Yang-Long Diao , Wen-Jie Wang , Feng Luo , Zhi-Qi Feng
{"title":"Macro-mesoscopic study of the deformation and failure mechanism of through-boundary type locked rock masses","authors":"Yang-Long Diao , Wen-Jie Wang , Feng Luo , Zhi-Qi Feng","doi":"10.1016/j.tafmec.2025.104891","DOIUrl":"10.1016/j.tafmec.2025.104891","url":null,"abstract":"<div><div>The instability of the locked segment in rock structures is a common geological hazard and has been widely studied. However, the instability of through-boundary type locked segment structures with rock bridges of the same length but different angles has not been fully reported. In this paper, three failure modes and the tensile-shear failure characteristics of the fracture surface were identified by physical experiments. Using PFC2D, the local displacement field, force field distribution, and crack evolution characteristics were studied. The results show that under different rock bridge inclinations, the rock mass penetration modes can be categorized into three types: penetration at the joint tip and upper end, penetration of the rock bridge between adjacent joint tips, and oblique straight-line penetration at the upper and lower ends. The local scratch surface exhibits three distinct distribution characteristics: the locked rock mass above the rock bridge, within the rock bridge region, and around the joint region. As the rock bridge inclination increases, the peak stress tend to decrease, with crack development becoming more concentrated (excluding 90°). The minimum local displacement field in the central part transitions from a shell shape to a core shape. In the direction of the force source, stress concentration at the ends of the rock bridge (LM1 and RM1, LM3 and RM3) becomes more pronounced, but the degree of concentration is constrained by the rock bridge inclination. The distribution range of normal contact forces increases, and the maximum tangential contact force deviates toward the axial direction.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"137 ","pages":"Article 104891"},"PeriodicalIF":5.0,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143445853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yunlong Wang , Peng Hou , Shanjie Su , Xin Liang , Yanan Gao , Feng Gao
{"title":"Effect of cyclic heating-rapid cooling on fracture behavior of notched semi-circular bend granite","authors":"Yunlong Wang , Peng Hou , Shanjie Su , Xin Liang , Yanan Gao , Feng Gao","doi":"10.1016/j.tafmec.2025.104889","DOIUrl":"10.1016/j.tafmec.2025.104889","url":null,"abstract":"<div><div>Cyclic liquid nitrogen (LN<sub>2</sub>) fracturing is a promising innovative technology expected to rapidly form fracture networks in geothermal reservoirs. The fracture characteristics are crucial for estimating the effect of the artificial fracturing. Therefore, a cyclic heating-rapid cooling (CHRC) experiment is conducted on the notched semi-circular bend (NSCB) granite, where LN<sub>2</sub> and water cooling are employed. The structural damage and fracture characteristics of the CHRC treated sample are analyzed using ultrasonic detection, three-point bending test, and acoustic emission (AE) technique. A grain-based model with thermo‑mechanical coupling is constructed to explore the micro-cracking mechanism of the CHRC treatment. The results indicate that the damage caused by the CHRC increases significantly in the first five cycles, especially under LN<sub>2</sub> cooling. The decline of fracture toughness with cycles under different cooling methods. LN<sub>2</sub> cooling can dramatically enhance the AE energy release and fracture surface roughness in the initial cycles. LN<sub>2</sub> cooling can promote the generation of tensile cracks and intra-granular microcracks. The fracture behaviors of the CHRC treated granite are mainly determined by the stable thermal stress, significantly affected by mineral distribution. These results can provide a comprehensive understanding of cyclic LN<sub>2</sub> fracturing compared to hydraulic fracturing, supporting theoretical guidance for geothermal extraction.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"137 ","pages":"Article 104889"},"PeriodicalIF":5.0,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143453947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Critical strain energy release rate in additively manufactured polymers through comparative study of ABS and PLA across various raster angles","authors":"M.J. Qadyani, B. Ameri, F. Taheri-Behrooz","doi":"10.1016/j.tafmec.2025.104890","DOIUrl":"10.1016/j.tafmec.2025.104890","url":null,"abstract":"<div><div>To effectively integrate 3D-printed components into real-world applications, it is crucial for designers to fully understand the behavior of these constructions, particularly their fracture characteristics. This study addresses the fracture behavior of Fused Deposition Modeling (FDM) 3D-printed Double Cantilever Beam (DCB) specimens by analyzing the Mode-I strain energy release rate. The investigation encompasses two materials: (Acrylonitrile Butadiene Styrene) ABS, a brittle reference, and Polylactic acid (PLA), a ductile reference. Finite Element Analysis (FEA) is utilized to predict fracture behavior and evaluate the applicability of the model across various unidirectional raster angles (0°, 30°, 45°, 60°, and 90°) based on the Cohesive Zone Model (CZM). The study systematically explores fracture initiation, crack propagation, and critical failure points. Scanning Electron Microscopy (SEM) fractography examines the effects of different raster angles and material properties on construction behavior. The results reveal that the 60-degree raster angle yields the highest critical energy release rate, attributed to the mixed Mode-I/II interaction and significant shear deformation, with 2.3 mJ/mm<sup>2</sup> values for ABS and 2.4 mJ/mm2 for PLA. This angle also demonstrates strand bridging, enhancing the material’s toughness. Conversely, samples with a 45-degree raster angle exhibit lower critical energy release rates, indicating reduced fracture resistance under these conditions. This comprehensive analysis provides valuable insights into optimizing 3D-printed structures for improved performance in practical applications.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"138 ","pages":"Article 104890"},"PeriodicalIF":5.0,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143453300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 of internal deformation in 3D solids with embedded parallel cracks during the fracture process using multi-material 3D printing and stereo digital image correlation","authors":"Yating Wang , Dongyi Xing , Meilu Yu , Qing Qiao","doi":"10.1016/j.tafmec.2025.104884","DOIUrl":"10.1016/j.tafmec.2025.104884","url":null,"abstract":"<div><div>Quantifying the internal deformation of three-dimensional (3D) fractured solids during crack propagation is crucial for understanding the failure mechanism of 3D fractured solids and quantifying fracture parameters at the embedded crack tip. At present, there are still certain difficulties in measuring the internal deformation of 3D fractured solids during the failure process through physical experimental methods. Utilizing advanced technologies, including multi-material/color 3D printing, simulated speckle algorithms, and stereo digital image correlation (stereo-DIC), this study innovatively achieves dynamic measurement of the internal displacement field in 3D solids containing parallel cracks during crack propagation. The obtained displacement field is used to analyze the deformation characteristics of embedded cracks and determine the parameters at the 3D crack tip (stress intensity factors and theoretical crack initiation angle). The influence of prefabricated crack spacing on the 3D solid failure process was quantitatively analyzed through the differences in initiation pressures, failure pressures and crack tip parameters. The experimental results indicate that as the spacing between parallel cracks decreases, the compression effect at the crack tip in the center of the model diminishes while the shear effect increases, ultimately reducing the model’s bearing capacity.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"137 ","pages":"Article 104884"},"PeriodicalIF":5.0,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143429424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shankun Zhao , Mingyuan Zhang , Guanghui He , Kun Lv , Dejian Li , Yingjun Li , Hainan Gao
{"title":"Experimental study on fracture behavior of coal-rock samples with varying sandstone strength using the ultrafast time-resolution method","authors":"Shankun Zhao , Mingyuan Zhang , Guanghui He , Kun Lv , Dejian Li , Yingjun Li , Hainan Gao","doi":"10.1016/j.tafmec.2025.104885","DOIUrl":"10.1016/j.tafmec.2025.104885","url":null,"abstract":"<div><div>The planning and construction of mine roadways inevitably involve crossing interfaces between coal and rock seams. While previous studies have extensively examined the mechanical properties of coal-rock combinations with varying coal and rock seam thicknesses, few research has focused on the fracture behavior of samples with different rock seam strengths. Three-point bending experiments were conducted on coal-rock combined samples with pre-crack and sandstone, which had uniaxial compressive strength of 34.4 MPa and 124.7 MPa, respectively, to analyze their influence on the mechanical properties of the samples. Each combination types featured coal-rock thickness ratios of 1:1, 2:1, and 5:1, respectively. The entire fracture process, from loading to failure, was captured using the ultrafast time-resolution method based on pulsed laser technology, achieving a time resolution of 15 picoseconds. The experimental results revealed distinct failure mechanisms between samples with weak versus strong sandstone seams. The macroscopic cracks in samples with weak sandstone emerged at the peak load, whereas in those with strong sandstone, macroscopic crack occurred prior to peak load. Furthermore, samples with weaker sandstone exhibited progressive failure modes at coal-rock thickness ratios of 2:1 and 5:1, whereas all other groups demonstrated brittle failure. The crack tip locations and mode I stress intensity factors (SIF) at crack initiation were determined using digital image correlation (DIC) in conjunction with the immune algorithm (IA). It is recommended that mine roadways construction account not only for the coal seam thickness-to- roadway height ratio but also for the strength of the overlying rock strata.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"137 ","pages":"Article 104885"},"PeriodicalIF":5.0,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143438131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Macro-meso crack propagation characteristics and safety performance assessment of flawed rock mass","authors":"Tao Zhou , Yuchun Lin , Jiarong Chen","doi":"10.1016/j.tafmec.2025.104867","DOIUrl":"10.1016/j.tafmec.2025.104867","url":null,"abstract":"<div><div>The propagation of internal cracks is a common cause of instability and failure in engineering rock masses, which can pose significant risks to their safety and operational integrity. This study systematically investigated the underlying mechanisms of crack propagation in red sandstone specimens containing a single flaw under uniaxial compressive loading. The entire cracking process including initiation, propagation, and coalescence, was recorded and analyzed from macro-meso scales scale using acoustic emission (AE) technology, high-speed photography systems, and a scanning electron microscope (SEM). Furthermore, two new parameters, the weakening parameter <em>R<sub>c</sub></em> and the brittleness parameter <em>R</em><sub>i</sub>, have been proposed for the evaluation of crack sensitivity and the assessment of crack-bearing working capacity in rock masses comprising diverse lithologies (sandstone, plaster, granite, marble, and rock-like materials) and flawed inclinations (0°, 15°, 30°, 45°, 60°, 75°, and 90°). Based on the comprehensive assessment of <em>R</em><sub>c</sub> and <em>R</em><sub>i</sub>, the study proposes a new classification system that divides the safety performance of rock masses into four distinct zones: a safe zone, a flaw sensitive zone, a dangerous zone, and a brittle zone. In terms of natural rock, approximately 60–75% of sandstone and granite specimens fall within the brittle and dangerous zones, indicating a higher tendency to rockburst. In contrast, this proportion decreases to 50% for marble specimens. The dangerous zone for natural rocks is concentrated between 0° and 45°, with the most hazardous flawed inclinations ranging from 15° to 30°. Over 60% of the specimens fall within the dangerous zone at these ranges. The incorporation of fillers has been demonstrated to significantly enhance the overall load-bearing capacity of natural rock masses, notably increasing the proportion of brittle and safe zones. In comparison to natural rocks, rock-like materials have been shown to demonstrate superior safety performance, particularly in their resistance to flaw weakening and their capacity to bear initial cracks. The present study demonstrates that 75% of concrete and 54% of plaster materials are situated within the safe zone when the flawed inclination is below 75°. This research offers a novel scientific reference point for the safety performance assessment of flawed rock masses, which is advantageous for the secure construction and operation of rock mass engineering.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"137 ","pages":"Article 104867"},"PeriodicalIF":5.0,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143418967","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Reverse bend experiments on the base plate and discussion of the appropriate amount of reverse bending for precrack straightness (Effect of the reverse bend process on the CTOD toughness evaluation and understanding of its mechanisms)","authors":"Tomoya Kawabata , Hoichi Kitano , Takumi Ozawa , Yoshiki Mikami","doi":"10.1016/j.tafmec.2025.104869","DOIUrl":"10.1016/j.tafmec.2025.104869","url":null,"abstract":"<div><div>Measurements of the critical value of the crack-tip opening displacement (CTOD) of welded joints often suffer from weld residual stresses, which prevent the introduction of a straight precrack front. In this study, the effects of reverse bending, a proven method for straightening the crack front shape, on evaluations of the critical CTOD are investigated. To compare the differences in the evaluation results, the authors used a base plate without residual stress inside the material for their experiments. Five different reverse bending treatments were applied to a 50 mm thick base metal, and the effects of reverse bending were evaluated via CTOD tests at low temperatures. Additionally, numerical simulations were carried out via the finite element method to exclude the effects of <em>a</em><sub>0</sub>/<em>W</em> and <em>a</em><sub>f</sub>, which cannot be unified in the experiments, and to understand the mechanism. After reverse bending and unloading, the tensile residual stress is distributed at the notch edge, and a high stress intensity at the fatigue crack tip during CTOD testing can be expected. In addition, when the amount of reverse bending is increased to <em>L</em><sub>r</sub> = 1.35, the compressive residual stress distribution in front of the specimen expands, and the <em>P–V</em><sub>g</sub> curve clearly decreases, which may impair the precrack shape flatness. Therefore, the controlled range of <em>L</em><sub>r</sub> should be at least less than 1.35.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"137 ","pages":"Article 104869"},"PeriodicalIF":5.0,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143429423","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xiaozhao Li , Qiulin Luo , Fayuan Yan , Chengzhi Qi
{"title":"Dynamic compressive micro-macro fracture mechanism with the water-saturated strengthening and weakening effect in brittle rocks","authors":"Xiaozhao Li , Qiulin Luo , Fayuan Yan , Chengzhi Qi","doi":"10.1016/j.tafmec.2025.104871","DOIUrl":"10.1016/j.tafmec.2025.104871","url":null,"abstract":"<div><div>The dynamic compressive mechanical properties of water-saturated brittle rocks are of significant practical importance for assessing the stability of deep underground rock masses during excavation. The coupled dynamic effect of free water and microcrack extension within the rocks severely affects the dynamic compressive mechanical properties of saturated rocks. However, there is a significant lack of research on the mechanisms relating the microcrack evolution to the macroscopic deformation behavior of saturated brittle rocks under dynamic compressive loading. This article aims to propose a feasible micro–macro fracture model to explain the enhancement and weakening mechanisms of free water on the dynamic mechanical properties of rocks. Based on the stress–strain constitutive model of dry rock under quasi-static crack extension action, the stress–strain constitutive model of water-saturated rock under quasi-static action is obtained by combining the change of mechanical parameters of rock with free water. Then the quasi-static fracture toughness and dynamic fracture toughness relationship, the crack extension rate and crack opening rate relationship and the crack extension rate and strain rate relationship are introduced and combined with the Stefan effect to derive the stress–strain constitutive model for water-saturated brittle rocks under dynamic compression. And the reasonableness of the theoretical model is verified by the experimental results. The changes in the intercrack friction coefficient <em>µ</em>, initial damage <em>D</em><sub>0</sub> and quasi-static fracture toughness <em>K</em><sub>ICQ</sub> due to free water have a weakening effect on the dynamic mechanical properties of the rock. The alterations in dynamic fracture toughness amplification factor <em>K</em><sub>V</sub> resulting from changes in the quasi-static elastic modulus <em>E</em> and density <em>ρ</em>, along with the Stefan force <em>F</em><sub>S</sub> effect, contribute to the enhancement of the dynamic mechanical characteristics of the rock. The changes in mechanical parameters and the Stefan effect together constitute the strengthening and weakening mechanisms through which free water affects the dynamic mechanical properties of the rock. And discusses the effects of confining pressure and strain rate on the dynamic compressive strength and crack initiation stress of water-saturated rock. These findings provide theoretical support for the stability analysis of saturated rock masses during deep underground excavation.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"137 ","pages":"Article 104871"},"PeriodicalIF":5.0,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143429420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Qinglin Guo , Panpan Zuo , Lili Li , Keyi Wang , Zhiyong Liu , Li Zhang , Wenli He , Pengfei Liu
{"title":"Influence of wet-dry history on the mixed fracture properties of dense asphalt mixture based on ASCB test","authors":"Qinglin Guo , Panpan Zuo , Lili Li , Keyi Wang , Zhiyong Liu , Li Zhang , Wenli He , Pengfei Liu","doi":"10.1016/j.tafmec.2025.104873","DOIUrl":"10.1016/j.tafmec.2025.104873","url":null,"abstract":"<div><div>The coupling effects of traffic loads and rainfall may cause premature cracking in asphalt layer. Consequently, it is of interest to study the influence of rainfall on the fracture resistance of asphalt mixtures. However, the on-site testing presents significant challenges. Thus, this study designs the wet-dry history to simulate the conditions experienced by asphalt mixture in the field, employing the asymmetric semi-circular bend (ASCB) test to determine the mixed fracture performance of asphalt mixture. The fracture criteria of the asphalt mixture before and after wet-dry cycling treatment were analyzed, and the propagation of crack mouth was measured using digital image correlation technology. Results indicate that wet-dry cycles lead to the mass loss in asphalt mixture, with higher loss correlating to more cycles. Wet-dry history causes an increase in the stress intensity factor at medium temperature. For the condition of 24 cycles, the low-temperature fracture toughness of mode I is significantly reduced, and the low-temperature fracture toughness increases under mixed and II modes, which results in an increased ratio of K<sub>II</sub>/K<sub>IC</sub>. The low-temperature fracture energy of asphalt mixture is susceptible to wet-dry history. Empirical fracture criteria such as linear model exhibit smaller deviation than the MTS and GMTS criteria. Wet-dry history notably reduces the low-temperature plastic deformation and diminishes the crack propagation deforming capability. The load-CMOD curve at low temperature is suggested to assess the impact of wet-dry history on the crack propagation capability of asphalt mixture.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"137 ","pages":"Article 104873"},"PeriodicalIF":5.0,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143418969","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fei Xue , Zhuoya Tong , Wei Chen , Tianzuo Wang , Xiaobo You , Zhongqin Lin
{"title":"Experimental study on anchorage mechanical effect of rock bolts on cross-jointed rock mass using DIC and AE","authors":"Fei Xue , Zhuoya Tong , Wei Chen , Tianzuo Wang , Xiaobo You , Zhongqin Lin","doi":"10.1016/j.tafmec.2025.104875","DOIUrl":"10.1016/j.tafmec.2025.104875","url":null,"abstract":"<div><div>Rock bolting is a commonly used reinforcement technique for jointed rock masses. This study investigates the anchorage effects of rock bolts on cross-jointed rock masses. Novel 3D-printed stainless steel bolts were used to reinforce rock-like specimens with main joint angles of 15°, 30°, 45°, 60°, and 75°. The integration of Acoustic Emission (AE) and Digital Image Correlation (DIC) techniques enabled comprehensive monitoring of crack propagation and strain evolution. The results show that bolt reinforcement significantly enhanced specimen strength (up to 79.9 %) and elastic modulus (up to 37.9 %) at smaller joint angles (≤45°). However, the reinforcement effectiveness diminished considerably at larger angles (≥60°), with strength reductions of up to 10.6 %. The combined AE-DIC analysis revealed distinct failure mechanisms: tensile-dominated failure at small joint angles and shear-dominated failure at larger joint angles. This study provides practical guidelines for optimizing rock bolt applications in jointed rock masses, particularly highlighting the need for alternative support strategies at large joint angles.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"137 ","pages":"Article 104875"},"PeriodicalIF":5.0,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143418966","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}