Study on the interaction mechanism between hydraulic fracture and natural karst cave with the extended finite element method

Abstract In this paper, a numerical model was established to simulate hydraulic fracture interaction with natural cave using the extended finite element method. The proposed model was verified by numerical model of crack interaction with void problem and analytic solution of stress intensity factors of hydraulic fracture. And the effects of cave location and horizontal stress difference on interaction patterns of fracture and cave were analyzed. It was found that the cave location is the main controlling factor affecting the interaction patterns of fracture and cave. The horizontal stress difference has a great effect on the interaction patterns of hydraulic fracture and cave only when the relative distance between the fracture and the cave has a moderate value.