Article

Journal of Central South University

, Volume 19, Issue 2, pp 578-585

Wing crack model subjected to high hydraulic pressure and far field stresses and its numerical simulation

  • Yan-lin Zhao赵延林Affiliated withSchool of Energy and Safety Engineering, Hunan University of Science and TechnologyHunan Provincial Key Laboratory of Safe Mining Techniques of Coal Mines, Hunan University of Science and TechnologySchool of Resources and Safety Engineering, Central South University Email author 
  • , Ping Cao曹平Affiliated withSchool of Resources and Safety Engineering, Central South University
  • , Wei-jun Wang王卫军Affiliated withSchool of Energy and Safety Engineering, Hunan University of Science and TechnologyHunan Provincial Key Laboratory of Safe Mining Techniques of Coal Mines, Hunan University of Science and Technology
  • , Wen Wan万文Affiliated withSchool of Energy and Safety Engineering, Hunan University of Science and TechnologyHunan Provincial Key Laboratory of Safe Mining Techniques of Coal Mines, Hunan University of Science and Technology
  • , Rui Chen陈锐Affiliated withSchool of Resources and Safety Engineering, Central South University

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Abstract

By considering the effect of hydraulic pressure filled in wing crack and the connected part of main crack on the stress intensity factor at wing crack tip, a new wing crack model exerted by hydraulic pressure and far field stresses was proposed. By introducing the equivalent crack length l eq of wing crack, two terms make up the stress intensity factor K I at wing crack tip: one is the component K I (1) for a single isolated straight wing crack of length 2l subjected to hydraulic pressure in wing crack and far field stresses, and the other is the component K I (2) due to the effective shear stress induced by the presence of the equivalent main crack. The FEM model of wing crack propagation subjected to hydraulic pressure and far field stresses was also established according to different side pressure coefficients and hydraulic pressures in crack. The result shows that a good agreement is found between theoretical model of wing crack proposed and finite element method (FEM). In theory, an unstable crack propagation is shown if there is high hydraulic pressure and lateral tension. The wing crack model proposed can provide references for studying on hydraulic fracturing in rock masses.

Key words

rock mechanics wing crack hydraulic pressure numerical simulation