Geotechnical Site Characterization
Geotechnical site characterization activities were conducted for the proposed runway reconfiguration area (airport vicinity) as well as a number of potential borrow areas. The site investigations resulted in the most comprehensive data set of quality data for the south and central bay as well as areas outside the Golden Gates.

Fugro's integrated geophysical/geotechnical approach was employed at both Airfield and Borrow areas. That approach involved the use of:

1. High quality geotechnical data to identify the primary geologic units and soil layers of interest and develop a general subsurface model; and
   
   
2. Geophysical data to map the units and soil layers between explorations and to refine the subsurface model.

Overwater geotechnical explorations were conducted from barges using Fugro's drill rigs. High quality geotechnical data collection involved collection and on-site strength testing of undisturbed samples, and extensive use of in situ testing. Those tasks were accomplished using Fugro's customized overwater drill rigs, Fugro's proprietary in situ testing tools developed for marine work and an on-board testing laboratory.

At the airfield data collected included

• 27 Land borings
• 86 Land cone penetration tests (CPT)
• 33 Marine borings
• 217 Marine cone penetration tests (CPT)
• 200 Environmental vibrocores
• Seismic reflection geophysical survey- 370 nautical miles
• Multi-beam bathymetry surveys
• 20 All terrain vehicle (ATV) mounted CPTs

At the borrow areas data collected included:

• 30 Marine borings
• 120 Marine cone penetration tests (CPT)
• 24 Environmental vibrocores
• Seismic reflection geophysical survey- ~340 nautical miles
• Multi-beam bathymetry surveys
• 26 grab samples

At the airfield area the integrated site characterization resulted in:

• Mapping of 5 geologic units (Franciscan Formation Bedrock, Lower Layered Sediments, Old Bay Mud, Upper Layered Sediments, and Young Bay Mud) and fill across the site;
• Evaluation of the presence of recency of faulting in the project vicinity;
• Characterization of the geotechnical material properties of the various sand, silt and clay layers underlying the site

At the Borrow Areas the site characterization activities focussed on:

• Defining the lateral and vertical extent of practicably obtainable potential sand borrow units
• Evaluating the suitability of that material for use as fill.