Mixed Reality (MR) technologies are increasingly used in construction to support inspection, visualization, and coordination. Despite growing adoption, the scientific understanding of how construction professionals evaluate the perceived value of MR technologies remains limited, particularly in the early stages of implementation. This study addresses the research gap by examining the scientific and applied dimensions of MR value, with a focus on usability and adaptability in construction environments. A cross-sectional survey of 129 construction professionals was conducted, and the data were analyzed using statistical methods including T-tests, exploratory factor analysis, and regression modelling. The results show that perceived value is not significantly influenced by device modality but is strongly determined by usability factors, particularly ease of use (beta = 0.330, p = 0.003) and adaptability to site conditions (beta = 0.206, p = 0.029). These findings contribute to scientific literature by conceptualizing perceived value as a multi-dimensional construct and provide practical insights for optimizing MR adoption in construction workflows. The study provides exploratory empirical evidence supporting user-centered design considerations for MR implementation and highlights the importance of contextual robustness for technology adoption in construction environments.

Weakly cemented rocks, characterized by poor cementation, loose internal structures, and well-developed pore networks, exhibit pronounced heterogeneous deformation. This heterogeneity limits the applicability of conventional methods for identifying characteristic stresses based on strain, acoustic emission, or wave velocity. In this study, stepwise cyclic loading–unloading tests were conducted on argillaceous siltstone, a representative weakly cemented rock. The partitioning and transformation of energy during the loading–unloading process were systematically analyzed. By accounting for stress–strain asynchrony, elastic energy and dissipated energy were rigorously separated, and elastic energy was further decomposed into particle elastic energy and crack elastic energy. A quantitative method for determining characteristic stresses was proposed based on the ratios of particle elastic energy and crack elastic energy, along with the increment of dissipated energy. The closure stress (σcc), crack initiation stress (σci), and damage stress (σcd) were determined by the energy-based method. Independent validation using the evolution of the dilatancy point and the acoustic emission hit count demonstrated strong consistency with the proposed energy-based method. By using the complete dataset obtained from stepwise cyclic loading–unloading tests and avoiding subjective interpolation or manual point selection, this approach provides a robust framework for accurately determining characteristic stresses in weakly cemented rocks.

Fibres can markedly enhance the uniaxial compressive strength (UCS) of cemented paste backfill (CPB). However, previous studies have mainly verified the effectiveness of polypropylene and straw fibres in improving the UCS of CPB experimentally, while systematic multi-factor evaluation remains limited. In this study, laboratory experiments were conducted on polypropylene- and straw fibre-reinforced CPB to construct a reliable dataset. The factors influencing the intensity of uniaxial compressive strength were divided into four aspects (mixture proportions, physical properties of the cement-tailings mixture, chemical characteristics of tailings, and fibre properties), and four intelligent models were developed for effectiveness analysis and UCS prediction. SHapley Additive exPlanations (SHAP) were employed to quantify the contributions of individual features, and the findings were experimentally validated. The GWO-LGBM model outperformed the SVR, ANN, and LGBM models, achieving R2 = 0.907, RMSE = 0.78, MAE = 0.515, and MAPE = 0.157 for the training set, and R2 = 0.949, RMSE = 0.627, MAE = 0.38, and MAPE = 0.115 for the testing set, respectively. Feature analysis reveals that mixture proportions contribute the most to UCS, followed by the tailings' physical properties, the fibre properties, and the tailings' chemical characteristics. This study found that cement content and tailings gradation control CPB structural compactness and fibres enhance bonding between hydration products and tailings aggregates, while the chemical composition of the tailings plays an inert role, functioning mainly as an aggregate.

The microbial-induced carbonate precipitation (MICP) is a cementation and solidification method for sand with environmental advantages. However, the bonding performance of MICP for tailings with different particle sizes, as well as its applicability within conventional backfilling processes under varying cementing solution concentrations and bacterial addition levels, remains insufficiently understood. In this study, a uniform proportioning experiment considering the influence of cement–sand ratio (CSR), cementing solution concentration (CSC), and the volumetric ratio of bacterial solution to cementing solution (VRBC) on the uniaxial compressive strength (UCS) was conducted, and a series of microscopic analyses were used to demonstrate microbial mineralization behavior. Results show that the UCS of microbial blended tailings backfill (MBTB) exhibits a general trend of increasing and subsequently decreasing with rising CSC and VRBC. The UCS of optimally proportioned MBTB exceeds that of conventional backfill without microbial addition and maintains stable long-term strength. Comparative analysis indicates that a CSC of 0.5 mol/L and a VRBC of 1:1 yield the most effective microbial bonding performance. Although the cementing solution alone suppresses UCS, the subsequent incorporation of microbes significantly enhances strength, confirming the critical role of microbial mineralization and cementation within the backfill. The optimal UCS values for MBTB prepared with coarse and fine tailings are 2.44 and 1.55 MPa, representing increases of 49.69

In underground excavation and associated stress adjustments,the surrounding rock mass typically experiences non-hydrostatic and deviatoric multi-axial stress conditions.Among the three principal stresses,the intermediate principal stress(σ2)has been increasingly recognized as a critical factor governing the deformation behavior,crack evolution,and failure mode of brittle geomaterials.Nevertheless,the stage-dependent regulatory mechanism of σ2 across different stress regimes remains insufficiently established,particularly under physical biaxial loading conditions that directly capture excavation-induced stress redistribution.To address this gap,comprehensive biaxial compression tests covering σ2 levels from 0 to 36 MPa were conducted on sandstone specimens using a self-developed biaxial static-dynamic loading system.Acoustic emission(AE)monitoring and three-dimensional digital image correlation(3D-DIC)techniques were simultaneously employed to capture multiscale responses ranging from internal microcracking to macroscopic failure.The mechanical behavior,AE multifractal spectrum characteristics,RA(Rise time/amplitude)-AF(Average frequency)-based crack-type discrimination,and evolution of DIC-derived apparent strain-dominant zones were integrated to systematically quantify the influence of σ2 on the progressive failure process.The results reveal a pronounced stage-dependent σ2 effect,with approximately 20 MPa identified as the critical transitional stress level at which the fracture mechanism undergoes a fundamental shift.In the low σ2 regime of 4-16 MPa,sandstone exhibits compaction-enhanced strengthening,simple and localized crack propagation,and a predominant shear fracture mode,which is consistent with a structurally stable microcracking process.However,when σ2 reaches 20 MPa,multiple indicators-including the abrupt increase in the peak strength deviation,marked widening of AE multifractal spectra,and reversal of RA-AF crack-type proportions—show synchronous transitions.At this stage,tensile cracks exceed shear cracks for the first time,indicating a shift from a shear-dominated failure regime to a tensile-shear interactive fracture mechanism.This transition is corroborated by the DIC strain-field evolution,which shows that the localized shear-dominant strain band observed at low σ2 evolves into a planar tensile-shear composite strain-dominant region at 20 MPa.As σ2 increases further to 24-36 MPa,the sandstone exhibits a more complex mixed cracking pattern,characterized by the coordinated propagation of tensile and shear fractures,as well as the formation of large-scale tensile-shear conjugate structures.Therefore,the high σ2 regime can be considered a mechanically enhanced but structurally unstable failure stage.Together,the consistent transitions observed across mechanical curves,AE multifractal indicators,crack-type discrimination,and strain-field evolution strongly support the identification of 20 MPa as the stage-dependent turning point governing the σ2 effect.Overall,this study provides experimentally validated insights into the transitional role of the intermediate principal stress in controlling the multiscale fracture evolution of sandstone.These findings contribute to a deeper understanding of the stage-dependent failure mechanisms of brittle rocks under non-hydrostatic confinement and offer practical implications for evaluating the stability and failure risks of rock masses subjected to complex in situ stress conditions.

Reliable evaluation of rock brittleness is crucial for understanding rock failure behavior and ensuring the stability and safety of underground mining and rock engineering. However, no universally accepted index currently exists, and many proposed indices exhibit limitations in terms of reliability, physical interpretation, and applicability across different rock types and stress conditions. This study introduces a novel brittleness index that integrates both energy dissipation and crack development characteristics, offering a more comprehensive and physically grounded assessment of rock brittleness. The new index is established based on the correlation between energy dissipation, acoustic emission parameters, and brittleness, providing a more robust framework that better reflects the fundamental mechanisms of brittle failure. To validate the new brittleness index, triaxial cyclic loading damage-controlled tests were performed on two representative rock types: siltstone (a porous, weakly cemented rock) and granite (a dense, crystalline rock). These tests generated quantitative data on energy evolution and acoustic emission parameters, which were analyzed to investigate brittleness evolution under varying confining pressures. The results show that the new brittleness index exhibits a nonlinear, monotonic decrease with increasing confining pressure for both siltstone and granite. Furthermore, under identical confining pressure conditions, granite exhibits higher brittleness index values than siltstone. Overall, the new brittleness index demonstrates strong stability and applicability, making it suitable for rocks with different characteristics and stress environments.

Digital inspection technologies are increasingly being adopted in the construction industry to improve efficiency, decision quality, and sustainability performance. Mixed reality (MR) systems can reduce rework, minimise human error, and support resource-efficient inspection processes. However, empirical evidence on how perceptions of efficiency and safety influence professional acceptance of MR technologies remains limited. This study investigates the adoption of MR for construction inspection using an extended technology acceptance model (TAM) that incorporates task efficiency and safety perception as domain-specific human factors. A within-subjects scenario-based experimental design was applied, in which 103 construction professionals evaluated four inspection modalities: HoloLens MR, smart glasses, tablet-based systems, and traditional paper-based methods. Data was analysed using linear mixed-effects models, structural equation modelling, mediation analysis, and dominance analysis. The results show that HoloLens MR achieved the highest perceived efficiency and safety perception, while imposing the lowest cognitive demand. Perceived efficiency was a strong predictor of device preference and significantly predicted perceived usefulness (beta = 0.322, p < 0.001), which fully mediated its effect on behavioural intention. Safety perception accounted for a substantial proportion of the variance in user evaluations (eta(2) = 0.237). These findings indicate that sustainable adoption of MR in construction inspection depends on combined perceptions of efficiency gains, usability, and safety support.

Mixed Reality (MR) overlays digital content onto the physical world, holding significant promise for improving construction collaboration and inspection. This study investigates its current role via a quantitative, survey based methodology, collecting data from 125 global construction professionals. Descriptive statistics revealed limited MR adoption, with 40.8% of respondents using the technology rarely and just 12.8% reporting frequent usage. Reliability analysis confirmed strong internal consistency for perceived benefits (α = 0.935) and acceptable consistency for barriers (α = 0.762). Exploratory factor analysis (KMO = 0.932; Bartlett’s test of sphericity, p < 0.001) validated the unidimensionality of the benefits construct. Multiple regression analysis revealed no significant relationship between perceived benefits or barriers and MR usage frequency (R2 = 0.011, p = 0.512). Chi square analysis found no significant regional differences in MR use (χ2 = 115.4, p = 0.899), though this result warrants cautious interpretation given the sparse expected cell counts. The findings suggest that MR adoption may be influenced by factors beyond user perceptions, highlighting the importance of organisational readiness, training, and infrastructure support.

In this article, the contemporary stress state of the Zhao–Ping metallogenic belt in eastern China was revealed using overcoring and hydraulic fracturing stress data, the relation between the stress field and geological tectonics was discussed, and the stability of regional faults under the present-day stress environment was evaluated. The results indicate that the stress level is considerably high, and the distribution of stress intensity is uneven. The stress regime is primarily characterized by σH > σv > σh. The σH orientation is well-oriented in the WNW–ESE, which is roughly identical to other stress indicators. Moreover, the σH direction reflected by joint strikes and inferred based on the fault characteristics agrees fairly with the identified stress orientation. The modern stress field basically inherited the tectonic stress field of the Yanshanian and Himalayan periods but is principally dominated by the Himalayan period. Additionally, the calculated µm ranges from 0.2 to 0.7, indicating that the possibility of shallow faults across this area being reactivated and experiencing shear failure is small overall under the current stress conditions. µm = 0.2 and 0.5 are suggested as the lower and upper limits for predicting and analyzing future fault activity in the area, respectively.

Rock failure and instability have been key research topics in rock mechanics domestically and internationally. Numerous geotechnical disasters, such as rock bursts and slope instability, are associated with these phenomena. Acoustic emission detection is recognized as an effective method for monitoring rock failure and instability processes. Uniaxial compression tests were carried out on marble and siltstone to investigate the anisotropic characteristics of rock wave velocity and their influence on the accuracy of acoustic emission location. Prior to reaching the peak, marble remains predominantly in the elastic stage, with the average wave velocity remaining nearly constant. The horizontal wave velocity is consistently higher than the oblique longitudinal wave velocity, indicating fewer longitudinal cracks in the initial state. In the compaction stage of siltstone, horizontal, oblique longitudinal, and average wave velocity show an increasing trend. During the elastic stage, the horizontal and average wave velocities decrease slowly, indicating the presence of small longitudinal fractures. In the damage stage, the horizontal, oblique longitudinal and average wave velocities decrease rapidly, signifying that the fractures have propagated. A 3D ellipsoid characterization method for rock anisotropic wave velocity using the Rodrigues matrix is proposed in accordance with the characteristics of rock wave velocity evolution in different directions. The long axis of the ellipsoid represents the maximum wave velocity within the rock, whereas the short axis reflects the minimum wave velocity. During the compression of marble, the maximum and minimum wave velocities in various directions remain relatively stable until the peak stress is reached. By contrast, for siltstone, the maximum wave velocity increases during the compaction phase, whereas the minimum wave velocity remains constant. In the damage stage, the minimum wave velocity decreases due to rock damage and crack formation, whereas the maximum wave velocity remains unaffected. The statistical results indicate that the azimuth of the wave velocity ellipsoid for marble and siltstone is over 77% consistent with the crack azimuth. This finding suggests that the method can effectively predict crack propagation. In addition, an acoustic emission location method that incorporates the anisotropic wave velocity evolution characteristics is proposed. The average error of the proposed method is determined to be 1.89 mm for marble and 2.76 mm for siltstone, as measured by the lead breaking test. The location error for siltstone is greater than that for marble due to three primary reasons. First, siltstone exhibits high porosity, resulting in unstable and noisy acoustic emission signals, which complicate the extraction of the received signals. Second, the wave velocity of siltstone varies at different stages, displaying distinct changing trends and significant amplitude fluctuations. Lastly, siltstone demonstrates stronger wave velocity anisotropy, with inconsistent variation trends observed across different stages. Compared with traditional simplex and Geiger methods, the positioning accuracy of the proposed method improves by more than 58% in both rock types, validating the effectiveness of the proposed location method. In addition, this method is applicable to microseismic positioning, offering a more accurate solution for monitoring and early warning in geotechnical engineering disasters.

Mineral resources, such as metal, coal, non-metal, etc., are an important material basis for human survival and social development. Green exploitation is the lifeblood to ensure the sustainable development of the mining industry, and green mine construction is necessary to coordinate and unify mining and ecological environment and to link the mine ecological environment, resource environment, economic environment, and human environment into an organic system. In this work, we focused on the current status and major problems of green mine construction in China and proposed a new connotation of green mine construction and major strategies and approaches to solve those problems from the aspects of mine design, green mining, mineral processing, harmless disposal and resource utilization of mine waste, and ecological environment restoration and governance. Besides, we also put forward that the existing mining development model and related technologies must be fundamentally reformed to meet the requirements of green mine construction. In addition, some necessary countermeasures and suggestions were put forward. These pragmatic and forward-looking perspectives contribute to accelerating the process of green mining construction.

Granite is a typical load-bearing rock in energy storage caverns. Due to the heterogeneity and widely existing joints, the mixed-mode crack propagation is likely to occur under high internal pressure. However, the mixed-mode fracture mechanisms of granite are still unclear. This paper designs a comprehensive experimental framework to investigate granite mixed-mode fracture. Three-Point Bending (TPB) tests on specimens with offset notches are carried out and the crack mouth opening displacement (CMOD) is controlled to obtain whole load-CMOD curves and stable cracks. The Acoustic emission (AE) and digital image correlation (DIC) techniques are employed to monitor the fracture process. Further, a random field model is developed to characterize the heterogeneity of granite based on the microscopic images. The heterogeneous random field model is implemented into the combined Finite and Discrete Element Method (FDEM) to simulate the mixed-mode fracture under offset TPB loads. The accuracy of the numerical method is verified through comparisons between numerical results and experimental results. The results show that: (1) As the offset increases (0–75 mm), the specimen transitions from pure Mode I fracture to a mixed Mode I/II fracture. Compared with offset 0, the peak load increases by 20

When predicting ground surface settlement caused by constructing a new tunnel beneath existing structures, traditional stochastic medium theory inadequately accounts for the effects of abrupt changes in the crosssectional areas of variable-section tunnels and the presence of existing structures, potentially leading to significant errors. In this paper, an enhanced ground surface settlement prediction model, based on stochastic medium theory, is proposed. The model equates the settlement of the existing structure's base slab to that of the overlying soil and divides the horseshoe-shaped tunnel cross-section into eight arc segments, which are calculated using a polar coordinate system. Furthermore, the model treats soil loss at the junctions of variable-section tunnels as a linear transition, introduces the concept of a linear transition segment for variable sections, and accounts for the superimposed effects of closely spaced twin-tunnel excavations. Based on this model, a general-purpose calculation program has been developed that enables the rapid prediction of ground surface deformation caused by a variable-section tunnel passing beneath existing structures, simply by inputting engineering parameters. Finally, the accuracy of the prediction model was validated through comparisons with field measurement data, finite element analysis results, and calculations based on traditional stochastic medium theory. The results indicate that the proposed prediction model demonstrates high consistency with field data and finite element analysis results, whereas traditional stochastic medium theory results exhibit significant errors. This model is scientifically valid and provides a reliable reference for predicting ground surface settlement in comparable variablesection metro tunnel construction projects.

To study the influence of the spatial distribution and structure of multi-scale cracks on the mechanical behavior of rocks, triaxial compression tests and cyclic triaxial complete loading and unloading tests were conducted on sandstone, with real-time wave velocity monitoring and CT scan testing. The quantitative classification criteria for multi-scale cracks on sandstone were established, and the constraint effect of confining pressure was analyzed. The crack with a length less than 0.1 mm is considered a small-scale crack, 0.1–1 mm is a medium-scale crack, and larger than 1 mm is a large-scale crack. As the confining pressure increases, the spatial fractal dimension of large-scale cracks decreases, while that of medium-scale cracks increases, and that of small-scale cracks remains stable. The respective nonlinear models of the aspect ratio were established with the length and density of multi-scale cracks. The results indicate significant differences in the effects of cracks of different scales on rock damage. The distribution density of medium-scale cracks in the failed specimen is higher, which is the main reason to produce damage. The small-scale cracks mainly originate from relatively uniform initial cracks in rocks, mainly distributed in medium-density and low-density areas. The results of this research provide important insights into how to quantitatively evaluate the damage of rocks.

Weakly cemented rock is a typical engineering material widely distributed in western China. The engineering disaster of weakly cemented rock is more complex than common granite and sandstone, and the effective surrounding rock support is difficult. It is of important significance for weak cementation geotechnical engineering to investigate the energy release behavior under various stress levels. In this study, the confining pressure effect of siltstone under triaxial compression was analyzed, and the rock energy release characteristics were studied using acoustic emission (AE) monitoring technology. The results indicate that the damage mechanical characteristics of weakly cemented rock are significantly different from those of granite, marble, sandstone. By analysing the AE b value and micro fracture surface, it is found that the dispersed secondary intergranular cracks of siltstone are constrained, under low stress level. Under high stress level, the mineral particles of siltstone extensively fracture, causing the release strongly of energy, and the b value fluctuates significantly. The energy release factor was introduced to modify the damage variable, then a damage constitutive model for weakly cemented rocks was established. Finally, the elastic energy release scale index was proposed to quantitatively characterize the hazard of weakly cemented rock engineering disasters under various stress levels.

To reveal the current state of in-situ stresses in the Heze coal basin and to interpret the implications of the stress regime for coal exploitation and regional geological tectonics evolution, hydraulic fracturing, overcoring, and acoustic emission stress measurements were performed in this region and seismic data in and around the region were compiled. The stress state in the study area exhibits significant complexity and variability. The σH, σh, and σv values increase in a roughly linear relationship with depth. Under the contemporary stress condition, a prevailing thrust faulting stress regime (σH > σh > σv) is favored, and a transition between thrust and strike-slip (σH > σv > σh) stress regime currently exists at the measurement depths. The stress level is comparatively high and is not conducive to the stability of underground structures. The stress ratios KH, Kh, Kav, and KHh have no significant mathematical relationship with depth, and their average values can respectively represent their variation trends versus depth. The σH directions derived from the stress measurements and focal mechanism solutions are principally between ENE–WSW and WNW–ESE, and the average near ENE, which is identical to other stress indicators in and around the study area. The contemporary stress conditions in this region generally inherit the fourth stage tectonic stress field, while some retain the features of the second and third stages tectonic stress field. A close correlation exists between the direction of the current stress field and historical geological structural elements in this region.

It is crucial to control surface subsidence and utilize solid wastes for sustainable mining. This paper proposes a short-wall roadway backfill mining method with advantages in avoiding surface subsidence and utilizing solid wastes. A mechanical model is developed to predict roof fractures based on tensile stress. The impact of mining parameters-such as mining height, working face length, and backfill mechanical properties-on roof stress distribution is examined. Further, a case study in a Chinese coal mine is carried out to determine the preliminary mining parameters using the analytical model. Numerical simulations then explore stress and deformation characteristics, followed by monitoring rock strata stability under the proposed mining conditions. Results show the backfill's elastic modulus is the primary factor affecting the tensile stress of the basic roof beam. With the elastic modulus increasing from 0.45 to 0.5 GPa, the maximum tensile stress reduces by 2.38 MPa. A suitable backfill materials mixture for the coal mine is further determined. Numerical simulations show that the main load-bearing structure shifts from the coal body to the backfill body, with surface subsidence remaining within acceptable limits for building safety. Field application and monitoring prove that roof movement and surface subsidence are well controlled by using the developed method.

Mastering the dynamic mechanical behaviors of pre-stressed fractured rocks under repeated impact loads is crucial for safety management in rock engineering. To achieve this, repeated impact loading experiments were performed on produced fractured samples exposed to varying pre-applied axial and confining pressures using a split Hopkinson pressure bar test system in combination with a nuclear magnetic resonance imaging system, and the dynamic failure mechanism and fractal features were investigated. The results indicate that the dynamic stress–strain curves exemplify typical class II curves, and the strain rebound progressively diminishes with growing impact times. The impact times, axial pressure, and confining pressure all significantly affect the dynamic peak strength, average dynamic strength, dynamic deformation modulus, average dynamic deformation modulus, maximum strain, and impact resistance performance. Moreover, under low confining pressures, numerous shear cracks and tensile cracks develop, which are interconnected and converge to form large-scale macroscopic fracture surfaces. In contrast, specimens under a high confining pressure primarily experience tensile failure, accompanied by localized small-scale shear failure. Under low axial pressure, some shear cracks and tensile cracks emerge, while at high axial pressure, anti-wing cracks and secondary coplanar cracks occur, characterized predominantly by shear failure. In addition, as the confining pressure grows from 8 to 20 MPa, the fractal dimensions are 2.44, 2.32, 2.23, and 2.12, respectively. When the axial pressures are 8, 14, and 20 MPa, the fractal dimensions are 2.44, 2.46, and 2.52, respectively. Overall, the degree of fragmentation of the sample decreases with growing confining pressure and grows with rising axial pressure.

1.Introduction Various geological phenomena on the surface and in the interior of the Earth,as well as their associated physical and chemical pro-cesses,are closely correlated with the action of in situ rock stress[1-5].Understanding the rock stress state at great depths is not only an indispensable foundation for solving scientific problems associated with geology,geophysics,and geodynamics-such as plate-driving mechanisms,the earth's energy equilibrium,earth-quake mechanisms,and tectonic activities-but also a necessary prerequisite for the evaluation,exploitation,and disposal of deep energy and resources,such as coal and metal minerals.Due to the complexity and uncertainty of the origin of in situ rock stress,it is a difficult quantity to evaluate,in comparison with other rock properties.Currently,reliable information on the stress state in a region can only be determined through field stress measurement.Therefore,a variety of stress measurement techniques have been developed and applied worldwide to provide information on crus-tal contemporary stress at specific depth ranges[6].