首页|Experimental study on failure characteristics of single-sided unloading rock under different intermediate principal stress conditions

Experimental study on failure characteristics of single-sided unloading rock under different intermediate principal stress conditions

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Investigation of unloading rock failure under different σ2 facilitates the control mechanism of excavation surrounding rock.This study focused on single-sided unloading tests of granite specimens under true tri-axial conditions.The strength and failure characteristics were studied with micro-camera and acoustic emission(AE)monitoring.Furthermore,the choice of test path and the effect of σ2 on fracture of unload-ing rock were discussed.Results show that the increased σ2 can strengthen the stability of single-sided unloading rock.After unloading,the rock's free surface underwent five phases,namely,inoculation,par-ticle ejection,buckling rupture,stable failure,and unstable rockburst phases.Moreover,at σ2≤30 MPa,the b value shows the following variation tendency:rising,dropping,significant fluctuation,and drop-ping,with dispersed damages signal.At σ2≥40 MPa,the tendency shows:a rise,a decrease,a slight fluc-tuation,and final drop,with concentrated damages signal.After unloading,AE energy is mainly concentrated in the micro-energy range.With the increased σ2,the micro-energy ratio rises.In contrast,low,medium and large energy ratios drop gradually.The increased tensile fractures and decreased shear fractures indicate that the failure mode of the unloading rock gradually changes from tensile-shear mode to tensile-split one.The fractional dimension of the rock fragments first increases and then decreases with an inflection point at 20 MPa.The distribution of SIF on the planes changes as σ2 increases,resulting in strengthening and then weakening of the rock bearing capacity.

Single-sided unloadingAcoustic emissionTrue triaxialIntermediate principal stressStress intensity factor

Chongyan Liu、Guangming Zhao、Wensong Xu、Xiangrui Meng、Zhixi Liu、Xiang Cheng、Gang Lin

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State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines,Anhui University of Science and Technology,Huainan 232001,China

Key Laboratory of Safe and Effective Coal Mining,Ministry of Education,Anhui University of Science and Technology,Huainan 232001,China

Post-Doctoral Research Station,Huaibei Mining Corporation Limited,Huaibei 235006,China

Laboratoire de Géologie,Ecole Normale Supérieure,Paris 75005,France

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Scientific Research Project of Anhui Province Universities,ChinaNational Natural Science Foundation of ChinaNational Natural Science Foundation of ChinaNational Natural Science Foundation of ChinaMajor Science and Technology Special Project of Anhui Province,ChinaCollaborative Innovation Project of Anhui Province Universities,ChinaHuaibei City Science and Technology Major Program

YJS20210388519740095200400652004005202203a07020011GXXT-2021-075Z2020005

2023

矿业科学技术学报(英文版)
中国矿业大学

矿业科学技术学报(英文版)

CSTPCDCSCD北大核心EI
影响因子：1.222
ISSN：2095-2686
年,卷(期)：2023.33(3)
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