Targeting Chang’E-8 mission’ in-situ resource utilization (ISRU) for sustainable lunar habitats, laser powder bed fusion (LPBF) provides a viable pathway for in-situ additive manufacturing of lunar regolith. To elucidate mission-relevant mechanical behavior and failure mechanisms of LPBF-fabricated lunar regolith simulants, mare-type and highland-type simulant specimens were produced. Microstructural characterization, mechanical test coupled with three-dimensional digital image correlation (3D-DIC), and an energy-dissipation framework were employed for comprehensive analysis. The pristine highland specimens achieved 5.79 MPa and a peak strain of 0.13 (50 mm × 50 mm × 30 mm), significantly outperforming their mare counterparts. Wire-cutting to 20 mm × 20 mm × 20 mm lowered strength by ∼ 20% and peak strain to 0.04, indicating cutting-induced defects reduce ductility. All specimens displayed multi-peaked stress-strain curves. 3D-DIC revealed band-type strain localization in pristine highland samples, diffuse strain patterns in cut highland samples, and highly tortuous, network-type bands in mare samples; the anisotropy index was also quantified. Fragmented particles exhibited fractal dimensions ranging from 1.6 to 2.0 (size 1.25-9 mm). Energy evolution progressed through three distinct stages: elastic energy storage, progressive energy dissipation delaying crack propagation, and final unstable collapse. An energy-based damage model was established and validated. The data and methods developed support Chang’E-8 missions’ ISRU demonstrations and establish a transferable framework toward sustainable lunar habitats.

This study investigates the performance of high-strength cable bolts under impact loading conditions representative of rock bursts in underground environments. Although widely used, the dynamic behaviour of these cable bolts has received limited experimental attention, and their effectiveness in seismically active zones remains a subject of ongoing debate. To address this gap, a reverse pull-out test machine integrated with a drop hammer rig was employed. Tests were conducted on 70-t SUMO bulbed and non-bulbed cable bolts with encapsulation lengths of 300 and 450 mm, subjected to an impact energy of 14.52 kJ. Results indicate that non-bulbed cables, despite showing lower initial peak loads (average 218 vs. 328 kN for bulbed cables at 300 mm encapsulation), demonstrated superior energy absorption (average 11.26 vs. 8.75 kJ) and displacement capacity (average 48.40 vs. 36.25 mm). Increasing the encapsulation length for bulbed cables led to a reduction in initial peak load but improved displacement and energy absorption. The dominant failure mechanism was debonding at the cable-grout interface, characterised by frictional sliding and cable rotation. These findings provide new insights into the energy dissipation mechanisms of cables and support the development of more resilient ground support systems for dynamically active conditions.

Underground carbon sequestration (CS) by solid waste backfill (SWB) offers an effective pathway for collaborative disposal of coal-based solid waste and CO₂, where the amount of carbon sequestration is an important evaluation parameter. In this study, the concept of whole-process carbon sequestration using coal-based solid waste and CO₂, including sequential stirring and curing stages, was proposed to evaluate the performance evolution of CS. The results showed that CO₂ pressure and ambient temperature positively correlated with the CS amount from coal-based SWB. In particular, CO₂ pressure prevailed in the stirring stage, while the ambient temperature effect was more significant in the curing stage. The CS amounts obtained during the stirring stage alone, the curing stage alone, and two sequential stages ranged from 0.66 %-3.10 %, 3.53 %-5.09 %, and 5.12 %-6.02 %, respectively. The functional group and micromorphology analyses revealed that the prevailing mechanism at the CS stirring stage was the stirring-driven gas dissolution-leaching-mineralization reaction, while that at the curing stage was the hydration-driven gas permeation-dissociation-CS reaction. Both were essentially solid-liquid-gas multiphase chemical reactions. The results are instrumental in substantiating the coal-based SWB carbon sequestration evolution patterns and mechanisms and providing data support for waste disposal and carbon emission reduction in the coal industry.

Early prevention and control of coal spontaneous combustion have emerged as a critical research area in coal mine safety. Due to their sustainability and environmental friendliness, microorganisms have gained attention. A filamentous fungus was collected in the coal mine and identified as Absidia spinosa. Results indicated that the mycelium effectively covered and repaired many coal pores. The oxygen consumption ratio of A. spinosa was higher in coal-containing environments than in coal-free conditions. The fungus significantly impacted aliphatic functional groups, disrupting bridging bonds and side chains connected to aromatic structures and reducing the relative content of C-O bonds. Additionally, A. spinosa increases the ignition temperature by 25.34 °C. The total heat release was decreased by approximately 32.58 %, and the activation energies were increased. The genome of Absidia spinosa revealed genes related to oxygen consumption, small molecule degradation, and secretion of metabolic products, such as those annotated under GO ID: 0140657, etc. The pathways involved in the degradation of small organic molecules (e.g., ko00626, etc.), carbon fixation, and nitrogen cycling, all linked to coal decomposition. Through oxygen consumption and the alteration of coal-active structures, A. spinosa effectively inhibits CSC, providing an experimental basis for exploring eco-friendly biological control methods in the goaf.

Investigations into the long-term creep behavior of Beishan granite in uniaxial compression were conducted. Four levels of axial stress (60, 70, 87, and 95 MPa) were applied to rock specimens. Contrasting with earlier research, the long-term creep data in this work present a substantial advancement in the time dimension. Except for the sample subjected to 60 MPa axial loading, which did not fail after a loading duration of 1650 d, the specimens under the other three stresses all failed after sustained constant loading durations of 1204, 1023, and 839 d, respectively. A lower envelope of driving stress-ratio for crystalline rocks was obtained, tending towards approximately 0.45 over an infinite time scale. According to the experimental results, as axial stress increases, both the axial strain accumulated in the transient creep process and the strain rate associated with steady-state creep deformation increase exponentially; however, the share of steady-state creep strain remains nearly constant at about 82.53 %. A novel damage-based creep model was put forward. It provides an enhanced depiction of the comprehensive creep process in rocks, notably improving the accuracy in forecasting the accelerated creep phase, which significantly impacts the long-term stability of engineering structures.

The stability of rock slopes is frequently controlled by the initiation and propagation of inherent dominant cracks. This study systematically investigated these processes in valley slopes by combining fracture-mechanics analysis with transparent soil model tests. An analytical expression for the stress field at the dominant crack tip was derived from the slope stress distribution by superposing the corresponding stress intensity factors (SIFs). The theoretical predictions were then validated against observations from transparent soil model tests. The influences of slope angle (β), crack inclination angle (α), crack position parameter (b), and crack length parameter (h) on crack initiation and propagation were quantified. The results indicated that: (1) cracks at the slope crest tended to propagate in shear mode, and the shear crack initiation angle (θ_s) was approximately 8°. Cracks at the slope toe might propagate in either tensile or shear mode. (2) θ_s at the slope crest increased with β, b, and l, and decreased with α. The maximum change in θ_s induced by the considered parameters was approximately 30°. (3) The tensile crack initiation angle (θ_t) at the slop toe decreased with β, α, and l, while the influence of b was comparatively minor. The maximum change in θ_t caused by individual parameters ranged approximately from 25° to 60°. Predicted crack propagation modes and directions showed good agreement with experimental results. These findings provide theoretical guidance for stability assessments of valley slopes controlled by dominant crack propagation.

The susceptibility of ore particles to electrical breakdown plays a critical role for high voltage pulse (HVP) breakage, yet its quantitative characterization still lacks deep understanding. Two indicators, namely breakdown delay time (T_d) and breakdown strength (E_b) were compared, based on analysis on the two breakdown modes namely wavefront mode and post-wave mode. It was found that T_d is more suitable to characterize the susceptibility of ore particles to electrical breakdown in HVP breakage than E_b. A probabilistic model based on the Weibull distribution is developed to describe the relation of breakdown probability to T_d. Regression analyses were conducted to investigate how operating parameters and particle properties influence T_d and size reduction degree of ore particles in HVP breakage. The regressed models demonstrate potential capability to predict metallic minerals content and HVP breakage degree based on operating parameters and particle properties.

Investigating the damage evolution of surrounding rock under thermal shock cycles is crucial for ensuring the stability of engineering rock masses. This study performed Brazilian splitting tests on granite specimens under varying temperature and cycle conditions, employing acoustic emission monitoring, digital image correlation, and three-dimensional scanning technology. A systematic analysis was conducted on the patterns of damage evolution, failure precursor, and response mechanisms under combined thermal and cyclic loading. Experimental results show that both P-wave velocity and tensile strength degrade significantly with increasing temperature and cycle count, with temperature having a more pronounced effect than cycle count. Notably, damage evolution exhibits a dual-threshold behavior in which degradation accelerates markedly above 400 °C and stabilizes after 5 thermal cycles. Fracture surfaces evolve from initially planar to rugged morphologies, with peak-valley height differences at 600 °C being approximately three times greater than those at 200 °C. Furthermore, based on acoustic emission energy entropy analysis, we introduce a novel failure precursor indicator where the sustained increase and critical surge in average entropy serve as reliable early-warning signals for impending rock failure. These findings establish a solid theoretical basis and practical methodology for damage assessment and instability early-warning systems in high-temperature rock engineering.

Rock mass stability is significantly influenced by the heterogeneity of rock joint roughness and shear strength. While modern technology facilitates assessing roughness heterogeneity, evaluating shear strength heterogeneity remains challenging. To address this, this study first captures the morphology of large-scale (1000 mm × 1000 mm) slate and granite joints via 3D laser scanning. Analysis of these surfaces and corresponding push/pull tests on carved specimens revealed a potential correlation between the heterogeneity of roughness and shear strength. A comparative evaluation of five statistical metrics identified information entropy (H_s) as the most robust indicator for quantifying rock joint heterogeneity. Further analysis using H_s reveals that the heterogeneity is anisotropic and, critically, that shear strength heterogeneity is governed not only by roughness heterogeneity but is also significantly influenced by the mean roughness value, normal stress, and intact rock tensile strength. Consequently, a simple comparison of roughness H_s values is insufficient for reliably comparing shear strength heterogeneity. To overcome this limitation, a theoretical framework is developed to explicitly map fundamental roughness statistics (mean and heterogeneity) to shear strength heterogeneity. This framework culminates in a practical workflow that allows for the rapid, field-based assessment of shear strength heterogeneity using readily obtainable rock joint roughness data.

Excessive blasting-induced vibration during drilling-and-blasting excavation of deep tunnels can trigger geological hazards and compromise the stability of both the rock mass and support structures. This study focused on the deep double-line Sejila Mountain tunnel to systematically analyze the spatial response of blasting-induced vibration and to develop a prediction model through field tests and numerical simulations. The results revealed that the presence of a cross passage significantly altered propagation paths and the spatial distribution of blasting-induced vibration velocity. The peak particle velocity (PPV) at the cross-passage corner was amplified by approximately 1.92 times due to wave reflection and geometric focusing. Blasting-induced vibration waves attenuated non-uniformly across the tunnel cross-section, where PPV on the blast-face side was 1.54-6.56 times higher than that on the opposite side. We propose an improved PPV attenuation model that accounts for the propagation path effect. This model significantly improved fitting accuracy and resolved anomalous parameter (k and α) estimates in traditional equations, thereby improving prediction reliability. Furthermore, based on the observed spatial distribution of blasting-induced vibration, optimal monitoring point placement and targeted vibration control measures for tunnel blasting were discussed. These findings provide a scientific basis for designing blasting schemes and vibration mitigation strategies in deep tunnels.

In- situ stress is a key parameter for underground mine design and rock stability analysis. The borehole overcoring technique is widely used for in-situ stress measurement, but the rheological recovery deformation of rocks after stress relief introduces errors. To improve accuracy, this study proposes an in-situ stress solution theory that incorporates time-dependent stress relief effects. Triaxial stepwise loading-unloading rheological tests on granite and siltstone established quantitative relationships between instantaneous elastic recovery and viscoelastic recovery under different stress levels, confirming their impact on measurement accuracy. By integrating a dual-class elastic deformation recovery model, an improved in-situ stress solution theory was derived. Additionally, accounting for the nonlinear characteristics of rock masses, a determination method for time-dependent nonlinear mechanical parameters was proposed. Based on the CSIRO hollow inclusion strain cell, time-dependent strain correction equations and long-term confining pressure calibration equations were formulated. Finally, the proposed theory was successfully applied at one iron mine (736 m depth) in Xinjiang, China, and one coal mine (510 m depth) in Ningxia, China. Compared to classical theory, the calculated mean stress values showed accuracy improvements of 6.0% and 9.4%, respectively, validating the applicability and reliability of the proposed theory.

To reveal the influence of coupled effects of dry-wet cycling and precompression stress (CEDWCPS) on the damage evolution of limestone with horizontal fissure (LHF), a series of degradation and uniaxial compression tests were conducted, and a corresponding piecewise damage constitutive model (PDCM) was established. We found that both dry-wet cycling and precompression stress deteriorate the physical properties, alter the microscopic characteristics, and reduce the mechanical properties of the LHF. These degradations are particularly pronounced under the CEDWCPS, although the magnitude of these changes gradually diminishes with the progression of dry-wet cycling. Meanwhile, they also reduce the deformation degree, prolong the micropore compaction stage, shorten the unstable crack propagation stage, lower the frequency and intensity of AE events, decrease the high-amplitude and high-frequency AE signals, enlarge crack scales, and shorten the crack initiation time. Among the changes of these indicators, the dry-wet cycling plays a dominant role. The crack types of LHF under the CEDWCPS (LHFCEDWCPS) are predominantly tensile cracks, supplemented by shear cracks. The failure mode can be defined as tensile-shear composite failure. Finally, the established PDCM effectively captures the nonlinear deformation of micropore and the linear deformation of the matrix in LHFCEDWCPS, with all corresponding R² consistently exceeding 0.97.