Time and Temperature Dependent Creep in Tournemire Shale - Département de mécanique Access content directly
Journal Articles Journal of Geophysical Research : Solid Earth Year : 2018

Time and Temperature Dependent Creep in Tournemire Shale


We conducted a series of triaxial creep experiments on shale specimens coming fromTournemire, France, using the stress-stepping method up to failure, at a confining pressure of 80 MPa, ontwo orientations (parallel and perpendicular to bedding), and at temperatures of 26 and 75 °C. In theseweek-long experiments, stress, strains, andPwave ultrasonic velocities were recorded (quasi-) continuously.The strength at creep failure of Tournemire shale was ~70% higher than the peak strength measuredduring constant strain rate (~107/s) experiments, and failure was reached at larger strains. An overalltransition fromPwave velocity increase at moderate differential stress toPwave velocity decrease closer tobrittle failure was also observed. At a smaller timescale,Pwave velocities initially decreased and then increasedgradually during each step of creep deformation. The magnitude of these variations showed important (i)stress, (ii) orientation, and (iii) temperature dependences: larger increase was observed forPwave propagatingalong the main compressive stress orientation, larger decrease forPwave propagating perpendicular to it, anda changing behavior enhanced at a higher temperature. Scanning electron microscopy performedpostmortem revealed evidence of time-dependent pressure solution, localized compaction, crack growth, andsealing/healing. Our data reveal that shale deformation is highly stress sensitive only in a narrow stress domainwhere stress corrosion cracking-induced brittle dilatant creep deformation is dominant. At stresses below,pressure solution compaction creep dominates the deformation and shales compact, consolidate, and heal.This has important implications for the mechanics of shallow fault zones and accretionary prisms
Fichier principal
Vignette du fichier
RG_2018-Geng-et-al-JGR.pdf (5.79 Mo) Télécharger le fichier
Origin : Publisher files allowed on an open archive

Dates and versions

hal-03480340 , version 1 (14-03-2023)



Zhi Geng, Audrey Bonnelye, Mian Chen, Yan Jin, Pierre Dick, et al.. Time and Temperature Dependent Creep in Tournemire Shale. Journal of Geophysical Research : Solid Earth, 2018, 123 (11), pp.9658-9675. ⟨10.1029/2018JB016169⟩. ⟨hal-03480340⟩
31 View
9 Download



Gmail Facebook Twitter LinkedIn More