Aggregate Pier Group Load Test Results For Large Infrastructure Project In The Middle East-Video

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GeoPeer Foundation Company designed a ground-improvement system for a confidential public transportation project in the Middle East. The site included loose fill and soft, liquefiable silts, with untreated post-earthquake settlements estimated at 200 mm. The design used 600 mm-diameter impact piers, installed 2.6 m apart and extending 12 m into denser sand.<br /><br />A group load test applied 150 kPa to a 7.5 m square footing centered over nine piers. After 24 hours at full load, average settlement was 30 mm—below the 50 mm project limit. Post-installation cone penetration tests showed improvement in the fill but little change in the soft silts, as expected.<br /><br />Using the measured settlement and soil-test data, the team back-calculated pier stiffness. The soft-silt pier modulus was at least 110 MPa, exceeding the 75 MPa design estimate; stiffness in the sands was close to expectations. The test confirmed the system met settlement requirements.

Keywords

ground improvement

impact piers

settlement test

cone penetration test

soil stiffness