The forensic geotechnical investigation included seven exploratory
borings, laboratory testing, groundwater level monitoring, and geotechnical
analyses.
Continuous core samples were taken in the borings
in the intervals between where California drive samples were
taken. The weathered claystone exhibited percent swell in amounts
up to 6.1% with a swelling pressure of 570 kPa (12,000 psf). For
the claystone, the percent swell ranged from 2.8 to 7.3% with swelling
pressures ranging from 240 to 720 kPa (5,000 to 15,000 psf).
The results of laboratory testing for the samples obtained for the
forensic geotechnical investigation are summarized in Table 2.