SLOPE AND FOUNDATION HAZARDS IN KARST TERRAIN

 

Gil G. Cardiel, Flavinson U. Almiron, and Rodel L. Concepcion

School of Earth and Material Science and Engineering

Mapua Institute of Technology

 

Results of preliminary hydrogeological and engineering geomorphological mapping, geotechnical zoning and kinematic admissibility analysis in selected areas in the Philippines indicate that various slope and/or foundation hazards may be associated with each stage of karstification. Major foundation and slope hazards can be expected in an early mature to late mature stage of karstification.

The recognition of such hazards is very crucial in civil engineering design since housing development and infrastructure projects such as roads, bridges and communication and transmission masts including gas pipelines   are sited in sloping areas that are underlain by limestone. It is therefore exigent that a thorough site investigation using a combination of surface (i.e. pitting, trenching, exposure characterization and scanline surveys) and subsurface exploration (i.e. drilling, geophysical probing using ground penetrating radars or tomography) be conducted in order to recognize the   various slope and foundation hazards that are associated with each stage of karstification. Whenever possible, a three dimensional geological and geotechnical model must be created in order to accurately assess the various hazards and predict the terrain’s responce to a major seismic event.