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Muon radiography, which relies on measuring the absorption and attenuation of muons as they pass through matters, offers a new imaging technique capable of revealing the internal structure of large objects. Recent technological advancement allows for the application or testing of muon radiography in various fields, including mining, civil engineering, security check, etc. This study investigates the factors that influence muon radiography, which is used in density inversion, through simulations and experiments. The materials considered for density inversion include water, standard rock, and iron. Our simulation studies show that the number of events detected and selected has an impact on the reconstruction results, and several factors, such as multiple Coulomb scattering processes, recording time, and spatial resolution, which influence the number of muons, must be taken into account when measuring the rock density. We design and conduct a laboratory scale experiment based on the simulation results. We filter the 220 h of recording signals through time coincidence and straight-line fitting to obtain the selected events. Our results reveal that the statistical error of muons survival ratio in recording time significantly impacts the inversion result and decreases the error can improve accuracy greatly. In the experiment, the deviation between the inversion mean value and the expected value can be reduced to 2.4%–2.9% for iron, 7% for water, and 1.5% for standard rock. This density inversion approach provides insight into future density detection of underground structures. [ABSTRACT FROM AUTHOR]

Shallow-buried cavities and underground structures are inevitably subjected to transient perturbation from earthquakes or engineering activities during their life circle, leading to the occurrence of dynamic failure. The investigation presented by this paper concentrates on the dynamic responses triggered by an aperiodic transient P wave around a circular lined tunnel with an imperfect interface in a half-space and the spring model is employed to describe the interface between rock mass and liner. Resorting to the wave function expansion scheme, the large arc assumption, the Graf's addition theorem and the numerical inversion algorithm of Laplace transformation, the dynamic responses around a circular shallow lined tunnel with an imperfect interface are evaluated theoretically. The good agreement of time–history curves and contour snapshots for stress between the theoretical solutions and the numerical counterparts validates the analytical scheme. The effect of disturbance direction, embedment depth, thickness of liner and interface coefficients on the dynamic responses around the shallow-buried lined tunnel is analyzed. The results indicate that the positions of peak hoop dynamic stress concentration factor (DSCF) are approximately perpendicular to the perturbation direction. The DSCF distributions converge to be stable when the ratio of embedment depth to excavation radius exceeds 10.0. The thickness of the liner mainly affects the dynamic responses around the interface. Increase of elastic coefficient induces a decreasing DSCF in rock mass and an increasing counterpart in the liner. The results may provide the theoretical basis for the transient responses and aseismic design of underground tunnels. [ABSTRACT FROM AUTHOR]

Engineering Planning is the primary task of underground engineering. The planning dimension of underground engineering still remains at the two-dimensional level, lacking a technical platform for processing and analyzing multi-dimensional and multi-source information. Especially due to insufficient information under hidden geological conditions, the quality of subsequent design and construction cannot be guaranteed. BIM + GIS can achieve the unification and technical application of data at the macro scale and three-dimensional models at the micro scale. Therefore, based on BIM + GIS, the technical architecture of an underground engineering auxiliary planning and design platform was established, Taking the underground pipe gallery project as an example, simulation analysis was conducted A comprehensive model integrating engineering and three-dimensional geology has been established. Based on the three-dimensional spatial conflict analysis results of geological and underground pipe gallery engineering, optimization design was carried out. The research results can clearly demonstrate the correlation between underground pipe gallery engineering and geographical environment, enabling planners to carry out planning and design work from both macro and micro perspectives, improving the technical level of planning and design, and providing new avenues for innovation in underground engineering planning and design technology. [ABSTRACT FROM AUTHOR]

The problem of seepage control is faced in the construction of large underground powerhouse cavern systems. To reduce leakage and improve the permeability stability of the surrounding rock, a complex seepage control system, including drainage hole arrays, drainage tunnels, and grouting curtains, was designed for the Wunonglong underground powerhouse caverns. In this study, we performed a seepage field numerical analysis of the Wunonglong underground powerhouse caverns system to optimize the seepage control system. A three-dimensional numerical model was established considering the complex seepage control system and the geological conditions. A steady seepage analysis method, with a variational inequality formulation, was adopted in order to calculate the long-term seepage field. A drainage substructure method was used to simulate the seepage behavior of the densely arranged drainage hole arrays. The seepage control effects of single and double grouting curtains were compared to determine a reasonable curtain layout scheme. The effect of the drainage system on the seepage control of the powerhouse caverns is further discussed. The findings offer reliable insights into the seepage behavior of underground powerhouse caverns and provide a reference for the design and construction of similar underground powerhouse cavern systems. [ABSTRACT FROM AUTHOR]

Anchors of various designs are crucial, especially in mining and underground construction, where they stabilise the excavation and prevent the movement of rocks. They make it possible to control the direction of cracking during explosions, limit the dispersion of rock material and minimise damage from vibrations. The use of anchors increases the safety and efficiency of work in difficult geological conditions. The authors propose the use of modified anchor construction for the detachment of rock lumps. The paper presents the results of a numerical analysis carried out using the finite element method (FEM) on the effect of the angle of the anchor conical head of a new breakout design on the formation of the detachment crack trajectory influencing the range and, consequently, the volume of detached rock output. The analysis was carried out with a view to explaining the mechanism of separation of lumps of rock by the anchor treated as a mining tool. [ABSTRACT FROM AUTHOR]

Assessment of rock mass quality significantly impacts the design and construction of underground and open-pit mines from the point of stability and economy. This study develops the novel Gromov-Hausdorff distance for rock quality (GHDQR) methodology for rock mass quality rating based on multi-criteria grey metric space. It usually presents the quality of surrounding rock by classes (metric spaces) with specified properties and adequate interval-grey numbers. Measuring the distance between surrounding rock sample characteristics and existing classes represents the core of this study. The Gromov-Hausdorff distance is an especially useful discriminant function, i.e. a classifier to calculate these distances, and assess the quality of the surrounding rock. The efficiency of the developed methodology is analyzed using the Mean Absolute Percentage Error (MAPE) technique. Seven existing methods, such as the Gaussian cloud method, Discriminant method, Mutation series method, Artificial neural network (ANN), Support vector machine (SVM), Grey wolf optimizer and Support vector classification method (GWO-SVC) and Rock mass rating method (RMR) are used for comparison with the proposed GHDQR method. The share of the highly accurate category of 85.71% clearly indicates compliance with actual values obtained by the compared methods. The results of comparisons showed that the model enables objective, efficient, and reliable assessment of rock mass quality. [ABSTRACT FROM AUTHOR]

Global research on the geological particularities of coal‐accumulating environments and the enrichment patterns of coalbed methane (CBM) is still relatively weak. This paper studies the geological characteristics and coal accumulation patterns of Carboniferous‐Permian coal‐bearing seams in the southern Qinshui Basin. The results show that the coal‐bearing strata in the basin represent the offshore marine and continental intercalated coal seam sediments developed. The southern part of the basin is dominated by lacustrine facies, and the delta front sub‐facies is locally developed. The characteristics of coal accumulation environment in the southern Qinshui Basin are characterized by basement properties, fault networks and coal‐bearing sedimentary facies, which collectively control the spatial and temporal distribution characteristics of the coal‐rich belt. The differences in coal accumulation environment in the southern basin affect the tectonic evolution, the thickness of the coal seam roof and floor and the hydrogeological conditions of the coal‐rich area, which further control the CBM enrichment in the Taiyuan‐Shanxi Formation. The aim of this study is to explore the factors of CBM enrichment and gas control mode, so as to enrich and improve the theory and method of CBM exploration, which will also help identify the appropriate underground geological structure environment for carbon sequestration (CCS), reduce greenhouse gas emissions and effectively respond to the challenge of global warming. [ABSTRACT FROM AUTHOR]

This study addresses a gap in previous research by thoroughly investigating the relationship between the optimal tunnel diameter and cable thermal effects in underground cable tunnels using a thermal-coupling correlation method. Our research innovatively integrates theoretical principles of cable thermal convection with practical applications. By integrating theories of cable thermal convection and factors such as cable heat dissipation performance, cable structure, tunnel radius, cable length, thermal conductivity, and temperature difference, we establish a precise electro-thermal-fluid multiphysics coupling model using the COMSOL Multiphysics simulation tool, offering new perspectives and methodologies for the design of underground cable tunnels. The simulation results effectively validate the proposed method, providing reliable theoretical guidance for the optimization design and construction of underground cable tunnels. The prominent conclusion is the significance of our proposed thermal-coupling correlation method in cable tunnel design. [ABSTRACT FROM AUTHOR]

Urban cover-collapse sinkholes pose a significant global challenge due to their destructive impacts. Previous studies have identified groundwater fluctuations, subsurface soil conditions, pipeline leakage, precipitation, and subterranean construction activities as key contributors to these phenomena. However, unique geological settings across different urban environments lead to variations in the primary factors influencing sinkhole formation. This study focuses on Shanghai, a city notable for its extensive urbanization and rich historical context, to explore the dynamics of sinkholes within urbanized areas worldwide. We employ spatial analysis and statistical methods to examine data on sinkholes recorded in the past two decades in Shanghai, correlating these events with the city's shallow sand layer, ground elevation, and proximity to surface water. Our goal is to identify the dominant factors governing sinkhole occurrence in Shanghai and to lay the groundwork for their effective scientific management and prevention. Key findings indicate that most sinkholes in the area are associated with a thin shallow sand layer, low to moderate ground elevations, and the absence of nearby rivers. Additionally, many sinkholes correlate with subterranean voids within the confined aquifer beneath the cohesive soil layer. The lack of historical river channels, obscured by urban development, also indirectly contributes to sinkhole formation. We recommend enhancing urban river management and drainage systems to mitigate potential damage from water accumulation. [ABSTRACT FROM AUTHOR]

Physical and cadastral data management practices for underground facilities are insufficient to represent underground assets' Rights, Restrictions, and Responsibilities (RRRs) and their relationships with the cadastre. For this reason, developing a 3D integrated data (underground and above‐ground) model may be an approach to an effective land management system. This research aims to develop a creative data model by integrating Turkish National Geographic Information System (TUCBS‐AY in Turkish) with international standards (Land Administration Domain Model (LADM) and CityGML) as a holistic approach. The requirements determined for underground facilities using TUCBS‐AY were used. Since the data produced in Turkey were modeled according to the CityGML 2.0 version, the CityGML 2.0 UtilityNetwork version was used in the study to be compatible with the existing Turkish cadastral system. While some classes in the model are generalized, they are expanded using LADM's classes for legal rights and part information. In addition, the CityGML classes have been expanded within the model so that parcels, buildings, and independent sections are represented separately, thus providing the opportunity to represent the underground utilities associated with them, their RRRs, and ownership situations. Requirements for the proposed model were determined based on Turkey's cadastral system and underground data. The main purpose is to manage the legal and physical relations of underground and surface objects at the city scale, compatible with the current Turkish cadastral system, with a holistic approach. The proposed integrated conceptual data model shows how legal rights and ownership of underground structures can be logically represented with a 3D data model. [ABSTRACT FROM AUTHOR]

The design of underground facilities in rock salt relies on constitutive models whose parameters are derived from laboratory tests and (when possible) recalibrated on the basis of field data. In this sense, laboratory tests should cover the load paths expected in real-scale applications. However, the literature review proves that most tests have been conducted at stress deviators greater than about 5 MPa, which is not representative of the whole spatial and temporal spans of the facilities. In this paper, results of confined multi-stage creep tests performed on salt samples from two different origins are shown. Stress deviators between 0.5 and 20 MPa have been applied to different samples under a constant temperature of 50 ∘ C. The experimental procedure allows to reduce uncertainty associated with sample-to-sample variability, sample preparation and preconditioning. The analysis of the experimental data shows that the stress dependency of the creep rate is different at low and high differential stresses. In particular, the creep rate is underestimated by several orders of magnitude when the creep tests are performed at high differential stress levels and the trends are extrapolated towards low and moderate levels. On the basis of these results, the Lemaitre and RTL constitutive models for rock salt have been modified, allowing for more accurate predictions of underground facilities. Properly designed laboratory tests are necessary to limit extrapolation; however, the duration of such experiments is negligible compared to the lifespan of the underground facilities, and long-term aspects should be further investigated. Highlights: Confined multi-stage creep tests were performed covering stress deviators from 0.5 to 20 MPa. Rock salt specimens from two different origins were tested. The deviatoric stress dependency of the creep rate is different at low and high deviatoric stresses. Two phenomenological viscoplastic models for rock salt are extended to better reproduce creep behavior. Although stress extrapolation is addressed, time extrapolation remains a major challenge. [ABSTRACT FROM AUTHOR]

Bentonite slurry is readily available, and extensively used in underground construction, where the in-situ infiltration behavior of the slurry is of great interest. As a solid–liquid biphasic fluid, slurry exhibits distinct fluid properties that set it apart from pure water. These unique properties play a significant role in determining its infiltration behavior during construction, making it a critical factor that cannot be overlooked. In this study, slurry shear tests were carried out using a rotational viscometer to characterize its fluid properties, and constant water head infiltration tests were conducted by a self-designed infiltration device to investigate the infiltration behavior of slurry in sand stratum. In addition, theoretical derivation based on the pipe flow was implemented to simulate the slurry flow in the stratum. The results show that, as the slurry infiltration continues, the relationship between the yield stress and initial hydraulic gradient experienced a "nonlinear to linear" process. The nonlinearity at the early stage of slurry infiltration is related to the evolution of the core phase of the slurry, which is the root cause of the nonlinear evolution of the fluid property and infiltration curves. A predicted relation between the fluid parameters of the slurry and its multiphase infiltration behavior was established, which are able to give a better understanding of the slurry behavior in engineering design. [ABSTRACT FROM AUTHOR]

FOUR FRANKFURT – New high‐rise buildings in Frankfurt am Main On the former Deutsche Bank site in Frankfurt's city centre, an impressive new ensemble of four high‐rise buildings and a shared six‐storey base building with underground car park is being built.The shell of the building is now largely complete and the topping‐out ceremony was held in September 2023. The high‐rise buildings are 233 metres (T1), 178 metres (T2), 125 metres (T3) and 105 metres (T4) high. Office use is planned for the T1 and T4 towers, and residential use and a hotel are planned for T2 and T3. The office space on the top floors of T1 will be the highest in Germany. The inner‐city location poses particular challenges for the project. For example, the excavation pit was constructed using the down method. The different requirements for the use of the towers led to different construction methods for the typical storeys: while the shell of the residential towers was made of in‐situ concrete, prefabricated elements proved to be the optimized construction method for the office towers. The report is divided into three parts. The first part presents the project and provides overviews of the components. The second part deals with the bracing system of the towers, including measures to increase stiffness. Finally, the third part describes special construction methods. [ABSTRACT FROM AUTHOR]

High-pressure groundwater brings great challenges to the construction of mountain tunnels. Hence, controlling and discharging groundwater are two key problems that must be addressed before constructing tunnels in high-pressure and water-rich region. Fluid–solid coupling seepage analysis method is used to analyze the variation of displacement, stress and pore water pressure of the tunnel. A waterproof and drainage method suitable for tunnels in high-pressure and water-rich region is proposed. Curtain grouting plays a dual role in waterproof and reinforcing surrounding rock. Decompression drainage holes are designed in order to further reduce the pore water pressure acting on the initial lining. The thickness of grouting circle, the permeability coefficient ratio and the decompression drainage holes distribution rate of the initial lining are the main factors that affect the waterproof and drainage effect of tunnels in high-pressure and water-rich region. Suggested parameters on waterproof and drainage measures for tunnels in high-pressure and water-rich region are given after comprehensive analysis, which can provide basis for the technology on high-pressure groundwater treatments and constructions of underground engineering under complex geological conditions. [ABSTRACT FROM AUTHOR]

Rock slope landslides and underground construction destabilization are frequently attributed to shear impairment by intermittent joints, and the support by bolts represents an indispensable technique for reinforcing jointed rocks. Therefore, we conducted laboratory experiments on intermittently jointed rock-like materials that were anchored, employing various anchoring inclination angles and methods, to investigate the influence of bolt anchoring on the shear properties and acoustic emission characteristics of intermittently jointed rock-like materials. Experimental results revealed that the peak shear strength of the anchored intermittently jointed rock-like materials is proportional to the bolt inclination angle. The strain on the joint is inversely related to the peak shear strength and the bolt inclination angle. The full-length anchorage and end anchorage can drastically enhance the mechanical traits of intermittently jointed rock-like materials, effectively impeding the proliferation of shear cracks after reaching the peak shear strength. The anchorage inclination exhibits a positive correlation with the accumulative acoustic emission (AE) energy and, conversely, a negative correlation with the peak AE count. In geotechnical engineering, the anchoring effect of anchor bolts can enhance the integrity of fractured rock masses and improve overall stability. [ABSTRACT FROM AUTHOR]

The underground hub of Xinghuo Station of M3 Line of Beijing Metro is an integral part of the underground comprehensive hub of Xinghuo Station of high-speed railway, and it is constructed by open-excavation method. Due to the different requirements of the main structure function inside the foundation pit of the hub, the foundation pit adopts the three-level layout. One side of the foundation pit is adjacent to the existing high-speed railway Xinghuo station, and the other side is adjacent to the urban road, the foundation pit is affected by four layers of groundwater. In order to solve the difficulties encountered in the design of the multi-stage foundation pit support structure of the underground hub of the Xinghuo Station on the metro line M3, this paper carries out the research of the foundation pit composite support structure system. Firstly, the spatial layout characteristics, surrounding environment and groundwater occurrence characteristics of the hub foundation pit are analyzed, and the problems of the conventional support structure system are discussed. Based on the concept of graded support and graded water stop, the combined foundation pit support structure system is developed. The paper presents in detail the layout, structural parameters and step sequence of multi-stage foundation pit excavation and support structure system at all stages, then establishes the three-dimensional numerical calculation model of multi-stage foundation pit excavation and support, analyzes the pit bottom uplift and the deformation of the retaining structure, and finally discusses the deformation characteristics of the combined retaining structure of the foundation pit based on the measured results of the deformation of the retaining structure at all stages. The results of numerical simulation and on-site monitoring show that the uplift of pit bottom and the deformation of supporting structure meet the requirements of control values. [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 construction of tunnels in conditions of dense urban development affects buildings, structures, and engineering communications located at the surface. In this work, through dispersion analysis, factors influencing the settlement of the earth's surface and buildings during tunneling were selected. Subsequently, a model based on statistically significant parameters that can predict deformations at the pre-design stage was created. This research was conducted using data from geotechnical monitoring obtained during the construction of underground structures, with information about the technological parameters of shield tunneling in the construction of the single-track lines of the Moscow Metro using TBM with face-support pressure and engineering–geological conditions. In the obtained model, there is a clear dependency between the additional displacement of the monitoring object located above the projected tunnel and the average face-support pressure causing the mentioned deformations. The response is also affected by the soil deformation model at the tunnel face, the depth of the tunnel, and the soil excavation for the installation of one ring. [ABSTRACT FROM AUTHOR]

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The increasing number of private cars, public transportation vehicles, and pedestrians, as well as the absence of adequate space for these ground amenities, are one of the primary causes of traffic congestion and accidents in the Kathmandu Valley. Investigations have indicated that the Kathmandu Valley has the greatest traffic accidents despite the heavy presence of the government and its agencies there. Most teens and young adults suffer injuries while using motor vehicles. The study's primary objective is to foresee and prevent such complications by planning for sufficient subsurface infrastructure (a cut‐and‐cover rectangular tunnel) for the Kathmandu Valley's transportation network. The overlying pressure, lateral earth pressure, live load, uplift pressure, and live surcharge are some of the forces acting on the tunnel, creating unique stress and moment zones. The tunnel meets the following geometric requirements: (a) Each of the tunnel's two cells has a clear span of 10 m and a clear height of 5.5 m. The side walls, inner walls, top slab, and bottom slab are all 700 mm thick. Soil has built up to a height of 4 m over the tunnel's roof. The analytical method is used in the tunnel segment's analysis. Furthermore, the designed tunnel has been evaluated for stability, considering the deflection and shear resistance. The analysis indicates that the tunnel meets the stability requirements. This implies that the structure is capable of withstanding the applied forces without excessive deflection. Non‐linear dynamic time history analyses of the El Centro earthquake and the Gorkha earthquake were computed. From the El Centro earthquake, the maximum displacement was 23.63 mm at 10.59 s, and from the Gorkha earthquake, the maximum displacement was 16 mm at 0.19 s for the modeled structures. [ABSTRACT FROM AUTHOR]

Understanding the time-dependent behavior of the rock mass is crucial to improve the reliability of underground structure design, particularly for projects with longer lifespans, such as nuclear waste repositories and hydrocarbon storage tanks. Creep is a time-dependent mechanism that plays a significant role in such designs but is often overlooked. Hence, a comprehensive study of the non-linear viscoelastic response of caverns over extended periods is needed to assess cavern closure under various scenarios. Therefore, this study investigates the time-dependent behavior of caverns constructed in rock-salt and shale rock using a finite element (FE) approach. The analysis was performed by the ABAQUS CAE tool, focusing on an axisymmetric approach. The time-dependent deformation behavior of the rocks was simulated using the Power-Law creep model. Furthermore, a parametric study was carried out to evaluate the influence of overburden depth, shape, volume, and time on the long-term behavior of caverns. The analysis revealed that the excavation of caverns in rock salt resulted in minimal displacements compared to that of shale rock. The results suggested inward displacement at the crown and wall of the cavern, with uplift found at the heel. Furthermore, the augmentation in the volume of the cavern and the depth of the overburden resulted in an enhanced displacement at the wall, crown, and heel of the cavern. Further, the examination of several cavern shapes revealed that spherical caverns show the least displacement compared to cylindrical and horseshoe-shaped caverns. Additionally, the normalized graphs were developed using normalized displacement, rock mass density, overburden depth, and Young's modulus as the basis. Engineers and designers can use these graphs as a useful tool to evaluate the long-term behavior of caverns and make well-informed judgments during the planning stage. Overall, this study contributes to safer and more reliable engineering practices in cavern construction and maintenance by offering insightful information about the time-dependent behavior of rock mass and useful suggestions for enhancing the stability and design of underground structures. [ABSTRACT FROM AUTHOR]

Open caissons are commonly used in the construction of various underground structures, such as launch and reception shafts for tunnel-boring machines, storage or attenuation tanks, and cofferdams. During the sinking phase, the cutting edge of a caisson wall with a cutting face encounters soil and is subjected to loading to facilitate and control the sinking process. In this regard, the bearing capacity factor (N) of the cutting face of a circular open caisson in heterogeneous clay is evaluated via finite element limit analysis, which accounts for the increase in the undrained shear strength with depth. The parameters considered in this study cover practical aspects, including the excavation geometry, soil strength profile, and caisson geometry. This investigation also explored the impacts of the cutting face angle (β), roughness (α), ratio of the internal embedment depth to the embedment width (H/B), ratio of the internal radius to the embedment width (R/B), and strength gradient ratio (ρB/su0). In particular, when the H/B > R/B ratio, the N value tends to stabilize. Crucially, when H/B > 4, an increasing trend in R/B leads to a rise in N until R/B exceeds 10, i.e., large diameter caissons, stabilizing the N value. Furthermore, the results reveal the significant dependency of the cutting face roughness and strength gradient ratio of clay on N. The artificial neural network model, which is a soft computing-based model, is also developed to present the undrained bearing capacity forecasting equation. Compared with conventional regression, including the multiple linear regression model and the multiple nonlinear regression model, it has excellent performance, as measured by eight indices. In addition, ANOVA and Z-tests can support the research hypothesis and reject the null hypothesis. [ABSTRACT FROM AUTHOR]

Dietary supplements are widely consumed. However, the lack of mandatory testing results in limited data on their quality, particularly in Eastern Europe. In this study, 21 legally registered and 9 illegal supplements, seized from an underground facility by the Polish Police, were examined. Contaminants were screened by utilising high-performance liquid chromatography coupled with untargeted mass spectrometry. The analysis identified 32 contaminants in the 30 dietary supplements examined. Untargeted analysis revealed a concerning issue: the intentional adulteration of both legal and illegal supplements with pharmacologically active substances that are prohibited in this category of products. This study indicated that many dietary supplements are of low quality due to deliberate adulteration or inadequate manufacturing conditions. The presence of unregistered or unapproved substances in these supplements poses serious health risks. Strong legal regulations are essential to address this issue effectively. [ABSTRACT FROM AUTHOR]

In this paper, to investigate the dynamic responses of underground circular shells subjected to subsurface denotations and provide a feasible engineering design method, a simplified mathematical modelling was proposed. The dynamic medium–structure interaction (MSI) was introduced into the equations of motions through an interfacial damping between the structure element and the surrounding geomaterial, in which the effects of the shear and the rotary inertia were neglected. By means of modal superposition, the analytical solutions of the dynamic responses were deduced. The effects of geometric parameters and acoustic impedances on the dynamic responses were discussed. It is suggested that protective structures are better to be constructed in geomaterial with small impedance to attenuate the intense shock wave effects. [ABSTRACT FROM AUTHOR]

In the absence of experimental investigations on column members of underground structures, full‐scale column specimens were tested to explore the seismic behavior of shallow‐buried subway stations at various depths. The axial compression ratios of internal column specimens were set as 0.16, 0.33, and 0.40. Both hybrid simulations and quasi‐static tests were performed on the station columns. The hybrid simulations illustrated the drift demands of internal columns, while the load‐carrying capacity and deformation capacity were obtained from the quasi‐static tests. Hybrid simulations at low, moderate, and high‐intensity levels were conducted to study the seismic responses of shallow‐buried rectangular stations. The hybrid simulations suggest that the most severe damage occurred in the station when the axial compression ratio of the tested column reached 0.40. Central columns suffered severe stiffness deterioration under high‐level earthquake excitation, especially in stations at greater depths. Meanwhile, the quasi‐static test results indicate that the ultimate load of the central columns increases with increasing axial compression, but this leads to a significant decrease in the ductility of columns. Besides, the sectional analysis results show that the central columns are prone to tension‐controlled failure, and the safety margin for flexural response deteriorates with an increasing axial compression ratio. The test results indicate that shallow‐buried rectangular stations are susceptible to flexure‐controlled structural failure when their central columns possess a relatively low axial compression ratio and a high shear span‐to‐depth ratio. The failure mechanism of station columns is revealed by both the hybrid simulations and quasi‐static tests, and the findings from the full‐scale tests are beneficial for the practical design of shallow‐buried rectangular stations. [ABSTRACT FROM AUTHOR]

Accurate estimation of the effects of dynamic disturbances on stress concentration is crucial for the stability of rock engineering and the corresponding analytical approaches are needed. This study presents an analytical approach to calculate the relative stress distribution with a point source inside and outside a hole using the linear theory of elasticity. The Helmholtz potentials and Sommerfeld integral are employed to describe the displacement and stress components, and then formulate the equilibrium equations to solve the equivalent stress distribution around the hole. Numerical examples demonstrate the impact of model parameters on the equivalent stress, such as frequency, hole radius, source location, etc. It is found that sometimes high frequencies can make the equivalent stress greater far from the source than that close to the source. Additionally, when the ratio of the distance between the source and the hole axis to the hole radius exceeds ten, the equivalent stress distribution around the hole remains nearly constant. This approach can be used for the design and assessment of underground engineering structures' stability under dynamic disturbances. [ABSTRACT FROM AUTHOR]

Surface waves are widely used in the study of underground structures at various scales because of their dispersion characteristics in layered media. Whether in natural seismology or engineering seismology, surface wave analysis methods have matured and developed for their respective fields. However, in oil and gas exploration, many data processors still tend to consider surface waves as noise that needs to be removed. To make more people pay attention to the application of surface waves and widely utilize surface waves carrying the near surface information in oil and gas exploration, this paper takes the data processing of LH site in Qinghai, China as an example to apply surface wave analysis methods to oil and gas exploration. We first preprocess and perform dispersion imaging method on the seismic record in the LH site to obtain frequency-phase velocity spectrum with good resolution and signal-to- noise ratio. Then, utilizing clustering algorithms, it automatically identifies and picks dispersion curves. Finally, through a simultaneous inversion algorithm of velocity and thickness, it inverts the dispersion curves and obtain S-wave velocity profiles in the depth range of 0-200 m. The near surface is divided into four zones based on velocity ranges and depth ranges. Additionally, we apply the surface waves inversion results as constraints to first-arrival tomography and obtain objectively accurate P-wave velocity profiles and Poisson's ratio profiles. The results indicate that by applying surface wave analysis methods, the near surface velocity information carried by surface waves can be extracted, providing near surface velocity models for static correction and migration. At the same time, compared with the surface wave application in engineering seismology, the scale of oil and gas exploration is larger, so that the data processing of surface waves is particularly important, otherwise it will affect the picking of the dispersion curve and inversion. [ABSTRACT FROM AUTHOR]

An experience in the design and construction of a combined footing for a high-rise building in the presence of underground excavations at its basement is presented. A brief review of the construction conditions is presented. Prediction calculations of settlements and the results of their monitoring during the construction process are analyzed. The calculated and actual characteristics of the foundation deformability are compared. [ABSTRACT FROM AUTHOR]

Seismic exploration has caught widespread attention in metal ore exploration due to its higher resolution. However, the presence of topography and complex underground structures in metal ore exploration complicates seismic records. Therefore, it is essential to apply a numerical simulation method suitable for metal ore exploration to study the propagation law of seismic waves in shallow and ore-forming zones, providing reliable theoretical support for multi-component seismic techniques. In particular, the presence of topography generates strong-amplitude surface waves, scattered waves, and converted waves, which consistently distort seismic records and affect the imaging accuracy of the metallogenic belts. Additionally, the propagation of seismic waves is also affected by the anisotropy and viscoelasticity of the underground medium. This paper proposes an elastic wave finite-difference numerical simulation method suitable for irregularly topographical and complex medium conditions, named the comprehensive parameter correction method, which implements a free-surface boundary condition based on the concept of medium averaging. It is algorithmically simple and implies no additional computational costs. Meanwhile, the results obtained by this method are highly consistent with those of the spectral element method, demonstrating its accuracy. By presenting several numerical simulation cases and illustrating the impact of topography and medium conditions on seismic records, this paper demonstrates the necessity of considering irregularly topographical and complex medium conditions in metal ore exploration. In conclusion, the numerical simulation method we propose provides a solid theoretical foundation for the application of seismic exploration methods in metal ore exploration. [ABSTRACT FROM AUTHOR]

Time-series monitoring of the land subsidence in the Yangtze River coastal area is crucial for maintaining river stability and early warning of disasters. This study employed PS-InSAR and SBAS-InSAR techniques to monitor the land subsidence along the Yangtze River in Nanjing, using a total of 42 Sentinel-1A images obtained between April 2015 and November 2021. The accuracy of both methods was compared and validated, while a comprehensive analysis was conducted to ascertain the spatial distribution characteristics and underlying causes of land subsidence. The maximum deviation between the two methods and six leveling point data did not exceed ±5 mm. Within the 5 km buffer zone on either side of the Yangtze River in Nanjing, four subsidence funnels were identified. Analysis of the factors contributing to land subsidence in this area indicates that underground engineering construction and operation, increasing ground building area, and geological condition all have certain correlations to the land subsidence. The results obtained through PS-InSAR and SBAS-InSAR technologies revealed a high degree of consistency in monitoring outcomes, and the latter method exhibited superior monitoring accuracy than the former one in this area. This study holds significant implications for guiding the scientific management of urban geohazards along the Yangtze River. [ABSTRACT FROM AUTHOR]

In response to the need for high‐resolution imaging of shallow crustal structure, we present a linear array double‐difference (DD) adjoint tomography method, using DD Rayleigh wave traveltime measurements for enhanced spatial resolution. This method, validated through synthetic experiments, improves velocity anomaly detection with fewer iterations compared to absolute traveltime measurements. Applied to data from four linear seismic arrays in the central Tanlu fault zone (TLFZ) in the eastern China, our approach integrated both DD and absolute difference (AD) of adjoint traveltime measurements. We performed cluster analysis for data quality control, reducing data outliers and increasing reliability, particularly in suppressing cycle skipping for short‐period measurements. The resulting high‐resolution S‐wave velocity profiles in the shallow crust well delineate geological structures, revealing a continuous low‐velocity anomaly beneath the eastern branch of TLFZ. Our comparative analysis with the southern segment of TLFZ further highlights the segmented nature of the fault zone structure. These variations might suggest a dominant influence of deep magmatic processes due to destruction of the North China Craton. Our study links shallow structural features to deeper geodynamic activities, emphasizing the role of TLFZ as a critical tectonic boundary. Plain Language Summary: The Tanlu Fault Zone (TLFZ) in Eastern China, a region crucial for its dense population and economic significance, has historically experienced severe earthquakes. Particularly, the Weifang segment of the central TLFZ, despite its current low seismic activity, raises questions about potential seismic risks. And the weak structures beneath the fault zone can promote earthquake rupture and its associated hazards. To get a clearer picture of the underground structures, we developed an imaging method focusing on the seismic traveltime differences between pairs of stations of linear seismic arrays. We also developed a data screening method for the linear array to reduce the effect of unusual or extreme data points on our analysis. We used this new technique and surface wave data recovered from ambient noise to produce clear images of in the upper crust of the central TLFZ. We found a weak structure beneath the eastern branch of the TLFZ, indicating a higher risk of earthquakes in this region. We compared our results with those from the southern TLFZ and noticed links between the shallow underground features and the deeper dynamic process associated with the destruction of the North China Craton. Key Points: A linear array double‐difference adjoint tomography using ambient noise data is proposed and applied to the central Tanlu fault zone (TLFZ)The refined upper crust Vs models reveal a continuous low‐velocity anomaly beneath the eastern branch of TLFZSeismic velocity variations along the TLFZ indicate the influence of deep magmatic processes resulting from the destruction of the North China Craton [ABSTRACT FROM AUTHOR]

Seismic intensity measures (IMs) can directly affect the seismic risk assessment and the response characteristics of underground structures, especially when considering the key variable of burial depth. This means that the optimal seismic IMs must be selected to match the underground structure under different buried depth conditions. In the field of seismic engineering design, peak ground acceleration (PGA) is widely recognized as the optimal IM, especially in the seismic design code for aboveground structures. However, for the seismic evaluation of underground structures, the applicability and effectiveness still face certain doubts and discussions. In addition, the adverse effects of earthquakes on tunnels in soft soil are particularly prominent. This study aims to determine the optimal IMs applicable to different burial depths for horseshoe-shaped tunnels in soft soil using a nonlinear dynamic time history analysis method, and based on this, establish the seismic fragility curves that can accurately predict the probability of tunnel damage. The nonlinear finite element analysis model for the soil–tunnel interaction system was established. The effects of different burial depths on damage to horseshoe-shaped tunnels in soft soil were systematically studied. By adopting the incremental dynamic analysis (IDA) method and assessing the correlation, efficiency, practicality, and proficiency of the potential IMs, the optimal IMs were determined. The analysis indicates that PGA emerges as the optimal IM for shallow tunnels, whereas peak ground velocity (PGV) stands as the optimal IM for medium-depth tunnels. Furthermore, for deep tunnels, velocity spectral intensity (VSI) emerges as the optimal IM. Finally, the seismic fragility curves for horseshoe-shaped tunnels in soft soil were built. The proposed fragility curves can provide a quantitative tool for evaluating seismic disaster risk, and are of great significance for improving the overall seismic resistance and disaster resilience of society. [ABSTRACT FROM AUTHOR]

The water-rich shield tunnel plays a significant role in the rapid development of underground space construction. The use of various special-shaped shield tunnels is gradually emerging for the need of functional diversity. In this study, a shield tunnel shape coefficient was proposed, and the analytical solution for the shallowest overburden thickness of special-shaped shield tunnels in double-layered soil was derived using both linear and nonlinear soil resistance models. The variables influencing the shallowest overburden thickness of shield tunnels were analyzed, and the buoyancy of shield tunnels at different construction stages was discussed. Furthermore, the solution to determine the shallowest overburden thickness of shield tunnels in multi-layered soil was presented. It was observed that the shallowest overburden thickness of shield tunnels is negatively correlated with the tunnel shape coefficient, the longest length of the cross section, and the cohesion, internal friction angle, and submerged bulk density of the soil layer. The analytical solution for the shallowest overburden thickness, considering the shear force based on the nonlinear soil resistance model, is more conducive to ensuring the anti-floating stability of the shield tunnel without excessive anti-floating capacity. [ABSTRACT FROM AUTHOR]

Robust approaches are needed for designing efficient dewatering systems of deep excavations below the water table to avoid unforeseen incidents (e.g., bottom instabilities in deep excavations and flooding, among others). This paper proposes a methodology, which integrates existing experiences, that was adopted to design the dewatering system of an excavation in the city of Barcelona (Spain). The approach consists of combining: (i) detailed geological and hydrogeological characterizations, (ii) numerical modelling for parameter estimation and drawdown predictions, and (iii) analytical assessment for stability evaluation and soil deformation predictions. The idea is that by combining a set of relatively easy to apply methods, it is possible to successfully solve a complex and risky problem. The methodology allows designing efficient dewatering systems, increasing safety and mitigating potential impacts of groundwater pumping. The most significant conclusion is that the most important step of the proposed approach is the hydrogeological characterization because it allows building realistic and representative numerical models to address most of the challenges associated to dewatering. [ABSTRACT FROM AUTHOR]

One of the primary concerns in the field of seismic risk assessment for underground structures is establishing an accurate connection between seismic intensity and structural responses. The objective of this work is to conduct a rational support vector machine (SVM) model for generating mass data and improved fragility curves of cross-fault hydraulic tunnels (CFHTs). The results highlight that the 900 sets, multiple earthquake intensity measures, and cubic polynomial kernel function of the SVM model can improve reliability in evaluating structural performance. Additionally, the improved Cloud analysis method is more suitable for seismic performance than the typical Cloud analysis. [ABSTRACT FROM AUTHOR]

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The construction of public buildings involves a significant amount of carbon emissions, particularly during the materialization phase of underground construction, which is characterized by a rapid and intense release of carbon emissions. In response to this issue, this study aims to develop a Building Information Modeling (BIM)-based method for assessing the factors influencing carbon emissions during the materialization phase of underground construction in public buildings. To achieve this goal, a process-based quantitative and qualitative method was established to evaluate carbon emissions at various stages, including raw material extraction and processing, building material/equipment production, and on-site processing of components, as well as construction and installation. The proposed method may serve as a valuable tool for selecting design schemes in the early stages of building design. By analyzing 125 actual cases in Xi'an, China and utilizing a carbon emission calculation model, accurate carbon emission data was obtained. This study's findings indicate a correlation between the embodied carbon emissions and the area of underground space in the cases analyzed. Specifically, larger underground spaces were associated with higher embodied carbon emissions in underground engineering. Furthermore, this study categorized the cases into two groups based on the presence or absence of underground space, resulting in the identification of 16 factors for cases without underground space and 19 factors for cases with underground space. These findings provide valuable insights for understanding and mitigating the impact of carbon emissions during the materialization phase of underground construction in public buildings. [ABSTRACT FROM AUTHOR]

In the construction of urban underground shield tunnels, uneven deformation can easily occur when the shield passes through soft soil and other poor strata. Such deformation has a significant impact on surface settlement and may cause potential safety hazards to the surrounding existing buildings, directly affecting the safety of urban operation. When simulating and predicting surface settlements, the small-strain soil hardening model can more accurately characterize the mechanical parameters of soil. Nevertheless, its parameters are numerous and complicated to determine accurately, so parameter inversion is needed to determine the accurate parameters of the soft soil layer in order to more accurately predict the surface settlement. This study uses the EFAST method to analyse the sensitivity of the HSS model parameters of soft soil strata. It is determined that the parameters that have the most significant impact on the surface settlement are the reference tangent modulus, rebound modulus, and effective cohesion. Then, XGBoost's fast calculation speed and high precision of SSA inversion are used to inverse and optimize the parameters with high sensitivity. Finally, according to the parameters of the soft soil layer obtained from inversion and measured data, the settlement deformation and safety behaviour of existing buildings are analysed. Combined with the actual shield tunnel project in a city along a river, the inversion calculation shows that the overall average error of the transverse monitoring section is 1.04 mm, and the average maximum error of each monitoring point in the overall shield process is 2.87 mm. The prediction effect is significantly improved compared with the original parameters. The accuracy of the inversion of soil layer parameters is verified from the perspective of time and space. The average settlement of the river embankment foundation is 2.5 mm. Compared with the original parameter data, the prediction results have been greatly improved, and the settlement deformation results are more consistent with the measured data. [ABSTRACT FROM AUTHOR]

In recent years, underground logistics systems have attracted more and more attention from scholars and are considered to be a promising new green and intelligent transportation mode. This paper proposes a yard design problem considering an underground container logistics system. The structure and workflow of the underground container logistics system are analyzed, and key features are recognized for the yard design problem, such as the container block layout direction, the lane configuration in the yard, and the number of container blocks. We formulate the problem into mathematical models under different scenarios of the key features with the comprehensive objective of maximizing the total throughput and minimizing the total operation cost simultaneously. An improved tabu search algorithm is designed to solve the problem. Experimental results show that the proposed algorithm can generate a satisfactory layout design solution for a real-size instance. Our research studies different container yard design options for introducing the underground logistics system into port terminals, which provides an important scientific foundation for promoting the application of underground container logistics systems. [ABSTRACT FROM AUTHOR]

During the Second Taiwan Strait Crisis from 1958 to 1979, a large number of underground tunnels were dug to meet the needs of the war on the island of Kinmen, which is located between Taiwan and China, to provide defense, refuge, and transportation of materials. However, the tunnels caused many problems during the post-war development of the island. For example, there are problems of property ownership between underground and aboveground objects, and difficulties in infrastructure construction. Therefore, it is necessary to clarify the relationship between assets of historical significance and value and aboveground objects to ensure that cultural assets are adequately protected and properly planned. In this study, the 3D point cloud model of underground tunnels and the ground surface will be integrated by ground-based lidar technology and analyzed by overlapping with cadastral maps and urban planning maps to obtain accurate spatial relationships. The point cloud data measurements can be used to obtain the location and depth of the tunnels, which can be used as a reference for land disputes, urban planning, engineering design, and preservation or restoration plans for cultural assets. [ABSTRACT FROM AUTHOR]

It is of great significance for coal safety production and water resource protection in the Yuheng mining area to master the evolution law of water-conducting fractures under the condition of thick and hard overburden. This research focuses on the 2102 fully mechanized mining face in the Balasu Coal Mine as the research background. The fracture evolution and strata movement characteristics in thick and hard overlying strata are simulated and analyzed by combining numerical simulation with physical simulation, and the formation mechanism of a water-conducting fracture in the overlying strata is revealed and verified by field measurements of the development height of "two zones". The results show that the anisotropy of fracture propagation in low-position overlying strata is high, and the fracture propagation in high-position overlying strata is mainly vertical, which indicates characteristics of leapfrog development. The number and development height of fractures undergo the change–growth process of "slow–rapid–uniform". Multiple rock strata together form a complex force chain network with multiple strong chain arches. The local stress concentration leads to the initiation of micro-cracks in contact fractures, and the cracks gradually penetrate from bottom to top and then the strong chain arches are broken. The water-conducting cracks in overlying strata show a dynamic expansion process of "local micro-cracks–jumping cracks–through cracks–water-conducting cracks". The fracture between the caving zone and fracture zone presents obvious layered characteristics, the overall shape of the water-conducting fracture zone is "saddle-shaped", and the maximum development height lags behind the coal mining face by about 180 m. Through the observation of water injection leakage and borehole TV observation of three boreholes under underground construction, combined with the results of water pressure tests, it is comprehensively determined that the height of the water-conducting fracture zone is 103.68~107.58, and the fracture–production ratio is 31.42~32.60, which is basically consistent with the results of numerical simulation and physical simulation. This research provides theoretical guidance and a scientific basis for coal mine water disaster prevention under similar geological conditions. [ABSTRACT FROM AUTHOR]

The structural health monitoring data of the Research Institute of Highway Ministry of Transportation Track (RIOHTRACK) are huge and complex, including a large amount of dynamic high-frequency sensor data of road underground structures. However, detecting anomalies in the overall distribution of the whole loading cycle data is difficult for traditional numerical data analysis methods. This study proposes an anomaly detection method that visualizes numerical values and designs a deep convolutional neural network DCNN6 for image classification to achieve anomaly detection of large-scale dynamic high-frequency sensor data. After training, the detection rate of DCNN6 for abnormal data reached 92.3% for the validation set. Compared with Residual Neural Network (ResNet50) and GhostNet, the detection accuracy of the method proposed in this study increased by 69% and 4%, respectively, reaching 97%, and the detection speeds were also faster by 5 s/epoch and 4 s/epoch, respectively. Therefore, the proposed method can accurately and quickly detect the abnormality of the dynamic high-frequency sensor data of underground structures, which can provide data support for quickly discovering that the vehicle deviates from the preset trajectory, rectifying the driver's driving deviation, analyzing the force of the whole road area, and grasping the evolution law of the rut. [ABSTRACT FROM AUTHOR]

A robust assessment of tunnels due to uncertainties present in soil and ground motion properties can affect the dynamic response of these structures. In this paper, a stochastic analysis considering an aleatory variability in shear velocity Vs by performing Monte Carlo simulations and assessing its influence on underground tunnels. To numerically assess the response of the soil‐tunnel system to near‐fault earthquake ground motion, the required computational domain usually spans multiple kilometers including both earthquake fault and the structure. Thus, these simulations are computationally expensive. An efficient alternative method, that is, the Domain Reduction Method (DRM), in which a modular two‐step methodology for reducing the computational costs in the large domain analysis is employed. A 3‐D soil‐tunnel structure interaction is modeled to simulate the response of tunnel subjected to an inclined earthquake fault. The numerical simulation of the soil‐tunnel‐fault system is conducted in an open‐source FE package called Multi‐hazard Analysis for STOchastic time DOmaiN phenomena (MASTODON) based on MOOSE framework. The interactive analyses are carried out for three distinct types of soils based on National Earthquake Hazards Reduction Program (NEHRP) provision, that is, soft, medium, and hard, by generating 130 realizations. The results provide many insights into the influence of local site effects, that is, frequency shift for the peak response and the importance of input ground motion characteristics that govern the response of underground structures. The dynamic response of the structure is very sensitive to the uncertainty in rock material properties, especially, the stiffness of the rock sample and the shear wave velocity. [ABSTRACT FROM AUTHOR]