Experimental Investigation on Joint Effects in Rock Cutting with a Conical Pick Under Unrelieved Cutting Conditions

In this study, a series of unrelieved cutting tests was conducted to analyze the effect of joints on rock cutting using a conical pick. The tests were performed on jointed rock mass specimens with joint spacings (<i>J<sub>s</sub></i>) of 30, 60, and 90 mm and at cutting depth...

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Main Authors: Han-Eol Kim, Min-Seong Kim, Wan-Kyu Yoo, Chang-Yong Kim, Ji-Seok Yun
Format: Article
Language:English
Published: MDPI AG 2025-05-01
Series:Applied Sciences
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Online Access:https://www.mdpi.com/2076-3417/15/10/5578
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author Han-Eol Kim
Min-Seong Kim
Wan-Kyu Yoo
Chang-Yong Kim
Ji-Seok Yun
author_facet Han-Eol Kim
Min-Seong Kim
Wan-Kyu Yoo
Chang-Yong Kim
Ji-Seok Yun
author_sort Han-Eol Kim
collection DOAJ
description In this study, a series of unrelieved cutting tests was conducted to analyze the effect of joints on rock cutting using a conical pick. The tests were performed on jointed rock mass specimens with joint spacings (<i>J<sub>s</sub></i>) of 30, 60, and 90 mm and at cutting depths of 3, 6, 9, and 12 mm. For each case, the distance between the cutting path and the joint plane (<i>d</i>) was varied from 0.1<i>J<sub>s</sub></i> to 0.5<i>J<sub>s</sub></i>. The cutting force decreased as the distance from the joint plane increased but reached the level observed in intact rock at the midpoint between adjacent joint planes (<i>d</i> = 0.5<i>J<sub>s</sub></i>). Regardless of joint spacing, the cutting force reached its minimum when <i>d</i> was between 0.2<i>J<sub>s</sub></i> and 0.3<i>J<sub>s</sub></i>. The rock fragmentation zone extended beyond the joint plane when d was 0.1<i>J<sub>s</sub></i> but became confined within the joint plane from around 0.2<i>J<sub>s</sub></i> to 0.3<i>J<sub>s</sub></i>. These results indicate that the influence of the joint is most pronounced within this range. Three types of crack propagation patterns were observed near the joint plane: (1) cracks that terminate at the joint along the shortest path, (2) cracks that pass through the joint and reach the opposite free surface, and (3) cracks that end at a free surface located just inside the joint plane. These observations suggest that the reduction in cutting force can be attributed to shorter crack propagation paths due to the presence of the joint. This study contributes to a better understanding of the cutting behavior of jointed rock masses when using a conical pick.
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institution Kabale University
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publishDate 2025-05-01
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spelling doaj-art-29c8dd65d88a41cf8b5917d0d1c99f0c2025-08-20T03:47:53ZengMDPI AGApplied Sciences2076-34172025-05-011510557810.3390/app15105578Experimental Investigation on Joint Effects in Rock Cutting with a Conical Pick Under Unrelieved Cutting ConditionsHan-Eol Kim0Min-Seong Kim1Wan-Kyu Yoo2Chang-Yong Kim3Ji-Seok Yun4Department of Geotechnical Engineering Research, Korea Institute of Civil Engineering and Building Technology, 283 Goyangdae-ro, Ilsanseo-gu, Goyang-si 10223, Republic of KoreaDepartment of Energy and Resources Engineering, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 61186, Republic of KoreaDepartment of Geotechnical Engineering Research, Korea Institute of Civil Engineering and Building Technology, 283 Goyangdae-ro, Ilsanseo-gu, Goyang-si 10223, Republic of KoreaDepartment of Geotechnical Engineering Research, Korea Institute of Civil Engineering and Building Technology, 283 Goyangdae-ro, Ilsanseo-gu, Goyang-si 10223, Republic of KoreaDepartment of Smartcity Engineering, Hanyang University, 55 Hanyangdaehak-ro, Sangnok-gu, Ansan-si 15588, Republic of KoreaIn this study, a series of unrelieved cutting tests was conducted to analyze the effect of joints on rock cutting using a conical pick. The tests were performed on jointed rock mass specimens with joint spacings (<i>J<sub>s</sub></i>) of 30, 60, and 90 mm and at cutting depths of 3, 6, 9, and 12 mm. For each case, the distance between the cutting path and the joint plane (<i>d</i>) was varied from 0.1<i>J<sub>s</sub></i> to 0.5<i>J<sub>s</sub></i>. The cutting force decreased as the distance from the joint plane increased but reached the level observed in intact rock at the midpoint between adjacent joint planes (<i>d</i> = 0.5<i>J<sub>s</sub></i>). Regardless of joint spacing, the cutting force reached its minimum when <i>d</i> was between 0.2<i>J<sub>s</sub></i> and 0.3<i>J<sub>s</sub></i>. The rock fragmentation zone extended beyond the joint plane when d was 0.1<i>J<sub>s</sub></i> but became confined within the joint plane from around 0.2<i>J<sub>s</sub></i> to 0.3<i>J<sub>s</sub></i>. These results indicate that the influence of the joint is most pronounced within this range. Three types of crack propagation patterns were observed near the joint plane: (1) cracks that terminate at the joint along the shortest path, (2) cracks that pass through the joint and reach the opposite free surface, and (3) cracks that end at a free surface located just inside the joint plane. These observations suggest that the reduction in cutting force can be attributed to shorter crack propagation paths due to the presence of the joint. This study contributes to a better understanding of the cutting behavior of jointed rock masses when using a conical pick.https://www.mdpi.com/2076-3417/15/10/5578conical pickcutting forcejointrock cutting testmechanical excavation
spellingShingle Han-Eol Kim
Min-Seong Kim
Wan-Kyu Yoo
Chang-Yong Kim
Ji-Seok Yun
Experimental Investigation on Joint Effects in Rock Cutting with a Conical Pick Under Unrelieved Cutting Conditions
Applied Sciences
conical pick
cutting force
joint
rock cutting test
mechanical excavation
title Experimental Investigation on Joint Effects in Rock Cutting with a Conical Pick Under Unrelieved Cutting Conditions
title_full Experimental Investigation on Joint Effects in Rock Cutting with a Conical Pick Under Unrelieved Cutting Conditions
title_fullStr Experimental Investigation on Joint Effects in Rock Cutting with a Conical Pick Under Unrelieved Cutting Conditions
title_full_unstemmed Experimental Investigation on Joint Effects in Rock Cutting with a Conical Pick Under Unrelieved Cutting Conditions
title_short Experimental Investigation on Joint Effects in Rock Cutting with a Conical Pick Under Unrelieved Cutting Conditions
title_sort experimental investigation on joint effects in rock cutting with a conical pick under unrelieved cutting conditions
topic conical pick
cutting force
joint
rock cutting test
mechanical excavation
url https://www.mdpi.com/2076-3417/15/10/5578
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AT wankyuyoo experimentalinvestigationonjointeffectsinrockcuttingwithaconicalpickunderunrelievedcuttingconditions
AT changyongkim experimentalinvestigationonjointeffectsinrockcuttingwithaconicalpickunderunrelievedcuttingconditions
AT jiseokyun experimentalinvestigationonjointeffectsinrockcuttingwithaconicalpickunderunrelievedcuttingconditions