Study on influencing characteristics of vertical penetrating crack on instability and breaking of hard roof

doi:10.16265/j.cnki.issn1003-3033.2020.01.011

China Safety Science Journal ›› 2020, Vol. 30 ›› Issue (1): 66-72.doi: 10.16265/j.cnki.issn1003-3033.2020.01.011

• Safety engineering technology • Previous Articles Next Articles

Study on influencing characteristics of vertical penetrating crack on instability and breaking of hard roof

WANG Haiyang^1,2, ZHAO Shulei¹, LIU Jialiang^1,2, XIA Binwei³, LI Shoulong⁴

1. School of Civil Engineering, Chongqing Jiaotong University, Chongqing 400074,China;
2. State Key Laboratory Breeding Base of Mountain Bridge and Tunnel Engineering, Chongqing Jiaotong University, Chongqing 400074, China;
3. State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400030, China;
4. Occupational Health Technical Service Center, Anhui Occupational Disease Prevention Hospital, Hefei Anhui 230022, China

Received:2019-10-24 Revised:2020-12-22 Online:2020-01-28 Published:2021-01-22

Abstract

Abstract: In order to reveal influencing characteristics of vertical penetrating crack on instability and breaking of hard roof, theoretical analysis was conducted on breaking span of such hard roof based on analysis of vertical crack's morphology caused by hydraulic fracturing. Then, deformation failure characteristics and damaged area distribution of hard roof were studied by means of numerical simulation. The results show that the breaking span of hard roof is shorter than its initial limited span when open vertical penetrating crack is in certain range. But if crack is closed, two bulks of the hard roof will deflect to crack face and shear slip will take place along it, which makes hard roof easier to break. The tension-compression destructive effect in biting point area of rotary blocks is a main reason for local buckling, greater rotating degree and roof breaking. The smaller normal stiffness coefficient of vertical crack face is, the easier roof breaking will be. Hard roof with open vertical penetrating crack instead of closed one is more likely be deform and break.

Key words: hydraulic fracturing, hard roof, vertical penetrating crack, breaking span, crack face

CLC Number:

X936

WANG Haiyang, ZHAO Shulei, LIU Jialiang, XIA Binwei, LI Shoulong. Study on influencing characteristics of vertical penetrating crack on instability and breaking of hard roof[J]. China Safety Science Journal, 2020, 30(1): 66-72.

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Study on influencing characteristics of vertical penetrating crack on instability and breaking of hard roof

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