Freeze–Thaw-Induced Degradation Mechanisms and Slope Stability of Filled Fractured Rock Masses in Cold Region Open-Pit Mines

In cold regions, the rock mass of open-pit mine slopes is continuously exposed to freeze–thaw (<i>FT</i>) environments, during which the fracture structures and their infilling materials undergo significant degradation, severely affecting slope stability and the assessment of service lif...

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Main Authors: Jun Hou, Penghai Zhang, Ning Gao, Wanni Yan, Qinglei Yu
Format: Article
Language:English
Published: MDPI AG 2025-07-01
Series:Applied Sciences
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Online Access:https://www.mdpi.com/2076-3417/15/13/7429
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author Jun Hou
Penghai Zhang
Ning Gao
Wanni Yan
Qinglei Yu
author_facet Jun Hou
Penghai Zhang
Ning Gao
Wanni Yan
Qinglei Yu
author_sort Jun Hou
collection DOAJ
description In cold regions, the rock mass of open-pit mine slopes is continuously exposed to freeze–thaw (<i>FT</i>) environments, during which the fracture structures and their infilling materials undergo significant degradation, severely affecting slope stability and the assessment of service life. Conventional laboratory <i>FT</i> tests are typically based on uniform temperature settings, which fail to reflect the actual thermal variations at different burial depths, thereby limiting the accuracy of mechanical parameter acquisition. Taking the Wushan open-pit mine as the engineering background, this study establishes a temperature–depth relationship, defines multiple thermal intervals, and conducts direct shear tests on structural plane filling materials under various <i>FT</i> conditions to characterize the evolution of cohesion and internal friction angle. Results from rock mass testing and numerical simulation demonstrate that shear strength parameters exhibit an exponential decline with increasing <i>FT</i> cycles and decreasing burial depth, with the filling material playing a dominant role in the initial stage of degradation. Furthermore, a two-dimensional fracture network model of the rock mass was constructed, and the representative elementary volume (REV) was determined through the evolution of equivalent plastic strain. Based on this, spatial assignment of slope strength was performed, followed by stability analysis. Based on regression fitting using 0–25 FT cycles, regression model predictions indicate that when the number of <i>FT</i> cycles exceeds 42, the slope safety factor drops below 1.0, entering a critical instability state. This research successfully establishes a spatial field of mechanical parameters and evaluates slope stability, providing a theoretical foundation and parameter support for the long-term service evaluation and stability assessment of cold-region open-pit mine slopes.
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spelling doaj-art-5cc10667c47848a6a5b1bf360c7dbf9f2025-08-20T03:28:25ZengMDPI AGApplied Sciences2076-34172025-07-011513742910.3390/app15137429Freeze–Thaw-Induced Degradation Mechanisms and Slope Stability of Filled Fractured Rock Masses in Cold Region Open-Pit MinesJun Hou0Penghai Zhang1Ning Gao2Wanni Yan3Qinglei Yu4School of Resources and Civil Engineering, Northeastern University, Shenyang 110819, ChinaSchool of Resources and Civil Engineering, Northeastern University, Shenyang 110819, ChinaSchool of Resources and Civil Engineering, Northeastern University, Shenyang 110819, ChinaSchool of Resources and Civil Engineering, Northeastern University, Shenyang 110819, ChinaSchool of Resources and Civil Engineering, Northeastern University, Shenyang 110819, ChinaIn cold regions, the rock mass of open-pit mine slopes is continuously exposed to freeze–thaw (<i>FT</i>) environments, during which the fracture structures and their infilling materials undergo significant degradation, severely affecting slope stability and the assessment of service life. Conventional laboratory <i>FT</i> tests are typically based on uniform temperature settings, which fail to reflect the actual thermal variations at different burial depths, thereby limiting the accuracy of mechanical parameter acquisition. Taking the Wushan open-pit mine as the engineering background, this study establishes a temperature–depth relationship, defines multiple thermal intervals, and conducts direct shear tests on structural plane filling materials under various <i>FT</i> conditions to characterize the evolution of cohesion and internal friction angle. Results from rock mass testing and numerical simulation demonstrate that shear strength parameters exhibit an exponential decline with increasing <i>FT</i> cycles and decreasing burial depth, with the filling material playing a dominant role in the initial stage of degradation. Furthermore, a two-dimensional fracture network model of the rock mass was constructed, and the representative elementary volume (REV) was determined through the evolution of equivalent plastic strain. Based on this, spatial assignment of slope strength was performed, followed by stability analysis. Based on regression fitting using 0–25 FT cycles, regression model predictions indicate that when the number of <i>FT</i> cycles exceeds 42, the slope safety factor drops below 1.0, entering a critical instability state. This research successfully establishes a spatial field of mechanical parameters and evaluates slope stability, providing a theoretical foundation and parameter support for the long-term service evaluation and stability assessment of cold-region open-pit mine slopes.https://www.mdpi.com/2076-3417/15/13/7429freeze–thaw cyclesfilled fractured rock massHoek–Brown criterionslope stability
spellingShingle Jun Hou
Penghai Zhang
Ning Gao
Wanni Yan
Qinglei Yu
Freeze–Thaw-Induced Degradation Mechanisms and Slope Stability of Filled Fractured Rock Masses in Cold Region Open-Pit Mines
Applied Sciences
freeze–thaw cycles
filled fractured rock mass
Hoek–Brown criterion
slope stability
title Freeze–Thaw-Induced Degradation Mechanisms and Slope Stability of Filled Fractured Rock Masses in Cold Region Open-Pit Mines
title_full Freeze–Thaw-Induced Degradation Mechanisms and Slope Stability of Filled Fractured Rock Masses in Cold Region Open-Pit Mines
title_fullStr Freeze–Thaw-Induced Degradation Mechanisms and Slope Stability of Filled Fractured Rock Masses in Cold Region Open-Pit Mines
title_full_unstemmed Freeze–Thaw-Induced Degradation Mechanisms and Slope Stability of Filled Fractured Rock Masses in Cold Region Open-Pit Mines
title_short Freeze–Thaw-Induced Degradation Mechanisms and Slope Stability of Filled Fractured Rock Masses in Cold Region Open-Pit Mines
title_sort freeze thaw induced degradation mechanisms and slope stability of filled fractured rock masses in cold region open pit mines
topic freeze–thaw cycles
filled fractured rock mass
Hoek–Brown criterion
slope stability
url https://www.mdpi.com/2076-3417/15/13/7429
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