Shearing of saturated clays in rock joints at high confining pressures

Journal Article · Thu Nov 01 04:00:00 EST 1979 · Geophys. Res. Lett.; (United States)

DOI:https://doi.org/10.1029/GL006i011p00825· OSTI ID:5637630

Wang, C; Mao, N

Saturated clays are sheared between rock joints at various pore water pressures and at confining pressures up to 3 kb (300 Mpa). Sliding on these joints is stable. For a given clay, the shear stress required to initiate sliding increases linearly with the effective normal stress across the sliding surface, with a slope of 0.08 +- 0.01 for joints filled with saturated montmorillonite, 0.12 +- 0.01 with saturated chlorite, 0.15 +- 0.01 with saturated kaolinite, and 0.22 +- 0.02 with saturated silty illite. Thus at high confining pressures the shear stress required to initiate sliding on joints filled with saturated clays are very much smaller than that required to initiate sliding on clean rock joints or on joints filled with dry gouge materials. In the crust, saturation of gouge materials along active faults would greatly lower the frictional resistance to faulting and would stabilize fault movement. Different fault behaviors such as stable creep along some faults and intermittent but sudden slip along others may reflect in part different degrees of saturation of fault zones at depth.

• Research Organization: Department of Geology and Geophysics, University of California, Berkeley, California 94720
• OSTI ID: 5637630
• Journal Information: Geophys. Res. Lett.; (United States), Journal Name: Geophys. Res. Lett.; (United States) Vol. 6:11; ISSN GPRLA
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580300* -- Mineralogy
Petrology
& Rock Mechanics-- (-1989)
CLAYS
FRICTION
GEOLOGIC FAULTS
GEOLOGIC STRUCTURES
MINERALS
POROSITY
ROCK MECHANICS
SLIDING FRICTION
SLIP
STRESSES
VERY HIGH PRESSURE