International Journal of Rock Mechanics and Mining Sciences最新文献

{"title":"Mutual feedback and fracturing effect of hydraulic fractures in composite coal−rock reservoirs under different fracturing layer sequence conditions","authors":"Bo Li ,&nbsp;Yizheng He ,&nbsp;Zhen Shi ,&nbsp;Wang Jian ,&nbsp;Nannan Wang ,&nbsp;Yapeng Zhang","doi":"10.1016/j.ijrmms.2024.105968","DOIUrl":"10.1016/j.ijrmms.2024.105968","url":null,"abstract":"<div><div>Multistage fractures in different reservoirs exhibit competitive extension and mutual feeding mechanisms under different fracturing sequence conditions. To better understand these mechanisms for a more efficient extraction of mine gases, a combination of true triaxial physical tests and numerical simulation was performed in this study. The expansion process of hydraulic fractures in different layers and the comprehensive effect of fracturing were analyzed. The directional deflection effect of the induced stress field on the hydraulic fractures can be summarized as follows. In terms of their behavioral pattern, the fractures in the rock seam extended “in the direction of maximum geo-stress and then deflected toward the interface.” The fracture behavior in the coal seams could be divided into two patterns: “deflection toward the interface and then extension along the direction of maximum geo-stress” and “deviation from the interface and then extension along the direction of maximum geo-stress.” The mutual feedback between the fractures manifested in the form of fracture “phase direction” in the case of stratified fracturing and “phase back” in the case of simultaneous fracturing, i.e., the fracture behaviors in the rock seams and in the first type of coal seams were promoted whereas the fracture behavior was inhibited in the second type of coal seams. In addition, the second fracturing process could be characterized by an increase in the fracture initiation pressure, a decrease in the rate of pressure drop, an increase in the fracture extension duration, and a decrease in the fracture width. When using a fracturing sequence of rock followed by coal, the formation of the seam network structure was found to be more favorable. When using a fracturing sequence of coal followed by rock, it was necessary to continue the injection of the hydraulic fluid into the first fracture during the second fracturing process, so as to obtain a higher fracturing yield. This research provides a certain theoretical support for the efficient co-exploitation of three gases, namely coalbed methane, tight gas, and shale gas, from coal composite reservoirs and in the prevention of gas disasters.</div></div>","PeriodicalId":54941,"journal":{"name":"International Journal of Rock Mechanics and Mining Sciences","volume":"184 ","pages":"Article 105968"},"PeriodicalIF":7.0,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental study on the interaction mechanism of two dynamic cracks under blasting loading","authors":"Linzhi Peng ,&nbsp;Zhongwen Yue ,&nbsp;Xu Wang ,&nbsp;Jun Zhou","doi":"10.1016/j.ijrmms.2024.105956","DOIUrl":"10.1016/j.ijrmms.2024.105956","url":null,"abstract":"<div><div>In this study, dynamic photomechanical blasting experiments were conducted to investigate the interaction mechanisms of dual cracks induced by explosions at different relative positions. The experimental results demonstrate that both cracks penetrate when the actual relative vertical distance at which the crack tips begin to interact is within 10 mm in the experimental group; however, when it exceeds 10 mm, the dual cracks finally expand in a relatively parallel manner. The relative horizontal distance has a weaker impact on the final fracture mode. When the dynamic cracks begin to interact, both the propagation speed of the crack tips and the stress intensity factor increase, the crack propagation angle increases, and the crack propagation path exhibits curved characteristics. Based on the final fracture states of the specimens, the interaction results of the crack tips can be classified into three categories: deflection without merging, curvilinear merging, and parallel overlapping without merging. Based on the results of dynamic photomechanical experiments and the relative verification theory of the crack-tip stress field in previous studies, an expression for the stress-field distribution between dynamic crack tips during interaction was proposed. During the interaction of dynamic blast-induced cracks, the stress intensity at crack tips increases to 1.3–1.5 times that at the onset of mutual interaction. The cracks initially repel each other. As the relative positions of the crack tips increased, the local stress weakened, and the repulsion phenomenon diminished accordingly. Consequently, after crack interaction, the cracks exhibited a spindle-shaped pattern.</div></div>","PeriodicalId":54941,"journal":{"name":"International Journal of Rock Mechanics and Mining Sciences","volume":"184 ","pages":"Article 105956"},"PeriodicalIF":7.0,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermo-Hydro-Mechanical (THM) wellbore analysis under sub-zero CO2 injection","authors":"Nikolaos Reppas ,&nbsp;Ben Wetenhall ,&nbsp;Yilin Gui ,&nbsp;Colin T. Davie","doi":"10.1016/j.ijrmms.2024.105954","DOIUrl":"10.1016/j.ijrmms.2024.105954","url":null,"abstract":"<div><div>A prototype finite element double porous Thermo-Hydro-Mechanical (THM) model that considers elastoplastic and damage evolution effects, is used to investigate deformability, fluid flow and heat transfer during injection of carbon dioxide (CO₂) injection. The primary objective is to explore the feasibility of injecting CO₂ at temperatures lower than the surrounding formation, including subzero conditions. This is done to enhance the energy efficiency of the CO₂ storage process by eliminating the need to pre-heat the CO₂ prior to injection. The numerical analysis investigates the impact of internal wellbore temperatures and pressures on the surrounding rock, using Stainton Sandstone as the reference material. Various internal wellbore temperatures and pressures are simulated to represent different CO₂ injection scenarios. The results suggest that injecting CO₂ at lower temperatures than the wellhead is feasible. However, the long-term integrity and lifespan of the wellbore may require further investigation. This study provides a novel approach to enhancing energy efficiency in CO₂ storage by exploring subzero injection, potentially reducing operational costs. Additionally, it identifies critical challenges regarding wellbore integrity, which warrant further research to ensure the safety and durability of the storage site.</div></div>","PeriodicalId":54941,"journal":{"name":"International Journal of Rock Mechanics and Mining Sciences","volume":"184 ","pages":"Article 105954"},"PeriodicalIF":7.0,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The effect of strain rate on inelastic strain development in porous sandstones deformed under reservoir conditions","authors":"Takahiro Shinohara,&nbsp;Mark Jefferd,&nbsp;Christopher J. Spiers,&nbsp;Suzanne J.T. Hangx","doi":"10.1016/j.ijrmms.2024.105947","DOIUrl":"10.1016/j.ijrmms.2024.105947","url":null,"abstract":"<div><div>Fluid extraction from sandstone oil, gas, or geothermal reservoirs causes elastic and inelastic compaction of the reservoir, which may lead to surface subsidence and induced seismicity, as observed in the Groningen Gas Field, Netherlands. The inelastic compaction is partly caused by rate- or time-dependent processes, meaning that compaction may continue even if production is stopped. To reliably evaluate the impact of prolonged reservoir exploitation and post-abandonment behavior (<span><math><mrow><mo>&gt;</mo><mspace></mspace></mrow></math></span>10–100 years), mechanism-based rate/time-dependent compaction laws are needed. We systematically investigated the effect of strain rate (rates of <span><math><mrow><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>3</mn></mrow></msup></mrow></math></span>–<span><math><mrow><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>9</mn></mrow></msup></mrow></math></span> s<span><math><msup><mrow></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math></span>) in triaxial compression experiments performed on clay-bearing Bleurswiller sandstone (as an analogue of the Groningen reservoir sandstone) and almost clay-free Bentheimer sandstone, to explore the effect of mineralogy. Our results showed a systematic lowering of stress–strain curves with decreasing axial strain rate in Bleurswiller sandstone at differential stresses exceeding 40%–50% of peak stress (i.e. comparable to typical reservoir stress conditions). By contrast, in Bentheimer sandstone, rate effects were only noticeable at differential stresses <span><math><mo>&gt;</mo></math></span> 70% of peak differential stress. Further investigation of the deformation behavior of Bleurswiller sandstone at varying confining pressure, temperature and pore fluid pH, complemented by microstructural analysis, suggested that the observed rate effects are likely controlled by rate-dependent intergranular frictional sliding at lower differential stress, with an increased role of stress corrosion cracking at higher stress. Extrapolation of our data to reservoir conditions suggests that additional strains of about 10% can be expected, compared to the strain accumulated at laboratory strain rates. Our results show that time-dependent inelastic deformation plays an important role in controlling reservoir deformation, such as of the Groningen gas reservoir. Such effects could lead to an underestimation of surface subsidence and induced seismicity, if not accounted for. The present experiments provide important data for developing physics-based constitutive models for predicting rate/time-dependent reservoir compaction.</div></div>","PeriodicalId":54941,"journal":{"name":"International Journal of Rock Mechanics and Mining Sciences","volume":"184 ","pages":"Article 105947"},"PeriodicalIF":7.0,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660333","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integration of automatic discontinuity identification and multi-scale hierarchical modeling for stability analysis of highly-jointed rock slopes","authors":"Ya-ping Wang ,&nbsp;Jia-wen Zhou ,&nbsp;Jun-lin Chen ,&nbsp;Yu-chuan Yang ,&nbsp;Fei Ye ,&nbsp;Hai-bo Li","doi":"10.1016/j.ijrmms.2024.105955","DOIUrl":"10.1016/j.ijrmms.2024.105955","url":null,"abstract":"<div><div>The geometric shape of the slope and the distribution characteristics of the complex fracture system significantly impact the stability of highly-jointed rock slopes. Constructing an accurate three-dimensional (3D) geological model is crucial for the 3D stability analysis of these slopes. However, the numerous minor discontinuities in rock slopes complicate model construction and reduce computational efficiency. This paper proposes a stability-analysis method for highly-jointed rock slopes that integrates automatic identification of real discontinuities with hierarchical modeling of 3D multi-scale fracture networks. Real discontinuity information was automatically extracted using a developed fuzzy k-means clustering algorithm, which calculated the number of dominant discontinuity sets and their spatial distribution laws. The Monte Carlo stochastic method was then employed to generate a complex 3D fracture-network system with statistical characteristics identical to those of the real discontinuities. The multi-scale fracture network was classified based on trace length. Given the numerous minor discontinuities that significantly impact computational efficiency, synthetic rock mass technology was utilized to determine the representative elementary volume with equivalent rock-mass characteristics to reasonably generalise the geological engineering model of rock slopes with complex fractures. In applying the slope-excavation stability analysis and evaluation to the Feishuiyan rock slope, the method achieved high automation in contactless scanning, efficient identification of discontinuity effects, accurate model calculations, and reliable stability analysis during the generalization of the geological engineering model. This method proved effective for stability analysis of highly-jointed rock-slope excavations, and is significant for engineering evaluation, as well as for disaster prevention and mitigation of complex rock slopes.</div></div>","PeriodicalId":54941,"journal":{"name":"International Journal of Rock Mechanics and Mining Sciences","volume":"184 ","pages":"Article 105955"},"PeriodicalIF":7.0,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of a dynamic cumulative damage model and its application to underground hydropower caverns under multiple blasting","authors":"Yimo Zhu,&nbsp;Yaolan Tang,&nbsp;Huachuan Wang,&nbsp;Qian-Bing Zhang","doi":"10.1016/j.ijrmms.2024.105948","DOIUrl":"10.1016/j.ijrmms.2024.105948","url":null,"abstract":"<div><div>Underground infrastructures are crucial for resource extraction, energy storage, and space utilisation. The geomaterials that make up these structures, such as rock and concrete, are subjected to multiaxial stress conditions and are frequently exposed to dynamic and extreme loadings caused by both natural disasters and human activities. These stresses are particularly significant during the construction phase, which involves operations such as drilling and blasting excavation, as well as during the operational phase, which may include events like explosions. For instance, while drilling and blasting induce rock breakage within the excavated profile as designed, they inevitably lead to the formation of a damage zone in the surrounding rock mass. Moreover, the cumulative effects of sequential excavations and multiple blasts can cause significantly greater damage, thereby threatening the stability of tunnel structures during the operation phase. This paper highlights the importance of thoroughly analysing these phenomena during both static and dynamic loadings to ensure the stability of underground infrastructures. To address these challenges, a rate-dependent damage constitutive model is proposed for geomaterials to assess the impacts of blasting loads and the cumulative damage resulting from repeated blasts. The model is conceptualised using the strength envelope of loading-unloading curves to represent the progressive accumulation of damage under repeated impacts. Through theoretical derivation, a dynamic cumulative damage model is developed, based on a modified Mohr-Coulomb strain-softening model incorporating rate-dependent parameters, and is validated against dynamic experimental data. The model captures the transition between static strain-softening and dynamic cumulative damage, triggered by a critical strain-rate threshold. The applicability of the model is demonstrated through simulations of tunnel excavation, emphasising the impact of blasting loads and the accumulation of damage zones. To assess its practical feasibility, the developed model is applied to simulate different excavation scenarios for an underground hydropower cavern. Damage in the surrounding rock mainly results from static unloading and/or dynamic disturbances. Blasting construction, in particular, causes significant damage in tunnel intersection zones and the connecting areas of two benches, leading to increased displacement and higher damage levels compared to static excavation. To mitigate excessive damage while maintaining the construction timeframe, it is recommended to consider alternating cycles of dynamic loading and static excavation unloading continuously, which helps understand damage formation in critical zones without significantly delaying project completion.</div></div>","PeriodicalId":54941,"journal":{"name":"International Journal of Rock Mechanics and Mining Sciences","volume":"184 ","pages":"Article 105948"},"PeriodicalIF":7.0,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142578527","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Asymmetric failure mechanisms of anisotropic shale under direct shear","authors":"Chunfeng Ye ,&nbsp;Heping Xie ,&nbsp;Fei Wu ,&nbsp;Jianjun Hu ,&nbsp;Li Ren ,&nbsp;Cunbao Li","doi":"10.1016/j.ijrmms.2024.105941","DOIUrl":"10.1016/j.ijrmms.2024.105941","url":null,"abstract":"<div><div>This study performed mechanical tests and monitored acoustic emissions (AE) in shale samples with six bedding layer orientations (<em>β</em> = 0°, 30°, 60°, 90°, 120°, and 150°) to investigate the progressive damage mechanisms under direct shear. The results revealed that the peak shear load (<em>P</em>_<em>cr</em>), crack initiation threshold (<em>P</em>_<em>ci</em>), crack damage threshold (<em>P</em>_<em>cd</em>), and cumulative AE count exhibited an approximate M-shaped trend as the bedding angle increased. The <em>P</em>_<em>ci</em>, <em>P</em>_<em>cd</em>, and <em>P</em>_<em>cr</em> values were minimal for shale specimens with <em>β</em> = 0°, <em>P</em>_<em>cd</em> and <em>P</em>_<em>cr</em> were maximal at <em>β</em> = 150° (followed by <em>β</em> = 60°), and <em>P</em>_<em>ci</em> reached the maximum at <em>β</em> = 60°. Thus, shale exhibits complex and asymmetric mechanical behavior under direct shear, a phenomenon seldom documented. The three-dimensional spatiotemporal evolution of the AE, evolution of <em>b</em>-values, peak frequency distribution, and the rise angle-average frequency (RA-AF) indicated that the microscale mechanism governing the asymmetric progressive failure of anisotropic shale under direct shear involved significant asymmetry in the formation type and scales of cracks. The AE characteristics of anisotropic shale were analyzed using multifractal theory. The width of the multifractal spectrum, Δ<em>θ</em>, accurately reflected the anisotropic characteristics of the AE time series. Moreover, the variation in the fractal dimension, Δ<em>f</em>, indicated that the different probabilities of microcracks with high AE energy are the fundamental cause of the shale's asymmetric failure.</div></div>","PeriodicalId":54941,"journal":{"name":"International Journal of Rock Mechanics and Mining Sciences","volume":"183 ","pages":"Article 105941"},"PeriodicalIF":7.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rock fragmentation of simulated transversely isotropic rocks under static expansive loadings","authors":"Chundong Shi ,&nbsp;Wen Nie ,&nbsp;Guowei Ma ,&nbsp;Jiangyong Sun ,&nbsp;Junlin Wang ,&nbsp;Li Wang","doi":"10.1016/j.ijrmms.2024.105944","DOIUrl":"10.1016/j.ijrmms.2024.105944","url":null,"abstract":"<div><div>Rock fragmentation is a critical process for mineral extraction and for mitigating overstressed rock in geotechnical applications. In this study, 3D-printed concrete was used to simulate the stratified rock mass, and experimental and numerical methods were employed to investigate crack propagation under static expansive loadings in transversely isotropic rocks. Two types of cracks were observed in the experiments: P-type (a crack propagates primarily along the weak layer) and T-type (a crack propagates across the weak layers) cracks. The findings revealed that the orientation of layers significantly influenced the initiation and propagation of cracks, with P-type cracks commonly observed in simpler P-P mode fragmentations and more complex P-P-T modes emerging under higher expansive loadings. P-T-T modes were characterized by the simultaneous presence of the T-type crack after an initial P-type crack. The AE energy levels in the P-P-T and P-T-T modes were much higher than those in the P-P mode. 2D-DDA models were further built to understand the effects of the loading scales, layer angles, and locations of weak layers on the cracking sequences. The results provided detailed insights into stress evolutions and the impact of expansive loadings on crack initiation and propagation.</div></div>","PeriodicalId":54941,"journal":{"name":"International Journal of Rock Mechanics and Mining Sciences","volume":"183 ","pages":"Article 105944"},"PeriodicalIF":7.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142561347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-stage evolution of pore structure of microwave-treated sandstone: Insights from nuclear magnetic resonance","authors":"Yao Zhang ,&nbsp;Yanan Gao ,&nbsp;Liyuan Yu","doi":"10.1016/j.ijrmms.2024.105952","DOIUrl":"10.1016/j.ijrmms.2024.105952","url":null,"abstract":"<div><div>Microwave fracturing has great potential in improving the efficiency of hard rock breaking. However, the pore evolution, which can be regarded as the damage accumulation and progressive failure of the rock subjected to microwave irradiation, remains unclear. In this study, nuclear magnetic resonance (NMR) is employed to investigate the pore evolution and fracture mechanism of the sandstone under different microwave power levels. The results show that the pore evolution of the specimens, including distribution of pore size, the weight in volume of various-sized pore, and porosity, exhibits different changing trends under various microwave power levels. The pore evolution of the specimens under microwave irradiation can be categorized into four phases: overall pore expansion, localized pore closure in the internal region, micro-cracks propagation induced by thermal stress, and macro-cracking (or melting). Moreover, pore evolution also plays a crucial role in the decomposition and evaporation of bound water, particularly when the specimens experience fractures triggered by thermal stress induced by the microwave treatment (TSIMT). The employing of NMR imaging (NMRI) description also provides an auxiliary and effective illustration on the pore evolution of the specimens under microwave irradiation. Finally, the mechanism of microwave-assisted rock breaking under different power levels is comprehensively discussed based on the NMR results from a microscopic perspective. It is anticipated that the findings of this study can provide valuable insights for enhancing the efficiency of microwave-assisted rock breaking.</div></div>","PeriodicalId":54941,"journal":{"name":"International Journal of Rock Mechanics and Mining Sciences","volume":"183 ","pages":"Article 105952"},"PeriodicalIF":7.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142573463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Monitoring stress-induced brittle rock mass damage for preventative support maintenance","authors":"Robert McMillan ,&nbsp;Erik Eberhardt ,&nbsp;Ryan Campbell ,&nbsp;Avesiena Primadiansyah","doi":"10.1016/j.ijrmms.2024.105927","DOIUrl":"10.1016/j.ijrmms.2024.105927","url":null,"abstract":"<div><div>Stress-induced brittle fracturing near an excavation boundary results in a volume increase, known as bulking. Excessive bulking places added demand on the rock support, which, if not detected and addressed through preventative support maintenance (i.e., proactively added reinforcement), can cause the support to fail, leading to a safety hazard and costly production delays for underground mining operations. For caving mines, these project risks are exacerbated during cave establishment due to the large abutment stress from undercutting that redistributes and concentrates stresses near excavations critical for production. This paper reports the findings from research conducted to develop and improve geotechnical monitoring practices to support preventative support maintenance in deep mining operations. This research uses a unique geotechnical monitoring database collected for the Deep Mill Level Zone panel cave mine. The data was collected across a large footprint during the mine's ramp-up period and represents an initial step toward best practices for data collection at cave mines operating in high-stress environments. Borehole camera surveys supplemented by multi-point borehole extensometers have been used to determine the depth of stress fracturing in pillar walls as a function of the distance away from the undercut. Convergence measurements and LiDAR scanning are used to characterize the corresponding rock mass bulking. The results show that the interpretation of monitoring data can be used to identify the long-term depth of stress fracturing and bulking trends in response to undercut advances. These show that direct measures of stress-induced fracturing damage provide an early indication of excavations vulnerable to bulking and that LiDAR scanning is an effective method for capturing the onset of bulking and anticipating local areas likely to experience greater deformation demand as bulking progresses. Proactive and strategic geotechnical monitoring based on the long-term depth of stress-induced fracturing trends is proposed to assist with preventative support maintenance practices.</div></div>","PeriodicalId":54941,"journal":{"name":"International Journal of Rock Mechanics and Mining Sciences","volume":"183 ","pages":"Article 105927"},"PeriodicalIF":7.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}