Landslides and great soil volume changes affecting an urban area of Barranquilla, Colombia

Abstract

In the Western hills of Barranquilla city, Colombia, landslides and severe surface deformation has been occurring after rapid urban development, and in spite of many conventional geotechnical studies, the solutions have been poor and the problems have increased continuously, causing a lot of damage and economical losses to the people living there. This paper shows the importance of understanding the geological conditions of formation and the characteristics and variability of material properties. In this particular case it was necessary to identify the causes of the significant soil volume changes and their relation to the landslide triggering mechanisms, based on the analysis of the existing information, detailed field observations and some additional tests on compressibility and expansion potential. It is now possible to advance a comprehensive failure mechanism related to water infiltration through soil cracks. Reduction of the crack openings by the dissolution of gypsum and calcite, volume increase and new crack formation due to water-mineral interaction, local soil collapse originated by further water entrance and rapid suction decreases, and finally, reduction of soil strength by the previous remoulding process, lead to potential failure planes. This paper presents part of the results of the project IPL 171 "Study of the geotechnical characteristics of an unstable urban area of Barranquilla (Colombia) severely affected for slope instabilities and soil volume changes". It may contribute to improving our knowledge of the clays and fractured rock materials and to give a new perspective to possible management and stabilization actions to be taken by the government authorities. Additionally, the paper presents important comments about the relevance of landslide hazard studies to urban development plans.