A portion of the proposed location of the metropolitan atlanta rapid transit authority (marta) chamblee station was underlain by uncontrolled fill and soft sandy alluvial soils atop residual piedmont soils. Due to high groundwater conditions and adjacent railroad tracks, it was not considered viable to excavate and replace these soils. Since this area was to support a reinforced earth (tm) wall and the station platform, deep foundations were considered unacceptable due to concerns over differential settlements between the wall, trackway, and platform. The original design called for dewatering, placement of fill, and a surcharge load to preconsolidate the soils. The area was to be monitored with settlement platforms and observation wells that were to be extended as fill was placed. The authors jointly devised a plan to utilize vibrating wire settlement transducers and piezometers to monitor pore pressure dissipation and consolidation. These instruments were used in conjunction with consolidation tests to evaluate the rate of consolidation. Predicted magnitudes and rates of settlement are presented and compared to field measurements. This paper appears in transporttion research record no. 1277, Modern geotechnical methods: instrumentation and vibratory hammers 1990.
Samenvatting