The shear strength characteristics of sandstone joints collected from a landslide site near Kangaroo Valley of Australia were investigated in the laboratory under Constant Normal Stiffness (CNS) condition. The joint surface profiles were characterised precisely using a digital Coordinate Measuring Machine (CMM) prior to testing. An initial normal stress (σ(no)) of 0.56 MPa to 2.69 MPa was used during this study. It is observed that the peak shear stress of the joint increases with the increase in σ(no). However, the increase in normal stress during shearing was observed up to σ(no) of 1.63 MPa for constant normal stiffness. The joint behaviour was dilatant for σ(no) less than 1.63 MPa and compressive (negative dilation) for greater σ(no). A plot of peak shear stress and corresponding normal stress shows that a linear strength envelope is appropriate for CNS testing. The small cohesion intercept of the strength envelope resulted from the infill material (iron oxide). The mathematical model proposed in this study, predicts very closely the behaviour of natural joints tested in the laboratory.
|Title of host publication||Consolidating knowledge. Proceedings of the 8th Australia New Zealand conference on geomechanics, Hobart, February 1999.|
|Editors||N. Vitharana, R. Colman, N. Vitharana, R. Colman|
|Publisher||Australian Geomechanics Society|
|Number of pages||7|
|Publication status||Published - 1 Dec 1999|