Symmetry, Asymmetry and Nonlinearity in Geomechanics

A special issue of Symmetry (ISSN 2073-8994). This special issue belongs to the section "Engineering and Materials".

Deadline for manuscript submissions: 31 August 2024 | Viewed by 2619

Special Issue Editors


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Guest Editor
Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China
Interests: rock mechanics; rock engineering; engineering geology
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Guest Editor
School of Architecture and Civil Engineering, Chengdu University, Chengdu 610106, China
Interests: dynamic characteristics of fractured rock mass; rock dynamic constitutive model; discrete element numerical simulation
Department of Water Resources, Hohai College, Chongqing Jiaotong University, Nan'an District, Chongqing, China
Interests: rock dynamics; nonlinearity; mechnical resposnse; failure property

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Guest Editor
School of Earth Science and Environmental Engineering, Southwest Jiaotong University, Chengdu 611756,China
Interests: discrete element (DEM) numerical simulation; granular media mechanics

Special Issue Information

Dear Colleagues,

Geomechanics is a branch of geology that focuses on the shapes, fabrics and physical properties of geological bodies as well as their responses to external forces. It mainly covers the strength, deformation, cracking, stability and destruction of geo-materials and geological bodies, and provides a crucial theoretical basis for geotechnical engineering. Geomechanics has a wide range of applications in fields such as mining, oil drilling, tunneling, water conservancy and geological disaster prevention and mitigation.

In geomechanics-related engineering and scientific problems, research objects may have symmetrical geometries, such as tunnels' cross-sections and the uniaxial compression specimens of rocks. The asymmetrical geometries and structures of research objects are also frequently encountered, such as asymmetrical geological fabrics and asymmetrical microscopic structures of geo-materials. Similarly, external loads can be either symmetric or asymmetric, while the mechanical behavior of geo-materials often displays strong nonlinearity and asymmetry. For example, the failure pattern of a cracked rock specimen with symmetrical geometry under symmetrical, purely tensile loading is not necessarily symmetrical.

This Special Issue aims to present studies that involve symmetry, asymmetry and nonlinearity in geomechanics, including experiments, theories and numerical simulations that help consider, analyze and interpret symmetry/asymmetry-related problems.

Dr. Mingdong Wei
Dr. Peng Feng
Dr. Hongbo Du
Dr. Weigang Shen
Guest Editors

Manuscript Submission Information

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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.

Published Papers (3 papers)

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Research

13 pages, 5413 KiB  
Article
Decay Law of Supercritical CO2 Phase Transition-Induced Shock Waves in Rocky Media
by Jie Zhang, Qifu Zeng, Fangqiang Wei, Lu Liu, Fayou Wu and Haotian Li
Symmetry 2023, 15(9), 1802; https://doi.org/10.3390/sym15091802 - 21 Sep 2023
Viewed by 553
Abstract
Supercritical CO2 phase change fracturing technology has been widely used in rock engineering, with the advantages of low disturbance and no pollution. However, the phase change shock wave inevitably affects the surrounding environment, and the influence range is still unclear. In this [...] Read more.
Supercritical CO2 phase change fracturing technology has been widely used in rock engineering, with the advantages of low disturbance and no pollution. However, the phase change shock wave inevitably affects the surrounding environment, and the influence range is still unclear. In this paper, we present a computational model for the symmetric generation, propagation, and attenuation of supercritical CO2 phase transition shock waves, with the center of the borehole as the origin, based on the C–J theory. The attenuation of the shock wave in the rock medium under the influence of the type of fracturing tube, the thickness of the shear sheet, and the rock performance parameters are further analyzed. The results show that the rock stress under the action of the phase change shock wave attenuates logarithmically with the propagation distance, which correlates with the magnitude of the incident rock stress at the borehole wall. The incident rock stress decreases with the increase in the initial density of CO2 in the fracturing tube, increases linearly with the thickness of the shear sheet, and correlates with the rock wave impedance. Full article
(This article belongs to the Special Issue Symmetry, Asymmetry and Nonlinearity in Geomechanics)
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13 pages, 4791 KiB  
Article
A Study on the Surface Vibration Effect of CO2 Phase Transition Cracking Based on the Time-Domain Recursive Analysis Method
by Erdi Abi, Lu Liu, Jie Zhang, Qifu Zeng, Fayou Wu and Haotian Li
Symmetry 2023, 15(7), 1419; https://doi.org/10.3390/sym15071419 - 14 Jul 2023
Viewed by 613
Abstract
Supercritical CO2 phase change fracturing technology has been widely used in rock engineering. However, the surface vibration characteristics induced by phase change rock breaking have not been sufficiently studied. In this paper, a model for calculating the surface vibration velocity induced by [...] Read more.
Supercritical CO2 phase change fracturing technology has been widely used in rock engineering. However, the surface vibration characteristics induced by phase change rock breaking have not been sufficiently studied. In this paper, a model for calculating the surface vibration velocity induced by supercritical CO2 phase change was established based on the time-domain recursive method, and the reliability of the model was verified using LS-DYNA nonlinear finite element software; based on the model for calculating the blasting energy of a compressed gas and water vapor container, the surface vibration velocity and decay law induced by CO2 phase change fracturing and equivalent explosive blasting were compared and analyzed. The results show that the ground vibration velocity calculation model based on the time-domain recurrence method can better evaluate the ground vibration characteristics induced by supercritical CO2 phase change fracturing, and the vibration velocity decays exponentially with the fracture distance; the peak pressure of supercritical CO2 phase change is only 1/3.36 of that of explosive blasting, but the action time is 100 times longer than that of explosive blasting, and the peak vibration velocity is 1/74~1/78 of that of equivalent explosive blasting. Full article
(This article belongs to the Special Issue Symmetry, Asymmetry and Nonlinearity in Geomechanics)
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22 pages, 7870 KiB  
Article
Effects of Support Friction on Mixed-Mode I/II Fracture Behavior of Compacted Clay Using Notched Deep Beam Specimens under Symmetric Fixed Support
by Shiyuan Huang, Xudong Li, Wenbing Yu, Xiaofeng Zhang and Hongbo Du
Symmetry 2023, 15(6), 1290; https://doi.org/10.3390/sym15061290 - 20 Jun 2023
Viewed by 960
Abstract
This paper investigates the effects of support friction on mixed-mode I/II fracture behavior of compacted clay using notched deep beam (NDB) specimens under symmetric fixed support. Numerical models of 330 NDB specimens were established considering the crack inclination angle, crack length, support span, [...] Read more.
This paper investigates the effects of support friction on mixed-mode I/II fracture behavior of compacted clay using notched deep beam (NDB) specimens under symmetric fixed support. Numerical models of 330 NDB specimens were established considering the crack inclination angle, crack length, support span, and support friction coefficient, and the normalized fracture parameters (YI, YII, and T*) of NDB specimens were calibrated. The numerical results showed that the values of YI, YII, and T* decreased at different degrees after considering the support friction. Notably, the support friction coefficient could significantly change the loading pattern at the crack tip. To verify this phenomenon, 12 compacted clay NDB specimens were prepared, and a mixed-mode I/II fracture test was performed under fixed support conditions; the phenomenon of asymmetric crack propagation was studied. The test data were processed using the numerical calibration results of YI, YII, and T* with and without consideration of friction. Afterward, the test data were compared and analyzed by combining the generalized maximum tangential stress (GMTS) and the maximum tangential stress (MTS) criteria. The analysis indicated that the real fracture characteristics of compacted clay NDB specimens could not be reflected when conducting mixed-mode I/II fracture tests under symmetric fixed support conditions if the test results were analyzed by YI, YII, and T* without considering support friction, as in previous studies. Full article
(This article belongs to the Special Issue Symmetry, Asymmetry and Nonlinearity in Geomechanics)
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