Search Results (138)

Migration of hydrocarbons along fault strike remains poorly understood, and its underlying mechanisms have not been fully clarified. Taking the Pinghu slope belt in the Xihu Sag, East China Sea Basin, as a case study, this study investigates the migration process, efficiency, and controlling factors of natural gas migration along fault strike using three-dimensional physical sandbox simulation experiments. The results show that: (1) under strong fault sealing conditions, hydrocarbons rarely migrate vertically across fault planes and instead preferentially migrate laterally along structural ridges developed on the hanging wall, forming stable migration pathways; (2) structural ridges serve as dominant conduits for efficient hydrocarbon transport, guiding hydrocarbons toward structurally elevated positions where accumulation and enrichment occur; and (3) the simulated migration patterns are consistent with exploration discoveries in the study area, where hydrocarbon accumulations are concentrated in ridge-controlled favorable zones. These findings indicate that the coupling between structural ridge development and fault sealing capacity is the key factor controlling hydrocarbon migration, accumulation, and enrichment in the Pinghu slope belt, providing theoretical support for hydrocarbon exploration in fault-controlled basins. Full article

Differential surface settlement is a critical trigger for engineering disasters, with buried ground fissure activity serving as one of the core factors driving such subsidence. In this study, four groups of physical model tests were conducted. High-precision laser displacement meters were used to monitor real-time settlement at varying distances from the ground fissure. Based on this, the surface displacement evolution patterns of both loess layer structures and interbedded sand–soil structures under slow (0.01 m/h) and rapid (2 m/h) ground fissure activities were summarized. To evaluate the predictive performance of different models for time- and space-dependent nonlinear displacement evolution, five methods, namely polynomial regression, support vector regression (SVR), multilayer perceptron (MLP), random forest (RF), and gradient boosting decision tree (GBDT), were constructed and compared using the experimental displacement dataset. The physical model test results indicate that the interbedded sand–soil structure tends to suppress localized crack propagation while expanding the affected zone range, whereas the loess layer is prone to near-field deformation localization. The activity rate exerts a pronounced influence on fracture propagation within the loess layer, while its influence on the deformation of the interbedded sand–soil structure is relatively limited under the present test conditions. The model comparison results show that a cubic polynomial can effectively describe the displacement evolution pattern under slow and homogeneous conditions. MLP exhibited the most stable performance among the four machine learning algorithms, while SVR, GBDT, and RF provided complementary information for interpreting continuous displacement evolution and local nonlinear displacement variations. Overall, under the present physical model test conditions, the machine learning models provide a useful data-driven basis for quantitatively characterizing displacement evolution trends and interpreting the development of ground fissure-affected zones. Based on the experimental results—scaled up by a similarity ratio of 20:1 and incorporated with a safety factor of 1.1~1.3—the preliminary reference engineering avoidance distance in the ground fissure-affected zone is 20~24 m for the hanging wall and 14~16 m for the footwall, which are broadly consistent with the current codes and regulations. The findings provide controlled experimental evidence and a quantitative reference for ground fissure hazard assessment and engineering protection. Full article

Phosphate rock is a finite resource whose extraction in sedimentary deposits generates substantial volumes of waste rock. This study develops a panel-scale 3D geological modeling workflow for operational material accounting in a multilayer sedimentary phosphate deposit. Phosphate layers were modeled using a hanging wall–footwall approach and evaluated against independent well data. Bone Phosphate of Lime (BPL) grades were estimated from borehole-layer composite assay values using nearest neighbor, inverse distance weighting, and ordinary kriging. Domain-wise external validation showed that ordinary kriging provided the most consistent agreement with withheld observations in most mineable layers. Each mineable layer was treated as an independent estimation domain, with one composite BPL value retained per drillhole and per mineable layer. The validated block models were regularized to the mine plan and aggregated into operational strips, enabling strip-scale material accounting and mineability filtering under operation-specific technical criteria. To limit disclosure of confidential operational quantities, panel-scale resource, recoverable resource, and residual ore results are presented in relative rather than absolute terms. The results show that most modeled phosphate-bearing material satisfies the applied criteria and is classified as recoverable, whereas residual phosphate-bearing material excluded by the operational criteria remains concentrated in a limited subset of layers. The terms ‘resource,’ ‘recoverable resource,’ and ‘residual ore’ are used throughout in an operational material-accounting sense only and are not intended in the sense of any international mineral reporting code. Strip-based stripping ratio maps further reveal spatial variability in waste-to-ore and waste-to-grade relationships. The resulting workflow provides a quantitative spatial basis for future scenario-based assessment of waste management and selective dumping alternatives in sedimentary phosphate mining. Full article

Orthorhombic normal fault networks in sedimentary basins and their formation mechanisms are of significant geological importance. Orthorhombic normal fault networks and planar H-shaped normal fault networks (HNF) developed in distinct locations along the Linshang dextral transtensional fault, with the HNF on the eastern hanging wall and the orthorhombic normal fault networks on the western footwall. Using 2D and 3D seismic data, we investigated the geometry, evolution, and formation mechanisms of these fault networks within the regional tectonic context. The HNF consists of systematically arranged E–W-trending normal faults and N–S-trending cross normal faults. The orthorhombic normal fault networks comprise four sets of normal faults. Expansion indices and balanced cross-section analyses indicate that both these networks formed contemporaneously during the E₂s³ stage. Mechanical analysis suggests that differences in the local stress field led to the development of these networks in different segments of the Linshang Fault. The HNF formed sequentially within a single tectonic phase. In contrast, the orthorhombic normal fault networks developed within a 3D strain field driven by the combined effects of dextral transtension along the Linshang Fault and footwall tilting. Hydrocarbon exploration results confirm that these normal fault networks exert significant control on hydrocarbon migration pathways and accumulation patterns. Full article

While conventional numerical studies often treat excavated stopes as empty voids or as backfilled, few investigations have simulated the post-mining void as a weak granular caved rock material that evolves naturally from a hanging wall failure. This study addresses this gap by modeling the caved rock progressively, which makes the excavation representation more realistic for sublevel caving operations. This study introduces stope stability for the Zarmitan gold mine in Uzbekistan, where mining occurs at about a 500 m depth in a narrow quartz vein. A hybrid approach combining empirical and numerical methods was adopted. The Mathews stability graph method provided initial design guidance, while three-dimensional FLAC3D numerical modeling was used to simulate the mining sequence with explicit representation of caved rock behavior. A various study was conducted, which included the effects of stress ratio, stope length along strike, and pillar thickness on overall stability. The obtained results show that the stress ratio is the dominant factor controlling stope behavior. Stope length significantly affects failure extent, with shorter stopes showing better performance under similar conditions. Pillar thickness was found to improve stability and reduce tensile stresses in critical areas, though in all cases, hanging wall support remains essential. The numerical results confirm empirical predictions while providing quantitative insights into stress distributions and failure mechanisms not captured by empirical methods alone. These results provide mine operators with quantitative, site-specific design criteria, most notably that, under the measured high horizontal stress, limiting stope length to 40 m and increasing pillar thickness to 8 m substantially improves hanging wall stability, which demonstrates how a hybrid empirical-numerical methodology can directly support safer and more economic extraction in deep, narrow-vein operations. Full article

An integrated numerical method is proposed for analyzing the nonlinear seismic response of near-fault building clusters, comprising three algorithms: (1) a structural investigated lump algorithm for elastoplastic dynamic response of structure; (2) a connecting investigated lump algorithm for bidirectional wave propagation between the site and elastoplastic building clusters; (3) a geomedia investigated lump algorithm for seismic wave propagation with an improved viscoelastic constitutive model, which allows independent definition of P/S-wave quality factors to characterize geomedia attenuation. Validated for its capability in simulating site-city dynamic interaction problems via a shaking table test, the method is applied to study the seismic response of near-fault building clusters in Xichang City under a hypothetical M_w6.8 earthquake. It is shown that irrespective of whether shallow geological structures are considered, clusters (c2–c4) situated in rupture-forward surface area within ~1.5 km of the fault trace entered the elastoplastic stage, while others (c1, c5) remained elastic. Shallow geological structures may reverse locally hanging-wall/footwall effects of both near-fault structural seismic response and ground motion. A notable seismic-response characteristic of near-fault structures undergoing the elastoplastic stage is that the permanent structural motion displacement (PSMD) at the slab of a specific floor incorporates not only the non-zero permanent ground motion displacement (PGMD) but also the non-zero final structural residual displacement (FSRD) relative to the supporting ground. The developed method could provide support for seismic damage assessment, site selection, and structural optimization design of near-fault building clusters. Full article

The complex surface architecture of natural oyster reefs is widely considered to promote biological attachment, yet the underlying mechanisms and the relevance to the design of artificial reefs are not fully understood. Here, we combined field experiments, 3D surface characterization, and numerical modelling to quantify how reef-like roughness regulates biofouling development and near-wall flow around artificial substrates. Surface morphological characteristics of natural oyster reefs were first obtained by 3D scanning and used to fabricate concrete panels with simulated rough textures, while traditional smooth concrete panels served as controls. The two types of panels were simultaneously deployed in the target sea area for a hanging-panel experiment. Samples were collected after 3, 6, 9, and 12 months to track changes in biofouling communities. At each sampling time, the panel surfaces were quantified by canopy roughness ($R_C$), surface heterogeneity ($\sigma$), and fractal dimension ($D$), and these metrics were integrated into numerical simulations combined to resolve the flow field, turbulence kinetic, and near-wall shear stress around the colonized panels. The research results show that, after 12-month immersion, the mean thickness of the biofouling layer on rough and control panels reached 6.39 mm and 5.91 mm, respectively. Rough panels exhibited consistently higher $R_C$ and $\mathsf{\sigma }$ than controls, and these two parameters are strongly linearly correlated ($R^2=0.891)$. Numerical simulations reveal that increased $R_C$ enlarges the oyster settlement shear-stress window (OSSW), indicating more favorable hydrodynamic conditions for oyster settlement and growth on rough panels. Nevertheless, the hydrodynamic differences between the initial rough panels and control panels gradually diminish over time, suggesting that biological growth can progressively naturalize initially smooth substrates. These findings advance the mechanistic understanding of how small-scale roughness and biofouling co-evolve to shape oyster habitat quality and provide a quantitative basis for the eco-engineering design of artificial oyster reefs. Full article

Many challenges are commonly encountered in the underground mining of steeply dipping thin-to-medium-thick orebodies associated with weak hanging wall rockmass, such as stope back collapse, high ore dilution, and poor stoping stability. To address these issues, a synergistic mining method combining sidewall retaining and open stoping with a delayed backfilling method is proposed. Taking the north wing orebody of the Erlihe lead–zinc mine as the engineering background, a 3D finite element numerical simulation model was established using MIDAS GTS(2026 version) to conduct a comparative analysis between the proposed mining method and the current mining method. The mechanical response characteristics of crown pillar stress, crown pillar settlement, hanging wall displacement, and plastic zone evolution were systematically investigated under different mining stages. The results show that the proposed method improves the stress and deformation distribution at the bottom of the crown pillar. The peak stress decreases from 13.72 MPa to 12.86 MPa, and the spatial extent of the high-stress zone is noticeably reduced. Meanwhile, the maximum crown pillar subsidence decreases, while the width of the main subsidence zone decreases from 11 nodes to 9 nodes, and the settlement of the end region decreases by 6.05%. In terms of hanging wall response, the maximum displacement is reduced by 9.3–26.5% during the stope extraction stage and 9.6–10.0% during the inter-pillar recovery stage, with an overall average reduction of approximately 14.0%. Furthermore, the plastic zone in the hanging wall surrounding rock becomes smaller and develops later under the proposed mining method. Our findings demonstrate that the new proposed mining method effectively modifies the stress transfer path, mitigates deformation of both the crown pillar and hanging wall rock, and delays the development of plastic failure, thereby improving stope stability under weak hanging wall rockmass conditions. The proposed method provides a practical technical solution for the safe and efficient extraction of steeply dipping thin-to-medium-thick orebodies. Full article

Portable Buddhist shrines refer to small-scale mobile or assembled shrines, typically made of wood, stone, clay, and metal. They were initially used as temporary ritual sites or ornamental attachments for temples and stupas, later becoming independent objects of devotion. This art form, the origins of which can be traced to ancient India and later diverse regional traditions, has been discovered in significant quantities along the Silk Road and neighboring regions. Previously, scholarly attention centered primarily on exquisite wall shrines, stupa-shaped shrines, and stele-shaped shrines. However, when factors such as the spatial arrangement and ritual functions of mobile ritual sites are taken into account, along with the materials and techniques employed in creating Buddhist shrines, artifacts such as badge-style bronze Buddha statues, painted silk banners, and wooden panel paintings may also be classified as portable Buddhist shrines. Accordingly, portable Buddhist shrines can be divided into three forms: pedestal, hanging, and open–close or mother–child. A key reason for this expanded classification is that all such forms are functionally and stylistically linked to large-scale cave temples. Moreover, these shrines share a common visual grammar, defined by the dynamic integration of images and texts and the mutual imitation and complementarity of statue and painting. This represents a quintessential example of cross-cultural dissemination and the coexistence of local traditions in Buddhist art. Full article

The Geological Strength Index (GSI) is a crucial tool for assessing jointed rock masses, but it is often hindered by subjectivity in visual assessments. In this study, we propose a novel quantitative GSI method wherein 3D laser-scanning point clouds are used to quantitatively derive empirical rock mass indices (SR and SCR) to estimate mechanical parameters. By integrating the GSI with the Rock Block Index (RBI) and joint spacing, a framework for quantifying the Structural Rating (SR) is established. Furthermore, the Analytic Hierarchy Process (AHP) is employed to assign weights to Surface Condition Rating (SCR) factors. The results indicate that infilling materials have the most significant impact on SCR (weight 0.6334), followed by weathering (0.2605) and roughness (0.1061). This method was applied to evaluate rock masses at depths of −915 to −960 m in the Sanshandao Gold Mine. The GSI values calculated for the foot wall, ore body, and hanging wall were 38.5, 33.8, and 37.8, respectively. Validation against conventional quantitative methods demonstrated high accuracy, with a maximum relative GSI difference of 1.5 and a deformation modulus difference of only 0.227 GPa. This data-driven approach effectively reduces subjectivity and provides a reliable tool for automated geotechnical parameter estimation. Full article

Background/Objectives: Hanging is the most common method of suicide in most countries worldwide. It is characterized by high lethality, technical simplicity, and typical autopsy findings. Autopsy plays a crucial role in determining the cause and mechanism of death. While external injuries are relatively consistent, internal findings show considerable variability in the literature. The aim of this prospective study was to analyze 660 cases of suicidal hanging over a ten-year period, focusing on the occurrence of forensically relevant internal autopsy findings. Methods: The study was conducted at the Department of Forensic Medicine in Bratislava between 2015 and 2024. All cases underwent standardized complete autopsy, including histology, toxicology, and analysis of death circumstances. Recently reported thoracic aortic adventitial hemorrhages described in 2024 were evaluated only in a targeted subset of cases examined between July and December 2024. Statistical evaluation was performed using the chi-square test to identify associations between internal findings and suspension type, knot location, age, sex, and body weight. Results: The argent line was present in 61.1% of cases, most frequently with posterior knot placement and complete suspension. Neck muscle hemorrhages occurred in 53.8%, predominantly at the periosteal-clavicular attachment of the sternocleidomastoid muscle, with higher incidence in complete and anterior suspension. Amussat’s sign was observed in 10.2% of cases, and Etienne-Martin’s sign in 1.1%. Fractures of the laryngo-hyoid complex were present in 49.7%, mainly in cases with complete suspension and posterior knot location. Cervical spine injuries were detected in 2.6%, predominantly in older males and with anterior knot placement. Simon’s hemorrhages occurred in 35.2%, mainly in younger individuals and complete suspension. Hemorrhages in the intestinal wall were detected in 7.4%, and rectal hemorrhages in 1.1% of cases. In the targeted 2024 subset, no thoracic aortic adventitial hemorrhages were identified. Conclusions: The findings suggest the forensic relevance of several internal findings associated with hanging, while emphasizing that the results were obtained using a uniform and consistently applied autopsy protocol. They also indicate the need for further research, particularly regarding recently reported adventitial hemorrhages of the thoracic aorta, which were assessed only in a limited subset of cases during the final months of the study and were not identified in our material. Full article

Ground fissures are widespread around the world and are particularly severe in the North China Plain. In order to investigate the crack propagation path and propagation mode of buried ground fissures from deep strata to the surface, physical simulation experiments and numerical simulation experiments were conducted based on the sand–clay interlayer strata in the Longyao area. The results show that during the settlement of the hanging wall strata, the propagation path of the cracks changes due to differences in soil properties. The crack propagation is interrupted in the sand layer and slowed down in the clay layer. The surface displacement is characterized by an alternating sequence of gradual and rapid growth phases. The process of crack propagation from depth to surface is divided into five stages, forming tensile cracks and causing the differential settlement of the surface. The strata are mainly under tensile stress, with the stress range of the hanging wall being 2.1 to 3.0 times that of the footwall. Under identical experimental conditions, buried ground fissures in the strata of sand–clay interlayers exhibit anti-dip crack propagation angles and surface deformation zone widths that are between those of homogeneous silty clay and sand. Based on the experimental results, an analytical formula for the hanging wall deformation zone was further proposed. The research results can provide an important reference and theoretical basis for the investigation and disaster prevention of buried ground fissures in the Longyao area of Hebei Province. Full article

To study the mechanical properties and displacement evolution of rock masses near coal-seam normal faults under mining disturbances; this paper utilizes fiber optic monitoring and distributed strain measurement techniques to achieve the fine monitoring of the entire process of stress–displacement–strain during mining. The experimental design adopts a stepwise mining approach to systematically reproduce the evolution of fault formation; slip; and instability. The results show that the formation of normal faults can be divided into five stages: compressive deformation; initiation; propagation; slip; and stabilization. The strength of the fault plane is significantly influenced by the dip angle. As the dip angle increases from 30° to 70°, the peak strength decreases by 23%, and the failure mode transitions from tensile failure to shear failure. Under mining disturbances, the stress field in the overlying rock shifts from concentration to dispersion, with a stress mutation zone appearing in the fault-adjacent area. During unloading, vertical stress decreases by 45%, followed by a rebound of 10% as mining progresses. The rock layers above the goaf show significant subsidence, with the maximum vertical displacement reaching 150 mm. The displacement between the hanging wall and footwall differs, with the maximum horizontal displacement reaching 78 mm. The force chain distribution evolves from being dominated by compressive stress to a compressive–tensile stress coupling state. The fault zone eventually enters a stress polarization state and tends toward instability. A large non-uniform high-speed zone forms at the fault cutting point in the velocity field, revealing the mechanisms of fault instability and the initiation of dynamic disasters. These experimental results provide a quantitative understanding of the multi-physics coupling evolution characteristics of coal-seam normal faults under mining disturbances. The findings offer theoretical insights into the instability of coal-seam normal faults and the mechanisms behind the initiation of dynamic disasters. Full article

While 3D seismic reflection is well established in hydrocarbon exploration at the kilometer scale in relatively simple offshore settings, its application to shallow faulting in continental basins is rare, owing to difficulties in adapting acquisition and processing to rugged terrains and complex near-surface conditions. We present the first high-resolution 3D seismic study of a seismogenic fault in a structurally complex intramontane basin at depths < 200 m. The survey focuses on the Pantano–Ripa Rossa Fault, ruptured during the 1980 Mw 6.9 Irpinia earthquake, the largest Italian event of the past century. This fault cuts across the Pantano di San Gregorio Magno, a small basin filled with Quaternary sediments and showing modest cumulative displacement. Our results demonstrate that in such environments, where morphotectonic analysis and 2D geophysics provide limited constraints, high-resolution 3D seismic imaging is crucial to resolve fault geometry and to assess surface-faulting hazard. The 3D volume reveals a ~35–40 m wide intra-basin deformation zone beneath the 1980 rupture, composed of synthetic and antithetic splays, and highlights lateral variations in fault geometry and stratigraphy. Deformation is distributed and complex, with fault-controlled depocenters, variable sedimentary architectures, and rapid basement-depth changes—features unresolved by 2D data. We infer that the Pantano–Ripa Rossa Fault is relatively young, active since the late Middle Pleistocene, and developed in the hanging wall of the NE-dipping southern basin-bounding fault, challenging previous models that located the master fault along the northern basin margin. Full article

Buildings crossing active faults often suffer severe damage due to fault dislocation during direct-type urban earthquakes. This study employs physical model tests to systematically investigate the dynamic response mechanisms of the integrated “surface rupture zone–overburden–foundation–superstructure” system subjected to bedrock dislocation. A testing apparatus capable of simulating reverse faults with adjustable dip angles (45° and 70°) was developed. Using both sand and clay as representative overburden materials, the experiments simulated the processes of surface rupture evolution, foundation deformation, and structural response under varying fault dislocation magnitudes. Results indicate that the fault rupture pattern is governed by the bedrock dislocation magnitude, soil type, and fault dip angle. The failure process can be categorized into three distinct stages: initial rupture, rupture propagation, and rupture penetration. The severity and progression of structural damage are primarily determined by the building’s location relative to the fault trace. Structures located entirely on the hanging wall exhibited tilting angles that remained below the specified code limit throughout the dislocation process, demonstrating behavior dominated by rigid-body translation. In contrast, buildings crossing the fault exceeded this limit even at low dislocation levels, developing significant tilt and strain concentration due to differential foundation settlement. The most severe damage occurred in high-angle dip sand sites, where the maximum structural tilt reached 5.5°. This research elucidates the phased evolution of seismic damage in straddle-fault structures, providing experimental evidence and theoretical support for the seismic design of buildings in near-fault regions. The principal theoretical and methodological contributions are (1) developing a systematic “fault–soil–structure” testing methodology that reveals the propagation of fault dislocation through the system; (2) clarifying the distinct failure mechanisms between straddle-fault and hanging-wall structures, providing a quantitative basis for targeted seismic design; and (3) quantifying the controlling influence of fault dip angle and soil type combinations on structural damage severity, identifying high-angle dip sand sites as the most critical scenario. Full article