Article
Mathematics, Interdisciplinary Applications
Yike Dang, Zheng Yang, Xiaoyu Liu, Chunting Lu
Summary: Investigating the strength characteristics and failure mechanism of thermally treated granite is crucial for geothermal energy storage and development. Acoustic emission is a widely used method to understand the process of rock crack generation and failure mechanism. However, previous studies showed limitations in directly observing the interaction between thermal cracks and thermal stress, as well as capturing a large percentage of tensile failure sources.
COMPUTATIONAL PARTICLE MECHANICS
(2023)
Article
Metallurgy & Metallurgical Engineering
Jian-feng Liu, Chun-ping Wang, Lu Wang, Li-na Ran, Chao-fu Deng
Summary: The tensile strength of rock salt is an important parameter in salt cavern gas storage project. This study discusses the alternative methods to obtain the tensile strength, including direct tensile test, Brazilian test with simplified ISRM standard, Brazilian test with China standard, and three-point-bending test. The results show that the testing method affects the tensile strength and acoustic emission characteristics of rock salt. The indirect tensile strength determined by three-point-bending test is closer to the direct tensile strength, suggesting that the three-point-bending test can be a good option for obtaining the tensile strength of rock salt.
JOURNAL OF CENTRAL SOUTH UNIVERSITY
(2023)
Article
Energy & Fuels
Honghao Yuan, Qiang Sun, Jishi Geng, Zhenlong Ge, Shihao Yuan
Summary: Experimental analysis of the acoustic emission characteristics of high-temperature granite under different cooling methods revealed that rapid cooling has a greater impact on rock damage, which can help improve rock fragmentation and drilling rates.
GEOMECHANICS AND GEOPHYSICS FOR GEO-ENERGY AND GEO-RESOURCES
(2022)
Article
Geosciences, Multidisciplinary
Yufei Liang, Qingwen Yang, Ling Zhu, Tao Jiang, Meibeng Gao
Summary: Acoustic emission and thermal infrared signals are related to the process of rock breaking. Freeze-thaw cycle affects the acoustic emission and thermal infrared radiation characteristics of rocks. Under the same stress, samples with more freeze-thaw cycles have higher surface temperature, and tensile failure is the main failure factor.
FRONTIERS IN EARTH SCIENCE
(2022)
Article
Energy & Fuels
Yuan Cui, Lei Xue, Mengyang Zhai, Chao Xu, Fengchang Bu, Li Wan
Summary: This study investigates the failure characteristics of high temperature granite under different heating-cooling cycles. By conducting uniaxial compression tests and monitoring acoustic emission (AE), it reveals the damage behavior and AE characteristics of the granite at different stages of damage. The results show that increasing the number of heating-cooling cycles leads to irreversible damage to the high temperature rock mass, as evidenced by the increased mass-loss and volume-increase rates and decreased P-wave velocity. The findings also provide insights into the evolution mechanism of microcracks and fracture modes in the rock, which can be valuable in designing geothermal-resource mining schemes and safe mining constructions.
GEOMECHANICS AND GEOPHYSICS FOR GEO-ENERGY AND GEO-RESOURCES
(2023)
Article
Engineering, Geological
Seong Jun Ha, Yejin Kim, Tae Sup Yun
Summary: In this study, hydraulic fracturing by liquid carbon dioxide (LCO2) and water in a granitic specimen was investigated to determine the micro-scale characteristics of generated microcracks. The results showed that LCO2 and water injection produced different fracture characteristics, with LCO2 requiring a greater fluid volume to generate a lower breakdown pressure. The developed microcracks were affected by the fracturing fluid and anisotropic properties of granitic rocks.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2021)
Article
Energy & Fuels
Yun Wu, Xiao-Zhao Li, Zhen Huang, Ying-Chao Wang, Long-Chuan Deng
Summary: The study found that the P-wave velocity of granite decreases with temperature, the porosity of granite increases rapidly above 500 degrees C, and the tensile strength of granite linearly decreases with temperature. Acoustic emission tests and thin section observations showed that temperature leads to an increase in the closure and unstable extension of cracks. The research findings can provide guidance for the construction safety of rock masses exposed to high temperatures.
GEOMECHANICS AND GEOPHYSICS FOR GEO-ENERGY AND GEO-RESOURCES
(2021)
Article
Energy & Fuels
Diyuan Li, Xiaoli Su, Feihong Gao, Zida Liu
Summary: The effects of temperature and cooling rate on the microstructural changes and mechanical properties of rocks in enhanced geothermal systems were investigated. The results showed that thermal-induced cracks destroy the rock microstructural integrity and cold water widens these cracks. The physical and mechanical properties of the rocks are weakened with increasing temperature. Rapid water cooling has a more significant effect on the rocks than slow cooling. Thermal-induced cracks alter the stress concentration and increase unstable crack propagation regions.
GEOMECHANICS AND GEOPHYSICS FOR GEO-ENERGY AND GEO-RESOURCES
(2022)
Article
Geosciences, Multidisciplinary
Huang Wang, Guiling Wang, Yuedu Chen, Lu Liu, Zhihong Zhao, Haonan Gan
Summary: Hydraulic fracturing (HF) technology plays a crucial role in forming connected fracture networks in low-permeability geothermal reservoirs, but the understanding of the HF process and failure mechanism is still incomplete. To evaluate the initiation and propagation of hydraulic fractures, a series of true triaxial hydraulic fracturing tests were conducted on large-scale natural granite samples under different confining conditions, combined with acoustic emission monitoring. The results showed that main hydraulic fractures were formed in three samples during the first fracturing process, with the majority being tensile fractures. These test results provide valuable insights into the effect of HF under different stress conditions.
FRONTIERS IN EARTH SCIENCE
(2022)
Article
Geosciences, Multidisciplinary
Yun Wu, Xiao-Zhao Li, Zhen Huang, Sen Xue
Summary: The study found a temperature threshold of 300 degrees C for granite, with increasing temperature leading to a sharp decrease in peak strength, P-wave velocity, and mass loss ratio. Additionally, the growth of thermal cracks at different elevated temperatures resulted in changes to the rock failure mode.
Article
Green & Sustainable Science & Technology
Fangchao Kang, Tianrang Jia, Yingchun Li, Jianhui Deng, Chun'an Tang, Xin Huang
Summary: This study experimentally investigates the physical and mechanical variations of granite, a typical type of HDR, after different cooling treatments. The results show that liquid-nitrogen cooling treatment induces the most alterations in granite properties, leading to more intensive crack networks and higher permeability, especially for specimens heated to temperatures over 400 degrees C.
Article
Engineering, Mechanical
Shaokun Ge, Chunlei Wu, Changlin He, Yuheng Wang, Deliang Chen, Bobo Shi
Summary: This study investigates the thermal damage of high-temperature sandstone subjected to cooling shock and its effect on capturing acoustic emission (AE) signals during fracture. The results show that cooling shock sandstone has increased crack density and volume, decreased p-wave velocity, and reduced mechanical strength. An attenuation coefficient alpha related to the elastic modulus and crack change rate is derived, providing an approach to calculate the attenuation of AE signal caused by thermal damage.
ENGINEERING FAILURE ANALYSIS
(2023)
Article
Energy & Fuels
Yanjun Shen, Jiangqiang Yuan, Xin Hou, Jianshuai Hao, Zhipeng Bai, Ting Li
Summary: This study investigates the effect of cooling shocks on high-temperature granite by inducing cooling shocks with different temperature refrigerants. The results show that the refrigerant temperature has a significant impact on the strength and failure modes of the granite, providing practical experience and references for geothermal development.
GEOMECHANICS AND GEOPHYSICS FOR GEO-ENERGY AND GEO-RESOURCES
(2021)
Article
Acoustics
Yihao Cheng, Chunming Song, Yizhong Tan, Songlin Yue, Gan Li, Yanyu Qiu, Tianhan Xu, Yong Liu, Fei Gao, Qian Yu
Summary: This study investigates the theoretical calculation method of the Hel of hard rock under dynamic loadings, and proposes a calculation method based on the Lundborg strength criterion. The factors influencing the Hel are analyzed, showing that Poisson's ratio and plastic limit could be the most important. The simplified model provides a rational prediction of the Hel of hard rock, while explaining the abnormal variations in plate impact experiments.
SHOCK AND VIBRATION
(2021)
Article
Geosciences, Multidisciplinary
Hong Tian, Zhennan Zhu, Pathegama Gamage Ranjith, Guosheng Jiang, Bin Dou
Summary: Understanding the drillability indices of thermal granite under different water-cooling conditions is crucial for deep geothermal energy extraction. This study found that as thermal temperature increased, the physico-mechanical parameters and hardness of thermal granite decreased linearly, while drilling rate and plasticity coefficient increased exponentially. The width and density of micro-cracks in thermal granite increased gradually with thermal temperature, leading to degradation in drillability indices.
NATURAL RESOURCES RESEARCH
(2021)
Article
Engineering, Geological
A. Srivastav, V. H. R. Pandey, A. Kainthola, P. K. Singh, V Dangwal, T. N. Singh
Summary: The study investigates the effect of different support systems on deformation in a shallow tunnel in the North-Western Himalayan region of India. By utilizing field investigation data and finite element back analysis, it was found that forepoling and steel liners can markedly reduce tunnel deformation in this geological setting.
INDIAN GEOTECHNICAL JOURNAL
(2022)
Article
Engineering, Environmental
Jagadish Kundu, Kripamoy Sarkar, A. K. Verma, T. N. Singh
Summary: Kinematic analysis is a widely used method to assess stability condition in jointed rock slopes and predict block detachments. A novel method based on adjustment factors of slope mass rating (SMR) has been introduced in this paper to quantify kinematic susceptibility, with the help of a computer application named EasySMR. The algorithm has been validated with results from 35 rock slopes in the Himalayan region, showcasing its rigorous and accurate analysis capabilities.
BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT
(2022)
Article
Engineering, Mechanical
Hari Om Singh, T. N. Singh, K. H. Singh
Summary: The study predicted potential instability of eight different slopes along NH-7 in Uttarakhand, India, with most slopes found to be unstable. Various methods were used to assess stability, including rock mass characterization, kinematic analysis, and numerical methods, showing that seismic forces significantly increased slope instability. The study also found that the Nonlinear Generalized Hoek-Brown failure criterion provided more accurate results in the seismically active jointed rocks of the Himalayas.
ENGINEERING FAILURE ANALYSIS
(2022)
Article
Geosciences, Multidisciplinary
Arunava Ray, Rajesh Rai, T. N. Singh
Summary: This study examines the effect of discontinuity orientations and thickness of the weathered layer on the stability of jointed phyllite rock slopes in the Lesser Himalayan region. Numerical simulation is used to assess the performance of the slope under different conditions. The results indicate that the stability of the slope depends on the relative orientation and distribution of the joint sets and the thickness of the weathered layer.
JOURNAL OF THE GEOLOGICAL SOCIETY OF INDIA
(2022)
Article
Geosciences, Multidisciplinary
Arunava Ray, Harshal Verma, Ashutosh Kumar Bharati, Rajesh Rai, Radhakanta Koner, Trilok Nath Singh
Summary: This study simulated and calibrated debris flow in a laboratory setting, validated with a case study of the Varunavat landslide, and evaluated the impact of various factors on debris flow. Qualitative and quantitative analysis of the debris flow was conducted, along with an examination of the role of retaining walls in mitigating debris flow.
Article
Engineering, Geological
Pawan Kumar Soni, Arun K. Singh, N. Sivakumar, Trilok N. Singh
Summary: This article experimentally studies the frictional properties of a wet granular layer on a rock surface and explores the relationship between the static, steady, and residual stresses of the wet layer and the shear rate. The adhesive stress and coefficient of friction are determined using Coulomb's law of friction, and it is found that both components of friction increase with shear rate. A friction model is used to predict the static friction of the granular layer, and scaling laws are proposed for static friction in terms of chain density, relaxation time, and extension of molecular chains.
INTERNATIONAL JOURNAL OF GEOMECHANICS
(2022)
Article
Engineering, Geological
Arunava Ray, Ashutosh Kumar Bharati, Harshal Verma, Rajesh Rai, T. N. Singh
Summary: The bioengineering technique of slope stabilisation requires a good understanding of root distribution and root-soil-slope relationship. Probability analysis is used to consider the variability of root features and slope material. Mean rooting depth plays a vital role in the effectiveness of the technique, particularly on steep slopes. Vegetation stabilisation is best suited for moderate slope inclinations, with maximum shear strength increase at a slope inclination of around 50 degrees.
GEOMECHANICS AND GEOENGINEERING-AN INTERNATIONAL JOURNAL
(2023)
Article
Environmental Sciences
Ujjwal Sur, Prafull Singh, Sansar Raj Meena, Trilok Nath Singh
Summary: This study utilized the modified frequency ratio and fuzzy analytical hierarchy process, as well as the object-based geon method, to delineate the landslide susceptibility map for the lesser Himalayan region. The results showed that the object-based geon method had higher accuracy, providing important references for future mitigation and development.
Article
Engineering, Geological
Hari Om Singh, Tariq Anwar Ansari, T. N. Singh, K. H. Singh
Summary: This study aimed to predict the geomechanical properties of three different metamorphic rocks using simple and multiple regression analysis. By establishing predictive models and performing statistical analysis, it was found that the developed empirical models had high prediction performance and could be used to predict the strength and elastic properties of rocks.
GEOTECHNICAL AND GEOLOGICAL ENGINEERING
(2022)
Article
Engineering, Environmental
Sahil Sardana, Rabindra Kumar Sinha, A. K. Verma, T. N. Singh
Summary: The freeze-thaw process has a significant impact on slope stability in cold regions, particularly in the upper mountainous areas of the Himalayas. Understanding the deterioration behavior of Himalayan rock before construction is crucial. Laboratory tests revealed that multiple freeze-thaw cycles caused microscopic damages and degradation in physico-mechanical properties of the rock specimens. Mathematical modeling was then used to determine various coefficients and the disintegration rate of Himalayan schist under the influence of freeze-thaw.
BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT
(2022)
Article
Environmental Sciences
Digvijay Singh, P. K. Singh, A. Kainthola, H. K. Pandey, Saurabh Kumar, T. N. Singh
Summary: Anisotropic sedimentary rocks are common globally and factors such as Geological strength index, weathering, and cohesion loss rate impact slope stability significantly; various indicators can be used to understand strength degradation over time and progressive failure processes.
ENVIRONMENTAL EARTH SCIENCES
(2022)
Article
Engineering, Geological
Sahil Sardana, Rabindra Kumar Sinha, A. K. Verma, Mamta Jaswal, T. N. Singh
Summary: This study focuses on the rockfall problem along the Lengpui-Aizawl highway in Northeastern India and develops equations to predict the rockfall parameters. Through site investigation, laboratory tests, and modeling, generalized rockfall equations were derived to predict the outcome of rockfall activity and assist in designing mitigative measures.
GEOTECHNICAL AND GEOLOGICAL ENGINEERING
(2022)
Article
Engineering, Environmental
Pradeep Kumar Gautam, Suraj Pratap Singh, Amar Agarwal, Trilok Nath Singh
Summary: This study investigated the physical and mechanical properties of two different granitic rocks with varying grain sizes at different heating rates. The results revealed that the heating rate had a significant impact on the micro- and macrocracks in the rocks, with an increase in the number of cracks observed in red granite as the heating rate increased. Quartz and biotite were found to be the main contributors to the formation of microcracks, with the thermal expansion anisotropy of quartz having a smaller effect on stress compared to the mismatched thermal expansion of biotite. The tensile strength of coarse-grained red granite specimens exhibited less significant increases compared to fine-grained white granite specimens.
BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT
(2022)
Article
Energy & Fuels
Debanjan Guha Roy, T. N. Singh
Summary: This paper investigates the relationship between the strength properties and fracture toughness of Dholpur sandstone at elevated temperatures. The study identifies a suitable brittleness index and examines the stress-strain behavior, degradation degree, peak strain, and porosity values to evaluate the brittle-ductile transition of the rock. The results show the exponential relationship of fracture toughness with Young's modulus, tensile strength, and brittleness index, and suggest a potential transition temperature for Dholpur sandstone.
GEOMECHANICS FOR ENERGY AND THE ENVIRONMENT
(2023)
Article
Engineering, Geological
Sahil Sardana, Rabindra Kumar Sinha, A. K. Verma, Mamta Jaswal, T. N. Singh
Summary: The rock slopes in the Indian Himalayan region experience reduced strength and microscopic damages due to freeze-thaw action. Numerical analysis indicates a decrease in safety factor for rock slopes as a result of freeze-thaw conditioning.
CANADIAN GEOTECHNICAL JOURNAL
(2022)
