Article

Journal of Coal Science and Engineering (China)

, Volume 17, Issue 1, pp 34-38

Wing crack propagation model under high hydraulic pressure in compressive-shear stress state

  • Yan-lin ZhaoAffiliated withHunan Provincial Key Laboratory of Safe Mining Techniques of Coal Mines, Hunan University of Science and TechnologySchool of Engery and Safty Enginerring, Hunan University of Science and Technology
  • , Wen-jun WangAffiliated withHunan Provincial Key Laboratory of Safe Mining Techniques of Coal Mines, Hunan University of Science and TechnologySchool of Engery and Safty Enginerring, Hunan University of Science and Technology Email author 

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Abstract

A new wing crack model subjected to hydraulic pressure and far-field stresses was proposed considering the effect of hydraulic pressure in wing crack and the connected part of the main crack on the stress intensity factor at the wing crack tip. With the equivalent crack length l eq of the wing crack introduced, the stress intensity factor K I at the wing crack tip was assumed to the sum of two terms: on one hand a component K I (1) for a single isolated straight wing crack of length 2l, and subjected to hydraulic pressure in the wing crack and far-field stresses; on the other hand a component K I (2) due to the effective shear stress induced by the presence of the equivalent main crack. The lateral tensile stress and hydraulic high pressure are the key factors that induce crack propagation unsteadily. The new wing crack theoretical model proposed can supply references for the study on hydraulic fracture in fractured masses, hydraulic fracturing in rock masses.

Keywords

rock mechanics wing crack hydraulic pressure