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Published Research PapersFiltered: Year 2025 • Vol. 32 • 8

Showing 18 of 147 peer-reviewed papers with full Graphical Abstracts.

Original ResearchVol. 32, Issue 8 • pp. 100-112DOI: 10.1016/j.ijmst.2025.08.010• Jan 15, 2025

A sediment sampling system for monitoring plume redeposition from deep-sea polymetallic nodule mining

Authors: Jiale Wu, Jiawang Chen, Xinghui Tan, Kaichuang Wang, Jianling Zhou, Zhangyong Jin, Congchi Huang, Yuan Lin, Chunsheng Wang, Junyi Yang, Shiquan Lin

The spatiotemporal characterization of plume sedimentation and microorganisms is critical for developing plume ecological monitoring model. To address the limitations of traditional methods in obtaining high-quality sediment, a novel sampling system with 6000 m operational capability and three-month endurance was developed. It is equipped with three sediment samplers, a set of formaldehyde preservation solution injection devices. The system is controlled by a low-power, timing-triggered controllers. To investigate low-disturbance rheological mechanisms, gap controlled rheological tests were conducted to optimize the structural design of the sampling and sealing assembly. Stress-controlled shear rheological tests were employed to investigate the mechanisms governing yield stress in sediments under varying temperature conditions and boundary roughness. Additionally, the coupled Eulerian-Lagrangian (CEL) method and sediment rheological constitutive models were employed to simulate tube-soil interaction dynamics and sediment disturbance. The radial heterogeneity of sediment disturbance and friction variation of the sampling tube were revealed. The tube was completely ''plugged'' at a penetration depth of 261 mm, providing critical data support to the penetration depth parameters. The deep-sea pressure test and South China Sea field trials demonstrated the system's capability to collect and preserve quantitative time-series sediment samples with high fidelity.

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A sediment sampling system for monitoring plume redeposition from deep-sea polymetallic nodule mining

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Original ResearchVol. 32, Issue 8 • pp. 100-112DOI: 10.1016/j.ijmst.2025.08.008• Jan 15, 2025

Prediction of lost circulation risk in fractured formations based on 3D geomechanical modeling

Authors: Jinfa Zhang, Yongcun Feng, Sijia Ma, Zhijuan Hao, Bing He, Jingyi Wei, Jingen Deng

Due to complex geological structures and a narrow safe mud density window, offshore fractured formations frequently encounter severe lost circulation (LC) during drilling, significantly hindering oil and gas exploration and development. Predicting LC risks enables the targeted implementation of mitigation strategies, thereby reducing the frequency of such incidents. To address the limitations of existing 3D geomechanical modeling in predicting LC, such as arbitrary factor selection, subjective weight assignment, and the inability to achieve pre-drilling prediction along the entire well section, an improved prediction method is proposed. This method integrates multi-source data and incorporates three LC-related sensitivity factors: fracture characteristics, rock brittleness, and in-situ stress conditions. A quantitative risk assessment model for LC is developed by combining the subjective analytic hierarchy process with the objective entropy weight method (EWM) to assign weights. Subsequently, 3D geomechanical modeling is applied to identify regional risk zones, enabling digital visualization for pre-drilling risk prediction. The developed 3D LC risk prediction model was validated using actual LC incidents from drilled wells. Results were generally consistent with field-identified LC zones, with an average relative error of 19.08%, confirming its reliability. This method provides practical guidance for mitigating potential LC risks and optimizing drilling program designs in fractured formations.

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$Prediction of lost circulation risk in fractured formations based on 3D geomechanical modeling$

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Original ResearchVol. 32, Issue 8 • pp. 100-112DOI: 10.1016/j.ijmst.2025.08.018• Jan 15, 2025

Study on mechanical properties and mesoscopic damage mechanism of composite jointed rock masses

Authors: Yao Bai, Zhibo Xu, Haoyu Dou, Nianzeng Liu, Ziyue Zhao, Sihao Qiu, Renliang Shan

Joints are widely distributed structural defects in rock masses, and their geometric characteristics play a decisive role in the overall stability of rocks under complex stress conditions. To clarify the influence of joint geometry on the mechanical behavior of jointed rock under such conditions, this study investigated the mechanical properties and failure mechanisms of composite jointed rock specimens with varying joint roughness and joint dip angles. Three typical failure modes under triaxial loading were identified, and a mechanical analysis model incorporating joint roughness and dip angle was established. The failure mechanism was revealed, and a discrete element model was developed to analyze the micro-damage evolution process of the specimens. The results show that the mechanical parameters of the specimens exhibit pronounced anisotropy. Both the elastic modulus and peak strength reach their minimum values at a joint dip angle of 60°. Increasing joint roughness significantly reduces the degree of anisotropy and enhances the energy storage capacity of the specimens. A strong linear relationship is observed between the elastic strain energy and the peak deviatoric stress, confirming the applicability of the linear energy storage law in composite jointed rocks. Discrete element simulations revealed the evolution path and dominant types of microcracks between the joint and matrix. The joint dip angle governs the transition of dominant crack types from tensile to shear and then back to tensile. Increased joint roughness significantly suppresses damage localization along the joint and results in an approximately 20% increase in the proportion of shear microcracks within the matrix. These findings clarify the regulatory role of joint geometrical parameters in the damage evolution process.

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Study on mechanical properties and mesoscopic damage mechanism of composite jointed rock masses

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Original ResearchVol. 32, Issue 8 • pp. 100-112DOI: 10.1016/j.ijmst.2025.08.016• Jan 15, 2025

Reverse floc-flotation of talc from chalcopyrite by using polyvinyl acetate as a flocculant: Adsorption and bubble capture studies

Authors: XIE Yu, YIN Wanzhong, LIU Qi, WANG Daowei, SUN Wenju

Chalcopyrite is often intergrown with talc, which, after grinding, forms ultrafine particles (<10 lm) that readily coat chalcopyrite surfaces, hindering flotation and causing significant losses in tailings. This study evaluates polyvinyl acetate (PVAc), a thermoplastic polymer, as a selective flocculant to enhance reverse flotation separation of chalcopyrite from ultrafine talc. Flotation tests showed that at a PVAc dosage of 40 mg/L, talc can be effectively and selectively removed, enabling efficient separation. Laser particle size analysis and scanning electron microscopy-energy dispersive spectrometry (SEM-EDS) confirmed that PVAc promotes selective talc aggregation without affecting chalcopyrite. X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations revealed that hydrogen bonding between PVAc ester groups and surface hydroxyls on talc drives the flocculation, while chalcopyrite lacks suitable binding sites. PVAc adsorption also enhances talc hydrophobicity. Furthermore, particle-bubble coverage angle measurements and extended Derjaguin-Landau-Verwey-Overbeek (DLVO) theory theoretical calculations demonstrated that PVAc-induced flocculation increases attractive interactions between talc and bubbles, shifting the total interaction energy from repulsive to attractive and promoting bubble-particle attachment. This study clarifies the selective adsorption and flocculation mechanisms of PVAc and reveals the coupling of flocculation and flotation of ultrafine talc from a particle-bubble capture perspective, while expanding the potential of ester-based polymers for ultrafine mineral recovery.

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Reverse floc-flotation of talc from chalcopyrite by using polyvinyl acetate as a flocculant: Adsorption and bubble capture studies

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Original ResearchVol. 32, Issue 8 • pp. 100-112DOI: 10.1016/j.ijmst.2025.08.007• Jan 15, 2025

A quantitative fracability evaluation method and its application to deep shale gas development in Sichuan Basin, China

Authors: Guokai Zhao, Yintong Guo, Chunhe Yang, Mingyang Wu, Junchuan Gui, Shilong Teng, Lei Wang, Xinao Zhang

Fracability evaluation is critical for efficiently extracting deep shale gas using hydraulic fracturing to avoid blind drilling and fracking. However, existing fracability indices often fail to systematically consider the mechanical behavior of rocks at high temperatures and high pressures (HTHP), coupled with geostress distributions and heterogeneous reservoir characteristics. This critical omission limits their effectiveness in accurately identifying the optimal fracability sweet spots within deep reservoirs. In this work, a fracability evaluation model was proposed based on the combined weighting method, integrating the improved brittleness index, rock strength, geostresses and natural weakness characteristics. A fracability grading evaluation was carried out to determine the potential fracture characteristics corresponding to shales with different fracability levels. Additionally, the fracability index was used for field validation and applications. Results show that rock brittleness and fracability are not equivalent for deep reservoirs. The fracability index is closely related to the pay zones and actual gas production, with a correlation as high as 84%, implying that the proposed method has practical significance in both experimental and field applications. The above findings can provide theoretical guidance for the selection of fracturing candidates and the optimal design of fracturing in deep resource development.

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$A quantitative fracability evaluation method and its application to deep shale gas development in Sichuan Basin, China$

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Original ResearchVol. 32, Issue 8 • pp. 100-112DOI: 10.1016/j.ijmst.2025.08.011• Jan 15, 2025

Experimental and numerical studies on rock damage law in straight-hole cut blasting under biaxial confining pressure

Authors: Xiantang Zhang, Zhaobin Li, Hui Yu, Hongmin Zhou, Hongli Wang, Xiangtuan Jiao, Fuzhi Wang

To study the relationships between rock mass crack propagation and damage and confining pressure under blast impact loading during straight-hole cut blasting, tests were performed under different confining pressures. Then, the characteristics of rock mass crack development were analyzed, and the pressure resistance values of core samples before and after blasting were compared to study the trends of rock mass damage. Moreover, a three-dimensional numerical simulation model was established by LS-DYNA to analyze the stress wave propagation, cavity shape and crack propagation characteristics under different confining pressures. The propagation of rock blasting cracks is negatively correlated with the confining pressure. The greater the confining pressure, the shorter the crack development time. Additionally, the crack width is reduced from 0.4–1.7 to 0.04–1.4 mm, and the length is shortened from 280 to 120 mm. A comparison of the compressive strength revealed that blasting reduces the compressive strength of the rock mass. The greater the distance from the explosion source, the lower the degree of strength attenuation. An increase in the confining pressure can inhibit strength attenuation. Numerical simulations revealed that under the same confining pressure, the stress first peaks at the bottom of the blast hole. The greater the confining pressure, the longer the stress peak duration, the smaller the cavity volume, and the shorter the crack propagation length and depth. Under a confining pressure of 4 MPa, the longest crack was only 154.5 mm in length and 102 mm in depth. The research results provide a scientific basis for controlling rock damage and optimizing design in the excavation of deep rock roadways by blasting.

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Experimental and numerical studies on rock damage law in straight-hole cut blasting under biaxial confining pressure

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Original ResearchVol. 32, Issue 8 • pp. 100-112DOI: 10.1016/j.ijmst.2025.08.017• Jan 15, 2025

Quantitative Characterization of Fracture Surface Undulations and Gas-Guiding Patterns in Fractured Rocks under Steady Loading

Authors: Zihan Chen, Quanle Zou, Feixiang Lv, Qican Ran, Xiaoyan Sun, Xianwei Heng

Fractures in rock strata serve as flow pathways for gas flow. The undulation of fracture channels can influence the guidance of gas flow. In this context, four-point bending experiments on prefabricated fractured rocks at different angles under stable stepped loading stress were conducted. The experiment results clarified the evolutionary law that the undulation degree of the rock tensile fracture surface is separated by an initial fracture angle of 45°. The high undulation intervals were less than 45°, whereas the low undulation intervals were more than 45°. Furthermore, the relative undulation degree, undulation frequency, and matching degree of the fracture surface were quantified. The relationship between the change in fracture surface undulation and gas flow guidance was established. Based on this, the stability, tortuosity, and uniformity of the gas flow in the fracture channel were quantitatively characterized. Subsequently, numerical models of the fracture channels were constructed to validate the indices proposed in this study. The results of the study clarified the influence of different initial fracture angles on the undulation changes of fracture surfaces, and established the relationship between these changes and gas flow, which is conducive to understanding the role of internal fracture channels in rocks in guiding the gas flow process.

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Quantitative Characterization of Fracture Surface Undulations and Gas-Guiding Patterns in Fractured Rocks under Steady Loading

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Original ResearchVol. 32, Issue 8 • pp. 100-112DOI: 10.1016/j.ijmst.2025.08.012• Jan 15, 2025

A PCM-based active temperature-preserved coring method for deep sea natural gas hydrate

Authors: WU Han, HU Yunqi, FU Chenghang, CHEN Ling, HE Zhiqiang, XU Meng, XIE Heping

Natural gas hydrate (NGH) has a bright future as a clean energy source with huge reserves. Coring is one of the most direct methods for NGH exploration and research. Preserving the in-situ properties of the core as much as possible during the coring process is crucial for the assessment of NGH resources. However, most existing NGH coring techniques cannot preserve the in-situ temperature of NGH, leading to distortion of the physical properties of the obtained core, which makes it difficult to effectively guide NGH exploration and development. To overcome this limitation, this study introduces an innovative active temperature-preserved coring method for NGH utilizing phase change materials (PCM). An active temperature-preserved corer (ATPC) is designed and developed, and an indoor experimental system is established to investigate the heat transfer during the coring process. Based on the experimental results under different environment temperatures, a heat transfer model for the entire ATPC coring process has been established. The indoor experimental results are consistent with the theoretical predictions of the heat transfer model, confirming its validity. This model has reconstructed the temperature changes of the NGH core during the coring process, demonstrating that compared to the traditional coring method with only passive temperature-preserved measures, ATPC can effectively reduce the core temperature by more than 5.25 °C. With ATPC, at environment temperatures of 15, 20, 25, and 30 °C, the duration of low-temperature state for the NGH core is 53.85, 32.87, 20.32, and 11.83 min, respectively. These findings provide new perspectives on temperature-preserving core sampling in NGH and provide technical support for exploration and development in NGH.

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A PCM-based active temperature-preserved coring method for deep sea natural gas hydrate

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Original ResearchVol. 32, Issue 8 • pp. 100-112DOI: 10.1016/j.ijmst.2025.08.003• Jan 15, 2025

Synergistic exploitation of gas hydrates through surface seawater injection coupled with depressurization: Application and optimization in the South China Sea

Authors: LI Yuxuan, ZHANG Zhaobin, CHALATURNYK Rick, LI Shouding, HE Jianming, BIAN Hang, LI Xiao, LU Cheng, QIN Xuwen

This study proposes and systematically evaluates an optimized integration of warm surface seawater injection with depressurization for the long-term exploitation of marine natural gas hydrates. By employing comprehensive multiphysics simulations guided by field data from hydrate production tests in the South China Sea, we pinpoint key operational parameters—such as injection rates, depths, and timings—that notably enhance production efficiency. The results indicate that a 3-phase hydrate reservoir transitions from a free-gas-dominated production stage to a hydrate-decomposition-dominated stage. Moderate warm seawater injection supplies additional heat during the hydrate decomposition phase, thereby enhancing stable production; however, excessively high injection rates can impede the depressurization process. Only injection at an appropriate depth simultaneously balances thermal supplementation and the pressure gradient, leading to higher overall productivity. A “depressurization-driven sensible-heat supply window” is introduced, highlighting that timely seawater injection following initial depressurization prolongs reservoir dissociation dynamics. In this study area, commencing seawater injection at 170 d of depressurization proved optimal. This optimized integration leverages clean and renewable thermal energy, providing essential insights into thermal supplementation strategies with significant implications for sustainable, economically feasible, and efficient commercial-scale hydrate production.

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Synergistic exploitation of gas hydrates through surface seawater injection coupled with depressurization: Application and optimization in the South China Sea

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Original ResearchVol. 32, Issue 8 • pp. 100-112DOI: 10.1016/j.ijmst.2025.08.013• Jan 15, 2025

PFC-FDEM Multi-Scale Cross-Platform Numerical Simulation of Thermal Crack Network Evolution and SHTB Dynamic Mechanical Response of Rocks

Authors: Yue Zhai, Shaoxu Hao, Shi Liu, Yu Jia

Underground engineering in extreme environments necessitates understanding rock mechanical behavior under coupled high-temperature and dynamic loading conditions. This study presents an innovative multi-scale cross-platform PFC-FDEM coupling methodology that bridges microscopic thermal damage mechanisms with macroscopic dynamic fracture responses. The breakthrough coupling framework introduces: (1) bidirectional information transfer protocols enabling seamless integration between PFC’s particle-scale thermal damage characterization and FDEM’s continuum-scale fracture propagation, (2) multi-physics mapping algorithms that preserve crack network geometric invariants during scale transitions, and (3) cross-platform cohesive zone implementations for accurate SHTB dynamic loading simulation. The coupled approach reveals distinct three-stage crack evolution characteristics with temperature-dependent density following an exponential model. High-temperature exposure significantly reduces dynamic strength ratio (60% at 800 °C) and diminishes strain-rate sensitivity, with dynamic increase factor decreasing from 1.0 to 2.2 (25 °C) to 1.0–1.3 (800 °C). Critically, the coupling methodology captures fundamental energy redistribution mechanisms: thermal crack networks alter elastic energy proportion from 75% to 35% while increasing fracture energy from 5% to 30%. Numerical predictions demonstrate excellent experimental agreement (±8% peak stress–strain errors), validating the PFC-FDEM coupling accuracy. This integrated framework provides essential computational tools for predicting complex thermal–mechanical rock behavior in underground engineering applications.

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PFC-FDEM Multi-Scale Cross-Platform Numerical Simulation of Thermal Crack Network Evolution and SHTB Dynamic Mechanical Response of Rocks

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Original ResearchVol. 32, Issue 8 • pp. 100-112DOI: 10.1016/j.ijmst.2025.08.015• Jan 15, 2025

Anisotropy of laser-induced electro-response in shale: Modelling and experimental validation

Authors: Xuecong Liu, Zhengchun Hong, Yuqi Jiao, Kun Zhao, Xinyang Miao

Laser-induced electro-response (LIER), as a new method that complements conventional rock physics testing techniques, is expected to address issues such as unclear mechanisms, model deficiency, inconsistent evaluation parameters, and difficulty in separating multiple coupling factors in shale anisotropy evaluation, and establish a more complete and reliable shale physical property evaluation system. A testing strategy for out-of-plane anisotropy (OPA) was proposed for characterising anisotropy by LIER, where near-infrared (NIR) continuous laser (CL) and nanosecond pulsed laser (PL) were used to irradiate the surface of oblique cut shale, and the transverse LIER of the surface was measured. A LIER detection model is constructed from the laser-thermal effect, residual transverse polarization electric field and thermionic emission transport mechanism, which is strongly relying on laser power, bias voltage, and inclination angle of the measurement direction relative to the bedding plane of shale. For OPA test on the slice of oblique cut shale under CL irradiation, the relationship between the product of LIER simulation parameters and the tilting angle can be described by a cubic function and an impulse function with a maximum value at the threshold angle. In addition, the thermal accumulation and transient thermal effects are induced in the shale under a high-energy short laser pulse irradiation, and the simulation results indicate that there is an exponential relationship between the product of parameters in the LIER model and the tilt angle. Thus, for OPA test under CL and PL irradiations, it is recommended to use the product of parameters as an evaluation index for shale anisotropy. Furthermore, to solve the problem of multiple influencing factors entangled in the exponential term of the LIER model, the tangential LIER measurement was performed on the side of cylindrical shale core, where the provided LIER model effectively presented the anisotropy of tight shale plug, especially the effects of bias voltage and laser power on LIER were relatively separated as independent variables. Finally, the LIER at the end of laser drilling is presented well using the optimized model under a focused ns NIR PL irradiation, indicating that LIER is expected to be a real-time means for characterizing shale anisotropy during laser drilling processes. These results show that the present work is fundamental for the precise evaluation and effective development of anisotropic shale reservoirs, and will drive the advances of LIER in the exploration for shale oil and gas.

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Anisotropy of laser-induced electro-response in shale: Modelling and experimental validation

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Original ResearchVol. 32, Issue 8 • pp. 100-112DOI: 10.1016/j.ijmst.2025.08.005• Jan 15, 2025

Shear mechanical responses and debonding failure mechanisms of bolt-resin-rock anchoring system under dynamic normal load boundary

Authors: Xinxin Nie, Qian Yin, Zhigang Tao, Manchao He, Gang Wang, Wenhua Zha, Zhaobo Li

Under external disturbances, the shear mechanical responses and debonding failure mechanisms at anisotropic interfaces of anchoring system composed of multiphase media are inherently difficult to characterize due to the concealment nature of interfacial interactions. This study establishes an equivalent shear model for a bolt-resin-rock anchoring system and conducts direct shear tests under dynamic normal load (DNL) boundary from both laboratory experiments and discrete element method (DEM) simulations. The research investigates the influence of normal dynamic load amplitude (An) and rock type on shear strength parameters, elucidating the evolutionary characteristics and underlying mechanisms of shear load and normal displacement fluctuations induced by cyclic normal loading, with maximum shear load decreasing by 36.81% to 46.94% as An increases from 10% to 70% when rock type varies from coal to limestone. Through analysis of strain field evolution, the critical impact of rock type on localization of shear failure surface is revealed, with systematic summarization of differentiated wear characteristics, failure modes, and key controlling factors associated with shear failure surface. Mesoscopic investigations enabled by DEM simulations uncover the nonuniform distribution of contact force chains within the material matrix and across the anisotropic interfaces under various DNL boundaries, clarify rock type dependent crack propagation pathways, and quantitatively assess the damage extent of shear failure surface, with the anisotropic interface damage factor increasing from 34.9% to 56.6% as An rises from 10% to 70%, and decreasing from 49.6% to 23.4% as rock type varies from coal to limestone.

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Shear mechanical responses and debonding failure mechanisms of bolt-resin-rock anchoring system under dynamic normal load boundary

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Original ResearchVol. 32, Issue 8 • pp. 100-112DOI: 10.1016/j.ijmst.2025.08.006• Jan 15, 2025

Controlling magnetic agglomeration in superconducting high gradient magnetic separation processing of iron ore tailings for high-grade silica recovery

Authors: Yongkui Li, Suqin Li, Zekun Zhao

The superconducting high gradient magnetic separation (S-HGMS) technology can be used to effectively extract silica from iron ore tailings (IOTs). However, particle agglomeration in strong magnetic fields poses a challenge in achieving optimal performance. In this study, we investigated the agglomeration of IOT particles and the mechanisms for its inhibition through surface analysis, density functional theory (DFT), and extended Derjaguin-Landau-Verwey-Overbeek (EDLVO) theory. Hematite was found to exhibit the highest magnetic moment among the minerals present in IOTs, making it particularly prone to magnetic agglomeration. The addition of the dispersant SDSH into the slurry was essential in promoting the dispersion of IOT particles during the S-HGMS process. This dispersant hydrolyzed to form HPO4 2− and RSO3 − groups in the solution, which then chemically adsorbed onto the metal ions exposed on the surfaces of non-quartz particles, increasing interparticle electrostatic repulsion. Furthermore, the RSO3 − groups physically adsorbed onto the surface of quartz particles, resulting in strong steric repulsion and enhancing the hydrophilicity of the particle surfaces, thereby inhibiting magnetic agglomeration between the particles. Under optimal conditions, the SiO2 grade of the obtained high-grade silica powder increased from an initial value of 76.32% in IOTs to 97.42%, achieving a SiO2 recovery rate of 54.81%, which meets the requirements for quartz sand used in glass preparation. This study provides valuable insights into the magnetic agglomeration of IOT particles and its inhibition while providing a foundation for regulating S-HGMS processes.

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Controlling magnetic agglomeration in superconducting high gradient magnetic separation processing of iron ore tailings for high-grade silica recovery

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Original ResearchVol. 32, Issue 8 • pp. 100-112DOI: 10.1016/j.ijmst.2025.08.001• Jan 15, 2025

Fracturing Mechanism of Pre-Damaged Granite Induced by Multi-Source Dynamic Disturbances in Tunnels

Authors: Biao Wang, Benguo He, Xiating Feng, Hongpu Li

To elucidate the fracturing mechanism of deep hard rock under complex disturbance environments, this study investigates the dynamic failure behavior of pre-damaged granite subjected to multi-source dynamic disturbances. Blasting vibration monitoring was conducted in a deep-buried drill-and-blast tunnel to characterize in-situ dynamic loading conditions. Subsequently, true triaxial compression tests incorporating multi-source disturbances were performed using a self-developed wide-low-frequency true triaxial system to simulate disturbance accumulation and damage evolution in granite. The results demonstrate that combined dynamic disturbances and unloading damage significantly accelerate strength degradation and trigger shear-slip failure along preferentially oriented blast-induced fractures, with strength reductions up to 16.7%. Layered failure was observed on the free surface of pre-damaged granite under biaxial loading, indicating a disturbance-induced fracture localization mechanism. Time–stress–fracture–energy coupling fields were constructed to reveal the spatiotemporal characteristics of fracture evolution. Critical precursor frequency bands (105–150, 185–225, and 300–325 kHz) were identified, which serve as diagnostic signatures of impending failure. A dynamic instability mechanism driven by multi-source disturbance superposition and pre-damage evolution was established. Furthermore, a grouting-based wave-absorption control strategy was proposed to mitigate deep dynamic disasters by attenuating disturbance amplitude and reducing excitation frequency.

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Fracturing Mechanism of Pre-Damaged Granite Induced by Multi-Source Dynamic Disturbances in Tunnels

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Original ResearchVol. 32, Issue 8 • pp. 100-112DOI: 10.1016/j.ijmst.2025.08.004• Jan 15, 2025

Dynamic failure analysis and support optimization for web pillars under static and dynamic loading using catastrophe theory

Authors: Juyu Jiang, Yulong Zhang, Laigui Wang, Changbo Du, Jun Xu

Web pillars enduring complex coupled loads are critical for stability in high-wall mining. This study develops a dynamic failure criterion for web pillars under non-uniform loading using catastrophe theory. Through the analysis of the web pillar-overburden system’s dynamic stress and deformation, a total potential energy function and dynamic failure criterion were established for web pillars. An optimizing method for web pillar parameters was developed in highwall mining. The dynamic criterion established was used to evaluate the dynamic failure and stability of web pillars under static and dynamic loading. Key findings reveal that vertical displacements exhibit exponential-trigonometric variation under static loads and multi-variable power-law behavior under dynamic blasting. Instability risks arise when the roof’s tensile strength-to-stress ratio drops below 1. Using catastrophe theory, the bifurcation set D<0 signals sudden instability. The criterion defines failure as when the unstable web pillar section length l1 exceeds the roof’s critical collapse distance l2. Case studies and simulations determine an optimal web pillar width of 4.6 m. This research enhances safety and resource recovery, providing a theoretical framework for advancing highwall mining technology.

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Dynamic failure analysis and support optimization for web pillars under static and dynamic loading using catastrophe theory

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Original ResearchVol. 32, Issue 8 • pp. 100-112DOI: 10.1016/j.ijmst.2025.08.002• Jan 15, 2025

Damage and fracture law of outburst coal bodies in tectonic zones under impact disturbances

Authors: Lingran Ren, Liping Li, Jupeng Tang, Yishan Pan, Song Yang, Xin Zhang

The geological tectonic zone is closely related to outburst. Taking the outburst coal bodies in tectonic zones as the research object, combined with DIC and AE monitoring technologies and discrete element simulation, the mechanical response, crack evolution and energy characteristics of coal bodies under different loading rates (impact disturbances) were studied. The results show that both the uniaxial compressive strength and elastic modulus are positively correlated with the loading rate, with a maximum increase in compressive strength of 25.15%. The uniaxial compressive strength is more sensitive to impact disturbances. The failure modes of coal bodies can be divided into the ''slip-crack synchronization (S & C) type'' and the ''crack-first-then-slip (C & S) type''. The slip in tectonic zones is more severe at high loading rates. At low loading rates, shear cracks dominate (60.01%), while the proportion of tensile cracks increases significantly (70.52%) at high loading rates. Additionally, the rate of axial crack growth decreases as the loading rate increases. The peak values of total energy and dissipated energy increase significantly with the loading rate, and the peak energy of the C & S type is greater than that of the S & C type. Energy is preferentially released through the slip of tectonic zones and the propagation of radial cracks.

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$Damage and fracture law of outburst coal bodies in tectonic zones under impact disturbances$

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Original ResearchVol. 32, Issue 8 • pp. 100-112DOI: 10.1016/j.ijmst.2025.08.014• Jan 15, 2025

An experimental and theoretical study on the influence of stress gradients on the propagation of hydraulic fractures

Authors: Junchi Liu, Yuping Sun, Pingping Liang, Yintong Guo, Yuting He, Wenjie Xu, Duanyang Zhuang, Jinlong Li, Liangtong Zhan, Jianfu Shao, Yunmin Chen

Hydraulic fracture growth is significantly influenced by the minimum horizontal principal stress gradient and the fracturing fluid pressure gradient. However, these gradients are often neglected in scaled physical modeling experiments due to difficulties in reproducing them. This study uses centrifugal hypergravity to simulate both gradients and investigate their effects on fracture propagation. Artificial mortar specimens (φ200 mm × 400 mm) are fractured under 1g (normal gravity), 50g, and 100g. Results show that compared to 1g, fractures under 50g and 100g exhibit increasingly uneven propagation, with higher g-values leading to greater asymmetry. To interpret this, a theoretical analysis based on fracture mechanics is conducted. When the fluid pressure gradient exceeds the stress gradient, a positive net gradient is generated, increasing net pressure at the lower fracture tip. This raises the stress intensity factor at the lower tip, promoting downward growth. As g increases, the disparity becomes more significant, resulting in greater fracture deviation. In conclusion, this study, for the first time, has verified and explained that the net gradient can change the propagation of hydraulic fractures, providing important guidance for wellbore placement under stress gradients.

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$An experimental and theoretical study on the influence of stress gradients on the propagation of hydraulic fractures$

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Original ResearchVol. 32, Issue 8 • pp. 100-112DOI: 10.1016/j.ijmst.2025.08.009• Jan 15, 2025

Micromechanical properties of granite with insights into mineral interface mechanics

Authors: Pengli Zhou, Cunbao Li, Heping Xie

Understanding the mechanical behavior of diagenetic mineral granules and interfaces in granite provides essential experimental references for constructing micromechanical models of granite. The micromechanical behavior of Yanshanian granite is investigated using scanning electron microscopy–energy dispersive spectroscopy (SEM-EDS) and nanoindentation tests. The results demonstrate transitional mechanical properties at mineral interfaces. The elastic modulus and hardness exhibit intermediate values between adjacent mineral phases. The higher plasticity indices at the interfaces suggest higher plastic deformation capacity of hard-phase minerals in these regions. Additionally, fracture toughness measurements of minerals and interfaces were obtained, with interfacial values ranging from 0.90 to 1.63 MPa m0.5. The analysis of mechanical property relationships shows a significant positive linear correlation between rock-scale elastic modulus and fracture toughness. However, this correlation is substantially lower at the mineral scale, demonstrating a scale effect in the relationship of different mechanical properties.

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Micromechanical properties of granite with insights into mineral interface mechanics

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