Project Description

Diaz•Yourman & Associates (DYA) provided geotechnical investigative services for a container terminal that included a 5,000-foot-long container handling wharf and 300 acres of upland facilities.  The site was previously filled using hydraulic methods.  The project required dredging an additional 5 to 35 feet, more than 4,000,000 cubic yards of material.  A 70-foot-high rock dike retained the new onshore fill.

The subsurface investigation techniques included more than 100 onshore and offshore borings, numerous onshore and offshore geophysical surveys, offshore vibrocores, onshore cone penetration tests (CPTs), and onshore pavement coring.  The onshore borings were between 5 and 150 feet deep, and were completed using hollow stem auger and water rotary wash drilling techniques.  Soil samples were obtained at 5- to 10-foot intervals (typically) using Modified California standard penetration test (SPT) and thin-walled Shelby tube samplers.  Offshore borings were completed using barge-mounted platforms and land-based rotary wash drilling techniques.  Nearly 100 vibrocores, between 5 and 20 feet deep, were performed from a workboat.  During construction, potential dredge obstructions were checked using a remotely operated vehicle (ROV) and divers.

Recommendations were provided for cut and fill embankment stability (static and seismic), lateral earth pressures for retaining structures, shallow and deep foundations, slope erosion protection and piping, ground improvement (stone columns and deep dynamic compaction), mechanically stabilized earth composite raft systems using geopsynthetics (geogrids), and asphalt and concrete pavements.  Recommendations were also provided for site stabilization for excavations near the groundwater.

V. R. (Nadesh) Nadeswaran, PE, GE – Geotechnical Manager

Allen M. Yourman, Jr., PE, GE – Geotechnical Principal