Strength Properties of Aalborg Clay

In the northern part of Vendsyssel, Denmark, the deposits made in the late glacial time are formed by the sea. The deposits are named after two mussels: Yoldia clay and Saxicava sand. However, in the southern part of Vendsyssel and in the area of Aalborg the clay and sand deposits from the late glacial time are characterised by the absence of this mussel. These deposits are named Aalborg Clay and Aalborg Sand. In the city of Aalborg, a fill layer superposes Aalborg Clay. This layer is at some places found to be 6m thick. This fill layer does not provide sufficient bearing capacity, which has resulted in many damaged buildings in Aalborg. To provide sufficient bearing capacity it is therefore necessary either to remove the fill or to construct the building on piles. Both methods imply that the strength of Aalborg Clay is important for the construction. This paper evaluates the strength of Aalborg Clay by
use of triaxial tests from four different locations. Both the drained strength (c and ϕ) and the undrained strength (cu) are assessed through two different methods: one where the strength is assumed to vary with the effective stress and another where the strength is found to be constant.