Pub Date : 2025-03-15DOI: 10.1016/j.rockmb.2025.100191
Yao Yin , Minxing Song , Yu Feng , Zhongqiang Liu , Xiaohui Chen , Qing Sun
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 φ 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.
{"title":"Theoretical and numerical investigation of the effects of in-situ stresses and dual-borehole combinations in eccentric decoupled charge blasting","authors":"Yao Yin , Minxing Song , Yu Feng , Zhongqiang Liu , Xiaohui Chen , 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":"2025-03-15","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}
Pub Date : 2025-02-20DOI: 10.1016/j.rockmb.2025.100190
Kang Tao , Wengang Dang , Heinz Konietzky , Yu Liu , Wenhao Zhang , Xingling Li
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.
{"title":"Velocity effects on slip evolution of faults subjected to constant and cyclic normal stress derived from laboratory tests","authors":"Kang Tao , Wengang Dang , Heinz Konietzky , Yu Liu , Wenhao Zhang , 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":"2025-02-20","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}
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.
{"title":"Investigation on stress distribution and prestress loss model of prestressed anchor cables considering corrosion-induced debonding","authors":"Hanfang Zheng , Yujing Jiang , Xuezhen Wu , Sunhao Zhang , 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":"2025-02-19","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}
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 PFC2D, with emphasis on the effects of grain geometry (reflected by the aspect ratio (a/b)) and shear rate. Under the low normal stress (i.e., 0.1 MPa), circular grains (a/b = 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 a/b 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 a/b value, while that of fine comminuted particles decreases. Shear rate also has a significant impact on grain behavior. The main movement of grain with a/b = 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.
{"title":"A microscopic DEM investigation on fracture shearing characteristics of infilled grains with different geometrical shapes in rock discontinuities","authors":"Zhicheng Tang , Zhifei Zhang , Lichun Zhao , 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<sup>2D</sup>, 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":"2025-01-09","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}
Pub Date : 2025-01-01DOI: 10.1016/j.rockmb.2024.100151
Wenqiang Xia , Chun Liu , Hui Liu , Tao Zhao , Yao Zhu
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.
{"title":"Modeling of particle migration in piping based on an improved discrete element method","authors":"Wenqiang Xia , Chun Liu , Hui Liu , Tao Zhao , 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}
Pub Date : 2025-01-01DOI: 10.1016/j.rockmb.2024.100153
Zhong-jian Zhang , Zhongqi Quentin Yue , Biao Li , Zhi-fa Yang
This paper presents a directional large-area rock fracturing method. The method had distinctive features compared with other common fracturing methods. The area of the fracturing surface could reach 10–500 m2. The fractured rock was sheet-like in shape, with a thickness of 6–8 cm. The main fracturing tools and procedures used were described in the paper. This paper analyzed the reason for controllable and directional (also mode-I) rupturing in rock from the view of fracture mechanics. Counter-intuitively, the fracturing surface of the rock sheet had an angle (approximately 25°) to the loading direction (i.e., the orientation of the maximum principal compressive stress). The rupture behavior was controlled by the relationship between the load and the geometric boundary of the rock. It is found that the fracturing surface can suddenly and rapidly propagate after a certain strike by calculating the energies of the rock sheet. The striking energy could be converted into elastic strain energy, which accumulates in a very-slightly bent rock sheet step by step until exceeds the bearing limit of rock sheet. Most of the stored elastic strain energy was subsequently released in the form of splitting energy, leading to rock fracturing. This study provides insights into the occurrence of tectonic earthquakes.
{"title":"Manually directional splitting of in-situ intact igneous rocks into large sheets","authors":"Zhong-jian Zhang , Zhongqi Quentin Yue , Biao Li , Zhi-fa Yang","doi":"10.1016/j.rockmb.2024.100153","DOIUrl":"10.1016/j.rockmb.2024.100153","url":null,"abstract":"<div><div>This paper presents a directional large-area rock fracturing method. The method had distinctive features compared with other common fracturing methods. The area of the fracturing surface could reach 10–500 m<sup>2</sup>. The fractured rock was sheet-like in shape, with a thickness of 6–8 cm. The main fracturing tools and procedures used were described in the paper. This paper analyzed the reason for controllable and directional (also mode-I) rupturing in rock from the view of fracture mechanics. Counter-intuitively, the fracturing surface of the rock sheet had an angle (approximately 25°) to the loading direction (i.e., the orientation of the maximum principal compressive stress). The rupture behavior was controlled by the relationship between the load and the geometric boundary of the rock. It is found that the fracturing surface can suddenly and rapidly propagate after a certain strike by calculating the energies of the rock sheet. The striking energy could be converted into elastic strain energy, which accumulates in a very-slightly bent rock sheet step by step until exceeds the bearing limit of rock sheet. Most of the stored elastic strain energy was subsequently released in the form of splitting energy, leading to rock fracturing. This study provides insights into the occurrence of tectonic earthquakes.</div></div>","PeriodicalId":101137,"journal":{"name":"Rock Mechanics Bulletin","volume":"4 1","pages":"Article 100153"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136140","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}
Pub Date : 2025-01-01DOI: 10.1016/j.rockmb.2024.100170
Saeed Vadiee , Biao Li , Jasmin Raymond , Mafalda M. Miranda
This study numerically investigates the thermo-poromechanical effects in a Canadian geothermal reservoir caused by long-term fluid production and injection. Using finite element modeling, it explores pore pressure diffusion and thermal dynamics, incorporating both the geological structure of the rock mass and faults. The simulations utilize the IAPWS (International Association for the Properties of Water and Steam) equations to model fluid density and viscosity, ensuring realistic representations of heterogeneous pressure fields. The system replicates a doublet configuration within a faulted zone, featuring two hydraulically stimulated fractures. The primary aim is to assess the likelihood of fault reactivation under varying in-situ stress conditions over a 100-year geothermal operation. Results show that stress distribution is largely influenced by thermal stresses along the fluid circulation pathway, with fluid velocity and temperature gradients affecting reservoir stability. Minimal pore pressure changes highlight the dominant role of thermal stresses in controlling fault behavior. The analysis indicates no potential for fault reactivation, as slip tendency values remain below the critical threshold, even when accounting for reduced mechanical properties using the Hoek-Brown criterion. Thermal effects continue to influence the surrounding rock throughout the operational period, suggesting that the reservoir maintains mechanical stability conducive to sustained geothermal production and injection. These findings provide valuable insights into the long-term safety and behavior of geothermal reservoirs, offering important implications for future geothermal energy development and management strategies.
{"title":"Numerical modeling of the long-term poromechanical performance of a deep enhanced geothermal system in northern Québec","authors":"Saeed Vadiee , Biao Li , Jasmin Raymond , Mafalda M. Miranda","doi":"10.1016/j.rockmb.2024.100170","DOIUrl":"10.1016/j.rockmb.2024.100170","url":null,"abstract":"<div><div>This study numerically investigates the thermo-poromechanical effects in a Canadian geothermal reservoir caused by long-term fluid production and injection. Using finite element modeling, it explores pore pressure diffusion and thermal dynamics, incorporating both the geological structure of the rock mass and faults. The simulations utilize the IAPWS (International Association for the Properties of Water and Steam) equations to model fluid density and viscosity, ensuring realistic representations of heterogeneous pressure fields. The system replicates a doublet configuration within a faulted zone, featuring two hydraulically stimulated fractures. The primary aim is to assess the likelihood of fault reactivation under varying in-situ stress conditions over a 100-year geothermal operation. Results show that stress distribution is largely influenced by thermal stresses along the fluid circulation pathway, with fluid velocity and temperature gradients affecting reservoir stability. Minimal pore pressure changes highlight the dominant role of thermal stresses in controlling fault behavior. The analysis indicates no potential for fault reactivation, as slip tendency values remain below the critical threshold, even when accounting for reduced mechanical properties using the Hoek-Brown criterion. Thermal effects continue to influence the surrounding rock throughout the operational period, suggesting that the reservoir maintains mechanical stability conducive to sustained geothermal production and injection. These findings provide valuable insights into the long-term safety and behavior of geothermal reservoirs, offering important implications for future geothermal energy development and management strategies.</div></div>","PeriodicalId":101137,"journal":{"name":"Rock Mechanics Bulletin","volume":"4 1","pages":"Article 100170"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136216","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}
The vibrations generated by rock blasting are a serious and hazardous outcome of these activities, causing harmful effects on the surrounding environment as well as the nearby residents. Both the local ecology and human communities suffer from the consequences of these vibrations. Assessing the severity of blasting vibrations necessitates a thorough evaluation of Peak Particle Velocity (PPV) and frequency, which are essential parameters for measuring vibration velocity. Accurate prediction of vibration occurrence is critically important. Therefore, this study employs five machine learning models for predicting the PPV and frequency resulting from quarry blasting. This work compares five machine learning models (XGBoost, Catboost, Bagging, Gradient Boosting, and Random Forest Regression) to choose the most efficient performance model. The performance evaluation of each five machine learning models demonstrates each model achieved a performance of more than 0.90 during the testing phase, there was a strong correlation observed between the actual and the predicted ones. The analysis of performance metrics shows Catboost regression model demonstrate better performance prediction comparing with the other models with R2 = 0.983, MSE = 0.000078, RMSE = 0.008, NRMSE = 0.019, MAD = 0.004, MAPE = 35.197 in the PPV prediction, and R2 = 0.975, MSE = 0.000243, RMSE = 0.015, NRMSE = 0.031, MAD = 0.008, MAPE = 37.281 for the frequency prediction. This study will help mining engineers and blasting experts to select the best machine learning model and its hyperparameters in estimating ground vibration, and frequency. In the context of the mining and civil industry, the application of this study offers significant potential for enhancing safety protocols and optimizing operational efficiency. By employing machine learning models, this research aims to accurately predict and assess ground vibrations with frequency resulting from rock blasting.
{"title":"Data-driven machine learning approaches for simultaneous prediction of peak particle velocity and frequency induced by rock blasting in mining","authors":"Yewuhalashet Fissha , Prashanth Ragam , Hajime Ikeda , N. Kushal Kumar , Tsuyoshi Adachi , P.S. Paul , Youhei Kawamura","doi":"10.1016/j.rockmb.2024.100166","DOIUrl":"10.1016/j.rockmb.2024.100166","url":null,"abstract":"<div><div>The vibrations generated by rock blasting are a serious and hazardous outcome of these activities, causing harmful effects on the surrounding environment as well as the nearby residents. Both the local ecology and human communities suffer from the consequences of these vibrations. Assessing the severity of blasting vibrations necessitates a thorough evaluation of Peak Particle Velocity (<em>PPV</em>) and frequency, which are essential parameters for measuring vibration velocity. Accurate prediction of vibration occurrence is critically important. Therefore, this study employs five machine learning models for predicting the <em>PPV</em> and frequency resulting from quarry blasting. This work compares five machine learning models (XGBoost, Catboost, Bagging, Gradient Boosting, and Random Forest Regression) to choose the most efficient performance model. The performance evaluation of each five machine learning models demonstrates each model achieved a performance of more than 0.90 during the testing phase, there was a strong correlation observed between the actual and the predicted ones. The analysis of performance metrics shows Catboost regression model demonstrate better performance prediction comparing with the other models with <em>R</em><sup>2</sup> = 0.983, <em>MSE</em> = 0.000078, <em>RMSE</em> = 0.008, <em>NRMSE</em> = 0.019, <em>MAD</em> = 0.004, <em>MAPE</em> = 35.197 in the <em>PPV</em> prediction, and <em>R</em><sup>2</sup> = 0.975, <em>MSE</em> = 0.000243, <em>RMSE</em> = 0.015, <em>NRMSE</em> = 0.031, <em>MAD</em> = 0.008, <em>MAPE</em> = 37.281 for the frequency prediction. This study will help mining engineers and blasting experts to select the best machine learning model and its hyperparameters in estimating ground vibration, and frequency. In the context of the mining and civil industry, the application of this study offers significant potential for enhancing safety protocols and optimizing operational efficiency. By employing machine learning models, this research aims to accurately predict and assess ground vibrations with frequency resulting from rock blasting.</div></div>","PeriodicalId":101137,"journal":{"name":"Rock Mechanics Bulletin","volume":"4 1","pages":"Article 100166"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136139","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}
Pub Date : 2025-01-01DOI: 10.1016/j.rockmb.2024.100155
Yanting Liu , Yuan Liang , Yueqiang Ma , Jingyi Liu , Derek Elsworth , Quan Gan
Retasking existing subsurface abandoned mines as infrastructure for solar energy storage could be a feasible approach in overcoming the low thermal gradient present in shallow formations. In this work, the potential for thermal storage in the high permeability goaf of abandoned mines through diurnal cyclic injection-then-extraction using coupled thermo-hydro-mechanical modeling was explored by coupling FLAC3D with TOUGH2. The temperature sensibility of reservoir during 30 days of cyclic injection-then-production was examined at various injection temperatures (ranging from 50 °C to 250 °C) and rates (ranging from 1 kg/s to 10 kg/s) and for representative reservoir physical and thermal properties, including variable thermal expansion coefficients. The simulation results reveal that: The principal mechanisms driving reservoir deformation result from the combined influence of thermal poroelastic and thermal effects. With the change of reservoir temperature, the reservoir is perturbed by pressure and thermal stresses causing permeability evolution. Permeability reduces ∼10% for a maximum injection temperature of 250 °C – although effects are reduced the lower injection temperatures. The pore pressure fluctuations for an injection rate of 10 kg/s is ∼6.5 times that for a rate of 1 kg/s. The pressure perturbation of the reservoir during the injection process decreases with the injection rate, and the reservoir is relatively more stable. When the thermal stress becomes predominant, the reservoir volume expands. Uplift displacements 220 m above the hot injection well are trivial an of the order of ∼1.5 mm at a mean temperature of 163 °C.
{"title":"Dynamic evolution of reservoir permeability and deformation in geothermal battery energy storage using abandoned mines","authors":"Yanting Liu , Yuan Liang , Yueqiang Ma , Jingyi Liu , Derek Elsworth , Quan Gan","doi":"10.1016/j.rockmb.2024.100155","DOIUrl":"10.1016/j.rockmb.2024.100155","url":null,"abstract":"<div><div>Retasking existing subsurface abandoned mines as infrastructure for solar energy storage could be a feasible approach in overcoming the low thermal gradient present in shallow formations. In this work, the potential for thermal storage in the high permeability goaf of abandoned mines through diurnal cyclic injection-then-extraction using coupled thermo-hydro-mechanical modeling was explored by coupling FLAC<sup>3D</sup> with TOUGH2. The temperature sensibility of reservoir during 30 days of cyclic injection-then-production was examined at various injection temperatures (ranging from 50 °C to 250 °C) and rates (ranging from 1 kg/s to 10 kg/s) and for representative reservoir physical and thermal properties, including variable thermal expansion coefficients. The simulation results reveal that: The principal mechanisms driving reservoir deformation result from the combined influence of thermal poroelastic and thermal effects. With the change of reservoir temperature, the reservoir is perturbed by pressure and thermal stresses causing permeability evolution. Permeability reduces ∼10% for a maximum injection temperature of 250 °C – although effects are reduced the lower injection temperatures. The pore pressure fluctuations for an injection rate of 10 kg/s is ∼6.5 times that for a rate of 1 kg/s. The pressure perturbation of the reservoir during the injection process decreases with the injection rate, and the reservoir is relatively more stable. When the thermal stress becomes predominant, the reservoir volume expands. Uplift displacements 220 m above the hot injection well are trivial an of the order of ∼1.5 mm at a mean temperature of 163 °C.</div></div>","PeriodicalId":101137,"journal":{"name":"Rock Mechanics Bulletin","volume":"4 1","pages":"Article 100155"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136204","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}
Pub Date : 2025-01-01DOI: 10.1016/j.rockmb.2024.100168
Rouhollah Basirat
This paper employs analytical and pseudo-static approaches to analyze the tunnel response under the compression (P) and shear (S) waves. In the first step, Einstein and Schwartz’s method is revised for calculating Tunnel Lining Internal Forces (TLIFs) under P-wave. Next, a comprehensive comparison is performed between TLIFs under S and P-waves in two extreme contact interfaces of no-slip (NS) and full-slip (FS) conditions. Lastly, the effect of the intermediate layer was investigated by quasi-static finite element numerical modeling. The results showed that the maximum value of the axial force under the P-wave exceeds that of the S-wave in both the NS and FS conditions. Also, the amount of bending moment and shear force in both the NS and FS conditions under the S-wave is almost twice the P-wave. In general, the weak interlayer causes a decrease in the maximum axial force and the axial force values in the range of placement of the weak interlayer with the tunnel. Besides, it increases the maximum bending moment and shear force compared to the homogeneous medium. It was also observed that the weak interlayer with low thickness causes unpredictable behavior under S and P-waves. Overall, the presence of a layer with different stiffness led to a significant effect on the TLIFs under S and P-waves and increased the complexity of the dynamic analysis of tunnel lining. Therefore, it should be simulated separately under NS and FS conditions.
{"title":"Analysis of tunnel lining internal forces under the influence of S and P-waves: An analytical solution and quasi-static numerical method","authors":"Rouhollah Basirat","doi":"10.1016/j.rockmb.2024.100168","DOIUrl":"10.1016/j.rockmb.2024.100168","url":null,"abstract":"<div><div>This paper employs analytical and pseudo-static approaches to analyze the tunnel response under the compression (P) and shear (S) waves. In the first step, Einstein and Schwartz’s method is revised for calculating Tunnel Lining Internal Forces (TLIFs) under P-wave. Next, a comprehensive comparison is performed between TLIFs under S and P-waves in two extreme contact interfaces of no-slip (NS) and full-slip (FS) conditions. Lastly, the effect of the intermediate layer was investigated by quasi-static finite element numerical modeling. The results showed that the maximum value of the axial force under the P-wave exceeds that of the S-wave in both the NS and FS conditions. Also, the amount of bending moment and shear force in both the NS and FS conditions under the S-wave is almost twice the P-wave. In general, the weak interlayer causes a decrease in the maximum axial force and the axial force values in the range of placement of the weak interlayer with the tunnel. Besides, it increases the maximum bending moment and shear force compared to the homogeneous medium. It was also observed that the weak interlayer with low thickness causes unpredictable behavior under S and P-waves. Overall, the presence of a layer with different stiffness led to a significant effect on the TLIFs under S and P-waves and increased the complexity of the dynamic analysis of tunnel lining. Therefore, it should be simulated separately under NS and FS conditions.</div></div>","PeriodicalId":101137,"journal":{"name":"Rock Mechanics Bulletin","volume":"4 1","pages":"Article 100168"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136217","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}
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