International Journal of Rock Mechanics and Mining Sciences最新文献

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Changes in the nanomechanical properties of the constituent minerals in the ductile fauske marble and the brittle kuru granite during progressive failure 韧性福斯克大理石和脆性库鲁花岗岩在渐进破坏过程中组成矿物的纳米力学特性变化
IF 7 1区 工程技术
International Journal of Rock Mechanics and Mining Sciences Pub Date : 2024-10-01 DOI: 10.1016/j.ijrmms.2024.105853
Wenkai Wan , Charlie C. Li , Siqi Liu , Jianying He
{"title":"Changes in the nanomechanical properties of the constituent minerals in the ductile fauske marble and the brittle kuru granite during progressive failure","authors":"Wenkai Wan ,&nbsp;Charlie C. Li ,&nbsp;Siqi Liu ,&nbsp;Jianying He","doi":"10.1016/j.ijrmms.2024.105853","DOIUrl":"10.1016/j.ijrmms.2024.105853","url":null,"abstract":"<div><div>The nanoscale elastic moduli and hardness of the constituent minerals of the Class II Kuru granite and the Class I Fauske marble were experimentally investigated. The aims were to correlate the microcrack patterns with the nanomechanical properties of the minerals, and to help understand the important roles of the nanomechanical properties of the minerals in brittle and ductile behaviors. Cylindrical rock specimens were uniaxially loaded to various stress levels in both the pre- and post-peak stages. The specimens were then unloaded to zero, and two thin sections –– one parallel with and the other perpendicular to the loading direction –– were prepared from each specimen. Nano-indentation tests were conducted on the thin sections to measure the elastic moduli and hardness of the major constituent minerals in the rocks. The test results showed that both the elastic moduli and hardness of the minerals abruptly decreased when the applied stress was above 80 % of the uniaxial compressive strength of the rock in the pre-peak stage and also in the entire post-peak stage. At the same time, the values of the two properties became more scattered with increasing damage to the minerals. The number of intragranular cracks was significantly less in the harder quartz and microcline than in the softer calcite. The abundant intragranular cracks in the calcite dissipated most of the strain energy in the Class I marble, such that the rock was not burstable after failure. A small number of intragranular cracks were created in the quartz and microcline in the Class II granite, such that most of the strain energy in the minerals was released to eject rock after failure. Intragranular cracking is thus a key factor in determining whether a rock is burst-prone or not.</div></div>","PeriodicalId":54941,"journal":{"name":"International Journal of Rock Mechanics and Mining Sciences","volume":"183 ","pages":"Article 105853"},"PeriodicalIF":7.0,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142356919","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}
引用次数: 0
A multi-step calibration strategy for reliable parameter determination of salt rock mechanics constitutive models 可靠确定盐岩力学组成模型参数的多步骤校准策略
IF 7 1区 工程技术
International Journal of Rock Mechanics and Mining Sciences Pub Date : 2024-09-28 DOI: 10.1016/j.ijrmms.2024.105922
Hermínio T. Honório , Maartje Houben , Kevin Bisdom , Arjan van der Linden , Karin de Borst , Lambertus J. Sluys , Hadi Hajibeygi
{"title":"A multi-step calibration strategy for reliable parameter determination of salt rock mechanics constitutive models","authors":"Hermínio T. Honório ,&nbsp;Maartje Houben ,&nbsp;Kevin Bisdom ,&nbsp;Arjan van der Linden ,&nbsp;Karin de Borst ,&nbsp;Lambertus J. Sluys ,&nbsp;Hadi Hajibeygi","doi":"10.1016/j.ijrmms.2024.105922","DOIUrl":"10.1016/j.ijrmms.2024.105922","url":null,"abstract":"<div><div>The storage of renewable hydrogen in salt caverns requires fast injection and production rates to cope with the imbalance between energy production and consumption. This raises concerns about the mechanical stability of salt caverns under such operational conditions. The use of appropriate constitutive models for salt mechanics is an important step in investigating this issue, therefore many constitutive models with several parameters have been presented in the literature. However, a robust calibration strategy to reliably determine which model and parameter set represents the given rock, based on stress–strain data sets, remains an unsolved challenge. In this paper, for the first time in the community, we present a multi-step strategy to determine a single parameter set based on many deformation data sets for salt rocks. Towards this end, we first develop a comprehensive constitutive model able to capture all relevant nonlinear deformation physics of transient, reverse, and steady-state creep. The determination of the single set of representative material parameters is then achieved by framing the calibration process as an optimization problem, for which the global Particle Swarm Optimization algorithm is employed. To allow for dynamic data integration, a multi-step calibration strategy is developed for a situation where experiments are included one at a time, as they become available. Additionally, due to the existing mild heterogeneity in the experimental rock samples, our optimization strategy is made flexible to allow for this slight heterogeneity. The devised optimization strategy, based on the multi-physics comprehensive constitutive modeling framework, results in a single set of representative material properties of all the deformation data sets. As a rigorous mathematical analysis for the presented method and the lack of relevant experimental data sets, we consider a wide range of synthetic experimental data sets, inspired by the existing sparse relevant data in the literature. The results of our performance analyses show that the proposed calibration strategy is robust. Moreover, the results become increasingly more accurate as more data sets become available.</div></div>","PeriodicalId":54941,"journal":{"name":"International Journal of Rock Mechanics and Mining Sciences","volume":"183 ","pages":"Article 105922"},"PeriodicalIF":7.0,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142356918","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}
引用次数: 0
Fault slip behaviors and frictional stability controlled by particle size of fault gouge under fluid injection 注入流体条件下由断层破碎带粒径控制的断层滑移行为和摩擦稳定性
IF 7 1区 工程技术
International Journal of Rock Mechanics and Mining Sciences Pub Date : 2024-09-28 DOI: 10.1016/j.ijrmms.2024.105919
Bin Liu , Zhi Geng , Yongshui Kang , Xuewei Liu , Yuan Zhou , Quansheng Liu , Youqi Huang , Xiubin Zhou
{"title":"Fault slip behaviors and frictional stability controlled by particle size of fault gouge under fluid injection","authors":"Bin Liu ,&nbsp;Zhi Geng ,&nbsp;Yongshui Kang ,&nbsp;Xuewei Liu ,&nbsp;Yuan Zhou ,&nbsp;Quansheng Liu ,&nbsp;Youqi Huang ,&nbsp;Xiubin Zhou","doi":"10.1016/j.ijrmms.2024.105919","DOIUrl":"10.1016/j.ijrmms.2024.105919","url":null,"abstract":"<div><div>Understanding the control mechanism of fault rock particle size in fluid-induced fault slip and rupture processes is crucial for mitigating the seismic risks associated with large-scale fluid injection. Here, we conducted laboratory experiments to present the effects of fault rock particle size on slip behavior, friction, and slip modes under fluid injection. Our results demonstrate that the particle size of the gouge controls the initiation of fault slip events and that the fluid pressure required for the initial fault slip is negatively correlated with the rock particle size. The increase in rock particle size can weaken the faults and induce the transition of the fault slip mode from creep to slow stick-slip events, which leads to the occurrence of seismic events. These results reveal the particle size of fault gouge exerts a potentially dominant control on the slip behavior, slip modes, and frictional characteristics of faults under fluid injection, providing crucial insights into fault slip and seismic events.</div></div>","PeriodicalId":54941,"journal":{"name":"International Journal of Rock Mechanics and Mining Sciences","volume":"183 ","pages":"Article 105919"},"PeriodicalIF":7.0,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142356920","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}
引用次数: 0
Difference in rock-breaking characteristics between water-coupling blasting and air-coupling blasting 水耦合爆破与空气耦合爆破的破岩特性差异
IF 7 1区 工程技术
International Journal of Rock Mechanics and Mining Sciences Pub Date : 2024-09-27 DOI: 10.1016/j.ijrmms.2024.105924
Zhiwei Ye , Jianhua Yang , Ming Chen , Chi Yao , Xiaobo Zhang , Yongli Ma , Chuangbing Zhou
{"title":"Difference in rock-breaking characteristics between water-coupling blasting and air-coupling blasting","authors":"Zhiwei Ye ,&nbsp;Jianhua Yang ,&nbsp;Ming Chen ,&nbsp;Chi Yao ,&nbsp;Xiaobo Zhang ,&nbsp;Yongli Ma ,&nbsp;Chuangbing Zhou","doi":"10.1016/j.ijrmms.2024.105924","DOIUrl":"10.1016/j.ijrmms.2024.105924","url":null,"abstract":"<div><div>The water-coupling blasting (WCB) technology has received widespread attention due to its advantages of high efficiency and environmental protection. However, the parameters of WCB in practical engineering are generally determined based on the experience and standards of air-coupling blasting (ACB), leading to poor blasting effects and wastage of explosive energy. The study focuses on comparing the rock-breaking effects of shock waves and explosive gases between WCB and ACB to offer insights for optimizing the design of WCB. Firstly, the stress field in blasting with different coupling mediums was calculated. Then, the shock failure characteristics of rocks between WCB and ACB were analyzed. The results show that the radius of shock failure zones decreases with the increasing decoupling coefficient in WCB and ACB. On this basis, a model for calculating the shock failure range in WCB and ACB was proposed. This model can be utilized to estimate the percentage of fine-grained stone in the two types of blasting. Further, a method for distinguishing between the rock-breaking effects of shock waves and explosive gases was proposed based on the numerical simulation results of blasting damage. A comparative analysis between WCB and ACB on the rock-breaking volume by shock waves and gases was conducted. The results indicate that the failure volumes of rocks induced by shock waves and gases in WCB are 1.4–2.1 times greater than those in ACB, with a decoupling coefficient ranging from 1.26 to 1.71. Finally, a method for determining the charging structure in WCB was discussed, which has been preliminarily validated by field tests. The findings can help regulate rock-breaking effects in blasting by rationally selecting coupling mediums and charging constructions.</div></div>","PeriodicalId":54941,"journal":{"name":"International Journal of Rock Mechanics and Mining Sciences","volume":"183 ","pages":"Article 105924"},"PeriodicalIF":7.0,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142326521","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}
引用次数: 0
A thermo-mechanical phase-field model for mixed-mode fracture and its application in rock-like materials 混合模式断裂的热机械相场模型及其在类岩材料中的应用
IF 7 1区 工程技术
International Journal of Rock Mechanics and Mining Sciences Pub Date : 2024-09-27 DOI: 10.1016/j.ijrmms.2024.105907
Qiang Yue , Qiao Wang , Timon Rabczuk , Wei Zhou , Xiaoying Zhuang , Xiaolin Chang
{"title":"A thermo-mechanical phase-field model for mixed-mode fracture and its application in rock-like materials","authors":"Qiang Yue ,&nbsp;Qiao Wang ,&nbsp;Timon Rabczuk ,&nbsp;Wei Zhou ,&nbsp;Xiaoying Zhuang ,&nbsp;Xiaolin Chang","doi":"10.1016/j.ijrmms.2024.105907","DOIUrl":"10.1016/j.ijrmms.2024.105907","url":null,"abstract":"<div><div>Thermally induced fracture is a common phenomenon for concrete and rock-like materials, which presents a significant challenge to numerical modelling. In this work, a thermo-mechanical model for mixed-mode fracture based on phase-field method is proposed. This approach overcomes the difficulties of modelling the thermally induced cracking process when it comes to complex fracture patterns. To simulate different failure modes in thermo-mechanical conditions, the model's constitutive expression includes a unified failure criterion that takes into account both tensile and shear strengths. The proposed formulation provides a length scale insensitive response for brittle materials such as rocks, although other prevalent phase-field theories for purely mechanical fracture can also be involved. The computational results of the representative examples for rock-like materials are highly consistent with prior findings. It demonstrates that the presented model can effectively reproduce the thermally induced cracking process for various cracking patterns, such as tensile, shear, and tensile-shear fractures, indicating the method's remarkable capabilities for further research.</div></div>","PeriodicalId":54941,"journal":{"name":"International Journal of Rock Mechanics and Mining Sciences","volume":"183 ","pages":"Article 105907"},"PeriodicalIF":7.0,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142326522","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}
引用次数: 0
Investigation on the pore size characteristics and mechanical properties of grouting materials scoured by flow water 流水冲刷灌浆材料的孔径特征和力学性能研究
IF 7 1区 工程技术
International Journal of Rock Mechanics and Mining Sciences Pub Date : 2024-09-25 DOI: 10.1016/j.ijrmms.2024.105923
Longji Wu, Zhijun Wu, Lei Weng, Yang Liu, Zhaofei Chu, Xiangyu Xu
{"title":"Investigation on the pore size characteristics and mechanical properties of grouting materials scoured by flow water","authors":"Longji Wu,&nbsp;Zhijun Wu,&nbsp;Lei Weng,&nbsp;Yang Liu,&nbsp;Zhaofei Chu,&nbsp;Xiangyu Xu","doi":"10.1016/j.ijrmms.2024.105923","DOIUrl":"10.1016/j.ijrmms.2024.105923","url":null,"abstract":"<div><div>Investigating the pore size characteristics and mechanical properties of the stone bodies formed by residual grout is crucial for understanding the authentic permeability and load-bearing capacity of grouting materials after being scoured by water flow. In this study, the pore size distribution, porosity, uniaxial compressive strength (UCS), and elastic modulus (<em>E</em>) of stone bodies formed by residual grout from polyacrylate latex-modified cement grouting material (PLMC) were systematically investigated, and pure cement grout (PC) as a control group. First, scouring tests were conducted on grouting materials with various water-to-cement ratios (w/c, 0.6–0.8) and polymer-cement ratios (p/c, 0–0.2) under different flow velocities (0–1 m/s). Subsequently, the pore size characteristics of stone bodies formed by residual grout under various conditions were studied via nuclear magnetic resonance test. Finally, the uniaxial compression tests were conducted to investigate the impact of water scouring on the mechanical properties of grouting materials, and the relationship between pore size characteristics and macro mechanical responses was analyzed. Results show that the stone bodies formed by residual grout compared to the non-scoured state develop mesopores and macropores, and the number of micropores also increased significantly. This porosity escalation results in a reduction in UCS and <em>E</em>. When the flow velocity reaches 1 m/s, the porosity of PLMC with w/c = 0.8 increases by 2.95 %, while UCS decreases by 14.6 % and <em>E</em> decreases by 37.4 %. PC demonstrates more pronounced changes, with a porosity increase of 7.01 %, UCS decreases by 32.9 %, and <em>E</em> decreases by 41.5 %. With the rise in w/c, the deterioration of pore structure and mechanical properties of the stone bodies formed by residual grout is more significant compared to the non-scoured state. Increasing p/c can mitigate the deterioration of the pore structure and mechanical properties. The findings provide meaningful guidance for the grouting reinforcement under dynamic water conditions.</div></div>","PeriodicalId":54941,"journal":{"name":"International Journal of Rock Mechanics and Mining Sciences","volume":"183 ","pages":"Article 105923"},"PeriodicalIF":7.0,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142319532","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}
引用次数: 0
Effects of crystal orientation, temperature, deviatoric stress, and confining stress on creep of rock salt 晶体取向、温度、偏差应力和约束应力对岩盐蠕变的影响
IF 7 1区 工程技术
International Journal of Rock Mechanics and Mining Sciences Pub Date : 2024-09-24 DOI: 10.1016/j.ijrmms.2024.105913
Timothy J. Truster, Amirsalar Moslehy, Khalid A. Alshibli
{"title":"Effects of crystal orientation, temperature, deviatoric stress, and confining stress on creep of rock salt","authors":"Timothy J. Truster,&nbsp;Amirsalar Moslehy,&nbsp;Khalid A. Alshibli","doi":"10.1016/j.ijrmms.2024.105913","DOIUrl":"10.1016/j.ijrmms.2024.105913","url":null,"abstract":"<div><div>The creep of rock salt greatly influences the performance and safety of rock salt caverns when they are used as an underground repository for oil, nuclear waste, or other hazardous materials. Creep may cause shearing of casings of oil wells drilled through thick layers of salt rock formation. The crystallographic structure of salt rock grains, in-situ deviatoric stress changes caused by excavation, confining stress from the surrounding environment, and ambient temperature can have a significant impact on the creep behavior of rock salt. Although the creep behavior of polycrystalline rock salt has been extensively studied by many researchers, the creep behavior of single-crystal natural rock salt is not yet fully understood. This paper investigates the influence of crystal orientation, temperature, deviatoric stress, and confining stress on the creep behavior of single-crystal and polycrystalline rock salt. 42 long-term creep experiments with various temperatures, confining stresses, and deviatoric stresses were conducted on natural single-crystal specimens. The temperatures were 20, 100, and 150 °C, the confining stresses were 0.1, 1.0, and 5.0 MPa, and the various deviatoric stresses were applied in different loading directions with respect to the specimen's crystal orientations. Additionally, 18 long-term creep experiments were performed on synthetic polycrystalline specimens with wet grain boundaries at temperatures of 20, 100, and 150 °C, at confining stresses of 0.1, 1.0, and 5.0 MPa, and various deviatoric stresses. The effects of the mentioned experimental conditions on the accumulated axial strain, transient strain rate, and steady-state strain rate during the creep of rock salt were then examined and discussed in detail. Moreover, the influence of temperature, deviatoric stress, and confining stress on the steady-state creep of single crystal rock salt is examined within the context of existing polycrystalline creep data available in the literature.</div></div>","PeriodicalId":54941,"journal":{"name":"International Journal of Rock Mechanics and Mining Sciences","volume":"183 ","pages":"Article 105913"},"PeriodicalIF":7.0,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142314332","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}
引用次数: 0
Acoustic emission and 4D X-ray micro-tomography for monitoring crack propagation in rocks 用于监测岩石裂缝扩展的声发射和 4D X 射线微断层扫描技术
IF 7 1区 工程技术
International Journal of Rock Mechanics and Mining Sciences Pub Date : 2024-09-22 DOI: 10.1016/j.ijrmms.2024.105917
Daniel Kytýř , Petr Koudelka , Daria Drozdenko , Martin Vavro , Tomáš Fíla , Václav Rada , Leona Vavro , Kristián Máthis , Kamil Souček
{"title":"Acoustic emission and 4D X-ray micro-tomography for monitoring crack propagation in rocks","authors":"Daniel Kytýř ,&nbsp;Petr Koudelka ,&nbsp;Daria Drozdenko ,&nbsp;Martin Vavro ,&nbsp;Tomáš Fíla ,&nbsp;Václav Rada ,&nbsp;Leona Vavro ,&nbsp;Kristián Máthis ,&nbsp;Kamil Souček","doi":"10.1016/j.ijrmms.2024.105917","DOIUrl":"10.1016/j.ijrmms.2024.105917","url":null,"abstract":"<div><div>Acoustic emission (AE) and 4D X-ray computed tomography (4D XCT) were used simultaneously to study crack initiation and propagation in two different types of quartz-rich sandstones during the four-point bending experiments. Statistical analysis of the AE response indicated the failure mechanisms and their dynamics. The characteristic changes observed in the AE response defined the timing of the bending interruptions for XCT scanning to reveal the development of the crack. It was possible to quantitatively describe the developing cracks in their dimensions and volume and relate this information to the rate of decrease in the post-peak region of the material response. It could be concluded that the combination and concurrent use of AE and XCT techniques represents a highly effective and reliable instrument for observation, description, analysis of the crack propagation process, and rock disintegration in detail at a microscale level. With regard to the specific sandstones studied, Mšené sandstone is softer, respectively, less brittle, while Kocbeře sandstone is characterised by a more brittle behaviour accompanied by an AE signal with higher amplitudes compared to those of Mšené.</div></div>","PeriodicalId":54941,"journal":{"name":"International Journal of Rock Mechanics and Mining Sciences","volume":"183 ","pages":"Article 105917"},"PeriodicalIF":7.0,"publicationDate":"2024-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S136516092400282X/pdfft?md5=ee99e274dc9f9e375fe497f889fc5e0f&pid=1-s2.0-S136516092400282X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312131","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}
引用次数: 0
Grading scalping and sample size effects on critical shear strength of mine waste rock through laboratory and in-situ testing 通过实验室和原位测试,分级标度和样本大小对矿山废石临界剪切强度的影响
IF 7 1区 工程技术
International Journal of Rock Mechanics and Mining Sciences Pub Date : 2024-09-21 DOI: 10.1016/j.ijrmms.2024.105915
Gilbert Girumugisha , Carlos Ovalle , Serge Ouellet
{"title":"Grading scalping and sample size effects on critical shear strength of mine waste rock through laboratory and in-situ testing","authors":"Gilbert Girumugisha ,&nbsp;Carlos Ovalle ,&nbsp;Serge Ouellet","doi":"10.1016/j.ijrmms.2024.105915","DOIUrl":"10.1016/j.ijrmms.2024.105915","url":null,"abstract":"<div><p>Geotechnical stability analyses of mine waste rock (WR) piles require the critical friction angle (<em>ϕ</em><sub><em>cr</em></sub>) of the coarse blasted rock. However, due to the presence of oversized rock clasts, shear strength can only be characterized on small samples prepared using grading scaling techniques, such as scalping. Thus, considering a testing device able to handle samples of characteristic size D, the material should be scaled down to a maximum particle size d<sub>max</sub> given by the minimum sample aspect ratio α = D/d<sub>max</sub>. However, a practical concern about how far the size scale can be reduced while keeping representative results remains a matter of debate in the geotechnical community. International standards do not agree on the minimum recommended α, and its effects on the mechanical behavior remain poorly understood. This paper aims to investigate the grading effects and sample size effects on <em>ϕ</em><sub><em>cr</em></sub> of WR materials using the scalping technique, to provide insights on the minimum recommended α. Triaxial tests were conducted on loose and dense samples of diameters D = 150 and 300 mm. Samples were scalped from field material having d<sub>max</sub> = 75 mm, to allow a range of α from 4 to 30. Additionally, one of the world largest in-situ direct shear boxes (120 × 120 × 38 cm<sup>3</sup>) was developed to test the same WR material. The results show that scalping is an appropriate technique to assess the critical shear strength of WR. The minimum α for <em>ϕ</em><sub><em>cr</em></sub> assessment in triaxial testing is not sensitive to grading nor sample size, but it is affected by sample density. The aspect ratio was found to be α ≥ 12 and α ≥ 16 for loose and dense samples, respectively. This finding advocates that α values recommended by worldwide standards, such as ASTM <span><span>D7181-20</span><svg><path></path></svg></span>, might be too low and should be revisited after comprehensive testing.</p></div>","PeriodicalId":54941,"journal":{"name":"International Journal of Rock Mechanics and Mining Sciences","volume":"183 ","pages":"Article 105915"},"PeriodicalIF":7.0,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1365160924002806/pdfft?md5=23ee9c8ff22b264ba9ac6352dae97856&pid=1-s2.0-S1365160924002806-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142270659","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}
引用次数: 0
A novel method for evaluating stability and mechanism of flexural toppling based on energy conservation principle and numerical simulation 基于能量守恒原理和数值模拟的新型挠性倾覆稳定性和机理评估方法
IF 7 1区 工程技术
International Journal of Rock Mechanics and Mining Sciences Pub Date : 2024-09-21 DOI: 10.1016/j.ijrmms.2024.105896
Leilei Jin, Wenxi Fu, Yang Wang, Qianfeng Xiao, Yajing Li, Fei Ye
{"title":"A novel method for evaluating stability and mechanism of flexural toppling based on energy conservation principle and numerical simulation","authors":"Leilei Jin,&nbsp;Wenxi Fu,&nbsp;Yang Wang,&nbsp;Qianfeng Xiao,&nbsp;Yajing Li,&nbsp;Fei Ye","doi":"10.1016/j.ijrmms.2024.105896","DOIUrl":"10.1016/j.ijrmms.2024.105896","url":null,"abstract":"<div><div>The flexural toppling occurring in anti-dip layered slopes exhibits complex mechanical behaviours and poses a serious threat to human engineering practices. In this paper, a novel method for evaluating the stability of flexural toppling is proposed by combining analytical solution and numerical simulation. The anti-dip rock layers in the slope are regarded as inclined slabs, and the deflection equations of each rock slab are calculated when the slab at the basal plane is restrict and that at the top is free. Critical length of the rock slab is then determined with the energy conservation principle, and it can be employed to evaluate the stability of flexural toppling. Numerical simulations have been conducted to validate the present calculation method and explore the mechanisms of flexural toppling. The simulation results indicate that failure initially occurs at the slope toe due to strong stress concentration, subsequently triggering a domino effect with failures propagate to the upper rock slabs as a result of the loss of support from the lower ones. These simulation results also combined with the analytical solution enhance the calculation accuracy of the method. This innovative approach not only advances our understanding of flexural toppling mechanisms but also provides a method for practical stability assessments.</div></div>","PeriodicalId":54941,"journal":{"name":"International Journal of Rock Mechanics and Mining Sciences","volume":"183 ","pages":"Article 105896"},"PeriodicalIF":7.0,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312133","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}
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