The development and utilization of lunar mineral resources is an important way to solve the earth’s energy crisis. Drilling and coring, an effective method for lunar section sample collection, is a key prerequisite for accurately identifying the characteristics of lunar resource endowments. Restricted by the extreme lunar environment, energy power constraints, and complex lunar subsurface profiles, current lunar drilling remains hampered by the core bottleneck of insufficient drilling depth. To address the challenge of deep lunar sample collection under low-power conditions, the team proposed a rope-tethered self-excavating drilling coring scheme. A rope-tethered self-excavating drilling coring robot was used to conduct 5-meter-deep drilling and coring tests in lunar regolith simulant. This study revealed the evolution laws governing coring and cuttings transport during the self-excavating drilling coring process in lunar regolith simulant, verifying the feasibility of the drilling scheme. In view of the harsh working conditions of the lunar base, the drilling load evolution law of different bit configurations is proved, and the suitable coring bit configuration and drilling procedure parameters were optimized. The test results demonstrate that: ① During the self-excavating drilling coring process in lunar regolith simulant, the drill pipe achieves efficient cuttings evacuation, with the rotational torque constrained within 4 N·m, thereby enabling reliable acquisition of soil core samples; Borehole inspection results verify that the boreholes formed by this drilling scheme possess smooth walls and excellent stability. ② In boulder and protruding rock drilling scenarios, the PDC bit outperforms the diamond bit in comprehensive drilling performance: it features significantly lower drilling force and load, a notably higher drilling rate, and a substantial increase in rotational speed can remarkably mitigate the drilling load. ③ For lunar soil simulant, an increase in rotational speed can effectively reduce the drilling load, while the coring rate exhibits a trend of first decreasing and then increasing with increasing rotational speed. Under the condition of a constant feed rate-to-rotational speed ratio, both the penetration rate and rotational speed are positively correlated with significant increases in drilling force/load and the coring rate. This implies that a balance between the coring rate and drilling force/load must be considered when selecting drilling parameters. This study can provide a reference for the future unmanned deep drilling exploration of the moon in China.

The temperature rise during drilling operations, caused by frictional heating between the machine and rock, is a critical factor limiting the “depth” and “fidelity” of lunar sampling missions. Experimental studies on the frictional characteristics of machine-rock interaction under lunar-based simulated conditions were conducted, revealing the influence of coring drill bit materials and drilling parameters on the friction coefficient and friction torque under high vacuum and extreme temperature conditions. The results indicate that: (1) the dynamic friction coefficient of machine-rock interaction is influenced limitedly by drilling parameters, with environmental conditions being the dominant controlling factor; (2) the effect of vacuum level on the interfacial friction coefficient is consistent for both diamond and cemented carbide materials, showing a decreasing trend in low and medium vacuum environments, but gradually increasing in high vacuum environments; (3) under extreme temperatures, the dynamic friction coefficient at the diamond – simulated lunar rock interface continuously increases during the heating process, whereas it remains essentially stable at the cemented carbide – simulated lunar rock interface. These findings are expected to guide the optimal design of coring bits and drilling parameters, providing technical and theoretical support for deep, fidelity-preserving coring on the lunar base.

The in-situ non-uniform stress environment and time-dependent deformation characteristics of coal mass surrounding gas drainage boreholes exert a pronounced influence on the permeability evolution during gas drainage in deep high-gas coal mines. Elucidating the influence mechanisms of non-uniform stress conditions on the time-dependent deformation of coal mass and gas transport behavior is of great significance for achieving safe and efficient gas drainage. This study incorporates non-uniform stress boundary conditions and a fractional order Maxwell viscoelastic model to derive a non-uniform visco-elastoplastic stress-strain solution for coal mass surrounding boreholes. Based on the assumption of equivalent fracture evolution in damaged coal, a permeability model is established by considering non-uniform visco-elastoplastic deformation and non-uniform adsorption swelling deformation. Furthermore, a new coupled model for gas flow under non-uniform pressure-relief conditions is developed using Darcy's law. The model is implemented in COMSOL Multiphysics for numerical analysis, enabling a quantitative investigation of the spatio-temporal evolution of stress-strain characteristics and permeability of coal mass surrounding boreholes. The results demonstrate that the proposed model accurately captures the zonal pressure-relief zones and the inhomogeneous evolution of gas permeability around boreholes. It reveals the underlying mechanisms by which time-dependent deformation induced by non-uniform loading influences gas drainage performance. By comparing different field gas drainage data with model predictions, the validity of the proposed model in characterizing gas migration under the influence of non-uniform time-dependent deformation is verified. In addition, a systematic investigation is conducted on the effects of key parameters controlling non-uniform time-dependent deformation, plastic yielding, and shear dilation on pressure-relief and permeability increase in coal mass.

Supercritical carbon dioxide (SC-CO2) fracturing, compared to water-based fracturing fluids, is a promising technology for developing shale gas because it can effectively solve problems related to shale swelling and increasing the fracturing complexity of rock matrix. However, the adaptability of this technology is unclear due to the influence of in-situ mechanics and environment for the shale gas reservoir. Then, a ’microscopic-macroscopic’ cross-scale mechanical parameters transfer framework was established and the macroscopic mechanical heterogeneity model was obtained through nanoindentation testing and SEM mineral scanning, as well as comprehensively utilising a deep convolutional generative adversarial network and Mori-Tanaka method. On this basis, a multi-physics coupled model of SC-CO2 fracturing, integrating thermal, hydraulic, mechanical, and damage(THMD) effects was developed to study in-situ mechanical heterogeneity and in-situ reservoir environment.The research results systematically explain the influence of in-situ reservoir temperature, reservoir mechanical heterogeneity, and injection construction conditions on the initiation pressure and transformation effect of supercritical carbon dioxide fracturing. This has important theoretical guidance significance for reservoir adaptability evaluation and optimization of fracturing transformation effects.

The mechanical behavior of lunar regolith is crucial for lunar exploration projects, particularly drilling and sampling equipment. However, the extremely limited quantity of returned lunar regolith is insufficient for systematic macroscopic mechanical testing. Lunar regolith simulants are therefore widely used to investigate the macroscopic mechanical behavior of lunar regolith. Most previous studies were conducted under ambient laboratory conditions, with limited consideration of temperature effects. In this study, direct shear tests were conducted on lunar regolith simulant specimens with relative densities Dr of 75%, 90%, and 100% under normal stresses of 50, 100, and 150 kPa and at temperatures of 25, 60, 120 and 180 °C. The effects of relative density, normal stress, and temperature on the shear response were systematically evaluated. The results showed that the peak and residual shear strengths generally increased with normal stress, whereas the effect of temperature on peak strength depended on relative density and normal stress. Three-dimensional laser scanning was used to reconstruct and quantitatively characterize the post-shear surface morphology, and its relationship with the measured shear response was examined. A damage-based phenomenological formulation incorporating a log-logistic function was used to parameterize the shear stress–displacement responses and to examine the fitted shear-stiffness parameter and phenomenological damage variable. The implications of the measured shear behavior for lunar drilling and sampling were also discussed. The study can provide laboratory-scale insights into the shear behavior of lunar regolith simulant relevant to lunar drilling and sampling.

Addressing the scientific problem of unclear understanding of in-situ internal stress and its evolution in deep rock masses, a scientific definition and implementation path for the concept of in-situ internal stress consolidation-sealing in deep rock masses are proposed, and a set of in-situ internal stress consolidationsealing test device for deep rock masses has been independently developed. The device consists of a material consolidation cultivation module, an in-situ internal stress environment simulation module, and a multi-source information capture module. And the three mechanical tests of internal stress preservation, internal stress release and conventional were carried out with the device. The evolution law of the deformation parameters in the internal stress consolidation-sealing stage was studied, and the difference characteristics of the deformation parameters before and after the internal stress releasing were compared and analyzed. The results show that the internal stress consolidation-sealing significantly affects the mechanical properties of the simulated rock material, while the internal stress release leads to the damage of the material properties, suggesting that the presence and influence of internal stress should not be overlooked. This study could provide a new research direction and scientific devices for the expansion and deepening of the field of deep in-situ rock mechanics. (c) 2026 China University of Mining & Technology. Publishing services by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

The discing phenomenon is intimately associated with the condition of in-situ stresses, representing an indirect approach to ascertain original in-situ stresses due to its simplicity, operational ease, and economic efficiency. Moreover, the fracture morphology of discing in rock cores can partially elucidate the disturbance and fracture process. Based on deep marble samples from 2400 m depth at Jinping, this study executed rapid triaxial unloading mechanical experiments under varied operational conditions. It unveiled stress combinations conducive to discing and examined parameter selection for laboratory simulations of the phenomenon. Findings demonstrate that the strength and yield stress of marble samples notably enhance with the increase of the minimum principal stress during triaxial compression tests, paralleled by a gradual reduction in axial strain at the stress peak. In true triaxial unloading experiments, axial strain under equal biaxial confining pressures surpasses that under unequal biaxial confining pressures, which in turn exceeds that under uniaxial confining conditions, thus favoring the laboratory simulation of discing. The selection of axial stress during unloading at the sample’s elastic–plastic critical point, maintaining stress advantageous for augmenting axial strain post-unloading, offers theoretical insights into the discing phenomenon's mechanism.

Laser rock breaking, an emerging noncontact and high-efficiency rock-breaking technique, has recently gained attention in deep resource development and extreme-environment drilling. Most studies focus on laser parameters, while the effects of real engineering environments on rock-breaking have received much less attention. In particular, the interaction mechanisms between lasers and rock under confining pressure remain poorly understood. In this study, typical red sandstone was selected as the research object, and a laser rock-breaking experimental system in which confining pressure is controlled was established. Combined with Computed Tomography (CT) scanning and uniaxial compression tests, the thermal response, fracture characteristics, and evolution of the mechanical behavior of rocks after laser irradiation under different confining pressures (0-3 MPa) were qualitatively and quantitatively analyzed. Furthermore, the influence mechanism of confining pressure on crack propagation was investigated. This research yielded the following results: (1) The laserinduced temperature field caused the red sandstone to undergo a heating-melting-evaporation-solidification phase transition process, altering its mineral composition. (2) The confining pressure affected the crack development morphology caused by the laser, and a lower confining pressure caused cracks to develop longitudinally. (3) The spatial distribution of internal cracks was analyzed by CT, revealing the fractal characteristics of different regions of the sample after laser irradiation under the influence of confining pressure. (4) After laser irradiation, both the uniaxial compressive strength and elastic modulus of red sandstone decreased relative to the original sample, and higher confining pressure led to weaker mechanical degradation. The research findings presented in this paper reveal the crack evolution mechanisms and strength degradation effects of laser-induced rock breaking under confining pressure, providing a basis for a deeper understanding of the multi-field coupling between lasers and rock, and offering valuable insights and guidance for the efficient application of laser technology in complex stress environments and engineering practice.

The mineralogical heterogeneity of deep hard rock is a critical factor governing the efficiency of laser-assisted drilling. This study investigates the micro-scale response differences of four constituent minerals, including fluorite, quartz, tourmaline, and plagioclase, by categorizing laser-affected zones into “weak, moderate, and strong” regions along the radial direction from the beam center. Utilizing an integrated characterization framework consisting of infrared thermography, 3D laser scanning, X-ray diffraction, and nano-indentation, we elucidated the thermal response, phase transformation, and spatial attenuation of mechanical properties. The findings reveal: (1) Fluorite, tourmaline, and plagioclase exhibit exceptionally high laser sensitivity, with spot center temperatures rapidly escalating to 925°C, triggering intense vaporization and melting. Conversely, quartz demonstrates superior structural stability, where energy dissipation is predominantly governed by thermal conduction. (2) Damage features are primarily controlled by the Gaussian energy distribution of the laser. Fluorite and plagioclase develop significant elevation gradients, while tourmaline undergoes typical brittle degradation. Quartz exhibits phase transformation only within the localized peak-energy region. (3) High-intensity laser thermal effects induce the enrichment of low-energy stable phases such as quartz. The primary component of fluorite decreases sharply by 54.5

The moon harbors exceptionally abundant and strategically valuable spatial and material resources. As human lunar exploration gradually enters a new phase of development and utilization, lunar mining is transitioning from a strategic concept to tangible possibility. However, the unique properties of lunar regolith and the extreme complexity of the deep-space environment pose significant challenges to lunar mining. It has become imperative to explore and establish fundamental theories and key technologies for lunar mining that are applicable to the in-situ lunar environmental conditions. From the perspective of mining engineering, this paper systematically reviews the types and distribution characteristics of lunar mineral resources and compares the complexity and particularity of the lunar mining environment with terrestrial mining. Focusing on the key technical processes of “exploration-mining-utilization”involved in lunar mining, it elaborates on the main technical approaches and their current development status across five critical areas: in-situ lunar resource exploration and identification, mining and processing, conversion and utilization, lunar base construction, and in-situ energy support. The core mechanisms and adaptive challenges are also discussed. Based on this, addressing the key theoretical and future technological demands of lunar mining, the paper proposes a new paradigm for theoretical research in deep-space geomechanics, spanning from micro to macro scales, and identifies research directions for remote sensing prediction theories of lunar geomechanical properties at a global scale. Furthermore, it refines the conceptual framework and research directions for key technologies that require breakthroughs, such as deep in-situ coring technology with in-situ environmental conditions preservation for lunar prospecting, in-situ thermoelectric power generation technology on the moon, and lunar subsurface tunneling technology. Suggestions for theoretical construction and technical implementation are provided, which are expected to offer theoretical and technical guidance for future lunar mining engineering, in-situ resource development and utilization, lunar surface base construction, and underground space development.

Rotary tillage–seeding combined operations require stable power take-off (PTO) speed during rotary tillage and accurate tracking of the prescribed travel speed for seeding. Existing energy management strategies for hybrid electric tractors mainly focus on fuel economy and commonly use fixed objective weights, limiting their ability to adjust control priorities under changing operating conditions. To address this issue, an operation-quality-oriented energy management strategy based on model predictive control, termed OQ-EMS/MPC, is proposed. An equivalent combined-operation condition was constructed using the PTO-side rotary-tillage load, drive-side equivalent traction load, segmented travel-speed reference, and equivalent seeding-quality risk. A condition-severity index integrating the PTO-load coefficient of variation, PTO-load impact intensity, and equivalent seeding-quality risk was developed to distinguish steady, fluctuating, and impact-dominated conditions. Based on the identified condition, the weights assigned to PTO-speed regulation, equivalent seed synchronization, and energy economy were adjusted online. These weights were used in the MPC to optimize torque allocation among the engine, motor-generator 1 (MG1), and motor-generator 2 (MG2). The proposed strategy was validated on a dual-side loading bench and compared with a rule-based energy management strategy and a fixed-weight MPC strategy. The overall PTO-speed root-mean-square error (RMSE) was reduced to 1.76 r/min, representing reductions of 58.40% and 45.66% relative to the two comparative strategies, respectively. The equivalent seed-synchronization RMSE was reduced by 69.15% and 52.66%, respectively. Under the impact-dominated condition, the PTO-speed RMSE decreased to 1.65 r/min. The normalized composite cost decreased by 13.53% and 6.26%, while the equivalent fuel consumption increased by 3.40% and 3.76%, respectively. The results demonstrate that the proposed strategy improves PTO-speed stability and equivalent seed-synchronization performance as operating severity increases while accounting for energy economy.

Triaxial mechanical tests were conducted on coal at various confining pressures and loading rates using the GCTS rock mechanics testing system to investigate the influence of these parameters on the mechanical behavior and energy evolution of the coal. The results indicate that the strength of the coal initially increases and then decreases with increasing loading rate. A higher pressure enhances the coal's capacity for elastic energy accumulation, leading to a decrease in the critical loading rate. When the loading rate approaches this critical value, coal samples exhibit premature and dense crack propagation, a reduced efficiency in the conversion of external work into elastic strain energy, and a failure mode that manifests as ductile-like. Conversely, at loading rates significantly different from the critical loading rate, fewer cracks develop within the samples, the conversion of external work to elastic strain energy is more efficient, and the failure mode is brittle.

As global oil and gas exploration advances into deep-sea and deep-earth reservoirs, the precise prediction of in situ rock mechanical parameters at depth has become a critical challenge for development optimization. Traditional macro-scale experiments are constrained by sample size and data volume, while nanoindentation technology, though capable of obtaining micro-scale continuous data, struggles to guarantee in situ conditions. Consequently, there is an urgent need to establish a set of in situ measurement techniques for downhole testing. This paper proposes an integrated framework for predicting in situ mechanical parameters, combining multi-scale experiments, numerical simulations, deep learning, and spatial interpolation algorithms. Nanoindentation experiments and numerical simulations were conducted to construct an inversion dataset encompassing load–displacement curves, elastic modulus, maximum load, maximum indentation depth, residual indentation depth, temperature, pressure, and other parameters. A Oliver–Pharr theory-constrained deep neural network establishes a single-point indentation FEM-DNN inversion model, achieving an accuracy of up to 97.19

For the wind energy sector, rapid and accurate online detection of surface damage on wind turbines is essential to minimize downtime and prevent catastrophic failures. Using drones to photograph wind turbines and detecting damage to the surface of wind turbines using computer vision techniques is an efficient solution. However, the sections in the drone-captured images that show signs of damage are usually quite small, but they are filled with numerous mountains, skies and other elements unrelated to wind turbines. It is difficult for traditional visual detection methods to accurately detect damage by relying on limited damage features. To address this challenge, we propose a detection model WTD-YOLO for surface damage detection of wind turbines. Based on PPYOLOE, we propose adjacent layer aggregated attention (ALAA) to optimize the extraction of damage features in the low-level feature maps by using the high-level feature maps as a guide to eliminate the negative impact of redundant features to reduce and enable efficient fusion of high- and low-level feature maps. We also integrate a transformer encoder block and a convolutional block attention module (CBAM) to exploit the prediction potential through the self-attention mechanism and control the model to focus on key regions in complex scenes. Experimental results on the wind turbine surface damage dataset show that our model achieves an average precision of 62.8

Deep lunar drilling is an effective means of obtaining complete lunar profile samples and high quality exploration data, which is of great historical importance in promoting the development of China?s lunar exploration. In this work, a finite element model of moonstone is constructed and a simulation study of drilled moonstone is carried out. In addition, the Drucker-Prager model to describe the intrinsic properties of moonstone is selected, based on the Abaqus finite element software, to complete the numerical simulation of lunar rock cutting by setting different drill feed rates to study their effects on the drill rock fracturing process. The simulation results show that at constant speed, the drilling displacement increases with increasing feed rate. To avoid a drill stop, it must be ensured that the feed speed is at least above 1.6 mm per second. The simulation results show that the drilling offset increases with increasing feed rate.

The objective of this study is to systematically examine the drilling efficiency and performance of various core drill bits in lunar rock formation using the discrete element method (DEM) and drilling experiments conducted in a lunar vacuum environment. This research aims to establish a scientific foundation for selecting core drill bits for lunar deep drilling operations. To achieve this, four distinct core drill bits were designed. Subsequently, a numerical model of lunar rock was constructed and the load characteristics and drilling efficiency of each bit during the drilling process were analyzed using DEM. Drilling and coring tests were then performed in both atmospheric and lunar vacuum environments, thereby validating the numerical simulation results and providing a comprehensive evaluation of the actual performance of the core drill bits. The study revealed that the carbide-tipped core drill bit with octagonal prisms design resulted in the core disking due to a significant rise in temperature, underscoring the critical importance of temperature control in maintaining core integrity. While the carbide-tipped core drill bit with cutting edges demonstrates exceptional drilling efficiency and coring quality, its inherent fragility and rapid wear of the cutting edges present considerable challenges for practical application. The diamond-impregnated core drill bit is unsuitable for drilling operations under lunar loads and power limitations due to its high weight-on-bit (WOB) requirements. In contrast, the PDC core drill bit exhibits excellent drilling stability, low rotary torque requirements, minimal temperature-rise effects, and significantly enhanced penetrating speed in the lunar vacuum environment, making it a recommended choice for lunar rock drilling. This study provides substantial theoretical and experimental support for the development of lunar drilling equipment and the formulation of effective drilling strategies.

Obtaining in-situ lunar soil samples is fundamental to studying the characteristics of lunar surface resources. A circular cutting sampling method is proposed, and its sampling characteristics are explored by theoretical analysis and numerical simulation. The results indicate that the traditional vertical cutting sampling will cause serious damage to the sequence structure and physical properties of samples. Circular inner blade cutting sampling can avoid the disorder of particle sequence, but the design of the inner blade will force the particles to move to the coring barrel, causing sample disturbance. Compared with vertical and inner-blade cutting method, circular outer blade cutting sampling reduces sample disturbance by 61% and 47.5%, respectively, making it the optimal sampling method. These research findings can provide theoretical and technical support for superficial sampling in deep space.

Laser rock-breaking is an emerging technology by rapid heating, high energy, non-contact rock breaking. Its effectiveness is affected by various factors, particularly in deep drilling environments where rocks are hard, water-rich zones exhibit high water content, and drilling fluids are commonly used for lubrication in drilling construction. Investigating rock fracture and damage behavior under laser irradiation in liquid environments is essential for advancing laser-assisted rock-breaking applications. Laser attenuation and rock-breaking experiments were conducted under different liquid conditions to analyze the temperature distribution, fracture behavior, and mechanical damage of rocks under the laser irradiation. The results indicate that laser power is significantly reduced after passing through liquids, with drilling fluids exhibiting a greater attenuation effect than clear water. Laser-induced rock weakening is primarily driven by melting and fracturing, with the increase of laser power, the molten hole depth of saturated rock increases from 17.90 to 38.88 mm. When the laser power is 1304 W, the fracture volume reaches 2985.66 mm3, and the fracture area reaches to 23,235.53 mm2. Water primarily affects the strength of the rock through the softening action. The uniaxial compressive strength of the water saturated rock was significantly reduced after the laser irradiation, and the strength reduction rate increases with laser power, reaching up to 70.3

Data on the distribution of water-conducting fissure zones (WCFZs) were collected in 40 Chinese coal mines and multivariate linear fitting of the data was carried out using SPSS software to establish a predictive model for the height of the WCFZ during integrated mining of a moderately thick coal seam. Focusing on working face 2108 in the Heilongguan coal mine in Shanxi, the development height and distribution of the WCFZ in the rock overlying the mine’s void space was quantitatively interpreted by measuring the amount of leakage of water injected through the drilling boreholes and by using FLAC3D numerical simulation to verify the validity of the predictive model for the height of the WCFZ in a moderately thick coal seam. A multivariate linear regression model was established for calculating the height of the WCFZ. The maximum vertical heights of the plastic deformation zones obtained from field tests of water injection leakage in actual engineering boreholes and numerical simulation methods were basically consistent with the results of the model proposed in this paper. The height and spatial development morphology of the WCFZ obtained using the three methods are in good agreement.

Object detection is the most crucial and challenging task of computer vision and has been used in various fields in recent years, such as autonomous driving and industrial inspection. Traditional object detection methods are mainly based on the sliding windows and the handcrafted features, which have problems such as insufficient understanding of image features and low accuracy of detection. With the rapid advancements in deep learning, convolutional neural networks (CNNs) and vision transformers have become fundamental components in object detection models. These components are capable of learning more advanced and deeper image properties, leading to a transformational breakthrough in the performance of object detection. In this review, we comprehensively review the representative object detection models from deep learning periods, tracing their architectural shifts and technological breakthroughs. Furthermore, we discuss key challenges and promising research directions in the object detection. This review aims to provide a comprehensive foundation for practitioners to enhance their understanding of object detection technologies.