Hydro-mechanical coupling non-uniform discretization peridynamics and its application in hydro-fracturing

Abstract

This paper proposes a hydro-mechanical coupling peridynamic model with non-uniform discretization, incorporating both constant and variable horizon approaches, to investigate hydraulic fracturing in rocks. The computational efficiency and accuracy of the two horizon schemes are systematically compared. The constant horizon method employs a uniform radius, simplifying implementation but leading to coarser crack representations and reduced efficiency in multi-field coupling. In contrast, the variable horizon approach dynamically adjusts the horizon radius, significantly reducing computational costs while improving crack resolution and coupling efficiency.

Several numerical examples are conducted to analyze key factors influencing hydraulic fracturing, validating the proposed model against conventional peridynamic methods and the continuous-discontinuous element method. The results demonstrate excellent agreement, confirming the model’s reliability. Notably, the study reveals that fracturing can occur even in intact materials without pre-existing cracks, though it requires higher injection pressure and longer initiation time. Furthermore, the shape of the water injection port and the arrangement of material points critically influence the fracture propagation path, particularly in cases involving circular injection ports. These findings provide new insights into rock fracturing mechanisms and offer a computationally efficient framework for simulating hydraulic fracturing in complex geological settings.