ENCL E_2a- P-495 Geotech Report 1999-01-19.pdf

This document is a geotechnical investigation report dated January 19, 1999, prepared by URS Greiner Woodward Clyde Federal Services for the Naval Facilities Engineering Command. The report documents a subsurface investigation for the proposed Bachelors Enlisted Quarters (P-495) at the Marine Corps Air and Ground Combat Center in Twentynine Palms, California. The investigation involved drilling six exploratory borings to depths of 1.7 to 7.9 meters using a TH-60 drill rig with air percussion, collecting soil samples, and conducting laboratory testing.

Key findings include that the site consists of medium dense to very dense alluvium composed primarily of sand and silt with some gravel, with no groundwater encountered during drilling. The soil is predominantly medium dense to very dense, with low potential for hazards like subsidence or soil liquefaction. The report recommends specific guidelines for site preparation, including grading, excavation, fill placement, foundation design, and drainage. Geotechnical recommendations cover aspects such as foundation types (continuous shallow footings), subgrade preparation, pavement construction, and potential corrosion considerations, with an emphasis on proper compaction and drainage to ensure structural stability.