2530 MADISON ST 2016-01-01 MF Import

1 AirTouch Cellula • 1 3 October 1997 ,r 7-9 7 M-11905-0 Pape 2 accurate only to the deoree perr�itted by our data sources and impl�ed by our measuring methods. It should 6e realized that our exploration revealed subsurface conditio^s only at a discrete location near the project site and that actual conditions could vary at the actual tower location. Furthermore, the nature and extent of any such variations will not become evident until constructian activities have begun. If significant variations are observed at that time, we may need to modify our conclusions and recommendarions to reflect actual conditions. 2_7 oil Borina Procedures Our exploratory boring was advanced with a hollow-stem auger, using a truck-mounted drill rig operated by an indopendent driiling company working under subcontract to AEE. An geotechnical engineer from our firm continuously observed the boring, logged the subsurface ccnditions, and collected representative soil samples. All samples were stored in watertight containers and later transported to our laboratory for further visual examination and testing, as deemed necessary. After each boring was complet�d, the bo;ehole was hackfilled �niith a mixture of bentonite chips and soil cuttings, and the surface was patched wikh asphalt or concreto (where appropriate). Throughout the driiling operation, soil samples were obtained at 2%:- to 5-foot depth intervals by means of the Standard Penetration Test (SPT) per ASTM:D-1586. This testing and sampling procedure consists of driving a standard 2-inch-diameter steel split-spoon sampler 18 inches into the soil with a 140-pound hammer free-falling 30 inches. The number of blows required to drive the sampler through each 6-inch interval is counted, and the total number of blows struck during the final 12 inches is recorded as the Standard Penetration Resistance, or "SPT blow count." If a t�tal of 50 blows is struck within any 6-inch interval, the driving is stopped and the blow count is recorded as 50 blows for the actuai penetration distance. The resulting Standard Penetration Resistance values indicate the relative density of granular soils and the relative consistency of cohesive soils. The enclosed Boring Log describes the vertical sequence of soils and materials encountered in each boring, based primarily on our field classifications and supported by our subsequent laboratory examination and testing. Where a soil contact was observed to be gradational, our log indicates the ave�ac�e contact depth. Where a soil type changed between sample intervals, we inferred the contact depth. Our log alsa graphicaily indicates the blow count, sample type, sample number, and approximate depth of each soil sample obtained from the borings, as well as any laboratory tests performed on these soil samples. If any groundwater was encounrered in a borehole, the approximate groundwater depth is depicted on the boring �ag. Groundwater depth estimates are 7�B1M�11B06-0