Factors Influencing Shear Strength And Slope Failures In Basalt Soils Of North Eastern New South Wales

Landslides are a common feature of the basalt terrain or north eastern New South Wales. Failures typically occur through residual soil layers, at strength between the peak soil substance strength, and typical residual strength values. Shear strength on soil fissures approach residual strength. Failure therefore seems to occur through a combination of turbulent or rolling shear of the soil substance and sliding shear on fissure surfaces. Fissure properties such as surface condition continuity, spacing and orientation need to be observed when investigating sites in the area, or in similar geological terrains to allow consideration of the likely influence on overall soil mass strength.