title: Avalanches in dry and saturated disordered media at fracture.
abstract: This paper analyzes fracturing in inhomogeneous media under dry and fully saturated conditions. We adopt a central force model with continuous damage to study avalanche behavior in a two-dimensional truss lattice undergoing dilation. Multiple fractures can develop at once and a power-law distribution of the avalanche size is observed. The values for the power-law exponent are compared with the ones found in the literature and scale-free behavior is suggested. The fracture evolves intermittently in time because only some avalanches correspond to fracture advancement. A fully saturated model with continuous damage based on the extended Biot's theory is developed and avalanche behavior is studied in the presence of fluid, varying the fluid boundary conditions. We show that power-law behavior is destroyed when the fluid flux governs the problem. Fluid pressure behavior during intermittent crack tip advancement is studied for the continuous-damage fully saturated model. It is found that when mechanical loading prevails, the pressure rises when the crack advances, while when fluid loading prevails, the pressure drops when the crack advances.
authors.affiliation: Civil, Architectural and Environmental Engineering Department, Università degli Studi di Padova (UniPD), Via Marzolo 9, 35131 Padova, Italy.
authors.forename: Enrico
authors.initials: E
authors.lastname: Milanese
authors.affiliation: Civil Engineering Institute, Materials Science and Engineering Institute, École Polytechnique Fédérale de Lausanne (EPFL), Station 18, CH-1015 Lausanne, Switzerland.
authors.forename: Okan
authors.initials: O
authors.lastname: Yılmaz
authors.affiliation: Civil Engineering Institute, Materials Science and Engineering Institute, École Polytechnique Fédérale de Lausanne (EPFL), Station 18, CH-1015 Lausanne, Switzerland.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Molinari
authors.affiliation: Civil, Architectural and Environmental Engineering Department, Università degli Studi di Padova (UniPD), Via Marzolo 9, 35131 Padova, Italy.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Schrefler