Energy Release Rate in hydraulic fracture: can we neglect an impact of the hydraulically induced shear stress?

摘要

A novel hydraulic fracture (HF) formulation is introduced which accounts forthe hydraulically induced shear stress at the crack faces. It utilizes ageneral form of the elasticity operator alongside a revised fracturepropagation condition based on the critical value of the energy release rate.It is shown that the revised formulation describes the underlying physics of HFin a more accurate way and is in agreement with the asymptotic behaviour of thelinear elastic fracture mechanics. A number of numerical simulations by meansof the universal HF algorithm previously developed in Wrobel & Mishuris (2015)are performed in order to: i) compare the modified HF formulation with itsclassic counterpart and ii) investigate the peculiarities of the former.Computational advantages of the revised HF model are demonstrated. Asymptoticestimations of the main solution elements are provided for the cases of smalland large toughness. The modified formulation opens new ways to analyse thephysical phenomenon of HF and also improves the reliability and efficiency ofits numerical simulations.