“…In the brittle field, the state evolution is fundamentally linked to changes in the real area of contact (Ben‐David & Fineberg,
2011; Ben‐David et al.,
2010; Dieterich & Kilgore,
1994; Rubinstein et al.,
2004; Selvadurai & Glaser,
2015,
2017) with the strength of contact modulated by chemical reactions near contact junctions and crack tips in aqueous solutions or atmospheric humidity (Bergsaker et al.,
2016; Dieterich & Conrad,
1984; Frye & Marone,
2002; Renard et al.,
2012; Rostom et al.,
2013; Zeng et al.,
2020). The physical basis of the model relies on quantifying the real area of contact, which varies instantaneously with shear and normal stress, but also evolves spontaneously over time (Dieterich & Kilgore,
1994,
1996; Maegawa et al.,
2015; Mergel et al.,
2019; Popov et al.,
2021; Sahli et al.,
2018; Weber et al.,
2019; Xu et al.,
2022). In this study, we consider a simple model whereby the area of contact is controlled by the effective normal stress and the local radius of curvature of micro‐asperities at contact junctions based on the roughness of natural surfaces with a fractal topography (Archard, 1957; Barbot,
2019b; Greenwood & Williamson,
1966)
where
is the density of real area of contact, c 0 is a cohesion term, μ 0 is the reference friction coefficient,
is the effective normal stress accounting for pore fluid pressure (Terzaghi, 1936), χ is the plowing hardness, d and d 0 are the effective and reference radii of curvature at contact junctions, and α is a power exponent.…”