Deep trench, landslide and effects on the foundations of a residential building: A case study

The case study discussed in this paper deals with the excavation of an excessively deep and long trench in a clay slope made at one edge of an urban connecting road. The subsequent failure of the top portion of the slope did not cause any human casualty, but did severe damage to a neighbouring retaining wall and to an adjacent building. The works aimed at the stabilization of the slope are suspected to have increased the damage to the foundation system of the building.The aim of this paper is to show that all these events could be foreseen just by relying on the basic concepts of mechanics and on proper engineering practice. The causes for the landslide, and subsequent problems, are to be found in an excessive confidence in soil cohesion and in the application of standard engineering procedures in a non-standard case.