Article
Chemistry, Multidisciplinary
Pu Yuan, Qinghe Zhang, Aobo Li
Summary: Numerical simulations using LS-DYNA were performed to study the effect of cyclic impacts and confining pressure on the damage evolution of rock materials. The results show that both the confining pressure and amplitude of incident stress waves significantly influence the damage evolution. High incident stress waves result in severe damage, while large confining pressure leads to minor damage. The damage to rock materials is alleviated under confining pressure due to the constraint effect on crack propagation. The cumulative damage of rock materials under confining pressure progressively increases with the number of cyclic impacts, exhibiting three distinct stages of evolution: rapid rising, steady development, and sharp rising.
APPLIED SCIENCES-BASEL
(2023)
Article
Engineering, Geological
Xinyu Wang, Bin Dong, Xicai Gao, Pengfei Li, Shuren Wang, Bin Hu
Summary: Drill and blast tunneling is a construction process that subjects rock to cyclic blast load, affecting the rock's behavior, energy characteristics, and damage. Dynamic tests were conducted on granite samples of 100-mm diameter at different impact velocities to study their dynamic mechanical properties and energy evolution under cyclic impact loading. The stress-strain relationship, energy and damage evolution, and microscopic features of the rock were analyzed. Results showed that the stress-strain relationship of granite is sensitive to impact velocity and impact number. The energy evolution presented a uniform trend, and the rock failure occurred at higher impact velocities.
ROCK MECHANICS AND ROCK ENGINEERING
(2023)
Article
Engineering, Geological
Xu Chen, Minggao Tang, Chun'an Tang
Summary: The study investigated the effect of confining pressure on damage evolution and failure behaviors of intact sandstone samples under cyclic disturbance. It was found that both the duration and number of cycles positively correlate with confining pressure, impeding crack formation and reducing damage during cyclic disturbance. Increasing confining pressure resulted in more flaking and exfoliation of rock samples after the cyclic disturbance tests.
ROCK MECHANICS AND ROCK ENGINEERING
(2022)
Article
Engineering, Geological
Qing-bin Meng, Jiang-feng Liu, Bing-xiang Huang, Hai Pu, Jiang-yu Wu, Zhi-zhen Zhang
Summary: This study investigated the influences of confining pressure and temperature on the energy evolution and distribution characteristics of high-temperature rock samples through triaxial cyclic loading and unloading tests. The results showed that the energy accumulation, dissipation, and release of loaded rock samples varied under different confining pressures and temperatures.
ROCK MECHANICS AND ROCK ENGINEERING
(2022)
Article
Mechanics
Yang Dongjie, Hu Jianhua, Ma Shaowei, Zeng Pingping
Summary: The study conducted an in-depth investigation on granite using high confining pressure cyclic loading for predamage experiments, demonstrating that granite exhibits varying degrees of damage during the cyclic loading process. The energy signal released by granite when rupturing in the predamage experiment weakens with an increase in cycle number, and the fracture mode also changes accordingly.
ENGINEERING FRACTURE MECHANICS
(2022)
Article
Engineering, Geological
Y. Wang, W. K. Feng, R. L. Hu, C. H. Li
Summary: This study investigates the fracture evolution and energy characteristics of marble under fatigue cyclic loading and confining pressure unloading conditions, showing that the damage accumulation during fatigue loading stage influences the final failure mode and energy conversion. The post-test CT scanning reveals the effects of fatigue cycles on crack pattern and scale after FC-CPU testing, providing insight into the energy changes during the process.
ROCK MECHANICS AND ROCK ENGINEERING
(2021)
Review
Engineering, Geological
Yi Liu, Feng Dai
Summary: This study comprehensively reviews the deformation, failure mechanism, and fatigue constitutive relationship of rocks subjected to cyclic loading over the past 60 years. It classifies cyclic tests on rocks, summarizes fatigue responses, discusses the influences of cyclic loads, outlines constitutive relationships, and suggests future research directions.
JOURNAL OF ROCK MECHANICS AND GEOTECHNICAL ENGINEERING
(2021)
Article
Engineering, Mechanical
Xuesong Wang, Lian Jun Guo, Zhenyang Xu, Xin Liu, Jinglong Xu, Bo Pan, Ding Deng
Summary: In this study, the relationship between cyclic impact, dynamic characteristics, and porosity variation was investigated by dynamically loading red sandstone specimens. It was found that a large number of microcracks occurred before particle crushing, and the change in porosity reflected the dynamic mechanical characteristics of the rock.
FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
(2023)
Article
Engineering, Mechanical
Yu Wang, Mingqi Yan, Weibin Song
Summary: This study aims to investigate the influence of cyclic stress amplitude (CSA) on the macro-meso failure characteristics of deeply buried rock during the process of confining pressure unloading. Experimental results demonstrate that the deterioration of rock structure is affected by the disturbed stress amplitude. The lateral expansion caused by confining pressure unloading has a significant impact on rock volumetric deformation, damage propagation, and failure characteristics. Additionally, a damage evolution model is proposed to describe the progressive damage evolution pattern, which can be expressed using the irreversible lateral strain. CT images reveal the complexity of the crack network, which decreases with increasing CSA. Furthermore, the final volumetric deformation depends not only on the stimulated crack pattern but also on the failure modes, with specimens exhibiting pure shear failure mode showing the largest volumetric deformation.
FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
(2023)
Article
Engineering, Geological
Dongjie Yang, Jianhua Hu, Tan Zhou, Xiaotian Ding
Summary: The study analyzed the mechanical properties and damage of granite under cyclic loading at different confining pressures. The results showed that with an increase in cycles, lateral deformation decreased gradually, residual displacement increased, and the deformation modulus decreased with increasing confining pressure.
INTERNATIONAL JOURNAL OF GEOMECHANICS
(2022)
Article
Energy & Fuels
Quanqi Zhu, Diyuan Li, Wenjian Wang
Summary: Permeability, a fundamental index related to rock damage, was studied through dynamic triaxial compression tests on sandstone under various conditions. Results showed that peak stress, strain, plasticity, damage, and permeability increase with higher incident energy. Only peak stress increases with higher confining pressure.
GEOMECHANICS AND GEOPHYSICS FOR GEO-ENERGY AND GEO-RESOURCES
(2021)
Article
Mechanics
Y. Wang, Y. Z. Hu, S. H. Gao
Summary: This study investigated the fracture evolution characteristics of rocks under different interbed orientations using multi-level cyclic compressive loading experiments. The results showed that rock structure significantly impacted fatigue deformation, strength, and dynamic elastic modulus. A damage evolution model was established to simulate the accumulation of damage, revealing the influence of interbed orientation on crack propagation path and failure mode.
ENGINEERING FRACTURE MECHANICS
(2021)
Article
Engineering, Environmental
Hanxiang Liu, Kefan Gao, Xing Zhu
Summary: This study investigated the dynamic fatigue properties of dolomite through triaxial multilevel cyclic loading tests, revealing a significant three-phase evolution process for the fatigue behavior. With each level of cyclic loading, cracks and pores generated in the prior level were closed, leading to recovery of sample stiffness in the initial period with initial decrease and subsequent increase in dynamic damping. Prior to failure, a sharp increase in cumulative residual strain and significant decrease in dynamic elastic modulus indicated severe unrecoverable damage in rock samples.
BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT
(2021)
Article
Engineering, Mechanical
Y. Wang, S. H. Gao, C. H. Li, J. Q. Han
Summary: The study investigates the fatigue mechanical behaviors of marble under freeze-thaw treatment, showing that fatigue strength and strain energy decrease while irreversible volumetric deformation increases with the number of cycles. The rate of dissipated energy increases as the cyclic loading level grows. A coupling damage variable is proposed to describe rock damage evolution after freeze-thaw treatment and fatigue loading, with a damage evolution model established to fit the experimental data showing two-phase damage accumulation characteristics.
INTERNATIONAL JOURNAL OF FATIGUE
(2021)
Article
Engineering, Mechanical
E. Madenci, A. Barut, A. Yaghoobi, N. Phan, R. S. Fertig
Summary: This study introduces a fatigue model for constant and variable amplitude cyclic loading by combining KTF with PD, demonstrating the reliability of this model through simulations of composite laminates with open-hole defects under cyclic loads.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2021)
Article
Engineering, Civil
Haojun Yu, Enlong Liu
Summary: A binary-medium constitutive model for artificially cemented mixed soils is proposed to reflect the mechanical properties well, considering the soils as a combination of bonded blocks and weakened bands. The model describes the deformation properties of the soil using modified Duncan-Chang and Lade-Duncan elastoplastic models, and introduces structural parameters for stress and strain distribution within a representative volume element.
EUROPEAN JOURNAL OF ENVIRONMENTAL AND CIVIL ENGINEERING
(2022)
Article
Engineering, Geological
Runing Hou, Ningsheng Chen, Guisheng Hu, Zheng Han, Enlong Liu
Summary: This study examines a semi-diagenetic landslide disaster that occurred in China, analyzing its failure characteristics, inducement, and mechanisms through field investigations and numerical calculations. The study also identifies issues with the current community early warning system and suggests improvements to enhance scientific disaster reduction efforts.
Article
Computer Science, Interdisciplinary Applications
Wei Xiao, Enlong Liu, Xiao Yin, Guike Zhang, Chong Zhang, Qihao Yu
Summary: This study helps to understand the thawing process of frozen soil by coupled thermo-hydro-mechanical numerical simulation. The larger temperature gradient, higher overburden pressure and higher water content could lead to larger thawing settlement. Temperature was observed to distribute height linearly in both frozen and unfrozen zones of the sample, while water migration forces a decrease in water content of the unfrozen zone and an increase at the thawing front.
ENGINEERING COMPUTATIONS
(2022)
Article
Environmental Sciences
Ziyin Cai, Enlong Liu, Ningsheng Chen, Jili Feng, Guisheng Hu, Yu Su
Summary: This study numerically simulates the entire dynamic process of the Yigong landslide in Tibet, China, focusing on its initiation and sliding mechanism. The continuous-discontinuous method is used, combining the finite element method with the discrete element method. The simulation results provide a clear presentation of the cracks in the landslide body and reproduce the landslide accumulation with acceptable accuracy. The findings contribute to understanding the deformation mechanism of landslides.
ENVIRONMENTAL EARTH SCIENCES
(2022)
Article
Engineering, Civil
Di Yu, Enlong Liu, Ping Sun, Huilin Xing, Qingsong Zheng
Summary: This paper investigates the dynamic properties and deformation features of rocks through triaxial cyclic tests, proposing a dynamic stress ratio Rs and a dynamic binary-medium constitutive model. The results demonstrate that the model can effectively replicate the typical features of hysteresis loops and is consistent with experimental results.
EUROPEAN JOURNAL OF ENVIRONMENTAL AND CIVIL ENGINEERING
(2022)
Article
Materials Science, Multidisciplinary
Yi Sun, Enlong Liu, Bin Zhi
Summary: The mechanical behaviors of cemented granular soils under undrained conditions and cyclic loads were studied through numerical simulations. The evolution of the internal structure and the residual pore-water pressure were analyzed based on complex network parameters. A new pore-water pressure model was proposed. The evolution of the mesostructure can describe the development of pore-water pressure in granular cemented soils.
Article
Engineering, Civil
Yanyang Yu, Enlong Liu, Qihao Yu, Guike Zhang, Xia Ye
Summary: In cold regions at high altitudes, freeze-thaw cycles in the construction process can weaken the mechanical properties of core-wall soil materials in dams. This study investigates the effects of freezing and thawing on the mechanical behaviors of contact clay through triaxial tests. The results show that freezing and thawing significantly decrease the modulus, strength, and internal friction angle of the clay, particularly in the first three freeze-thaw cycles. After approximately five cycles, these parameters tend to stabilize.
INTERNATIONAL JOURNAL OF CIVIL ENGINEERING
(2022)
Article
Computer Science, Hardware & Architecture
Zengle Li, Bin Zhi, Enlong Liu
Summary: In response to the challenges of China's transition to green low-carbon energy, cross-boundary thinking using energy Internet can help integrate renewable clean energy and buildings. Through experiments and modeling, the influence of temperature on the stress-strain relationship of structural loess was explored.
JOURNAL OF CIRCUITS SYSTEMS AND COMPUTERS
(2022)
Article
Engineering, Geological
Jianqiu Tian, Yuanming Lai, Enlong Liu, Yunming Yang
Summary: This paper presents a micromechanical model of granular materials based on the Cosserat continuum theory, aggregating micro elasto-plastic inter-particle contact laws to describe both macro and micro responses of granular materials, such as strain softening/hardening, volumetric compaction/dilatancy, particle rotation, and evolution of the coordination number. The model is integrated using an implicit multiscale algorithm and simplified for a two-dimensional condition, with Romberg integration introduced for numerical quadrature.
Article
Chemistry, Physical
Peng Cao, Xuebing Hu, Enlong Liu, Jianzhong Chen, Shouchao Jiang, Hao Ding
Summary: Studied the mechanical behavior and damage characteristics of a new composite structure under high temperature fire. Results showed that the internal part of the structure was directly affected by the high temperature, while the part far from the fire surface experienced a lag effect. The roof deformation exhibited three stages. The overall cracks were symmetrically distributed and the structure presented a shear failure mode.
Article
Geosciences, Multidisciplinary
Jules Maurice Habumugisha, Ningsheng Chen, Mahfuzur Rahman, Providence Habumuremyi, Etienne Tuyishimire, Zheng Zhong, Shufeng Tian, Md Monirul Islam, Enlong Liu, Zheng Han, Huayong Ni, Ashraf Dewan
Summary: This study explored the factors influencing soil mass failure in hollows through experimental methods and found that initial moisture content, slope angle, and clay content have significant effects on soil mass collapse. The study also provides a detailed insight into the processes and factors involved in soil mass failure, which can be utilized to improve monitoring, early warning, and forecasting systems.
Article
Engineering, Civil
Yanbin Chen, Enlong Liu, Peng He
Summary: This paper focuses on studying the inelastic responses of geological materials using a binary-medium-based constitutive model. The progressive transformation of the bonded medium into the frictional medium is considered to understand the evolution of meso-structure upon loading. The double-inclusion model is used to analyze the interactions between inclusions and the matrix, taking into account the varying breakage ratio. The proposed model successfully reproduces the typical behaviors of cemented/structured geomaterials.
EUROPEAN JOURNAL OF ENVIRONMENTAL AND CIVIL ENGINEERING
(2023)
Article
Engineering, Civil
Xiao Yin, Enlong Liu, Chong Zhang
Summary: Based on the similarity between the drying-wetting process and freezing-thawing process in the soil, a physically based equation predicting the soil freezing characteristic curve (SFCC) is formulated. The equation is extended for double-porosity soil, with the ability to characterize the bimodality of the SFCC. A systematic approach is presented to account for the effects of pore size distribution and hydraulic conditions on the SFCC. Good agreements are found between model predictions and experimental data.
JOURNAL OF HYDROLOGY
(2022)
Article
Green & Sustainable Science & Technology
Yongtao Zhang, Huiwu Luo, Peishuai Chen, Enlong Liu, Yanbin Chen
Summary: The mechanical and deformation mechanism of coral-reef limestone is crucial for the stability and safety of infrastructures. A new constitutive model based on uniaxial compression testing was developed to accurately reflect the salient features of coral-reef limestone, such as strain softening and bonding breakage.
Article
Engineering, Geological
Xiao Yin, Yuanming Lai, Enlong Liu
Summary: Based on current knowledge, this paper proposes a method to determine the effective stress of unsaturated frozen soils by considering the soil microstructures. The degrees of saturation at both micro- and macroscopic scales are used to separate water in different pores. The derived effective stress accounts for the morphology and mechanical properties of ice and can be simplified under various assumptions. The paper also derives the elastic bulk modulus of the solid matrix and investigates the dissipation inequality during inelastic deformation. This theoretical work provides important insights into the mechanical constitutive study of unsaturated and saturated frozen soils in cold regions engineering.
INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS
(2023)