Instrumentation Applied to Slope Stability Problems

Unfavorable geologic conditions along proposed transportation routes often cannot be avoided by simple changes in grades and alignments. When such situations occur or when conditions cannot be defined with precision, it becomes necessary to supplement engineering judgement with field observations during and subsequent to construction. The collection of field data through fixed instrumentation is an effective means of evaluating embankment performance in areas where stability is questionable or where the effects of construction on adjacent lands must be determined. Inclinometers which measure subsurface displacements, and piezometers which record fluid pressures within the foundation soils are commonly employed in conjunction with field evaluation. These and several other methods often used to monitor field performance are briefly described. Three case histories are presented in which fixed instrumentation was used to control construction scheduling of an embankment over soft ground and to determine the effects on adjacent ground.