Monitoring for Successful Site Improvement

Computer aided installation of stone columns combined with insitu instrumented surcharging provided the necessary feedback to improve a difficult site for support of a new gymnasium and health center. The low lying site consists of an ancient landslide with loose sands over bedrock which is overlain by peaty soils. Both liquefaction of the loose saturated sands and settlement of the organic soils needed improvement. Vibro-displacement stone columns combined with surcharging was employed to improve both types of soil present, thus providing the long term performance needed. Computer monitored vibro-replacement provided the necessary real-time information to confirm the stratigraphy, and control the diameter of column installed within the softer surface soils. Final improvement of the surface organic soils was provided by surcharge. An in-situ vibrating wire water level system was installed after the vibro improvement, providing the necessary feedback to confirm completion of the primary consolidation.