SPECIAL PUBLICATION NO. 57


 4. Note weight-of-rod or weight-of-hammer strength materials
 and voids will be noted in the boring logs. Note variable
 depth of bedrock.

 ii. Color photographs or soil samples should be taken of key soil
 conditions, such as the presence of debris or organic. Note
 whether sample is wet or dry when being photographed. A
 statement that roots were found is not sufficient to attribute the
 subsidence to decaying organic. If construction debris or other
 anthropogenic material is encountered, photograph sample
 materials to ensure adequate documentation.

 iii. If site relief is more than one foot, the graphic logs of the borings
 in the report should be placed in their relative vertical positions
 using the arbitrary datum used for leveling of their elevations.

 k. Soil / Sediment / Rock Sample Containers

 i. All soil, rock, or debris samples will be stored in properly marked,
 sealed containers in anticipation that they will be retained for long
 periods of time and are likely to be used as evidence.

 ii. "Chain of custody" procedures should be established and
 followed.

 1. Other down hole testing.

 i. Based upon professional judgment and site specific circumstances
 (structure size, economics, etc.) geophysical logging may provide
 useful information. This typically may include a natural gamma
 log and an induction (conductivity) log. See ASTM Standard
 Guide for Planning and Conducting Borehole Geophysical
 Logging D 5753-95.

 ii. As above (site specific judgment), hole to hole Up-hole or Down-
 hole testing may be utilized in some cases to provide seismic P and
 Shear wave velocities or resistivity or radar data. For hole to hole
 seismic tests see ASTM Standard Test Methods for Cross-hole
 Seismic Testing D 4428/D 4428M-91.

8. Laboratory Testing

 a. If clay-rich strata are found within 20 feet of the land surface, the
 following laboratory tests are suggested:

 i. A minimum of three samples should be tested according to these
 procedures.