Rock Mechanics Bulletin最新文献

{"title":"The phlogiston theory of rock mass Classification: Philosophical and mathematical critique of ordinal data usage","authors":"Junzhe Liu ,&nbsp;Yu Feng ,&nbsp;Yuyong Jiao","doi":"10.1016/j.rockmb.2025.100205","DOIUrl":"10.1016/j.rockmb.2025.100205","url":null,"abstract":"<div><div>The widespread use of rock mass classification systems in engineering practice relies on mathematical operations and assumptions that violate fundamental principles of measurement theory. This paper presents a critical analysis of current classification methodologies, focusing on the Rock Mass Rating (RMR), Q-system, and Geological Strength Index (GSI), drawing parallels with historical scientific misconceptions such as the phlogiston theory. Through detailed examination of measurement theory principles and their application to geological characterization, we demonstrate that these classification systems contain inherent flaws in their treatment of ordinal data and parameter independence. The paper identifies four critical issues: the invalid summation of ordinal ratings in the RMR system, the inappropriate multiplication and division operations in the Q-system, the unjustified visual interpolation in the GSI system, and the universal problem of assumed parameter independence. Through examination of measurement theory principles and their application to geological characterization, we demonstrate that current classification systems violate basic mathematical rules in their treatment of ordinal data and parameter independence. The implications of these violations extend beyond theoretical concerns, affecting practical engineering decisions and risk assessment. We also illustrate how these theoretical flaws manifest in practice and propose directions for developing more theoretically sound approaches to rock mass characterization. This critical analysis aims to initiate a necessary dialogue about the future of rock mass classification in engineering practice.</div></div>","PeriodicalId":101137,"journal":{"name":"Rock Mechanics Bulletin","volume":"4 3","pages":"Article 100205"},"PeriodicalIF":0.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144572728","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhancing production rates at El Teniente's black cave mine through optimizing HF hole distribution using discrete fracture network modeling and geostatistical simulation methods","authors":"Amin Hekmatnejad ,&nbsp;Fernando Manscilla ,&nbsp;Paulina Schachter ,&nbsp;Pengzhi Pan ,&nbsp;Ehsan Mohtarami ,&nbsp;Alvaro Pena ,&nbsp;Abbas Taheri ,&nbsp;Benoit Crespin ,&nbsp;Francisco Moreno ,&nbsp;Roberto Gonzales","doi":"10.1016/j.rockmb.2024.100165","DOIUrl":"10.1016/j.rockmb.2024.100165","url":null,"abstract":"<div><div>This study at the Esmeralda Mine, part of the El Teniente Division of CODELCO, investigates optimizing hydraulic fracturing (HF) holes’ spatial distribution to improve rock material production in one of the world's largest copper-molybdenum deposits. Utilizing diverse data sources, including borehole, oriented borehole, and photogrammetry data, along with hang-up frequency and hydrofracturing details, we applied discrete fracture network (DFN) modeling to analyze in-situ block size distribution and fragmentation. These results are based on 12,000 realizations of discrete fracture network (DFN) models using R-Dis-Frag computer pacakge at real cave volumes of 200 m × 200 m × 200 m, with varying parameters, which significantly enhances their reliability. The incorporation of DFN modeling and geostatistical simulation allows for capturing the interaction berween several spatial variables and explaining the variations observed in the production results at the draw points. Key findings of spatio-statistical analysis highlight the significance of volumetric fracture intensity (P32) and extraction column height in reducing hang-up events and enhancing fragmentation efficiency. The study integrates HF-induced and natural fracture intensities, revealing that higher P32 values and higher draw columns correlate with fewer hang-ups and better fragmentation. We recommend non-regular HF patterns for high P32 zones to improve operational efficiency. This research provides insights into optimizing mining operations, acknowledging the limitations of HF propagation efficacy and paving the way for further exploration into the interplay between hydraulic fracturing and natural discontinuities.</div></div>","PeriodicalId":101137,"journal":{"name":"Rock Mechanics Bulletin","volume":"4 2","pages":"Article 100165"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143163313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Velocity effects on slip evolution of faults subjected to constant and cyclic normal stress derived from laboratory tests","authors":"Kang Tao ,&nbsp;Wengang Dang ,&nbsp;Heinz Konietzky ,&nbsp;Yu Liu ,&nbsp;Wenhao Zhang ,&nbsp;Xingling Li","doi":"10.1016/j.rockmb.2025.100190","DOIUrl":"10.1016/j.rockmb.2025.100190","url":null,"abstract":"<div><div>Understanding the slip-style evolution of tectonic faults is important for exploring the earthquake mechanisms. To reveal the fault slip characteristics under a complex stress state, we conducted a series of laboratory friction tests on saw-cut granite joint surfaces. The effects of load point velocity and normal stress disturbances were investigated. Based on laboratory observations, a one-dimensional Spring-Block model was developed to interpret the frictional behavior. Under constant normal stress, the simulated fault (granite joint) exhibits a regular stick-slip phenomenon at different load point velocities with stable recurrence intervals and stress drop magnitudes. Under cyclic normal stress, when the load point velocity is slow, stick-slip events occur only after 4–5 cycles of normal stress loading. When the load point velocity is large, due to the rapid sliding of the joint interface, one normal stress cycle can lead to 4–5 stick-slip events. We find that the cyclic normal stress weakens the joint shear strength when the load point velocity is slow and improves the strength when the velocity is fast. There is a critical value of load point velocity for resonance where the stick-slip occurrence timespan is identical to the normal stress cyclic period. This work sheds light on the frictional evolution of tectonic faults during the seismic cycles influenced by a complex stress state.</div></div>","PeriodicalId":101137,"journal":{"name":"Rock Mechanics Bulletin","volume":"4 2","pages":"Article 100190"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143724794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prediction of rock fracture pressure in hydraulic fracturing with interpretable machine learning and mechanical specific energy theory","authors":"Xiaoying Zhuang ,&nbsp;Yuhang Liu ,&nbsp;Yuwen Hu ,&nbsp;Hongwei Guo ,&nbsp;Binh Huy Nguyen","doi":"10.1016/j.rockmb.2024.100173","DOIUrl":"10.1016/j.rockmb.2024.100173","url":null,"abstract":"<div><div>Hydraulic fracturing stimulation technology is essential in the oil and gas industry. However, current techniques for predicting rock fracture pressure in hydraulic fracturing face significant challenges in precision and reliability. Traditional approaches often result in inadequate accuracy due to the complex and diverse nature of underground formations. However, recent advances in computational power and optimization techniques have enabled the application of machine learning in mining operations, resulting in improved prediction and feedback. In this study, various machine learning techniques are employed to predict hydraulic fracturing pressure based on the concept of mechanical specific energy. Additionally, the study interprets the models through feature importance analysis. The findings suggest that most machine learning models deliver highly accurate predictions. Feature importance analysis indicates that for an approximate assessment of fracture pressure, the characteristics of well depth and torque are sufficient. For more precise predictions, incorporating additional characteristics from the mechanical specific energy framework into the machine learning model is essential. The study emphasizes the feasibility of employing machine learning methods to predict fracture pressure and their usefulness in determining optimal engineering sites.</div></div>","PeriodicalId":101137,"journal":{"name":"Rock Mechanics Bulletin","volume":"4 2","pages":"Article 100173"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143716152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation on stress distribution and prestress loss model of prestressed anchor cables considering corrosion-induced debonding","authors":"Hanfang Zheng ,&nbsp;Yujing Jiang ,&nbsp;Xuezhen Wu ,&nbsp;Sunhao Zhang ,&nbsp;Satoshi Sugimoto","doi":"10.1016/j.rockmb.2025.100189","DOIUrl":"10.1016/j.rockmb.2025.100189","url":null,"abstract":"<div><div>Corrosion can significantly impact the safety and stability of the entire structure by reducing the service life and load-bearing capacity of anchors. This study provides an in-depth examination of the effects of corrosion on prestressed anchor cables, covering the effects on the anchor cables themselves and the bond interface. The force characteristics and load transfer mechanisms within the anchorage structure were explored through a detailed analysis of the three key components: the anchor cable, the grout, and the surrounding rock. The distribution functions of axial force and interfacial shear stress considering the debonding of the anchor-grout interface were derived, and the prestressed corrosion damage model was further developed. Taking the anchoring project on the slopes in Nagasaki as an example, the stress distribution of anchor cables under different surrounding rock conditions was analyzed in depth. The results showed that the relative deformation of the grout and the surrounding rock decreases when the elasticity modulus of the surrounding rock increases, resulting in a reduced axial force in anchor cables and an increased interface shear stress. Thresholds exist for the effect of the total anchor length and radius on prestressing stability. When designing anchor structures in corrosive environments, there is no need to choose excessive anchor length or anchor radius to achieve better cost-effectiveness. In practical underground engineering, the force in anchor cables is transferred to the surrounding rock through the anchoring section, where the length of the anchorage section has a more direct impact on prestress transfer and stability.</div></div>","PeriodicalId":101137,"journal":{"name":"Rock Mechanics Bulletin","volume":"4 2","pages":"Article 100189"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143704655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A microscopic DEM investigation on fracture shearing characteristics of infilled grains with different geometrical shapes in rock discontinuities","authors":"Zhicheng Tang ,&nbsp;Zhifei Zhang ,&nbsp;Lichun Zhao ,&nbsp;Suguang Xiao","doi":"10.1016/j.rockmb.2025.100174","DOIUrl":"10.1016/j.rockmb.2025.100174","url":null,"abstract":"<div><div>Rock discontinuities or faults often contain a layer of granular material. However, the evolutionary behavior (movement and breakage) of such infilled grains under shearing have not been comprehensively studied. To better understand this issue microscopically, numerical direct shear tests are performed on small rock discontinuity with single-grain infilled under different normal stresses by PFC^2D, with emphasis on the effects of grain geometry (reflected by the aspect ratio (<em>a</em>/<em>b</em>)) and shear rate. Under the low normal stress (i.e., 0.1 ​MPa), circular grains (<em>a</em>/<em>b</em> ​= ​1.0) undergo in pure rolling during the shear process, with slight surface erosion, and the shear stress remains almost constant except for several fluctuations. The movement of grains with larger <em>a</em>/<em>b</em> changes from rolling to sliding or even crushing as the shear displacement increases. Under the high normal stress (i.e., 0.6 ​MPa), grains can eventually be crushed into a few large angular fragments and many fine comminuted particles, accompanied by severe damage to discontinuity surfaces, significant shear shrinkage, and violently fluctuating shear stress. The volume fraction of large angular fragments increases with the increase in <em>a</em>/<em>b</em> value, while that of fine comminuted particles decreases. Shear rate also has a significant impact on grain behavior. The main movement of grain with <em>a</em>/<em>b</em> ​= ​2.0 changes from rolling to sliding and even crushing under the low normal stress with the increase in shear rate. Rock discontinuities exhibit unstable shearing, and surface damage is less significant under the high normal stress and higher shear rate. The dominant failure mode in grains and discontinuity surfaces involves tension microcracks at different shear rates, while tension microcracks in the grain under high normal stress decrease drastically as the shear rate increases. Effects of micro-parameters of infilled grain are also investigated through sensitivity analysis. The observations provide implications for the macro-shear mechanism of rock discontinuity infilled with granular materials.</div></div>","PeriodicalId":101137,"journal":{"name":"Rock Mechanics Bulletin","volume":"4 2","pages":"Article 100174"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143686596","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evolution of mechanical and rockburst parameters of gypsum-like rock under fatigue stress disturbance","authors":"Chongyang Wang ,&nbsp;Sijiang Wei ,&nbsp;Dongming Zhang ,&nbsp;Beichen Yu ,&nbsp;Yisha Pan ,&nbsp;Xunjian Hu","doi":"10.1016/j.rockmb.2024.100171","DOIUrl":"10.1016/j.rockmb.2024.100171","url":null,"abstract":"<div><div>To investigate the deterioration of mechanical properties in engineering rock masses subjected to fatigue stress, this study conducted laboratory tests, theoretical analysis, and model building to analyze the evolution of mechanical and rockburst characteristics in gypsum-like rock before and after fatigue loading. The results showed that the effects of cyclic stress and loading frequency on fatigue damage characteristics of the samples are interrelated. The effect of fatigue cyclic stress on the mechanical parameters and rockburst parameters of the samples after fatigue loading is relatively straightforward, while the impact of frequency on the mechanical properties of samples after fatigue loading is more complex. The impact of frequency on mechanical properties and rockburst parameters varies distinctly under different cyclic stress conditions. A deterioration index model (<span><math><mrow><mi>λ</mi><mo>=</mo><mi>p</mi><mo>+</mo><mi>j</mi><mi>q</mi></mrow></math></span>) was established for the samples after fatigue loading, and the real part, imaginary part, and <span><math><mrow><mo>|</mo><mi>λ</mi><mo>|</mo></mrow></math></span> of the model were calculated to plot the function in the complex plane. This model provided insight into the evolution of mechanical properties and rockburst characteristics in gypsum-like rock before and after fatigue loading with different stress levels and frequencies. By examining the <em>λ</em> curve’s position within the complex plane, the overall variation in mechanical properties was assessed. Finally, neural network methods were employed to extend and test the complex plane model, expanding the input factors from discrete data points to continuous definition fields on the number line, thereby increasing the model's practicality and applicability.</div></div>","PeriodicalId":101137,"journal":{"name":"Rock Mechanics Bulletin","volume":"4 2","pages":"Article 100171"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143163314","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Research on narrow coal pillar width optimization and surround rock control in Shiquan mine","authors":"Rui Wang ,&nbsp;Zhen Shi ,&nbsp;Jiulin Fan ,&nbsp;Yajun Wang ,&nbsp;Yanghao Peng ,&nbsp;Manchao He ,&nbsp;Bo Zhang","doi":"10.1016/j.rockmb.2024.100172","DOIUrl":"10.1016/j.rockmb.2024.100172","url":null,"abstract":"<div><div>To address the issue of severe coal resource waste and substantial deformation of the surrounding rock caused by the retention of coal pillars for protective lanes during the excavation along the void of the 30108 working face at Shiquan Coal Mine, a study was conducted on the stress distribution of coal pillars and the deformation of surrounding rocks in the 30108 haulage roadway under different coal pillar widths and tunneling methods. Initially, theoretical calculations of coal pillar width in the goaf mining section were conducted. Subsequently, a numerical model was established to simulate and analyze the stress distribution of coal pillars and the deformation characteristics of surrounding rock under different coal pillar widths and tunnel layout methods. Finally, support schemes were proposed and verified through field application. The study indicates that the coal pillar width within the 30108 haulage roadway should not be less than 8.94 ​m; The failure of the coal pillar is primarily characterized by plastic shear failure within the pillar and tensile failure on both sides of the pillar, the deformation of the surrounding rock in the tunnel is mainly manifested as tensile failure of the roof and floor slabs and shear failure of the sidewalls, as the width of the coal pillar increases, the deformation of the surrounding rock on the surface of the tunnel within the pillar gradually decreases, and when the coal pillar width reaches 8–10 ​m, the deformation of the surrounding rock in the tunnel becomes stable; The field application has been effective.</div></div>","PeriodicalId":101137,"journal":{"name":"Rock Mechanics Bulletin","volume":"4 2","pages":"Article 100172"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143724793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Theoretical and numerical investigation of the effects of in-situ stresses and dual-borehole combinations in eccentric decoupled charge blasting","authors":"Yao Yin ,&nbsp;Minxing Song ,&nbsp;Yu Feng ,&nbsp;Zhongqiang Liu ,&nbsp;Xiaohui Chen ,&nbsp;Qing Sun","doi":"10.1016/j.rockmb.2025.100191","DOIUrl":"10.1016/j.rockmb.2025.100191","url":null,"abstract":"<div><div>Eccentric decoupled charge (EDC) blasting is a widely used technique for rock fragmentation and tunnel excavation, yet the underlying rock damage mechanisms, particularly in relation to in-situ stresses and multi-borehole combinations, remain underexplored. First, we developed an analytical model for single-borehole EDC blasting, providing insights into the theoretical relationship between the formation of different rock damage zones around the borehole and various influencing factors, including decoupling coefficient, in-situ stress, rock and explosive properties, and peak blast pressure. Using a finite element fluid-solid coupling algorithm, we performed numerical simulations for a simple case of single-borehole EDC blasting, verifying the effectiveness of the adopted numerical approach. We then performed numerical simulations for dual-borehole EDC blasting with varying in-situ stress conditions and borehole combinations. The results indicate that: (1) rock damage is primarily concentrated on the eccentric side of the borehole due to its smaller decoupling coefficients and the resulting larger peak blast pressure; (2) the formation of through cracks between two boreholes is highly dependent on the relative angle <em>φ</em> between them, while the extent and direction of the cracks are largely controlled by the application of in-situ stress. This work provides a theoretical basis and reference for optimizing the design of multi-borehole contour blasting in deep rock excavation under significant in-situ stresses, facilitating desired crack propagation while minimizing damage to the surrounding rock.</div></div>","PeriodicalId":101137,"journal":{"name":"Rock Mechanics Bulletin","volume":"4 2","pages":"Article 100191"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143724795","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modeling of particle migration in piping based on an improved discrete element method","authors":"Wenqiang Xia ,&nbsp;Chun Liu ,&nbsp;Hui Liu ,&nbsp;Tao Zhao ,&nbsp;Yao Zhu","doi":"10.1016/j.rockmb.2024.100151","DOIUrl":"10.1016/j.rockmb.2024.100151","url":null,"abstract":"<div><div>Pore-scale particle migration in piping is the main reason of the suffusion-induced damage, which poses a significant threat to earth-rock dams. In order to investigate the micro-mechanism of piping seepage process, an improved fluid-solid coupling discrete element method is proposed in this paper. In this method, particles in a packed model are divided into coarse- and fine particle groups. Pores can be defined based on the coordinates of the coarse particles and the Delaunay triangulation algorithm. A pore density flow method is introduced to calculate the overall fluid pressure of each pore and the fluid flow via pore throats. Further, the drag force on fine particles inside a pore can be calculated according to the fluid velocities of the neighboring four pore throats. The proposed method was implemented in the discrete element software MatDEM, and was successfully used to simulate fine particle migration of piping, the particle loss process, and the related variation of permeability coefficient. The pore-jamming phenomenon during the fine particle migration is observed. The model provides an effective way for the numerical analysis and mechanism study of piping seepage process at the pore scale.</div></div>","PeriodicalId":101137,"journal":{"name":"Rock Mechanics Bulletin","volume":"4 1","pages":"Article 100151"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136215","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}