“…For such rock types, the transient phase is usually followed by secondary creep, although primary creep was sometimes immediately succeeded by accelerating dilatant (tertiary) behavior (Heap, Baud, Meredith, Bell, et al, 2009). Some creep tests on sandstones (Brantut et al, 2013;Heap, Baud, Meredith, Bell, et al, 2009), shales (Rybacki et al, 2017), and clayey rocks (Fabre & Pellet, 2006) show secondary creep regime (~60 and~30 min and~200 days, respectively); secondary creep rates are better observed in soils and unconsolidated sands (see e.g., Enomoto et al, 2015). Yet, it could be argued that secondary creep simply represents a transition from primary to tertiary regimes (Heap, Baud, Meredith, Bell, et al, 2009;Lockner, 1993).…”