TY - GEN
T1 - A threshold stress for pressure solution creep in rock salt
T2 - 10th Conference on the Mechanical Behavior of Salt
AU - van Oosterhout, B.G.A.
AU - Hangx, S.J.T.
AU - Spiers, C.J.
PY - 2022/7/5
Y1 - 2022/7/5
N2 - At low deviatoric stress, flow of rock salt is expected to be controlled by pressuresolution creep. This requires a fluid phase to be present in grain boundaries in the form ofadsorbed grain boundary films or a dynamically wetting island-channel structure. However,whether such structures can persist at low stress or will be eliminated by healing phenomenais open to question. In this study, a model is derived describing a threshold stress for pressuresolution, below which healing occurs, and creep is stopped. The results predict that pressuresolution creep in rock salt, at depths up to 3 km, is inhibited below a deviatoric stress of 0.07to 0.7 or at most 0.90 MPa. When deviatoric stresses in rock salt drop below this thresholdstress, a decrease in strain rate from ~10−13 to 10−18 s−1 is expected, due to a switch todislocation creep. The model needs to be tested against CT experiments or opticalobservations on grain boundary behavior under stress, and against confined creep tests atvery low deviatoric stress, as far as technically feasible. If confirmed, the effect of this thresholdstress needs to be considered in future numerical studies of flow in rock salt.
AB - At low deviatoric stress, flow of rock salt is expected to be controlled by pressuresolution creep. This requires a fluid phase to be present in grain boundaries in the form ofadsorbed grain boundary films or a dynamically wetting island-channel structure. However,whether such structures can persist at low stress or will be eliminated by healing phenomenais open to question. In this study, a model is derived describing a threshold stress for pressuresolution, below which healing occurs, and creep is stopped. The results predict that pressuresolution creep in rock salt, at depths up to 3 km, is inhibited below a deviatoric stress of 0.07to 0.7 or at most 0.90 MPa. When deviatoric stresses in rock salt drop below this thresholdstress, a decrease in strain rate from ~10−13 to 10−18 s−1 is expected, due to a switch todislocation creep. The model needs to be tested against CT experiments or opticalobservations on grain boundary behavior under stress, and against confined creep tests atvery low deviatoric stress, as far as technically feasible. If confirmed, the effect of this thresholdstress needs to be considered in future numerical studies of flow in rock salt.
U2 - 10.1201/9781003295808-6
DO - 10.1201/9781003295808-6
M3 - Conference contribution
SN - 9781032282206
SP - 57
EP - 67
BT - The Mechanical Behavior of Salt X
A2 - Bresser, J.H.P. de
A2 - Drury, M.R.
A2 - Fokker, P. A.
A2 - Gazzani, M.
A2 - Hangx, S.J.T.
A2 - Niemeijer, A.R.
A2 - Spiers, C.J.
PB - CRC Press
CY - London
Y2 - 6 July 2022 through 8 July 2022
ER -