a range of two times the tunnel diameter along the tunnel axis. The bridge pile and bridge deck experience less disturbance from tunnel approaching construction, with a maximum disturbance zone characterized as medium disturbance. On the other hand, underground pipelines are subjected to more significant disturbances from tunnel construction, with a maximum disturbance zone classified as strong disturbance. The implementation of "bridge pile sleeve valve pipe grouting & underground pipeline ground grouting & tunnel advance grouting" in the field effectively limits the vertical settlement of bridges and pipelines, resulting in a decrease of approximately 0.1 in disturbance level for the structures. The disturbance zoning method can assess tunnel disturbance with structures, identify high-risk interference locations, and facilitate targeted design reinforcement solutions. [ABSTRACT FROM AUTHOR]

Copyright of Coal Geology & Exploration is the property of Xian Research Institute of China Coal Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Preserving the structural integrity of critical infrastructure systems necessitates a heightened focus on fortifying the protection of underground pipelines. To this end, this paper presents an innovative approach, namely the Multi-Sample Joint Localization Method (MSJLM) utilizing Cross-Correlation Convolutional Neural Networks (CC-CNN), aimed at precisely localizing intrusion sources in the vicinity of underground pipelines. Traditional techniques for detecting and pinpointing pipeline intrusions primarily rely on a single sensor monitoring point, which is susceptible to inherent errors and constraints. In contrast, the MSJLM proposed in this study leverages data from multiple samples, integrating diverse data sources through correlation analyses to elevate precision and reliability. The utilization of the CC-CNN framework for processing aggregated data has proven highly successful in extracting spatial features and identifying patterns. Furthermore, the effectiveness of this method is corroborated through validation via a pile-driving model test. [ABSTRACT FROM AUTHOR]

High-accuracy deformation monitoring is crucial for investigating landslide–pipeline interaction problems, in which the fiber optic nerve system (FONS) holds enormous potential. This paper presents a theoretical framework for interpreting landslide–pipeline interactions using the FONS and proposes a novel method for calculating characteristic parameters of pipe–soil interfaces based on distributed strain measurements. The feasibility of this method is validated through a full-scale model test, and its application for studying pipeline behaviors is demonstrated in the Xinpu landslide, situated in the Three Gorges Reservoir region, China. The field monitoring results reveal that short-duration, high-intensity rainfall events triggered immediate acceleration of landslide movements, leading to pipeline elongation and flexure. Strain measurements of the underground pipeline allow for the identification of the local slipping interface of the landslide. Furthermore, the relationships between reservoir water level (RWL) fluctuations, rainfall events, landslide deformation, and the structural response of the pipe are analyzed. The findings suggest that the deformation of the landslide in the leading and middle parts exhibits high correlations with the combined effect of rainfall and RWL drawdown. [ABSTRACT FROM AUTHOR]

Construction of underground pipelines on cropland impacts the soil ecosystem, resulting in crop yield losses persisting for several years after right‐of‐way (ROW) reclamation. Information on whether higher than recommended fertilizer application rates could improve productivity of reclaimed ROWs is scarce. The objective of this growth room bioassay was to determine the productivity response of a chronosequence of reclaimed ROW soils to differential fertilizer rates. Bulk soil samples were collected from the 0 to 20 cm soil layer on two ROWs of different ages (i.e., time since reclamation, TSR). The experiment was laid out in a completely randomized design with a 3 × 3 factorial treatment structure with three replications per treatment. The factors were TSR (4 and 10 year plus undisturbed (off‐ROW) sites) and fertilizer application rates (no fertilizer (Check); recommended rate (100%) of nitrogen (N), phosphorus (P), potassium (K), and sulphur (S); and 150% of the recommended N, P, K, and S rates). The recommended nutrient rates produced 66% lower canola dry matter yield (DMY) and 45% lower wheat DMY in the 4‐year ROW soil relative to the off‐ROW soil. Increasing the rate to 150% of the recommended rate significantly increased canola and wheat DMY in the 4‐year ROW soil to levels similar to those in the off‐ROW soil receiving the recommended rate. Nitrogen uptake by canola and wheat was 30%–45% lower, while P uptake was 40%–55% lower in the ROW soils than in the off‐ROW soil. These results indicate incomplete recovery of the ROW soils within at least the first 4 year following completion of reclamation. However, crop yields were not significantly different between the 10 year ROW and the off‐ROW at 100% fertilizer rate suggesting that productivity had been restored to off‐ROW levels by year 10 following reclamation. Findings from this study will contribute towards the formulation of strategies for improving the productivity of reclaimed ROWs on cropland. [ABSTRACT FROM AUTHOR]

This study was conducted to investigate the presence of benzene in the ground and drinking water in the eastern Niger Delta, where multiple oil and gas production facilities are present. Samples from drinking water wells were collected for measurements of benzene, toluene, ethylbenzene, and xylenes (BTEX). Additionally, the dissolved organic carbon (DOC) concentration was determined for the first time to establish the groundwater's total hydrocarbon and non-hydrocarbon load. The groundwater BTEX and benzene levels were up to 3904 µg/L and 3500 µg/L, respectively. DOC concentrations were up to 49 mg/L. The highest benzene concentrations were detected in wells near an underground petroleum pipeline. However, the concentrations decreased with distance from the pipeline to levels less than 0.1 µg/L. Despite benzene contamination, the aquifer has shown promising aerobic attenuation potential, having up to a 7.5 (95%) mg/L DO level and 2.11 mg/L BTEX biodegradation capacity for DO. However, the high groundwater temperature of up to 32.5 °C may weaken attenuation. The benzene and BTEX point attenuation rates ranged from 0.128 to 0.693 day−1 and 0.086 to 0.556 day−1, respectively. Hence, by natural attenuation alone, up to 66.5 and 85 years would be required to reach Nigeria's groundwater benzene and BTEX remediation goals, respectively. [ABSTRACT FROM AUTHOR]

The interaction between a semi-infinite underground pipeline and the surrounding soil during longitudinal seismic wave propagation is examined in the article. The wave travels through the soil with its front perpendicular to the pipeline's axis, and the nonlinear laws of interaction (friction) on the surface of their contact, including the Amonton-Coulomb law, are used to solve related wave problems for the pipeline and soil. The method of characteristics and the finite difference method are sequentially used to solve these problems numerically. The implementation of the law of interaction (friction) processes is shown, depending on the parameters of the wave in soil and the mechanical characteristics of soil. It was determined that a wave in soil that involves the pipeline generates a powerful wave in the pipeline. The amplitude of this wave is many times greater than the amplitude of the wave in soil, and it propagates through the pipeline without attenuation. The dependences of the amplitude of this wave on the parameters of the law of friction, waves in soil, and the mechanical characteristics of soil are determined. [ABSTRACT FROM AUTHOR]

Coal seam mining causes fracture and movement of overlying strata in goaf, and endangers the safety of surface structures and underground pipelines. Based on the engineering geological conditions of 22,122 working face in Cuncaota No.2 Coal Mine of China Shenhua Shendong Coal Group Co., Ltd. a similar material model test of mining overburden rock was carried out. The subsidence of overburden rock was obtained through the full-section strain data of distributed optical fiber technology, and the characteristics of mining surface subsidence were studied. The Weibull model was used to adjust the mathematical form of the first half of the surface subsidence curve via the MMF function. On this basis, the prediction model of coal seam mining surface subsidence was established, and the parameters of the prediction model of surface subsidence were determined. The test results show that with the advancement of coal seam mining, the fit goodness of the surface subsidence prediction curve based on the MMF optimization model reaches 0.987. Compared with the measured values, the relative error of the surface subsidence prediction model is reduced to less than 10%. The model displays good prediction accuracy. The time required for settlement stability in the prediction model is positively correlated with parameter a and negatively correlated with parameter b. The research results can be further extended to the prediction of overburden "three zones" subsidence, and provide a scientific basis for the evaluation of surface subsidence compression potential in coal mine goaf. [ABSTRACT FROM AUTHOR]

This investigation explores the erosion dynamics in sandy soils triggered by underground pipeline fractures, applying transparent soil technology for visualization. Through this approach, the erosion process within the transparent soil model was meticulously recorded using photography, enabling the quantitative analysis of collapse pit dimensions over time. Results reveal that soil erosion primarily manifests directly above the pipeline fracture, varying significantly with hydraulic conditions. In scenarios devoid of water flow within the pipeline, an increase in collapse pit depth is halted, attributed to the accumulation and blockage of soil particles at the fracture point. Contrastingly, under half-pipe and full-pipe flow conditions, the depth of the collapse pit swiftly reaches the fracture site. The flow of water notably escalates the expansion rate of the erosion pit, especially above the rupture, leading to continuous enlargement of the central area and subsequent secondary and tertiary collapses at the pit's apex. The study further identifies the impact of water flow on soil scouring near the pipeline rupture, with pronounced effects in full-pipe flow, predominantly ahead of the rupture point, and less significant impacts observed in half-pipe flow scenarios. Differential image analysis facilitated the categorization of soil into distinct zones: collapsed, loosened, stable, and eroded, with a direct correlation observed between the extent of the loosened zone and the velocity of water flow. [ABSTRACT FROM AUTHOR]

The transportation of coal-based solid waste filling slurry (CSWFS) through pipelines for underground goaf injection is essential for enhancing mine safety and promoting green, low-carbon coal mining. To address the issue of pipeline blockage caused by the suspension sensitivity of CSWFS during long-distance transportation, this study proposes the addition of the suspending agent hydroxypropyl methyl cellulose (HPMC) to transform the filling slurry into a stable suspending slurry. The mechanism by which the suspending agent modifies the rheological property of CSWFS was elucidated and verified. Firstly, an evaluation index system for the suspending state of CSWFS based on the "experimental test and theoretical calculation" was established. The values for layering degree, bleeding rate time-loss, and the corresponding average time-loss rate over 0 to 120 min of A1–A5 CSWFS were recorded as 24 mm–2 mm, 3.0–0.2%, 252.4–54.2%, and 149.6–14.6%, respectively. The concentration gradient evaluation result, C/CA = 0.91 (≥0.8), confirmed that the suspending agent maintained a stable suspending state over time for CSWFS. Secondly, it was demonstrated that the suspending agent HPMC modified the rheological property of A1–A5 CSWFS by increasing its plastic viscosity, which strengthened the viscous resistance to particle settling, thereby transforming a semi-stable slurry into a stable one. Additionally, the formation of a spatial suspending network by the suspending agent ensures that no pipeline blockage accidents occured in practical engineering applications. Furthermore, the XRD and SEM tests were utilized to verify the microstructure of the top (T) and bottom (B) samples in A4 block. It was concluded that the type of hydration products, occurrence forms, lapping compactness, and microstructural development were consistent, ultimately forming a high-strength, dense, hardened filling block. Finally, numerical simulation confirmed that the addition of suspending agent in A4 slurry formed a comprehensive spatial suspending network and a well-structured, unified system. This is one effective approach which could contribute to addressing the technical issue of pipeline blockage during long-distance pipeline transportation. [ABSTRACT FROM AUTHOR]

The inertial measurement method of pipelines utilizes a Micro-Electro-Mechanical Systems Inertial Measurement Unit (MIMU) to get the three-dimensional trajectory of underground pipelines. The initial attitude is significant for the inertial measurement method of pipelines. The traditional method to obtain the initial attitude uses three-axis magnetometers to measure the Earth's magnetic field. However, the magnetic field in urban underground pipelines is intricate, which leads to the initial attitude being inaccurate. To overcome this challenge, a novel multi-position initial alignment method based on data backtracking for a single-axis FOG and a three-axis Micro-Electro-Mechanical Inertial Measurement Unit (MIMU) is proposed. Firstly, the configuration of the sensors is determined. Secondly, according to the three-point support structure of the pipeline measuring instrument, a three-position alignment scheme is designed. Additionally, an initial alignment algorithm using the data backtracking method is developed. In this algorithm, a rough initial alignment is conducted by the data from single-axis FOG, and a fine initial alignment is conducted by the data from FOG/MIMU. Finally, an experiment was conducted to validate this method. The experiment results indicate that the pitch and roll angle errors are less than 0.05°, and the azimuth angle errors are less than 0.2°. This improved the precision of the 3-D trajectory of underground pipelines. [ABSTRACT FROM AUTHOR]

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The paper analyzes the problem of protection of underground metal pipelines using active cathodic protection. Shortcomings and emergency situations of active defense complexes are given. Analytical dependences of determining the levels of the protective potential in the conditions of a heterogeneous environment, various variations of the topology of laying the pipeline system are generally presented. The results of comprehensive monitoring of the operation modes of electrotechnical complexes of electrochemical protection allowed to develop a universal methodology for creating energy-efficient and reliable systems of cathodic protection of pipelines. [ABSTRACT FROM AUTHOR]

Recent industrial explosions globally have intensified the focus in mechanical engineering on designing infrastructure systems and networks capable of withstanding blast loading. Initially centered on high-profile facilities such as embassies and petrochemical plants, this concern now extends to a wider array of infrastructures and facilities. Engineers and scholars increasingly prioritize structural safety against explosions, particularly to prevent disproportionate collapse and damage to nearby structures. Urbanization has further amplified the reliance on oil and gas pipelines, making them vital for urban life and prime targets for terrorist activities. Consequently, there is a growing imperative for computational engineering solutions to tackle blast loading on pipelines and mitigate associated risks to avert disasters. In this study, an empty pipe model was successfully validated under contact blast conditions using Abaqus software, a powerful tool in mechanical engineering for simulating blast effects on buried pipelines. Employing a Eulerian-Lagrangian computational fluid dynamics approach, the investigation extended to above-surface and below-surface blasts at standoff distances of 25 and 50 mm. Material descriptions in the numerical model relied on Abaqus' default mechanical models. Comparative analysis revealed varying pipe performance, with deformation decreasing as explosion-to-pipe distance increased. The explosion's location relative to the pipe surface notably influenced deformation levels, a key finding highlighted in the study. Moreover, quantitative findings indicated varying ratios of plastic dissipation energy (PDE) for different blast scenarios compared to the contact blast (P0). Specifically, P1 (25 mm subsurface blast) and P2 (50 mm subsurface blast) showed approximately 24.07% and 14.77% of P0's PDE, respectively, while P3 (25 mm above-surface blast) and P4 (50 mm above-surface blast) exhibited lower PDE values, accounting for about 18.08% and 9.67% of P0's PDE, respectively. Utilising energy-absorbing materials such as thin coatings of ultra-high-strength concrete, metallic foams, carbon fiber-reinforced polymer wraps, and others on the pipeline to effectively mitigate blast damage is recommended. This research contributes to the advancement of mechanical engineering by providing insights and solutions crucial for enhancing the resilience and safety of underground pipelines in the face of blast events. [ABSTRACT FROM AUTHOR]

In order to reduce heat loss and diffusion of underground heating pipelines, this research incorporated phase change material (PCM) into the controlled low-strength material (CLSM) to prepare a pipeline backfill material with temperature control performance. In response to the problem that PCM leaks easily, a new type of paraffin–rice husk ash composite PCM (PR-PCM) was obtained by adsorbing melted paraffin into rice husk ash. Through mixing PR-PCM with dredged sediment (DS) and ordinary Portland cement (OPC), a controlled low-strength material (CLSM) with temperature control performance was prepared. The flowability, mechanical properties, microscopic characteristics, thermal characteristics, and durability of CLSM were analyzed through flowability, unconfined compressive strength (UCS), X-ray diffraction (XRD), scanning electronic microscopy (SEM), differential scanning calorimetry (DSC), and phase change cycle tests. The results show that when water consumption is constant, as the PR-PCM content increases, the flowability of CLSM increases, and the strength decreases. The CLSM has an obvious paraffin diffraction peak in the XRD pattern, and its microstructure is dense with few pores. The melting point of CLSM is 50.65 °C and the latent heat is 4.10 J/g. Compared with CLSM without PR-PCM, the maximum temperature difference during the heating process can reach 3.40 °C, and the heat storage performance is improved by 4.1%. The strength of CLSM increases and the melting point decreases after phase change cycles. CLSM containing PR-PCM has the characteristics of phase change temperature control, which plays a positive role in reducing heat loss by heating pipelines and temperature change in backfill areas. [ABSTRACT FROM AUTHOR]

The urban lifeline safety project is a major national livelihood project, which ensures the safe operation of urban gas, water, electricity and other systems. Nowadays, the project is confronted with three types of difficulties: Difficulties in mechanism discovery and experimental reproduction; difficulties in risk detection and early identification, and difficulties in accurate early warning and collaborative prevention and control. In order to reveal the mechanism and reproduce the experiments, a full-size urban lifeline multihazard large-scale scientific device is firstly developed in the world, a series of dis-aster modes with 5 categories and 169 kinds of disasters coupled are established, based on which a comprehensive risk dynamic assessment method coupled with underground pipelines and above-ground disaster-bearing body is presented. To improve the risk detection and early identification, highly sensitive gas sensing laser chip as well as detector with active grating and wavelength-biased are invented. We develop an intelligent ball for leakage located in water supply pipe network based on the inertial guidance, force balance, acoustic spectrum and Bei Dou. Bridge overall modal (fingerprint) monitoring technology is break-through. In order to solve the problem of accurate early warning and collaborative prevention and control, an urban lifeline safety risk physical heuristic artificial intelligence early warning technology is presented, based on which a monitoring and early warning system is developed with collaborative sensing, fusion monitoring, targeting early warning, linkage response and other functions. The related studies result in the development of the safety and emergency response industry, followed by the pioneering and substantial contributions to the prevention and control of urban lifeline risks [ABSTRACT FROM AUTHOR]

[Objective] In order to study the displacement variation law of adjacent underground pipelines during the excavation of deep foundation pits. [Method] Based on a deep foundation pit project of Nanchang No.4 line, FLAC 3D software is used to simulate the whole process of dynamic construction of foundation pit, and the influence of different pipe materials, pipe diameter, buried depth and buried distance of internal support on pipeline displacement is analyzed. And the field deformation monitoring data are used for comparison and verification. [Result] The results show that the internal support plays a good role in limiting the displacement of the adjacent pipeline during the construction of the foundation pit. In the process of foundation pit excavation, the change of pipe material and pipe diameter mainly affects the settlement of pipeline. [Conclusion] The stiffness of different types of pipes is different. The greater the stiffness, the stronger the pipeline's ability to resist soil de formation. The settlement variation of the pipeline is negatively correlated with the variation of the pipe diameter. The buried depth of the pipeline has a significant effect on the horizontal displacement of the pipeline. The horizontal displacement of the pipeline increases first and then decreases with the increase of the buried depth, and reaches the maximum when the buried depth of the pipeline is close to 1/2 of the design depth of the foundation pit. Under the principle of following a single variable, there are differences in the influence range of displacement of pipelines with different buried distances. Compared with pipeline settlement, foundation pit excavation has a greater influence range on the horizontal displacement of adjacent pipelines. [ABSTRACT FROM AUTHOR]

The corrosion mechanism of L245NS steel and L360QS steel of gas injection/withdrawal pipeline of underground gas storage in different acidic gas environments was studied by means of SEM, EDS, XRD, XPS, and GC-MS. The results show that Fe2O3, Fe3O4, and CaCO3 with poor protection were formed on the surface of L245NS steel, which provided a channel for the corrosive medium to contact the surface of the metal matrix and accelerated the corrosion rate of the pipeline. Meanwhile, CI− had a small radius and strong penetrability, which was easy to pass through the product film to reach the surface of the metal matrix to participate in the reaction, resulting in corrosion defect pits. The inner wall of L360QS steel was attached with gum, forming a dense protective film on the inner surface of the pipeline, and it was difficult for corrosive substances to enter the metal matrix, which played a role in inhibiting the corrosion of the pipeline. [ABSTRACT FROM AUTHOR]

In this subsection, a simulation model of underground pipeline leaks was created. Modeling the flow fields of overhead pipelines and underground pipelines with different soil porosity was conducted. The influence of the underground environment and soil porosity on the pipeline leakage field was analyzed. The influence of changes in the underground environment and soil porosity on the loss of kinetic energy at gas leakage was defined. Thus, the law of change in the characteristics of the sound signal of a leak on the pipe wall was obtained. Based on the results of study, it was determined the area of damage to a gas pipeline which is depended on proportionality of the diameter of the gas jet. As the gas is released from a crack in the gas pipeline and with different porosity of the pipe material, the gas diffusion occurred. As a result, the explosion zone increased which ultimately the release of gases into the environment under the influence of pressure increased. [ABSTRACT FROM AUTHOR]

In the rapid development of urban construction, underground pipelines play a crucial role. However, the current underground pipelines have poor association with relevant management departments, and there are deficiencies in data completeness, accuracy, and information content. Managing and sharing information resources is relatively difficult, transforming the constructed 3D underground pipeline geographic information systems into an 'Information silo'. This results in redundant construction and resource wastage of underground utilities. The complex distribution characteristics of underground utilities make rapid batch modeling and post-model maintenance challenging. Therefore, researching a 3D spatial data fusion model for urban underground utilities becomes particularly important. Given the above problem, this paper proposes a spatial data fusion model for underground pipeline scene modeling. It elaborates on the geometric, semantic, and temporal characteristics of underground pipelines, encapsulating these features. With underground pipeline objects as the core and pipeline characteristics as the foundation, a spatial data fusion model integrating multiple characteristics of underground pipelines has been constructed. Through software development, the data model designed in this paper facilitates rapid construction of underground pipeline scenes. This further enhances the consistency and integrity of underground pipeline data, enabling shared resources and comprehensive supervision of facility operations on a daily basis. [ABSTRACT FROM AUTHOR]

The logistics transportation system is critical to the United States economy. Underground Logistics Transportation (ULT) is a class of automated transportation systems in which vehicles carry freight through pipelines and tunnels between terminals. Being able to use a part of the underground space of existing highways will greatly facilitate the construction of such pipelines and tunnels and reduce their construction costs. Underground Logistics Transportation (ULT) could be the answer to make freight transport more sustainable and competitive. Texas highways and railroads are expected to increase by nearly 207% from 2003 to 2030. Truck tonnage will grow by 251%, while rail tonnage is forecasted to increase 118%. The number of trucks carrying NAFTA goods will increase by 263%, and the number of rail units will grow by 195%. This will have a profound impact on the highway and rail systems. The objective of this paper is to present requirements and operational components for three types of ULT lines: standard shipping containers, a standard crate size, and a standard pallet size. This study examines the use of ULT as a mode of underground transportation with the help of three case studies. This research shows that ULT is financially viable, feasible, greener, cost effective, and can become an important part of intermodal freight mobility. [ABSTRACT FROM AUTHOR]

The evolution and mechanism of ground collapse caused by underground water pipeline leakage have become increasingly significant as more urban areas experience collapses. Based on the principle of similarity, and considering the engineering context of road collapses in Anqing City, Anhui Province, this study designed a 3 m × 2 m × 2 m rupture-collapse model test device. Digital Image Correlation (DIC) technology was employed to investigate the erosion process and collapse mechanisms caused by underground pipeline leakage. The results indicate that groundwater seepage provides the driving force for collapses, combined with the migration space provided by defects, collectively triggering the collapses. When groundwater seepage is minimal, the cohesive forces between soil particles maintain soil stability. As groundwater seepage increases, the soil particle framework is eroded, leading to soil structure destabilization and collapse initiation. The depth of collapse significantly influences stress evolution: stress evolution intensity beneath and above the collapse pit is positively correlated with the distance from the collapse pit bottom, but negatively correlated with the distance from the defect. The research provides insights for the early warning and management of ground collapse. [ABSTRACT FROM AUTHOR]

The correct prediction of heating network pipeline failure rates can increase the reliability of the heat supply to consumers in the cold season. However, due to the large number of factors affecting the corrosion of underground steel pipelines, it is difficult to achieve high prediction accuracy. The purpose of this study is to identify connections between the failure rate of heating network pipelines and factors not taken into account in traditional methods, such as residual pipeline wall thickness, soil corrosion activity, previous incidents on the pipeline section, flooding (traces of flooding) of the channel, and intersections with communications. To achieve this goal, the following machine learning algorithms were used: random forest, gradient boosting, support vector machines, and artificial neural networks (multilayer perceptron). The data were collected on incidents related to the breakdown of heating network pipelines in the cities of Kazan and Ulyanovsk. Based on these data, four intelligent models have been developed. The accuracy of the models was compared. The best result was obtained for the gradient boosting regression tree, as follows: MSE = 0.00719, MAE = 0.0682, and MAPE = 0.06069. The feature «Previous incidents on the pipeline section» was excluded from the training set as the least significant. [ABSTRACT FROM AUTHOR]

The purpose of this study is to put forward a feature extraction and pattern recognition method for the flow noise signal of natural gas pipelines in view of the complex situation brought by the rapid development and expansion of urban natural gas infrastructure in China, especially in the case that there are active and abandoned pipelines, metal and nonmetal pipelines, and natural gas, water and power pipelines coexist in the underground of the city. Because the underground situation is unknown, gas leakage incidents caused by natural gas pipeline rupture occur from time to time, posing a threat to personal safety. Therefore, the motivation of this study is to provide a feasible method to accelerate the aging, renewal and transformation of urban natural gas pipelines to ensure the safe operation of urban natural gas pipeline network and promote the high-quality development of urban economy. Through the combination of experimental test and numerical simulation, this study establishes a database of urban natural gas pipeline flow noise signals, and uses principal component analysis (PCA) to extract the characteristics of flow noise signals, and develops a mathematical model for feature extraction. Then, a classification and recognition model based on backpropagation neural network (BPNN) is constructed, which realizes the detection and recognition of convective noise signals. The research results show that the theoretical method based on acoustic feature analysis provides guidance for the orderly and safe construction of urban natural gas pipeline network and ensures its safe operation. The research conclusion shows that through the simulation analysis of 75 groups of gas pipeline flow noise under different working conditions. Combined with the experimental verification of ground flow noise signals, the feature extraction and pattern recognition method proposed in this study has a recognition accuracy of up to 97% under strong noise background, which confirms the accuracy of numerical simulation and provides theoretical basis and technical support for the detection and recognition of urban gas pipeline flow noise. [ABSTRACT FROM AUTHOR]

This paper is devoted to the issue of efficiency of application of fibre optic leak detection systems for identification of small leaks on trunk pipelines. The main methods of leak detection currently in use have been considered, and parametric and fibre optic LDS have been selected for comparative analysis. In the course of the research a model of product leakage from an underground oil pipeline equipped with a fibre-optic LDS was built in the COMSOL Multiphysics software package. The result of the simulation was the estimated time of leak identification by the fibre-optic system, which turned out to be much shorter than that of the parametric LDS. Compensable environmental damage for each type of system was then calculated, confirming the effectiveness of fibre optic LDS for detecting small leaks on trunk pipelines due to the significant reduction in compensable damage. [ABSTRACT FROM AUTHOR]

As a popular nondestructive technique, ground penetrating radar (GPR) is extensively utilized for detecting underground pipelines. In this paper, an efficient and automatic scheme is presented for the detection and classification of underground pipelines by combining electromagnetic modeling and machine learning techniques. By virtue of open-source gprMax software, the B-scan signatures of underground pipelines are simulated and analyzed in detail, with four types of underground pipelines taken into account, i.e., iron pipelines, concrete pipelines, copper pipelines, and PVC pipelines. On the basis of electromagnetic modeling, B-scan profiles of underground pipelines are preprocessed by using the average method and time gain compensation method to obtain a dataset for training neural network of YOLOv8 model. The simulations indicate that our scheme combining simulated B-scan profiles and YOLOv8 model is able to detect and classify underground pipelines with high accuracy, and the category and material of underground pipelines can be determined with a high confidence level. Specifically, the detection time of a single B-scan image for underground pipelines is about 0.02 s, and the average detection accuracy can reach 0.995, which is potentially valuable for the automatic detection and classification of underground pipelines in GPR applications. [ABSTRACT FROM AUTHOR]

As the strategy for building China's strength in transportation continues to advance, people's demand for the quality of travel is increasing. Rail transit has become the lifeline for high-quality development in urbanization. Especially for intercity railways, suburban railways, and metros, which are mainly built through urban areas and are mostly laid underground, resulting in numerous urban tunnels. Due to the complex urban environment, tunnels inevitably pass above, below, or alongside existing buildings and structures such as railways, metros, highways, main urban roads, and high-rise buildings (hereinafter referred to as close-spaced engineering). How to ensure the normal operation and safety of close-spaced engineering during tunnel construction, as well as how to reasonably determine the deformation control standards for close-spaced engineering, are the focus, difficulty, and control points of urban tunnel construction. This article categorizes by adjacent railway, highway, urban rail transit, and underground pipelines, systematically sorts out the standards of related industries, and proposes protection ranges and requirements for tunnels in different environments, deformation control standards for close-spaced engineering construction. Based on the control standards and engineering experience, a set of design and construction control measures for close-spaced engineering are proposed: During the survey phase, it is necessary to ascertain the surrounding environment and geological conditions. During the design phase, on the basis of reasonably designing the route scheme and keeping enough safe clearance, adopt reasonable construction methods and reliable supporting structures, and set up effective isolation, protection, and reinforcement measures. During the construction phase, strengthen tunnel geological prediction and monitoring, and establish perfect contingency plans. [ABSTRACT FROM AUTHOR]