Rock Mechanics Bulletin最新文献_第2页

Three-dimensional numerical study of DTH bit-rock interaction with HPWJ downhole slotting: Influence of bit design and bottom hole geometric conditions on rock breaking efficiency in percussive drilling HPWJ井下开槽潜孔钻头-岩石相互作用的三维数值研究：钻头设计和井底几何条件对冲击钻井破岩效率的影响

Rock Mechanics Bulletin Pub Date : 2025-01-01 DOI: 10.1016/j.rockmb.2024.100169

S. Dumoulin , A. Kane , T. Coudert , N. Morin , L. Gerbaud , N. Velmurugan , E. Jahangir , H. Sellami , J.-P. Latham , S. Naderi , J. Xiang

{"title":"Three-dimensional numerical study of DTH bit-rock interaction with HPWJ downhole slotting: Influence of bit design and bottom hole geometric conditions on rock breaking efficiency in percussive drilling","authors":"S. Dumoulin , A. Kane , T. Coudert , N. Morin , L. Gerbaud , N. Velmurugan , E. Jahangir , H. Sellami , J.-P. Latham , S. Naderi , J. Xiang","doi":"10.1016/j.rockmb.2024.100169","DOIUrl":"10.1016/j.rockmb.2024.100169","url":null,"abstract":"<div><div>The EU H2020 ORCHYD project seeks to enhance drilling efficiency in hard rock environments, particularly for deep geothermal wells, by integrating innovative rock weakening techniques. In this context, 3D finite element simulations of bit-rock interactions were performed to assess how combining high pressure water jetting (HPWJ)-induced groove and bottom-hole geometry can contribute to improve the down-hole percussive drilling performance. A Red Bohus granite rock was modelled using a continuum, elasto-visco-plastic, and damage-based model calibrated using Brazilian, uniaxial compression, and triaxial material tests as well as single insert impact tests. Bit-rock interaction with an HPWJ groove was studied through modelling of twelve different groove depths and bottom-hole configurations. Results demonstrate that deeper grooves significantly reduce impact loads by up to 35% and increase penetration up to 40%, leading to higher material removal (up to 240%). Groove depth also influences damage propagation between adjacent indents, with grooves facilitating a broader zone of fractured rock, particularly near the groove itself. Notably, the drilling efficiency benefits from HPWJ slotting are highly dependent on bit design: flat and concave bit profiles exhibit 70% greater improvement in drilling performance compared to other profiles.</div></div>","PeriodicalId":101137,"journal":{"name":"Rock Mechanics Bulletin","volume":"4 1","pages":"Article 100169"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136218","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}

引用次数: 0

The effects of staggered and non-staggered joints on the ultimate bearing capacity, load settlement behavior, and failure mechanism with the change of excavation depths 交错节点与非交错节点对基坑极限承载力、荷载沉降行为及破坏机制的影响

Rock Mechanics Bulletin Pub Date : 2025-01-01 DOI: 10.1016/j.rockmb.2024.100154

Argha Biswas, Aditya Singh, Mahendra Singh

{"title":"The effects of staggered and non-staggered joints on the ultimate bearing capacity, load settlement behavior, and failure mechanism with the change of excavation depths","authors":"Argha Biswas, Aditya Singh, Mahendra Singh","doi":"10.1016/j.rockmb.2024.100154","DOIUrl":"10.1016/j.rockmb.2024.100154","url":null,"abstract":"<div><div>Extensive research is available on excavation walls in soils. However, very few studies address their performance in rocks and jointed rock masses. This study aimed to investigate the effect of staggered and non-staggered joints on ultimate bearing capacity, load settlement behavior, failure mechanism, and lateral wall displacement for a jointed rock mass supported by an excavation wall. The present study has been conducted on scaled 2D physical laboratory model tests. Tests were performed on artificial jointed rock masses comprising orthogonal joint sets and an excavation wall supporting a nearby foundation. Two sets of rock masses were prepared, one with continuous joints and another with slightly staggered joints. Three different excavation depths were used in this study. The results revealed that minor staggering significantly enhanced bearing capacity by two to three times compared to continuous joints. Furthermore, the presence of minor staggering reduced both vertical settlement of the footing and lateral movement of the excavation wall, thereby altering the failure patterns. Additionally, a discrete element model (DEM) was developed using the Universal Distinct Element Code (UDEC) to compare numerical simulation results with the physical model test results. The discrepancies between the numerical and physical model results were attributed to the difficulty in accurately representing the physical position of individual blocks in the UDEC model. This issue was addressed by introducing the concept of “apparent cohesion” and aligning DEM results closely with experimental outcomes, confirming the effectiveness of this approach in reconciling numerical and physical model differences.</div></div>","PeriodicalId":101137,"journal":{"name":"Rock Mechanics Bulletin","volume":"4 1","pages":"Article 100154"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136219","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}

引用次数: 0

Finite domain solution of a hydraulic fracture in a permeable rock 渗透性岩石水力裂缝的有限域解

Rock Mechanics Bulletin Pub Date : 2025-01-01 DOI: 10.1016/j.rockmb.2024.100156

Cexuan Liu , Fengshou Zhang , Emmanuel Detournay

引用次数: 0

Prediction of rock fracture pressure in hydraulic fracturing with interpretable machine learning and mechanical specific energy theory 基于可解释机器学习和机械比能理论的水力压裂岩石破裂压力预测

Rock Mechanics Bulletin Pub Date : 2024-12-30 DOI: 10.1016/j.rockmb.2024.100173

Xiaoying Zhuang , Yuhang Liu , Yuwen Hu , Hongwei Guo , Binh Huy Nguyen

{"title":"Prediction of rock fracture pressure in hydraulic fracturing with interpretable machine learning and mechanical specific energy theory","authors":"Xiaoying Zhuang , Yuhang Liu , Yuwen Hu , Hongwei Guo , 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":"2024-12-30","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}

引用次数: 0

Evolution of mechanical and rockburst parameters of gypsum-like rock under fatigue stress disturbance 疲劳应力扰动下石膏类岩石力学参数和岩爆参数的演化

Rock Mechanics Bulletin Pub Date : 2024-12-30 DOI: 10.1016/j.rockmb.2024.100171

Chongyang Wang , Sijiang Wei , Dongming Zhang , Beichen Yu , Yisha Pan , Xunjian Hu

{"title":"Evolution of mechanical and rockburst parameters of gypsum-like rock under fatigue stress disturbance","authors":"Chongyang Wang , Sijiang Wei , Dongming Zhang , Beichen Yu , Yisha Pan , 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":"2024-12-30","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}

引用次数: 0

Research on narrow coal pillar width optimization and surround rock control in Shiquan mine 石泉矿窄煤柱宽度优化与围岩控制研究

Rock Mechanics Bulletin Pub Date : 2024-12-28 DOI: 10.1016/j.rockmb.2024.100172

Rui Wang , Zhen Shi , Jiulin Fan , Yajun Wang , Yanghao Peng , Manchao He , Bo Zhang

{"title":"Research on narrow coal pillar width optimization and surround rock control in Shiquan mine","authors":"Rui Wang , Zhen Shi , Jiulin Fan , Yajun Wang , Yanghao Peng , Manchao He , 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":"2024-12-28","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}

引用次数: 0

Enhancing production rates at El Teniente's black cave mine through optimizing HF hole distribution using discrete fracture network modeling and geostatistical simulation methods 利用离散裂缝网络建模和地质统计模拟方法优化高频孔分布，提高El Teniente黑洞矿的产量

Rock Mechanics Bulletin Pub Date : 2024-09-26 DOI: 10.1016/j.rockmb.2024.100165

Amin Hekmatnejad , Fernando Manscilla , Paulina Schachter , Pengzhi Pan , Ehsan Mohtarami , Alvaro Pena , Abbas Taheri , Benoit Crespin , Francisco Moreno , Roberto Gonzales

{"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 , Fernando Manscilla , Paulina Schachter , Pengzhi Pan , Ehsan Mohtarami , Alvaro Pena , Abbas Taheri , Benoit Crespin , Francisco Moreno , 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":"2024-09-26","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}

引用次数: 0

Viscoelastic plastic interaction of tunnel support and strain-softening rock mass considering longitudinal effect 考虑纵向效应的隧道支护与应变软化岩体的粘弹性塑性相互作用

Rock Mechanics Bulletin Pub Date : 2024-09-02 DOI: 10.1016/j.rockmb.2024.100152

Chen Xu , Sheng Wang , Caichu Xia , Lei Liu , Zhifu Ma , Jun Yang

{"title":"Viscoelastic plastic interaction of tunnel support and strain-softening rock mass considering longitudinal effect","authors":"Chen Xu , Sheng Wang , Caichu Xia , Lei Liu , Zhifu Ma , Jun Yang","doi":"10.1016/j.rockmb.2024.100152","DOIUrl":"10.1016/j.rockmb.2024.100152","url":null,"abstract":"<div><p>A simplified two-stage method was employed to provide an explicit solution for the time-dependent tunnel-rock interaction, considering the generalized Zhang-Zhu strength criterion. Additionally, a simplified mechanical model of the yielding support structure was established. The tunnel excavation is simplified to a two-stage process: the first stage is affected by the longitudinal effect, while the second stage is affected by rheological behavior. Two cases are considered: one is that the rigid support is constructed during the first stage, and the other is that constructed at the second stage. Distinguished by the support timing at the seconde stage, different kinds of the “yield-resist combination” support method are divided into three categories: “yield before resist” support, “yield-resist” support, and “control-yield-resist” support. Results show that the support reaction of “control-yield-resist” is much higher than that of “yield before resist” if the initial geostress is not very high, but the effect is not obvious on controlling the surrounding rock deformation. So, the “yield before resist” support is much more economical and practical when the ground stress is not very high. However, under high geostress condition, through applying relatively high support reaction actively to surrounding rock at the first stage, the “control-yield-resist” support is superior in controlling the deformation rate of surrounding rock. Therefore, in the high geostress environment, it is recommended to construct prestressed yielding anchor immediately after excavation, and then construct rigid support after the surrounding rock deformation reaches the predetermined deformation.</p></div>","PeriodicalId":101137,"journal":{"name":"Rock Mechanics Bulletin","volume":"3 4","pages":"Article 100152"},"PeriodicalIF":0.0,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2773230424000519/pdfft?md5=940293f144d1155c8f26823e892af562&pid=1-s2.0-S2773230424000519-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142167444","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}

引用次数: 0

Shear behavior and dilatancy of an artificial hard-matrix bimrock: An experimental study focusing on the role of blocky structure 人造硬基质双岩的剪切行为和扩张性：以块状结构的作用为重点的实验研究

Rock Mechanics Bulletin Pub Date : 2024-09-01 DOI: 10.1016/j.rockmb.2024.100149

Amir Yazdani , Saeed Karimi-Nasab , Hossein Jalalifar

{"title":"Shear behavior and dilatancy of an artificial hard-matrix bimrock: An experimental study focusing on the role of blocky structure","authors":"Amir Yazdani , Saeed Karimi-Nasab , Hossein Jalalifar","doi":"10.1016/j.rockmb.2024.100149","DOIUrl":"10.1016/j.rockmb.2024.100149","url":null,"abstract":"<div><p>Bimrocks are characterized by their geotechnically significant blocky structure, presenting complex shear behavior. This study investigates the shear behavior and dilatancy of bimrocks featuring a rock-like matrix, such as conglomerates. The study addresses a gap in current research, which has predominantly examined the shear behavior of soil-matrix bimrocks (bimsoils). Laboratory direct shear tests were performed on idealized models with varying volumetric block proportions (VBPs). The results highlight that blocks exert both positive and negative effects on shear strength, dilation, and block breakage factor (BF), depending on VBP. Results indicate 40% and 60% as critical VBPs, revealing distinct shear strength trends within this range, contrary to the dominant downward trend. Blocks positively impact dilation and BF between 20% and 50% VBP, while negatively affecting them beyond this range. Blocky skeleton inherently promotes stable dilatancy under normal stress increments and intensifies stress dependency of shear strength. Variations in dilation angle concerning normal stress and VBP suggest the potential for characterizing this factor using equivalent strength and roughness, akin to rockfill materials. Indirect assessments of equivalent strength revealed positive effects of blocks when VBP was between 30% and 70%. Lastly, the findings indicate that blocks notably impact pre- and post-peak behaviors by reducing shear stiffness and inducing local hardening phases. This study also discusses the similarities and distinctions in the function of blocks within soil-like and rock-like matrices. It offers new insights into the exact role of blocks in bimrock shear behavior beyond the traditional interpretation through the variation of friction and cohesion.</p></div>","PeriodicalId":101137,"journal":{"name":"Rock Mechanics Bulletin","volume":"3 4","pages":"Article 100149"},"PeriodicalIF":0.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2773230424000489/pdfft?md5=351bcae800d46eb3f1ebfe4f2271787f&pid=1-s2.0-S2773230424000489-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142171864","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}

引用次数: 0

Effects of joint persistence and testing conditions on cyclic shear behavior of en-echelon joints under CNS conditions 连接持久性和测试条件对 CNS 条件下 en-echelon 接头循环剪切行为的影响

Rock Mechanics Bulletin Pub Date : 2024-08-31 DOI: 10.1016/j.rockmb.2024.100147

Bin Wang , Yujing Jiang , Qiangyong Zhang , Hongbin Chen

{"title":"Effects of joint persistence and testing conditions on cyclic shear behavior of en-echelon joints under CNS conditions","authors":"Bin Wang , Yujing Jiang , Qiangyong Zhang , Hongbin Chen","doi":"10.1016/j.rockmb.2024.100147","DOIUrl":"10.1016/j.rockmb.2024.100147","url":null,"abstract":"<div><p>Cyclic shear tests on rock joints serve as a practical strategy for understanding the shear behavior of jointed rock masses under seismic conditions. We explored the cyclic shear behavior of en-echelon and how joint persistence and test conditions (initial normal stress, normal stiffness, shear velocity, and cyclic distance) influence it through cyclic shear tests under CNS conditions. The results revealed a through-going shear zone induced by cyclic loads, characterized by abrasive rupture surfaces and brecciated material. Key findings included that increased joint persistence enlarged and smoothened the shear zone, while increased initial normal stress and cyclic distance, and decreased normal stiffness and shear velocity, diminished and roughened the brecciated material. Shear strength decreased across shear cycles, with the most significant reduction in the initial shear cycle. After ten cycles, the shear strength damage factor <em>D</em> varied from 0.785 to 0.909. Shear strength degradation was particularly sensitive to normal stiffness and cyclic distance. Low joint persistence, high initial normal stress, high normal stiffness, slow shear velocity, and large cyclic distance were the most destabilizing combinations. Cyclic loads significantly compressed en-echelon joints, with compressibility highly dependent on normal stress and stiffness. The frictional coefficient initially declined and then increased under a rising cycle number. This work provides crucial insights for understanding and predicting the mechanical response of en-echelon joints under seismic conditions.</p></div>","PeriodicalId":101137,"journal":{"name":"Rock Mechanics Bulletin","volume":"3 4","pages":"Article 100147"},"PeriodicalIF":0.0,"publicationDate":"2024-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2773230424000465/pdfft?md5=31d18ae0b6d5232e6700fb099e2bf10e&pid=1-s2.0-S2773230424000465-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142272657","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}

引用次数: 0