5828 GLENWOOD AVE CINGULAR WIRELESS ANTENNA Geotech Report 2022-10-25 (2)

Adapt Engineering It should be noted that the exploration performed for this evaluation revealed subsurface conditions only at a discrete location across the project site and that actual conditions in other areas could vary. Furthermore, the nature and extent of any such variations would not become evident until additional explorations are performed or until construction activities have commenced. If significant variations are observed at the time of construction, we may need to modify our conclusions and recommendations contained in this report to reflect the actual site conditions. Auger Boring Procedures The boring was advanced using a track-mounted,hollow-stem auger drill rig operated by an independent company working under subcontract to Adapt. A geotechnical representative of Adapt was on-site to observe the boring,obtain representative soil samples,and log the subsurface conditions. After the boring was completed,the borehole was backfilled with a mixture of soil cuttings and bentonite chips. During drilling, soil samples were obtained on 2.5-foot intervals for the initial 10 feet and on 5-foot intervals thereafter, using the Standard Penetration Test(SPT)procedure (ASTM: D 1586). This test and sampling method consists of driving a standard 2-inch outside diameter (OD) split-barrel sampler a distance of 18 inches into the soil with a 140-pound hammer, free-falling a distance of 30 inches. The number of blows required to drive the sampler through each of the three, 6-inch intervals is noted. The total number of blows struck during the final 12 inches of penetration is considered the Standard Penetration Resistance, or "blow count". If 50 or more blows are struck within one 6-inch interval, the driving is ceased and the blow count is recorded as 50 blows for the actual number of inches of penetration. The resulting Standard Penetration Resistance values provide a measure of the relative density of granular soils or the relative consistency of cohesive soils. The Boring Log attached to this report describes the various types of soils encountered in the boring, based primarily on visual interpretations made in the field and supported by our subsequent laboratory examination and testing, as needed. The log indicates the approximate depth of the contacts between different soil layers, although these contacts may be gradational or undulating. Where a change in soil type occurred between sampling intervals, we inferred the depth of contact. Our log also graphically indicates the blow count, sample type, sample number, and approximate depth of each soil sample obtained from the boring, along with any laboratory tests performed on the soil samples. If any groundwater was encountered in the boreholes, the approximate groundwater depths are depicted on the boring log. Groundwater depth estimates are typically based on the moisture content of soil samples, the wetted height on the drilling rods, and the water level measured in the borehole after the auger has been extracted. Subsurface materials encountered were logged and classified in general accordance with the Manual Visual Classification Method(ASTM D 2488)by the geotechnical representative. SITE CONDITIONS The following sections describe our observations, measurements, and interpretations concerning surface, soil, groundwater,and seismic conditions at the project site. AT&T Mobility do General Dynamics October 10,2016 Adapt Project No.WA16-20654-GEO .Psse■2* 61