Experimental Study on Shear Characteristics of Structural Plane with Different Fluctuation Characteristics

With the increasing scale and depth of underground engineering, the geological environment that engineering is faced with is becoming more complex. As the weak position of rock mass, the structural surface has a particularly great influence on the mechanical characteristics of the rock mass. In orde...

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Main Authors: Yintong Guo, Qiqi Ying, Duocai Wang, Hong Zhang, Famu Huang, Haitao Guo, Lei Hou, Mingnan Xu, Hejuan Liu, Debin Xia
Format: Article
Language:English
Published: MDPI AG 2022-10-01
Series:Energies
Subjects:
Online Access:https://www.mdpi.com/1996-1073/15/20/7563
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author Yintong Guo
Qiqi Ying
Duocai Wang
Hong Zhang
Famu Huang
Haitao Guo
Lei Hou
Mingnan Xu
Hejuan Liu
Debin Xia
author_facet Yintong Guo
Qiqi Ying
Duocai Wang
Hong Zhang
Famu Huang
Haitao Guo
Lei Hou
Mingnan Xu
Hejuan Liu
Debin Xia
author_sort Yintong Guo
collection DOAJ
description With the increasing scale and depth of underground engineering, the geological environment that engineering is faced with is becoming more complex. As the weak position of rock mass, the structural surface has a particularly great influence on the mechanical characteristics of the rock mass. In order to obtain the shear strength characteristic of the structural plane and analyze the influence of morphological parameters such as the undulating angle and bulge degree on shearing, taking medium-low permeability tight sandstone as the research object, four kinds of structural plane samples with different undulating angles (10, 20, 30 and 40°) were prepared with a Python and high-precision engraving machine. Direct shear tests under different normal stresses (2, 4, 6 and 8 MPa) and shear rates (0.6, 1.2 and 2.4 mm/min) were performed, and the shear mechanical properties were analyzed. The structural surfaces before and after shearing were scanned using a high-precision three-dimensional scanner, so as to evaluate the roughness of the structural surface and determine the influence from various factors on the shear characteristics. The test results showed that for the structural plane with the same undulating angle, the peak shear stress increased approximately linearly with an increase in normal stress at a 0.6 mm/min shear rate and an increment speed of approximately 0.82, while the peak shear stress negatively correlated with the shear rate at a value of 4 MPa for normal stress. The larger the undulating angle was, the greater the influence of the shear rate (the shear stress decreased by 2.31 MPa at a 40° angle). When the normal stress and the shear rate were fixed, the peak shear stress corresponding to the structural surface gradually increased with the increase in the undulating angle, and the maximum increment was 5.04 MPa at 4 MPa normal stress and a 0.6 mm/min shear rate. An analysis of the morphological characteristics of the structural plane showed that when the undulating angle (40°) and the normal stress (6 and 8 MPa) were larger, the damage of the structural plane became more obvious, the shear point was closer to the tooth valley position, and the mechanical bite force and friction force of the structural plane were better utilized. When the shear rate was lower (0.6 mm/min), the friction characteristics of the shear surface were more visible, the shear was increasingly sufficient, and the corresponding shear strength was also greater.
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spelling doaj.art-81d212443fc34a2cb49e580accc3c95c2023-11-23T23:56:55ZengMDPI AGEnergies1996-10732022-10-011520756310.3390/en15207563Experimental Study on Shear Characteristics of Structural Plane with Different Fluctuation CharacteristicsYintong Guo0Qiqi Ying1Duocai Wang2Hong Zhang3Famu Huang4Haitao Guo5Lei Hou6Mingnan Xu7Hejuan Liu8Debin Xia9State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, ChinaState Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, ChinaPipe China West East Gas Pipeline Company, Shanghai 200120, ChinaPipe China West East Gas Pipeline Company, Shanghai 200120, ChinaPipe China West East Gas Pipeline Company, Shanghai 200120, ChinaPipe China West East Gas Pipeline Company, Shanghai 200120, ChinaPipe China West East Gas Pipeline Company, Shanghai 200120, ChinaState Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, ChinaState Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, ChinaState Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, ChinaWith the increasing scale and depth of underground engineering, the geological environment that engineering is faced with is becoming more complex. As the weak position of rock mass, the structural surface has a particularly great influence on the mechanical characteristics of the rock mass. In order to obtain the shear strength characteristic of the structural plane and analyze the influence of morphological parameters such as the undulating angle and bulge degree on shearing, taking medium-low permeability tight sandstone as the research object, four kinds of structural plane samples with different undulating angles (10, 20, 30 and 40°) were prepared with a Python and high-precision engraving machine. Direct shear tests under different normal stresses (2, 4, 6 and 8 MPa) and shear rates (0.6, 1.2 and 2.4 mm/min) were performed, and the shear mechanical properties were analyzed. The structural surfaces before and after shearing were scanned using a high-precision three-dimensional scanner, so as to evaluate the roughness of the structural surface and determine the influence from various factors on the shear characteristics. The test results showed that for the structural plane with the same undulating angle, the peak shear stress increased approximately linearly with an increase in normal stress at a 0.6 mm/min shear rate and an increment speed of approximately 0.82, while the peak shear stress negatively correlated with the shear rate at a value of 4 MPa for normal stress. The larger the undulating angle was, the greater the influence of the shear rate (the shear stress decreased by 2.31 MPa at a 40° angle). When the normal stress and the shear rate were fixed, the peak shear stress corresponding to the structural surface gradually increased with the increase in the undulating angle, and the maximum increment was 5.04 MPa at 4 MPa normal stress and a 0.6 mm/min shear rate. An analysis of the morphological characteristics of the structural plane showed that when the undulating angle (40°) and the normal stress (6 and 8 MPa) were larger, the damage of the structural plane became more obvious, the shear point was closer to the tooth valley position, and the mechanical bite force and friction force of the structural plane were better utilized. When the shear rate was lower (0.6 mm/min), the friction characteristics of the shear surface were more visible, the shear was increasingly sufficient, and the corresponding shear strength was also greater.https://www.mdpi.com/1996-1073/15/20/7563undulating anglestructural planenormal stressshear rateshear characteristics
spellingShingle Yintong Guo
Qiqi Ying
Duocai Wang
Hong Zhang
Famu Huang
Haitao Guo
Lei Hou
Mingnan Xu
Hejuan Liu
Debin Xia
Experimental Study on Shear Characteristics of Structural Plane with Different Fluctuation Characteristics
Energies
undulating angle
structural plane
normal stress
shear rate
shear characteristics
title Experimental Study on Shear Characteristics of Structural Plane with Different Fluctuation Characteristics
title_full Experimental Study on Shear Characteristics of Structural Plane with Different Fluctuation Characteristics
title_fullStr Experimental Study on Shear Characteristics of Structural Plane with Different Fluctuation Characteristics
title_full_unstemmed Experimental Study on Shear Characteristics of Structural Plane with Different Fluctuation Characteristics
title_short Experimental Study on Shear Characteristics of Structural Plane with Different Fluctuation Characteristics
title_sort experimental study on shear characteristics of structural plane with different fluctuation characteristics
topic undulating angle
structural plane
normal stress
shear rate
shear characteristics
url https://www.mdpi.com/1996-1073/15/20/7563
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