Rock Strata Research Articles

A Dynamic Prediction Model for Water Accumulation Volume Based on Bed-Separation Development Discrimination

During the development of coal resources in China, mine bed-separation water damage has become a new type of disaster in recent years, bringing severe casualties and economic losses to mining areas. This study aims to solve the limitations of the existing bed-separation calculation methods. It proposes a new method of bed-separation discrimination based on the bending deflection of rock strata and a spatial volumetric calculation model that considers the development stage of bed separation. The improved stepwise comparison combination method (ISCCM) was combined with the theory of thin elastic plates to determine the developmental stage of the bed separation, which was able to predict the location of the bed separation and its volume more accurately. An example analysis of the 21301 working face in Cui mu Coal Mine, Shaanxi Province, shows that the proposed method exhibits higher accuracy and reliability in predicting the location of bed-separation development and the water inrush risk. The study shows that changes in the morphology of bed-separation development significantly affect the amount of water accumulation, and the traditional calculation method may produce a significant error after long-distance coal mining. This research result helps to improve the early warning ability and management effect of water damage in the mine bed separation. It provides technical support for the safe and efficient production of the mine.

Comparative Evaluation of Presented Strength Criteria of Anisotropic Rocks Based on Triaxial Experiments

The inherent mineralogical alignment in stratified rock formations engenders pronounced mechanical anisotropy, presenting persistent challenges across geological, geotechnical, and petroleum engineering disciplines. While substantial progress has been made in modeling transversely isotropic media, current methodologies exhibit limitations in reconciling theoretical predictions with complex failure mechanisms. This investigation examines the anisotropic response of diverse lithologies through triaxial testing across bedding orientations (0–90°) and confinement levels (0–60 MPa), revealing a pressure-dependent attenuation of directional strength variations. Experimental evidence identifies three dominant failure modes: cross-bedding shear fracturing, bedding-parallel sliding, and hybrid mechanisms combining both, with transition thresholds governed by confinement intensity and bedding angle. Analytical comparisons demonstrate that conventional single weakness plane models produce characteristic shoulder-shaped strength curves with overpredictions, particularly in hybrid failure regimes. Conversely, the modified patchy weakness plane formulation achieves superior predictive accuracy through parametric representation of anisotropy gradation, effectively capturing strength transitions between end-member failure modes. The Pariseau criterion, though marginally less precise in absolute terms, provides critical insights into directional strength contrasts through its explicit differentiation of vertical versus parallel bedding responses. These findings advance the fundamental understanding of anisotropic rock behavior while establishing practical frameworks for optimizing stability assessments in bedded formations, particularly in high-confinement environments characteristic of deep reservoirs and engineered underground structures.

Analysis of Main Roof Mechanical State in Inclined Coal Seams with Roof Cutting and Gob-Side Entry Retaining

The non-uniform deformation and failure phenomena encountered in steeply inclined coal seams during roof-cutting and gob-side entry retaining operations demand urgent resolution. Taking the haulage roadway of the 3131 working face in Longmenxia South Coal Mine as the research background, the theoretical analysis method is adopted to explore the mechanical state of the main roof in inclined coal seams and the design of roadside support resistance. According to the structural evolution characteristics of the main roof, it is divided into four periods. Based on the elastic theory, corresponding mechanical models are established, and the mechanical expressions of the main roof stress and deflection are derived. The distribution characteristics of the main roof’s mechanical state in each zone and the influence law of the coal seam dip angle on the main roof’s mechanical state are studied. This study reveals a critical transition from symmetric to asymmetric mechanical behavior in the main roof structure due to the coal seam dip angle and roof structure evolution. The results show that, in the absence of roadside support, during the roadway retaining period, the upper surface of the main roof is in tension, and the lower surface is under compression. The stress value increases slowly from the high-sidewall side to the middle, while it increases sharply from the middle to the short-sidewall side. Under the inclined coal seam, as the dip angle of the coal and rock strata increases, the component load perpendicular to the roof direction decreases, and the roof deflection also decreases accordingly. On this basis, the design formula for the roadside support resistance of gob-side entry retaining with roof cutting in inclined coal seams is presented, and the roadside support resistance of the No. 3131 haulage roadway is designed. Building upon this foundation, a design formula for roadside support resistance in steeply inclined coal seams with roof-cutting and gob-side entry retaining has been developed. This formula was applied to the No. 3131 haulage roadway support design. Field engineering tests demonstrated that the maximum roof-to-floor deformation at the high sidewall decreased from 600 mm (unsupported condition) to 165 mm during the entry retaining period. During the advanced influence phase of secondary mining operations, the maximum deformation at the high sidewall was maintained at approximately 193 mm.

Field-of-view subsampling: A novel 'exotic marker' method for absolute abundances, validated by simulation and microfossil case studies.

Key parameters of biological systems-e.g., productivity, population sizes, biomass-are best expressed as absolute values. Exotic markers (e.g., Lycopodium spores introduced into microfossil populations) have long been used to estimate population sizes from representative samples. However, the traditional approach-the 'linear method' herein-can be extremely time consuming and impractical for routine use. Here, we present a new variant of this technique: the 'field-of-view subsampling method' (FOVS method). This new method requires a few simple, easily obtainable statistical parameters, beyond the standard inputs for the traditional linear method. The FOVS method adds error from sample heterogeneity, but enables the collection of very large sample sizes with low additional effort. We compared the FOVS and linear methods with two case studies: 1, Monte Carlo simulations to validate the methods with idealised datasets; and 2, terrestrial organic microfossils from Permian-Triassic rock strata in southeastern Australia as 'real-world' empirical datasets. Three output parameters were measured: 1, absolute abundance; 2, precision (=error rate); and 3, data collection effort (typically, this translates to data collection time). The linear method showed superior efficiency only for assemblages with very low specimen densities and/or near-equivalent target-to-marker ratios, conditions we predict are rare under real-world conditions. In contrast, the FOVS method provided greater precision and/or reduced effortunder almost all conditions, without sacrificing accuracy. Although originally developed for microfossils, the new method may apply to any spatial data collection where markers of known quantity can be introduced to a population. Given its demonstrable increased speedand precision, we recommend the FOVS method as the new standard for such absolute abundance estimates. Guidelines and a user-friendly digital interface for implementing both of these count methods are provided, in addition to simulation codes aimed to assist readers in designing their own experiments.

Study on the Formation and Evolution of Constant Stress Concentration Shell in Overburden Rock Strata During Coal Seam Mining

Study on the Formation and Evolution of Constant Stress Concentration Shell in Overburden Rock Strata During Coal Seam Mining

Study on the mutual interference and propagation characteristics of three-dimensional vibration during shield tunnel construction in hard rock strata

Vibrations generated by shield tunnel construction in hard rock strata can have adverse effects on the surrounding environment. To investigate the mutual interference of three-dimensional vibrations and the propagation characteristics of vibration waves during the construction process, this study is based on the shield tunnel project of a Jinan urban rail transit construction zone. The research integrates on-site vibration monitoring, FLAC3D numerical simulations, and theoretical analysis of transfer functions. The results show that: 1)Single-direction vibration input has the greatest impact on the output in the same direction, with minimal interference in the other two directions. A vibration input in one direction generates new harmonic components not only in the same direction but also in the other two directions.2)Vibration generated by shield tunnel construction shows a stronger correlation between the vibration wave propagation speeds in the tunneling direction of the shield machine and the direction perpendicular to the tunneling direction.3)When only a single direction of vibration signal is input, the waveform of the output vibration signal at the monitoring point is similar to that obtained with simultaneous input of three-direction vibration signals, but there are differences in the vibration speed values.4)The vibration monitoring signals from the building pile foundation exhibit periodicity over time, with fluctuations. As the distance from the excavation surface increases, the peak vibration speed decreases, the decay rate slows, and the arrival time is delayed.5)The peak vibration speed at the monitoring point after the shield machine passes is slightly higher than before its passage. The arrival time of the vibration wave at the monitoring point is later after the shield machine passes.6)For vibrations at different locations of the same pile foundation, the vibration speed at the same depth near the tunnel center is the highest. When the distance from the excavation surface is the same, the vibration speed near the bottom of the pile is slightly higher than that at the middle of the pile.

Identification of crustal fault zones, affecting the southern section of the Sakhalin-2 pipeline, according to satellite surveys

Relevance. The need to promptly obtain information about the state of the main pipeline routes and the activity of endogenous processes occurring in the rock strata located in the zone of interaction with the pipe. The movements of the blocks of the earth crust serve as triggers for the appearance of defects or accidents during the operation of pipeline systems. Due to their visibility, accuracy and efficiency, aerospace monitoring tools best meet the requirements for information that provides an analysis of the dynamics of the development of natural processes. In this light, the development methods of operational automated decoding to determine the places of active impact on pipelines is very relevant. Aim. To identify the intersections of the route on the Sovetskoe–Prigorodnoe section with zones of active faults to assess the risks of negative impacts during operation of pipeline and organize geotechnical monitoring in these zones. Object. Images of the territory along which pipelines are laid, obtained from Landsat, Sentinel, and Shuttle spacecraft during the implementation of the SRTM project, suitable for identifying disjunctive faults, as well as data on the position of earthquake epicenters in this territory. Methods. Decoding of space images, methods of mapping in a geographic information environment, statistical, lineament analysis. Using software packages QGIS, ArcGIS, LEFA. Results and conclusions. The authors have analyzed the satellite and geophysical information on the condition of the studied territory, identified the fault zones crossing the pipeline route of the Sakhalin-2 project. The authors identified the areas of active faults, which should be paid close attention to when organizing monitoring in places of possible movements of blocks of the earth crust, which are sources of emergency pipe defects. Active fault zones have been mapped that warrant focused monitoring efforts in areas susceptible to crustal block displacements, which pose significant risks to pipeline structural safety. The authors established the main transregional fault zones of the meridional strike (rank I) on the territory: Khokkaido-Sakhalinskaya (Okhotsk-Ozerskaya branch of the Tunaichinsky synclinal depression fault zone), Tsentralno-Sakhalinskaya (Klyuchevskaya feathering fault zone) and Zapadno-Sakhalinskya (Slepikovsko-Nevelskiy section of the fault zone). They identified the fault zones of the II rank: Susunayskaya on the border of the Susunai ridge and the Susunai lowland, as well as a large chain of faults of the north-west-south-east diagonal strike crossing the pipeline route at the Vakhrushevsko-Khristoforovsky section. In addition, smaller grade III and IV faults are highlighted in the images. Information on the condition of pipelines at the points of intersection with fault zones should be collected in databases of aerospace monitoring of pipeline systems. Such data are in demand during engineering surveys, design and construction of pipeline transport facilities, as well as during the operation of pipelines.

Geophysical Characterization of Aquifers Using Vertical Electrical Sounding in Perumatty Panchayat, Palakkad, India

Groundwater is an essential resource for drinking water, agriculture, and industrial use, particularly in regions where surface water is scarce. This study delineates subsurface aquifer configurations using the Vertical Electrical Sounding (VES) method to examine the hydrogeological features of the overfished Perumatty Panchayat in Kerala's Palakkad District. IPI2WIN software was used to evaluate the results of 13 VES surveys that were carried out over a 30.99 km² area using the Schlumberger electrode design. Three primary curve types were identified by the resistivity sounding: the H-type, K-type, and A-type. H-type curves indicate a shallow weathered zone overlying deeper, resistant bedrock, suggesting groundwater in fractures at greater depths, making deep wells more suitable. K-type curves represent a thicker weathered zone above compact bedrock, ideal for borewells due to its greater water retention. A-type curves show a conductive topsoil over a resistive weathered rock layer, making dug wells effective for tapping into shallow groundwater stored in the weathered rock. These types correlate to various aquifer conditions. The existence of lateritic topsoil, weathered zones, and basement rock strata was indicated by the 13 sites' 5 H-type, 5 K-type, and 3 A-type curves. Layer thicknesses ranged from 0.325 m to 11.43 m, while resistivity values ranged from 23.7 Ω-m to 43421 Ω-m, according to quantitative research. Aquifer potential varied spatially, with depth to foundation rock ranging from 2.68 m (VES 9) to 16.82 m (VES 5). Interestingly, VES 6 recorded an exceptionally low third-layer resistivity of 0.734 Ω-m, suggesting water-saturated zones, while VES 3 showed a second-layer resistivity of 43421 Ω-m, indicating a highly resistant compact rock. According to the study, fractured weathered zones favour borewells, especially in K-type and A-type curves, although H-type profiles suggest that dug wells may be possible. The effectiveness of VES as an affordable, non-invasive method for identifying aquifer structures in intricate geological terrains is demonstrated by this study. The results provide vital information for planning and managing groundwater resources sustainably in semi-arid and water-stressed areas.

Evaluation of Hypoxia Mitigation and Spontaneous Combustion Risks During Gas Extraction in Tailgate Corner of a Mining Face

ABSTRACT With the westward shift of China’s coal industry, the extraction of shallow-buried coal seams has intensified, leading to frequent hypoxia in the tailgate corner of mining faces. Current mitigation strategies are inadequate in addressing the challenges posed by low oxygen levels at the localized tailgate corner. This study proposes a novel harmful gas extraction technology for the tailgate corner, designed to remove harmful gases and improve safety. It addresses two key scientific challenges: the impact of extraction rates on low-oxygen mitigation and the technology’s influence on spontaneous combustion risks in the goaf. Through systematic analysis of the causes of hypoxia phenomenon in a specific tailgate corner, this study employs Computational Fluid Dynamics simulations (CFD), using O2 concentration as the primary evaluation metric. The findings indicate that the hypoxia phenomenon is primarily due to the infiltration of inert gases from the surrounding coal and rock strata. The relationship between the hypoxia area and extraction rate follows a quadratic function model. While the technology significantly reduces hypoxia risks, its impact on expanding the oxidation zone in the goaf is limited, enhancing spontaneous combustion management. These findings provide theoretical and practical support for applying this technology under similar geological and mining conditions.

Characterization of carbon storage systems in central Taiwan and its offshore area

Geological carbon storage is widely used to reduce CO2 emissions to the atmosphere. Cenozoic rock strata up to 8 km in thickness, consisting of thick sandstone and shale layers in central Taiwan and offshore areas, where major emitting sources are located, are investigated for their carbon storage potential. Four carbon storage systems are characterized in the aspects including the spatial distribution of lithologies, formation thicknesses, depths, permeability, and porosity of the reservoirs, using data from 22 boreholes and a few seismic sections. Three sites, the Taichung Power Plant (TPP), Changhua Coastal Industrial Park (CCIP), and Mailiao Taisu Industrial Park (MTIP), are selected for detailed site characterization. The storage systems, each composed of a caprock and reservoir pair, are (1) R1 system of the lower Cholan Formation (Fm); (2) R2 system from the Chinshui Shale (Sh), Kueichulin Fm, to Nanchuang Fm, and Kuanyinshan Sandstone (Ss); (3) R3 system from the Talu Sh to Peiliao Fm and Shihti Fm; and (4) R4 system from the Piling Sh to Mushan Fm and Wuchishan Fm. The four systems above show spatial depth variations and lateral changes in the lithofacies of caprocks and reservoirs, leading to different storage systems from site to site. Our results indicate that central Taiwan and offshore areas are ideal for the geological sequestration of CO2 and that their capacity to host CO2 requires further investigation.

Permeability Distribution Characteristics and Water Resistance Evaluation of Interlayer Rock Strata During Multi-seam Coal Mining

Permeability Distribution Characteristics and Water Resistance Evaluation of Interlayer Rock Strata During Multi-seam Coal Mining

Dynamic response of single pile induced by the vibration of tunnel boring machine in hard rock strata

During metro tunnel construction, Tunnel Boring Machine(TBM) often induces surface and nearby pile vibrations. However, these vibrations are often overlooked due to the short-term passage of the cutterhead beneath the foundation structures. In fact, these vibrations had adverse effects on certain sensitivity structures. Therefore, to analyze the dynamic characteristics of environmental vibrations induced by TBM, on-site vibration monitoring and a numerical modeling method coupling Discrete Element Method with Finite Difference Method were employed for the research. The study focused on a metro tunnel segment passing beneath the foundation of an interchange bridge. The results show that the acceleration of the cutterhead vibration reached 2.55 g during tunnel boring machine operation, with the nearest segment to the cutterhead experiencing a maximum vibration displacement 20% of that at the cutterhead. In weathered limestone formations, when the tunnel depth is less than 10 m, peak accelerations of the ground directly above the excavation face exceed 0.05 g, while pier accelerations reach 0.005 g. Due to cutterhead vibrations, the piers above pile foundations experience low-frequency vibrations (< 12 Hz), with four peak segments identified in the frequency domain, and vibration energy primarily concentrated between 7 and 10.6 Hz. Numerical simulation data based on the DEM-FDM coupling method indicates a negative exponential relationship between peak acceleration and frequency of piles, with a linear positive correlation with amplitude. Piles exhibit the highest sensitivity to vibrations below 4 Hz. Sensitivity analysis results indicate that during tunnel construction, nearby piles are most sensitive to the frequency of the vibration source, followed by the amplitude of the vibration source and the spacing between piles and the tunnel.

Study on the mechanism of mining-induced seismicity triggered by fracture of hard and extremely thick rock stratum: a case study

The control of mining-induced seismicity caused by hard and extremely thick rock stratum (HETRS) has become an important topic in more and more coal mines. This study investigates the mechanisms of mining-induced seismicity through a discrete element numerical model (UDEC-Trigon) calibrated with field data from the Dongtan Coal Mine, China. The failure process of HETRS was categorized into three stages: deformation (Stage I), initial fracture (Stage II), and periodic fracture (Stage III). In the initial fracture stage, the change of vertical displacement is 4.33 m, the change of vertical stress is 26.21 MPa, and the change of seismic energy is 1.91E8 J. The change values during the initial fracture are the largest. A novel method was developed to dynamically track seismic events, identifying tensile failures in central HETRS and shear failures along interfaces. The total decrement of gravitational potential energy is 2.27E10J. The total increment of shear dissipation energy, plastic strain energy and mining-induced seismic energy are 1.16E9J, 1.49E9J and 2.84E10J. Therefore, in addition to elastic energy, gravitational potential energy is also the main source of mining-induced seismic energy and dissipation energy. The mining-induced seismicity energy comes from the fractured strata as well as the surrounding rock. The results provide a unique perspective to understand the mechanism of mining-induced seismicity triggered by HETRS.

Study on the fracture characteristics of overlying rock strata under different mining face widths

To evaluate the influence of mining face width on the fracture characteristics of overlying rock strata, a mechanical model of overlying rock strata before fracture is established based on Winkler’s elastic foundation hypothesis. This model incorporates Timoshenko’s solution to calculate the variation of bending moment and shear force under different foundation conditions. The physical experimental results reported in relevant literature have also verified that the overlying rock strata are fractured with trapezoidal structure. Subsequently, the relevant parameters of this trapezoidal spatial structure about overlying rock strata before and after periodic roof weighting are analyzed in detail, and the calculation results show that the height of trapezoidal spatial structure is directly affected by the width of mining face, and the fractured form of rock layers changes from a horizontal “O-X” structure to a vertical “O-X” structure from the bottom up. Afterwards, the stability verification of inferior key layers is conducted following the trapezoidal spatial structure. Based on elastic thin plate theory, the mine pressure characteristics are analyzed, and the relationship curve of hanging length and hanging width of any rock layer in the overlying rock strata is obtained. Finally, the influence analysis of mining face width on type selection of hydraulic support is demonstrated based on the Panels 1302 and 1305 belonging to Zhaozhuang No.2 underground mine, and the on-site engineering application effect is significant.

Numerical simulation of hydraulic fracture extension patterns at interfaces of coal-measure rock strata and a new theoretical prediction model

Numerical simulation of hydraulic fracture extension patterns at interfaces of coal-measure rock strata and a new theoretical prediction model

Research on the spatiotemporal evolution of deformation and unloading mechanical effects in underlying coal and rock during upper protective layer mining

The spatiotemporal rule of pressure release in rock–coal strata within the mining zone serves as the theoretical basis for the prevention and control of dynamic disasters during the mining of the stress-concentration stratum. Taking the mining of the upper protective layer of the Hulusu coal mine located in Ordos City, Inner Mongolia Autonomous Region, China, as the engineering background, this study, based on the theory of elastic–plastic mechanics, investigates the pressure relief mechanics of the underlying coal and rock during the upper protective layer mining. The research is conducted across different scales through rock mechanics experiments, numerical simulations, and on-site industrial experiments. The spatiotemporal evolution of the stress and displacement fields in the underlying coal and rock strata during the upper protective layer mining was simulated and analyzed using the 3-Dimensional Distinct Element Code. Brillouin optical time-domain analysis distributed fiber-optic sensing technology was used to monitor the deformation and unloading dynamic process of different rock–coal strata under the mining floor in real-time. The results indicate that the stress changes in the underlying rock–coal strata during the mining of the upper stress-concentration stratum can be divided into four phases, namely, in situ stress, stress concentration, stress release, and stress restoration. Due to the uneven distribution of the waste rock collapse in the mined-out area, stress is alternately distributed in the unloading stable zone, unloading recovery zone, and boosting zone. The mining-induced stress distribution curve in the protected coal seam changes from a U-shape to a W-shape and then to a “WWW”-shape. The stress-relieving effect of upper stress-concentration stratum mining is significant, but the stress-relieving parameters vary depending on time and spatial factors. The research results have important theoretical and practical significance for guiding the layout and key parameter design of stress-concentration stratum mining.

Detection and updation of landslide inventory before and during impoundment in the Baihetan reservoir area using multi-temporal InSAR datasets

The Baihetan Hydropower Station, the second largest in the world, is currently impounded, posing significant challenges to reservoir slope stability and nearby community’s safety. Thus, continuous monitoring as well as updation of landslide inventory is pressing requirements. InSAR technology, with its mm-scale precision and round-the-year usability, will be highly effective in this region. However, single-source SAR data are limited for long-term detection, and traditional atmospheric models in InSAR grapple with attenuating the external atmospheric disturbances caused by impoundment, affecting InSAR accuracy. Therefore, we used multi-source SAR data (ALOS PALSAR and Sentinel-1A/B), and used time-series InSAR with the GACOS atmospheric correction model to accurately detect and update landslide inventory before and during impoundment. The results show that a total of 52 landslides were detected, including 31 newly detected during impoundment. Among them, 22 landslides have toe slopes in direct contact with water. Comparing landslides before and during impoundment, deformations exhibit three behaviors: new deformation emergence, weakening of existing deformation, and continuous increase. These landslides mainly develop in landforms with an inclination angle of 30° to 40°, trending northeast and northwest, and an altitude of 800 to 1200 m. Most landslides reside in non-massive rock strata and are modulated by fault zones, and their frequency diminishes with increasing distance from the reservoir boundary. Moreover, the deformation time series results show that intense summer rainfall and rapid reservoir water level rise are key factors accelerating deformation in active landslides and reactivating unstable slopes. Thus, this research can be directly used for landslide prevention and mitigation in the Baihetan reservoir area, providing an important reference for detecting similar reservoir landslides in atmospherically influenced areas.

Application and prospects of mathematical geology to sedimentary stages in deep-water channels

The method of mathematical geological model construction is used to quantita-tively express the parameters of deep-water channel sedimentary geological body shape and sedimentary sequence configuration. At the same time, the res-ervoir configuration research is carried out in combination with seismic and logging data, in order to obtain a universal mathematical geological method for further lithologic identification and rock stratum division of oil and gas reser-voir structure "generation, reservoir, cap, circle, transportation and preserva-tion" based on the results of sedimentary sequence obtained by using the mathematical method of parameter characterization. The results show that the combination of geological description of deep-water channel sedimentation model and mathematical geological method, and the configuration research idea of "well seismic combination, mathematical transformation, model fitting, and dynamic verification" can finely depict and characterize the spatial distribution, superposition relationship, and sedimentation period of different levels of con-figuration units, and improve the recognition and division accuracy of single deep-water channel. However, it is still necessary to summarize simpler and more intelligent mathematical geological theories and methods to explain the specific conditions and mathematical laws of "source, reservoir, cap, trap, transportation and preservation" of deep-sea oil and gas reservoirs, so as to fully explore new uses of well seismic data.

Construction and Application of Feature Recommendation Model for Remote Sensing Interpretation of Rock Strata Based on Knowledge Graph

The enhancement of remote sensing interpretation accuracy for rock strata in complex terrain areas has long been limited by challenges in field validation and the insufficient integration of geological knowledge in traditional spectral–spatial feature selection methods. This study proposes a geological remote sensing interpretation framework that integrates textual geological data, which enhances lithological identification accuracy by systematically combining multi-source geological knowledge with machine learning algorithms. Using a dataset of 2591 geological survey reports and scientific literature, a remote sensing interpretation ontology model was established, featuring four core entities (rock type, stratigraphic unit, spectral feature, and geomorphological indicator). A hybrid information extraction process combining rule-based parsing and a fine-tuned Universal Information Extraction (UIE) model was employed to extract knowledge from unstructured texts. A knowledge graph constructed using the TransE algorithm consists of 766 entity nodes and 1008 relationships, enabling a quantitative evaluation of feature correlations based on semantic similarity. When combined with Landsat multispectral data and digital elevation model (DEM)-derived terrain parameters, the knowledge-enhanced Random Forest (81.79%) and Support Vector Machine (75.76%) models demonstrated excellent performance in identifying rock-stratigraphic assemblages in the study area. While reducing subjective biases in manual interpretation, the method still has limitations. These include limited use of cross-modal data (e.g., geochemical tables, outcrop images) and a reliance on static knowledge representations. Future research will introduce dynamic graph updating mechanisms and multi-modal fusion architectures to improve adaptability across diverse geological lithological and structural environments.

Study on the damage constitutive characteristics of coal-rock composites under uniaxial compression: Influence of prefabricated crack angle and geometric dimensions.

In coal mining environments with complex topographic and geological conditions, the presence of primary cracks in the rock strata of the upper mining airspace is critical to mine safety, especially when roof slabs are broken. Cracked roof slabs not only increase risks during mining but also make mining operations more challenging. Therefore, studying the initial damage state of the roof rock formation is great significance. In this study, the effects of different prefabricated crack sizes and inclination angles on the mechanical properties of the coal-rock composite containing cracks were analyzed through the uniaxial compression experiments and PFC2D numerical simulations. The results show that the peak strength and elastic modulus of the coal-rock composites fall between those of pure coal and sandstone, while the macroscopic mechanical parameters of crack-containing composites are significantly lower than those of non-crack-containing composites. Coal-rock composites with different crack characteristics exhibited different mechanical properties, with their damage modes were caused by the combined effects of tensile and shear damage. The increase in crack inclination altered the crack extension path, and the final damage of the specimen manifested first in the upper part, then the middle part, and ultimately in the lower part of the coal body, with tension-induced bulk damage being the dominant failure mode. Analysis of the radial cumulative map revealed that cracks primarily extended along 90° and 270° directions, indicating a strong tendency for crack propagation under axial pressure. The damage evolution curves indicate a nonlinear relationship between the damage factor and strain. While increased crack inclination enhances the compressive performance of coal-rock composites, it simultaneously accelerates structural destabilization. These findings offer theoretical insights into the damage mechanisms of coal-rock composites with cracks, serving as valuable references for coal mining safety.