Civil Engineering Association

The Effect of Weathering on the Shear Strength Properties of Keuper Marl

This Paper presents a study of the modification as a result of weathering of the behaviour of mudstones from the Keuper Marl series. These soils have previously been heavily overconsolidated and contain considerable proportions of silt-sized aggregations of clay-sized particles. A classification scheme is presented which recognizes one unweathered and three weathered zones, and based upon these four zones a study is made of the influence of weathering on index properties, stress–strain relations, peak and residual effective stress parameters and consolidation behaviour. It is concluded that many of the soil properties that result from overconsolidation are modified by the weathering process, leaving the soil in a pseudo-overconsolidated state similar to that obtained when soils are remoulded at water contents below the liquid limit.