Mechanical Properties and Fracture Surface Morphology of Quartz Sandstone Under Triaxial Shear

To study the shear damage deformation characteristics of intact rock in rock slopes under three-dimensional compressive–shear stress conditions, 16 sets of triaxial shear tests were conducted on saturated intact fine-grained quartz sandstone with simple composition and homogeneous structure under di...

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Main Authors: Zhinan LIN, Shihong FENG, Jiaquan WANG, Qiang ZHANG, Haifeng LONG
Format: Article
Language:English
Published: Editorial Department of Journal of Sichuan University (Engineering Science Edition) 2024-07-01
Series:工程科学与技术
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Online Access:http://jsuese.scu.edu.cn/thesisDetails#10.15961/j.jsuese.202201120
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author Zhinan LIN
Shihong FENG
Jiaquan WANG
Qiang ZHANG
Haifeng LONG
author_facet Zhinan LIN
Shihong FENG
Jiaquan WANG
Qiang ZHANG
Haifeng LONG
author_sort Zhinan LIN
collection DOAJ
description To study the shear damage deformation characteristics of intact rock in rock slopes under three-dimensional compressive–shear stress conditions, 16 sets of triaxial shear tests were conducted on saturated intact fine-grained quartz sandstone with simple composition and homogeneous structure under different confining pressures by using the Rock Top–50HT full-stress multi-field coupling triaxial test system. In the tests, the corresponding triaxial shear stress–strain curves and the shear–failure fracture surfaces containing original rock debris were obtained, the nonlinear variations of the strength characteristics of quartz sandstone under triaxial shear stress were analyzed, and the triaxial shear failure mode and the roughness characteristics of the fracture-surface morphology of quartz sandstone were explored. Also, based on the Delaunay point–cloud discretization algorithm, the failure fracture surface of quartz sandstone was reconstructed, and the variation characteristics of its potential contact part with the effective inclination threshold of the surface were analyzed. The results show that with increasing normal stress, the triaxial shear failure mode of quartz sandstone changes gradually from brittle failure to plastic failure and finally to plastic flow failure. The triaxial shear strength of quartz sandstone shows obvious nonlinear variation with increasing confining pressure. The Mohr–Coulomb criterion is used to fit the triaxial shear strength of quartz sandstone via piecewise linear fitting, and it is found that with increasing confining pressure, the cohesion increases while the internal friction angle decreases. The three-dimensional roughness characteristics of the shear–failure fracture surface are evaluated using the traditional Grasselli model, and its nonlinear fitting parameters <inline-formula><tex-math id="M6">$\theta _{{\mathrm{max}}}^*$</tex-math></inline-formula> and <italic>c</italic> fully describe the roughness characteristics of the fracture surface under triaxial shear failure. The present results are very important for predicting the triaxial shear strength of rock under complex stress and for evaluating the stability of slopes in rock engineering and optimizing the design schemes for supporting them.
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spelling doaj-art-87bf290aa5f442e78d63a94121dba9582025-08-20T02:56:44ZengEditorial Department of Journal of Sichuan University (Engineering Science Edition)工程科学与技术2096-32462024-07-015616117255277655Mechanical Properties and Fracture Surface Morphology of Quartz Sandstone Under Triaxial ShearZhinan LINShihong FENGJiaquan WANGQiang ZHANGHaifeng LONGTo study the shear damage deformation characteristics of intact rock in rock slopes under three-dimensional compressive–shear stress conditions, 16 sets of triaxial shear tests were conducted on saturated intact fine-grained quartz sandstone with simple composition and homogeneous structure under different confining pressures by using the Rock Top–50HT full-stress multi-field coupling triaxial test system. In the tests, the corresponding triaxial shear stress–strain curves and the shear–failure fracture surfaces containing original rock debris were obtained, the nonlinear variations of the strength characteristics of quartz sandstone under triaxial shear stress were analyzed, and the triaxial shear failure mode and the roughness characteristics of the fracture-surface morphology of quartz sandstone were explored. Also, based on the Delaunay point–cloud discretization algorithm, the failure fracture surface of quartz sandstone was reconstructed, and the variation characteristics of its potential contact part with the effective inclination threshold of the surface were analyzed. The results show that with increasing normal stress, the triaxial shear failure mode of quartz sandstone changes gradually from brittle failure to plastic failure and finally to plastic flow failure. The triaxial shear strength of quartz sandstone shows obvious nonlinear variation with increasing confining pressure. The Mohr–Coulomb criterion is used to fit the triaxial shear strength of quartz sandstone via piecewise linear fitting, and it is found that with increasing confining pressure, the cohesion increases while the internal friction angle decreases. The three-dimensional roughness characteristics of the shear–failure fracture surface are evaluated using the traditional Grasselli model, and its nonlinear fitting parameters <inline-formula><tex-math id="M6">$\theta _{{\mathrm{max}}}^*$</tex-math></inline-formula> and <italic>c</italic> fully describe the roughness characteristics of the fracture surface under triaxial shear failure. The present results are very important for predicting the triaxial shear strength of rock under complex stress and for evaluating the stability of slopes in rock engineering and optimizing the design schemes for supporting them.http://jsuese.scu.edu.cn/thesisDetails#10.15961/j.jsuese.202201120rock mechanicstriaxial shear testfailure modenonlinear shear strengthmorphological characteristics of fracture surface
spellingShingle Zhinan LIN
Shihong FENG
Jiaquan WANG
Qiang ZHANG
Haifeng LONG
Mechanical Properties and Fracture Surface Morphology of Quartz Sandstone Under Triaxial Shear
工程科学与技术
rock mechanics
triaxial shear test
failure mode
nonlinear shear strength
morphological characteristics of fracture surface
title Mechanical Properties and Fracture Surface Morphology of Quartz Sandstone Under Triaxial Shear
title_full Mechanical Properties and Fracture Surface Morphology of Quartz Sandstone Under Triaxial Shear
title_fullStr Mechanical Properties and Fracture Surface Morphology of Quartz Sandstone Under Triaxial Shear
title_full_unstemmed Mechanical Properties and Fracture Surface Morphology of Quartz Sandstone Under Triaxial Shear
title_short Mechanical Properties and Fracture Surface Morphology of Quartz Sandstone Under Triaxial Shear
title_sort mechanical properties and fracture surface morphology of quartz sandstone under triaxial shear
topic rock mechanics
triaxial shear test
failure mode
nonlinear shear strength
morphological characteristics of fracture surface
url http://jsuese.scu.edu.cn/thesisDetails#10.15961/j.jsuese.202201120
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AT jiaquanwang mechanicalpropertiesandfracturesurfacemorphologyofquartzsandstoneundertriaxialshear
AT qiangzhang mechanicalpropertiesandfracturesurfacemorphologyofquartzsandstoneundertriaxialshear
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