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Advances and Challenges in Rock Mechanics and Rock Engineering
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Advances and Challenges in Rock Mechanics and Rock Engineering

A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Civil Engineering".

Deadline for manuscript submissions: closed (20 April 2024) | Viewed by 15807

Special Issue Editors

Dr. Meng Li

E-Mail Website
Guest Editor
State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Xuzhou 221116, China
Interests: rockmass mechanics; fractured rock mass; constitutive models; backfill mining; rock engineering
Special Issues, Collections and Topics in MDPI journals
Dr. Peng Huang

E-Mail Website
Guest Editor
1. School of Mines, China University of Mining and Technology, Xuzhou 221116, China
2. State Key Laboratory of Coal Resources and Safe Mining, China University of Mining & Technology, Xuzhou 221116, China
Interests: rockmass instability; fractured rock mass; constitutive models; energy evolution; strata control; environmental effects
Dr. Nan Zhou

E-Mail Website
Guest Editor
School of Mines, China University of Mining and Technology, Xuzhou 221116, China
Interests: backfill mining; cemented paste backfill materials; mine solid waste utilization and management
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The mining activities disrupt the balance of the in situ stress, resulting in the instability and collapse of the rock formation, as well as the surface subsidence. Mining-induced rock mass stability is essential for controlling rock movement and mastering mine pressure. The roadway support design, working face support selection, and dynamic disaster prevention measures, for example, are closely related to the mechanical properties, fracture mechanism and stability form of rock mass. Currently, the prevention and control of rock mass instability focus primarily on backfilling goaf, enhancing rock mass strength, and optimizing mining design. As the mining depth increases, the mechanism underlying rock mass instability and fracture formation will become more complicated. Consequently, novel methods for preventing and controlling rock mass instability are critical for ensuring the safety and efficiency of mining activities.

The primary objective of this Special Issue is to encourage scholars to present new perspectives, advances and challenges in rock mechanics and rock engineering induced by mining. Topics of interest include, but are not limited to, the following: the proposition of mine rock mass mechanics; predicting mechanical behavior of rock mass; rock strata movement; rockmass mechanics tests; constitutive models and instability criterion; fracture and energy evolution of rock mass; seepage analysis of fractured rock mass; grouting reinforcement of fractured rock mass; key technology of preventing and controlling rock mass instability; underground mining with backfill; safety and environmental effects; and other engineering applications.

Dr. Meng Li
Dr. Peng Huang
Dr. Nan Zhou
Guest Editors

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Applied Sciences is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • rockmass instability
  • rockmass mechanics
  • fractured rock mass
  • constitutive models
  • energy evolution
  • strata control
  • backfill mining
  • rock engineering

Published Papers (17 papers)

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16 pages, 8529 KiB  
Article
Comparative Analysis of the Stability of Overlying Rock Mass for Two Types of Lined Rock Caverns Based on Rock Mass Classification
by Qi Yi, Zhen Shen, Guanhua Sun, Shan Lin and Hongming Luo
Appl. Sci. 2024, 14(8), 3525; https://doi.org/10.3390/app14083525 - 22 Apr 2024
Viewed by 3
Abstract
Lined rock caverns (LRCs) are becoming the preferred option for air storage at sites where there are no natural cavities, such as salt caverns, and this storage technology is being developed and utilized in markets around the world. The stability of the overlying [...] Read more.
Lined rock caverns (LRCs) are becoming the preferred option for air storage at sites where there are no natural cavities, such as salt caverns, and this storage technology is being developed and utilized in markets around the world. The stability of the overlying rock mass is one of the key factors to ensure the successful operation of LRCs. In this paper, a stability assessment method is presented that first calculates the potential fracture surfaces of the surrounding rock based on the limiting stress field and the Mohr–Coulomb damage criterion, and then, based on these fracture surfaces, solves for the factor of safety defined on the basis of the concept of strength reserve. Using this method, this study evaluates the stability of two types of LRCs, tunnel- and silo-type, under three different geological conditions. The results of the analysis show that the silo-type LRCs are more economical for engineering purposes. Also, this paper provides some guidance for engineers in site selection and preliminary design. Full article
(This article belongs to the Special Issue Advances and Challenges in Rock Mechanics and Rock Engineering)
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18 pages, 5510 KiB  
Article
Analytical Solution of Ice–Rock-Model Stress Field and Stress Intensity Factors in Inhomogeneous Media
by Feifei Cao, Laiwang Jing and Shaochi Peng
Appl. Sci. 2024, 14(4), 1412; https://doi.org/10.3390/app14041412 - 08 Feb 2024
Viewed by 527
Abstract
The stress distribution and fracture parameter calibration of ice–rock models are important aspects of studying rock properties at high altitudes and latitudes. However, progress in ice–rock modeling has been slow and singular, and it is limited due to the discrete nature of rocks [...] Read more.
The stress distribution and fracture parameter calibration of ice–rock models are important aspects of studying rock properties at high altitudes and latitudes. However, progress in ice–rock modeling has been slow and singular, and it is limited due to the discrete nature of rocks and the applicability of fracture mechanics. In this study, a circular inhomogeneous ice–rock model is proposed for the first time, and a method is provided for calculating the stress field of the model under biaxial loading. A method for calculating the single-crack stress intensity factor of the model subjected to biaxial compressive loading is also provided. The novelty of this work is that the inhomogeneous ice–rock model is treated as a superposition of two models, namely, a circular pore plate and circular ice, according to the superposition principle. The key is that the stress field distribution law of the ice–rock model is obtained based on the basis of the displacement continuity of the ice–rock interface. The analytical and approximate solutions of the stress intensity factor of a single crack were also obtained by considering the normal phase effect of the crack surface and combining the stress distribution law of the ice–rock model. Comparison with the CAE method was made to verify the correctness of the stress field and stress intensity factor calculation methods. The evolution laws of lateral pressure coefficients, the elastic modulus ratio of ice and rock on the stress field, and the stress intensity factor were analyzed. The effects of lateral pressure coefficients, elastic modulus ratios, and crack distributions on the failure modes were investigated using the extended finite element method (XFEM). This study can provide a theoretical basis for the evaluation of mechanical properties and prediction of the failure modes of frozen rock bodies. Full article
(This article belongs to the Special Issue Advances and Challenges in Rock Mechanics and Rock Engineering)
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21 pages, 8303 KiB  
Article
Study on Voids and Seepage Characteristics within Rock Fracture after Shear Dislocation Viewing from CT Test and Numerical Modeling
by Tingfa Dong, Jian Zhou, Ziqian Yan, Yanfang Wu and Tianqiao Mao
Appl. Sci. 2024, 14(3), 1013; https://doi.org/10.3390/app14031013 - 24 Jan 2024
Cited by 1 | Viewed by 512
Abstract
In rock mass engineering, stress balance changes often cause the relative slip of fractures along a wall surface, impacting the seepage behavior of fluid in the fractures. Using computer tomography (CT) scanning, spatial models of fractures with dislocations ranging from 0 to 10 [...] Read more.
In rock mass engineering, stress balance changes often cause the relative slip of fractures along a wall surface, impacting the seepage behavior of fluid in the fractures. Using computer tomography (CT) scanning, spatial models of fractures with dislocations ranging from 0 to 10 mm were created to explore the relationship between changes in fracture dislocation and changes in fluid flow behavior, respectively. The spatial fractal dimension of cavity distribution within the fractures was calculated using a thin-plate filling approach to characterize the complexity of the fracture cavity distribution. The fluid flow within the dislocation fractures was then simulated using COMSOL, and the effect of cavity alterations in the form of dislocation on the fluid seepage behavior was analyzed using the spatial fractal. The results show that the values of mechanical aperture after dislocation of the fracture obtained by a CT test are normally distributed, the distribution range of mechanical aperture gradually widens with an increase in the dislocation distance, and the average mechanical aperture increases on a logarithmic curve. The relative spatial fractal dimension decreases gradually with an increase in dislocation distance, and the interconnected pathways within the fracture decrease; in addition, it is observed that the change in the relative spatial fractal dimension is closely correlated with the change in the mean mechanical aperture. Numerical simulations of dislocation fracture seepage found that the permeability increases nonlinearly with increasing dislocation distance. When the dislocation distance reaches 5 mm, nonlinear behaviors such as eddy currents occur, and the influence range of eddy currents gradually expands with the increase in dislocation distance under the influence of the boundary. Moreover, the inertia coefficient B in the Forchheimer equation and the critical hydraulic gradient Jc, which can describe the nonlinear seepage characteristics, show a power function decreasing trend with increasing dislocation distance, and the fluid in the fracture is more likely to produce nonlinear flow. Full article
(This article belongs to the Special Issue Advances and Challenges in Rock Mechanics and Rock Engineering)
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15 pages, 5019 KiB  
Article
Novel Understandings of Biomineralization in Backfill Materials: A Fundamental Investigation of Coal Gangue and Fly Ash Impact on B. pasteurii to Enhance Material Properties
by Shijie Guo, Alessandro Pasquale Fantilli, Hao Yan, Kai Sun and Luwei Ding
Appl. Sci. 2024, 14(2), 799; https://doi.org/10.3390/app14020799 - 17 Jan 2024
Viewed by 659
Abstract
This paper proposes a fundamental investigation of coal gangue and fly ash impact on B. pasteurii to enhance the properties of backfill materials. The goal is to obtain effective microbial mineralization and potential mechanical properties of coal gangue and fly ash as backfill [...] Read more.
This paper proposes a fundamental investigation of coal gangue and fly ash impact on B. pasteurii to enhance the properties of backfill materials. The goal is to obtain effective microbial mineralization and potential mechanical properties of coal gangue and fly ash as backfill materials and to mitigate the impact of the most common binders used in the backfill material of mines. Micro-scale mineralization was performed with B. pasteurii bacteria using microbially induced carbonate precipitation (MICP) technology to clarify solid waste impact on B. pasteurii and to bind coal gangue and fly ash. Several tests were carried out to analyze the behavior of B. pasteurii, especially when it coexists with these two waste materials separately. In such cases, it was possible to observe a reduction in mineralization initiation time with respect to the natural mineralization of the MICP technology. Moreover, at the macro-scale, the new mineralized backfilling material shows good workability in the fresh state, whereas the strength at 28 days is 5.34 times higher than that obtained with non-mineralized coal gangue and fly ash. Full article
(This article belongs to the Special Issue Advances and Challenges in Rock Mechanics and Rock Engineering)
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20 pages, 4532 KiB  
Article
Effect of Cyclic Loading on Mode I Fracture Toughness of Granite under Real-Time High-Temperature Conditions
by Fei Lv, Fan Zhang, Subiao Zhang, Kangwen Li and Shuangze Ma
Appl. Sci. 2024, 14(2), 755; https://doi.org/10.3390/app14020755 - 16 Jan 2024
Viewed by 571
Abstract
Under hot dry rock development, rock formations undergo the combined challenges of cyclic loading and high temperatures, stemming from various sources such as cyclic hydraulic fracturing and mechanical excavation. Therefore, a fundamental understanding of how rocks fracture under these demanding conditions is fundamental [...] Read more.
Under hot dry rock development, rock formations undergo the combined challenges of cyclic loading and high temperatures, stemming from various sources such as cyclic hydraulic fracturing and mechanical excavation. Therefore, a fundamental understanding of how rocks fracture under these demanding conditions is fundamental for cyclic hydraulic fracturing technology. To this end, a series of three-point bending tests were conducted on granite samples. These tests entailed exposing the samples to cyclic loading under varying real-time high-temperature environments, ranging from 25 °C to 400 °C. Furthermore, different upper load limits (75%, 80%, 85%, and 90% of the peak load) obtained in monotonic three-point bending tests were used to explore the behavior of granite under these conditions. The analysis encompassed the study of load–displacement curves, elastic stiffness, and mode I fracture toughness under cyclic loading conditions. In addition, the microscopic features of the fracture surface were examined using a scanning electron microscope (SEM). The findings revealed notable patterns in the behavior of granite. Cumulative vertical displacement in granite increased with the growing number of cycles, especially at 25 °C, 200 °C, and 300 °C. This displacement exhibited a unique trend, initially decreasing before subsequently rising as the cycle count increased. Additionally, the critical damage threshold of granite exhibited a gradual decline as the temperature rose. As the temperature ascended from 25 °C to 200 °C, the damage threshold typically ranged between 80% and 85% of the peak load. At 300 °C, this threshold declined to approximately 75–80% of the peak load, and at 400 °C, it fell below 75% of the peak load. Within the temperature ranging from 25 °C to 300 °C, we noted a significant increase in the incidence of cracks, crystal microfracture zones, and the dislodging of mineral particles within the granite as the number of cycles increased. Full article
(This article belongs to the Special Issue Advances and Challenges in Rock Mechanics and Rock Engineering)
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13 pages, 3180 KiB  
Article
A Study of the Characteristics of Micro-Seismic (ME) and Electromagnetic Radiation (EMR) Signals under the Static Load Conditions of Rocks
by Liao He, Qingfeng Li and Baifu An
Appl. Sci. 2023, 13(23), 12910; https://doi.org/10.3390/app132312910 - 02 Dec 2023
Viewed by 714
Abstract
Geological hazards, such as the frequent occurrence of rock bursts in deep mining, emphasize the critical necessity for the early warning and prediction of dynamic fractures in coal and rock masses, as well as the destabilization of the surrounding rock. This study delves [...] Read more.
Geological hazards, such as the frequent occurrence of rock bursts in deep mining, emphasize the critical necessity for the early warning and prediction of dynamic fractures in coal and rock masses, as well as the destabilization of the surrounding rock. This study delves into the mechanisms of electromagnetic radiation (EMR) signals and their synchronous coupling with micro-seismic (ME) signals. EMR and ME signals from rock specimens were systematically collected during the uniaxial compression fracture process using a dedicated monitoring and acquisition system. Employing the wavelet analysis method, the original data underwent reconstruction and denoising, while the EMR and ME spectra, derived through fast Fourier transform, were subjected to detailed scrutiny. The comprehensive analysis unveiled that EMR signals arising from rock fractures exhibited precise timing synchronization with ME signals. Moreover, the dominant frequencies of both signals are closely aligned within the low-frequency band, indicating a remarkable degree of similarity and homology. These findings establish an experimental basis for the development of monitoring and early warning systems geared toward assessing damage to coal and rock masses using EMR and ME signals. Full article
(This article belongs to the Special Issue Advances and Challenges in Rock Mechanics and Rock Engineering)
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21 pages, 4559 KiB  
Article
Evaluation of the Rock Mechanical Properties of Shale Oil Reservoirs: A Case Study of Permian Lucaogou Formation in the Jimusar Sag, Junggar Basin
by Jian Xiong, Renzhong Gan, Xiangjun Liu, Lixi Liang and Xiucheng Guo
Appl. Sci. 2023, 13(23), 12851; https://doi.org/10.3390/app132312851 - 30 Nov 2023
Viewed by 573
Abstract
Rock mechanical properties play an important role in the exploration and development of shale oil reservoirs. To study the rock mechanical properties continuously distributed along the longitudinal direction of the formation, physical and mechanical property data of shales from the Permian Lucaogou Formation [...] Read more.
Rock mechanical properties play an important role in the exploration and development of shale oil reservoirs. To study the rock mechanical properties continuously distributed along the longitudinal direction of the formation, physical and mechanical property data of shales from the Permian Lucaogou Formation of the Junggar Basin were gathered through experimental tests. The regression analysis method was applied to obtain relationships between physical properties and rock mechanical properties. Based on this, new empirical relationships between rock mechanical properties were established. The results show that the uniaxial compressive strength (UCS) ranged from 48.40 to 147.86 MPa, the Young’s modulus (Es) was between 3.02 and 20.63 GPa, the Poisson’s ratio (νs) ranged from 0.13 to 0.36, the cohesive force (C) ranged from 14.65 to 34.60 MPa, and the internal friction angle (φ) was between 27.61 and 46.94°. The rock mechanical properties were more sensitive to the P-wave interval transit time (Δtc) and bulk density (DEN). Among them, the UCS was more sensitive to Δtc, while the C, Es, and νs were more sensitive to Δtc/DEN. For UCS and Es, an exponential function correlation is more reliable than linear expression and power function, whereas for C and νs, power function and linear expression were adopted for higher accuracy, respectively. Compared with the empirical equations presented in the literature, the empirical equations established in the paper are more accurate and reliable, making them applicable to the Permian Lucaogou Formation shale oil reservoirs in the Jimusar Sag of the Junggar Basin. Full article
(This article belongs to the Special Issue Advances and Challenges in Rock Mechanics and Rock Engineering)
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25 pages, 21086 KiB  
Article
A Thorough Investigation of the Dynamic Properties of Granite under Cyclic Loading
by Xiaobin Ding, Junxing Zhao, Yaojun Dong and Mi Zhou
Appl. Sci. 2023, 13(22), 12514; https://doi.org/10.3390/app132212514 - 20 Nov 2023
Cited by 2 | Viewed by 656
Abstract
We propose a novel inverse analysis method that utilizes shockwaves to detect the operational condition of tested rock. To achieve this back analysis, an in-depth investigation of the dynamic properties of granite specimens was conducted. The dynamic properties of the granite specimens were [...] Read more.
We propose a novel inverse analysis method that utilizes shockwaves to detect the operational condition of tested rock. To achieve this back analysis, an in-depth investigation of the dynamic properties of granite specimens was conducted. The dynamic properties of the granite specimens were investigated using a triaxial cyclic loading machine, under different confining pressures, loading frequencies, stress amplitudes, and numbers of cycles, and a dynamic response model was constructed from the test data. The results show that the dynamic elastic modulus increased with the increase in confining pressure, while its damping ratio decreased. The dynamic elastic modulus and damping ratio increased with the increase in loading frequency. As the dynamic stress amplitude increased, the dynamic elastic modulus of the granite increased, but the dynamic damping ratio decreased. As the number of cycles increased, the dynamic elastic modulus and dynamic damping ratio of the granite decreased and gradually stabilized. The modified Duncan–Chang model was used to construct the dynamic response model of the specimens. It is worth saying that the correlation coefficient of the model is low at a loading frequency of 20 Hz. This indicates that the frequency has a greater effect on the dynamic response of the specimen compared with the confining pressure. The conclusions obtained from these tests can be used to study more comprehensively the interaction and causal relationship between different factors, and to prepare for the next steps of tunnel rock stress-state prediction. Full article
(This article belongs to the Special Issue Advances and Challenges in Rock Mechanics and Rock Engineering)
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13 pages, 2761 KiB  
Article
Study on Experimental and Constitutive Model of Granite Gneiss under Hydro-Mechanical Properties
by Lin Liu and Bo Wen
Appl. Sci. 2023, 13(22), 12130; https://doi.org/10.3390/app132212130 - 08 Nov 2023
Viewed by 535
Abstract
Permeability, as a critical element in making sure the underground facilities are secure, is a vital consideration in analyzing the rock material seepage. Selecting granite gneiss from underground oil storage as the research sample in this study. Triaxial mechanical property tests under different [...] Read more.
Permeability, as a critical element in making sure the underground facilities are secure, is a vital consideration in analyzing the rock material seepage. Selecting granite gneiss from underground oil storage as the research sample in this study. Triaxial mechanical property tests under different hydro-mechanical properties were carried out under the rock full-automatic triaxial servo system that controls the application of axial pressure, confining pressure, and seepage pressure. Through experiments carried out, we obtained the rock samples’ mechanical properties and permeability in three stages of the stress–strain process. The study shows that the seepage pressure considerably affects granite gneiss strength and deformation parameters under hydro-mechanical properties. On the basis of the same confining pressure, in pace with the growth in seepage pressure, elastic modulus, the deformation modulus, and the peak strength present a prominent decreasing inclination. The derived mechanical parameters are bound up with the stages we divided. This study analyzes and discusses the relationship among the strains and permeability, establishing the granite gneiss hydro-mechanical coupling constitutive model. Verification shows the results in numerical and experimental matches well, indicating that the rock hydro-mechanical properties could be effectively represented by the constitutive model. Full article
(This article belongs to the Special Issue Advances and Challenges in Rock Mechanics and Rock Engineering)
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12 pages, 40464 KiB  
Article
Mechanical and Acoustic Emission Characteristics of Grouted Reinforcement in Fissure-Containing Rock-like Specimens
by Zhonglin Yu and Chenchen Song
Appl. Sci. 2023, 13(21), 11661; https://doi.org/10.3390/app132111661 - 25 Oct 2023
Viewed by 632
Abstract
In order to study the reinforcing effect of the different grouting materials applied in fissure rock engineering, ultra-fine cement slurry, cement–silicate slurry, and MARITHAN® were used to carry out grouting tests on specimens of fissure-containing rocks. With the help of a uniaxial [...] Read more.
In order to study the reinforcing effect of the different grouting materials applied in fissure rock engineering, ultra-fine cement slurry, cement–silicate slurry, and MARITHAN® were used to carry out grouting tests on specimens of fissure-containing rocks. With the help of a uniaxial compression acoustic emission test system, the mechanical characteristics of the grouted specimens were obtained, and the damage process of the specimens was revealed by using the acoustic emission signals. The tested results showed the following: the residual strength of the grouted specimens using the three grouting materials increased by 16.931%, 13.075%, and 39.998%, respectively; the ultra-fine cement grouting and cement–silicate grouting specimens showed damage patterns of shear-slip damage along the original rupture surface; the specimens of MARITHAN® grouting cracked from a position near the end of the specimen with no damage to the grouted body portion; the cumulative acoustic emission energy curves of the grouted specimens showed obvious stage characteristics; and the acoustic emission energy distribution characteristics of the grouted specimens differed depending on the grouting materials. Full article
(This article belongs to the Special Issue Advances and Challenges in Rock Mechanics and Rock Engineering)
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25 pages, 19832 KiB  
Article
Study on the Influence of Rock Shape on Rolling Distance
by Feng Liu, Ning Hu, Gangchen Sun and Bai Yang
Appl. Sci. 2023, 13(20), 11351; https://doi.org/10.3390/app132011351 - 16 Oct 2023
Viewed by 638
Abstract
To explore the influence of rock shape on rolling distance and effectively mitigate rockfall hazards, the following research was conducted. Factors influencing the rolling distance of rocks were determined through model experiments, and the mechanics of rolling resistance were analyzed. The coefficient RF, [...] Read more.
To explore the influence of rock shape on rolling distance and effectively mitigate rockfall hazards, the following research was conducted. Factors influencing the rolling distance of rocks were determined through model experiments, and the mechanics of rolling resistance were analyzed. The coefficient RF, reflecting the ease of rock rolling, and the shape parameter ψ, quantifying the rolling distance, were proposed. By incorporating the shape parameter into kinematic equations, formulas for calculating the rolling distance of rocks with varying shapes on diverse ground characteristics were derived. These formulas underwent validation using data from model experiments, revealing minimal disparities between the experimental and calculated values. Irregularities on the rolling surface, commonly referred to as “steps” due to the differences in surface hardness among various materials, as well as deviations and shifts in the rolling axis during rock movement, were identified as the primary factors influencing rolling distance and contributing to calculation errors. Combining these deviations for rocks of distinct shapes with theoretical formulas enabled the determination of the range of influence of rock rolling at various velocities, offering valuable insights for assessing areas prone to rockfall hazards. Full article
(This article belongs to the Special Issue Advances and Challenges in Rock Mechanics and Rock Engineering)
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18 pages, 23730 KiB  
Article
Experimental Research into the Ultrasonic P-Wave Velocity of Coal Slime Based Backfill Material
by Baifu An, Chenghao Cui, Jinfang Ren, Dongda Wang, Jiale Wang and Qiaomei Yi
Appl. Sci. 2023, 13(19), 11043; https://doi.org/10.3390/app131911043 - 07 Oct 2023
Viewed by 667
Abstract
To study the influences of different mix proportions of materials on the ultrasonic p-wave velocity of coal slime based backfill materials, influences of four factors on the p-wave velocity of specimens were investigated by designing orthogonal tests and taking coal slime as the [...] Read more.
To study the influences of different mix proportions of materials on the ultrasonic p-wave velocity of coal slime based backfill materials, influences of four factors on the p-wave velocity of specimens were investigated by designing orthogonal tests and taking coal slime as the principal raw material. The four factors included the following: (A) the mass concentration of coal slime, (B) the content of high-water-content material, (C) cement content, (D) and content of fly ash. Test results revealed the following: (1) the ultrasonic p-wave velocity is in the range of 3.916 to 8.319 km/s and various factors are listed in a descending order as A, D, B, and C according to their influences on the ultrasonic p-wave velocity; (2) the ultrasonic p-wave velocity is positively correlated with the compressive strength and shear strength, with correlation coefficients separately of 0.87 and 0.65; (3) the equations for variations in the ultrasonic p-wave velocity under influences of different factors are fitted. The ultrasonic p-wave velocity has a quadratic polynomial relationship with factor A, while following exponential relationships with factors B, C, and D. A predictive model for characteristic parameters of the ultrasonic p-wave velocity of coal slime based backfill materials jointly influenced by the four factors was established based on the fitting equation for variations of single factors and ultrasonic p-wave velocity. The predictive model was then verified. Full article
(This article belongs to the Special Issue Advances and Challenges in Rock Mechanics and Rock Engineering)
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11 pages, 805 KiB  
Article
Emphasizing the Creep Damage Constitutive Model of Hydro-Mechanical Properties of Rocks: A Case Study of Granite Gneiss
by Lin Liu and Bo Wen
Appl. Sci. 2023, 13(19), 10967; https://doi.org/10.3390/app131910967 - 04 Oct 2023
Viewed by 690
Abstract
The constitutive model of rock materials can describe the mechanical behavior of rocks in creep tests. Also, it is one of the important means to study the deformation and strength characteristics of rocks in complex stress environments. This paper is based on the [...] Read more.
The constitutive model of rock materials can describe the mechanical behavior of rocks in creep tests. Also, it is one of the important means to study the deformation and strength characteristics of rocks in complex stress environments. This paper is based on the analysis of the porosity variation characteristics of the internal structure under the coupling effect of rock hydro-mechanical properties. The concept of the hydro-mechanical properties variable is proposed, and the relationship between the coupling variable, damage and plastic deformation is established. By introducing the coupling variable, instantaneous damage variable and time-dependent damage variable into the yield surface equation, as well as the plastic potential energy equation and the stiffness matrix of the elastic–plastic creep constitutive equation, a hydro-mechanical properties creep damage coupling model was established to simulate the creep mechanical properties of rock under coupling. Based on the triaxial creep test results of granite gneiss, the model parameters are determined. By comparing the test results with numerical results, it was revealed that the model can better describe the creep mechanical properties of rocks under the coupling effect of hydromechanical properties. Full article
(This article belongs to the Special Issue Advances and Challenges in Rock Mechanics and Rock Engineering)
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12 pages, 6178 KiB  
Article
Investigation of Rock Joint and Fracture Influence on Delayed Blasting Performance
by Pengfei Zhang, Runcai Bai, Xue Sun and Tianheng Wang
Appl. Sci. 2023, 13(18), 10275; https://doi.org/10.3390/app131810275 - 13 Sep 2023
Viewed by 627
Abstract
Geological structures such as joints and faults in rock mass have a significant influence on open-pit mining. Hence, it is critical to develop an understanding of dynamic joint behavior under blasting loading. This, in turn, can provide both theoretical and practical guidance to [...] Read more.
Geological structures such as joints and faults in rock mass have a significant influence on open-pit mining. Hence, it is critical to develop an understanding of dynamic joint behavior under blasting loading. This, in turn, can provide both theoretical and practical guidance to improve blasting rock fragmentation and associated bucket excavating efficiency. In this paper, delayed blasting on a highwall bench at an open-pit mine is used as an example; a nonlinear joint blasting model is also constructed. By simplifying the blasting wave propagation velocity and combining the relevant stress and displacement theories of type I and II cracks, equipotential diagrams of the stress and displacement field with the vibration velocity of the particle are obtained. Additionally, ANSYS is used to analyze the distribution of the stress field. This is able to be visualized by the degree of color change post-processing. It is concluded that, with the attenuation of the detonation wave energy, the stress exhibited a decreasing trend in this process. According to the distribution of the peak effective stress, it is found that the peak value first increases to 10–12 MPa and then shows a downward trend. Full article
(This article belongs to the Special Issue Advances and Challenges in Rock Mechanics and Rock Engineering)
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19 pages, 5324 KiB  
Article
Research on Particle Size and Energy Consumption Law of Hard Coal Crushing under Impact Load Based on SHPB Test
by Haibo Wang, Wenqing Xu, Bing Cheng and Qi Zong
Appl. Sci. 2023, 13(5), 3298; https://doi.org/10.3390/app13053298 - 04 Mar 2023
Cited by 1 | Viewed by 1418
Abstract
To study the particle size distribution and energy variation law of hard coal under a load, an impact compression test of hard coal specimens under different impact loading conditions was carried out using a Φ50 mm diameter Separate Hopkinson Press Bar (SHPB) test [...] Read more.
To study the particle size distribution and energy variation law of hard coal under a load, an impact compression test of hard coal specimens under different impact loading conditions was carried out using a Φ50 mm diameter Separate Hopkinson Press Bar (SHPB) test system. We implemented the theory of dynamic impact energy of rock to establish the calculation expression of hard coal impact crushing energy dissipation, and we established the Weibull distribution model of a crushing body to analyze the impact velocity in relation to the particle size distribution of hard coal crushing and crushing energy consumption. The results demonstrate that due to the different original states of the specimens, the damage to the specimens under static action is in the mode of conjugate plane shear damage, single bevel shear damage, and tensile damage. The damage process of the specimen under impact load loading is divided into three stages: elastic deformation, elastic–plastic deformation, and plastic softening, while the increase in the strain rate caused the peak stress of the specimen to increase. The Weibull distribution can characterize the impact crushing size distribution of hard coal specimens very well. The parameter of coal rock crushing degree is a power function that is influenced by the impact velocity; the greater the impact velocity, the higher the coal rock crushing degree, but the characteristic index of coal rock crushing fluctuates with the increase in impact velocity. As the impact velocity increases, the incident energy and reflected energy increase linearly, while the transmitted energy increases first and then decreases. The dissipation energy of coal rock crushing also increases linearly with the impact velocity. There is no obvious regular change between the energy dissipation rate of coal rock and impact velocity during impact damage, and the dissipated energy of macroscopic crushing only accounts for 10~20% of the incident energy; most of the energy is used for damping loss and damage loss. Full article
(This article belongs to the Special Issue Advances and Challenges in Rock Mechanics and Rock Engineering)
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16 pages, 14650 KiB  
Article
Study on Characteristic Strength and Constitutive Model of Red Sandstone under Hydraulic Coupling
by Xinwei Li, Zhishu Yao, Xianwen Huang, Xiaohu Liu and Xuesong Wang
Appl. Sci. 2023, 13(1), 391; https://doi.org/10.3390/app13010391 - 28 Dec 2022
Viewed by 1081
Abstract
The newly built shaft in the western region needs to pass through the deep Cretaceous stratum, where the pores and fissures are developed, the cementation ability is poor, and the surrounding rock is rich in water. Under the coupling effect of the stress [...] Read more.
The newly built shaft in the western region needs to pass through the deep Cretaceous stratum, where the pores and fissures are developed, the cementation ability is poor, and the surrounding rock is rich in water. Under the coupling effect of the stress field and seepage field, the surrounding rock is easy to deteriorate and loses stability. The hydraulic coupling test of Cretaceous red sandstone was carried out by using the TAW-2000 rock mechanics testing system, and the characteristic strength evolution law of red sandstone was analyzed; Mohr’s circle and strength envelope were obtained by the M–C criterion, and the influence mechanism seepage pressure on red sandstone was explored; and combined with the effective stress principle and M–C strength criterion, a constitutive model under hydraulic coupling was established. Confining pressure limits the development of cracks and strengthens the mechanical properties. The results revealed that red sandstone has the characteristics of low less clay, loose particles, and weak cementation capacity; under the action of water pressure, the cement between particles disintegrates and loses the cementation strength, resulting in a significant decrease in cohesion, and the loss of cementation strength is the internal reason for the softening of red sandstone. The constitutive model based on the effective principle and M–C criterion can better reflect the mechanical behavior of red sandstone under hydraulic coupling. This paper provides a research basis for understanding the microscopic characteristics and hydraulic coupling characteristics of Cretaceous weakly cemented sandstone. Full article
(This article belongs to the Special Issue Advances and Challenges in Rock Mechanics and Rock Engineering)
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Review

Jump to: Research

18 pages, 3401 KiB  
Review
Underground Disposal of Coal Gangue Backfill in China
by Weijian Song, Jixiong Zhang, Meng Li, Hao Yan, Nan Zhou, Yinan Yao and Yaben Guo
Appl. Sci. 2022, 12(23), 12060; https://doi.org/10.3390/app122312060 - 25 Nov 2022
Cited by 13 | Viewed by 3013
Abstract
China’s total coal production in 2021 exceeded 4.13 billion tons, 52% of the world’s total. Coal gangue, a solid waste of coal mining accounts for 15–20% of coal production, when directly discharged on the ground surface as waste heaps, it occupies large areas [...] Read more.
China’s total coal production in 2021 exceeded 4.13 billion tons, 52% of the world’s total. Coal gangue, a solid waste of coal mining accounts for 15–20% of coal production, when directly discharged on the ground surface as waste heaps, it occupies large areas of land and cause environmental pollution. This paper summarizes the existing gangue backfilling methods, their working principles, efficiency, and application status. The methods that are meeting Middle and Western China’s mining demands are discussed in detail. The state-of-the-art technologies that can realize high-efficiency, centralized, and large-scale underground backfilling of coal gangue are analyzed. This paper shows that the industrial implementation of these technologies can increase the current maximum disposal capacity of coal gangue by three times, reaching five million tons per year. The equipment innovation and automation are analyzed, and the environmental effect of coal gangue backfilling is discussed. This review offers inspirations and guidelines for coal gangue disposal and the environmental hazard reduction of coal mining. Full article
(This article belongs to the Special Issue Advances and Challenges in Rock Mechanics and Rock Engineering)
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