The engineering appraisel of slopes which are safe, and stable depend upon an adequate understanding of the nature of the ground.
Common geological hazards that should be considered by the designer include landslide, earthquake, reactive or expansive soils and limestone terrain. The likelihood and consequences of hazards may be assessed through desktop studies and geological mapping, but more commonly through previous experience of similar hazards (particularly if problems have been experienced with nearby projects).
A detailed investigation should assist in the following:
designing foundations for structures
determining the requirements for and design of earth retaining structures
designing subsurface drainage systems and special de-watering systems to intercept and
direct ground water to the surface drainage systems
determining the requirement for, and designing of, ground improvement works
predicting the magnitude and rate of settlement of embankments
assessing feasibility and producing cost estimates of alternatives