8407 BROADWAY SECURE SPACE STORAGE Geotech Report 2025-04-24

FIELD EXPLORATION PROCEDURES The subsurface evaluation for this project included completion of three (3) test borings on June 2, 2022. The approximate locations of the explorations are presented on Figure 1, the Site and Exploration Plan. Exploration locations were determined in the using GPS. As such, the exploration locations should be considered accurate to the degree implied by the measurement method. The following sections describe our procedures associated with the explorations. Descriptive logs of the explorations are enclosed in this appendix. Soil Boring Procedures Borings were advanced with a hollow-stem auger, using a truck-mounted drill rig operated by an independent drilling company (Holocene Drilling) working under subcontract to our firm. A geotechnical engineer from ZGA continuously observed the borings, logged the subsurface conditions encountered, and obtained representative soil samples. All samples were stored in moisture-tight containers and transported to our laboratory for further visual classification and testing. As part of the testing program, all of the samples were visually examined in the laboratory. Throughout the drilling operation, soil samples were obtained at 2.5-foot intervals by means of the Standard Penetration Test (ASTM: D-1586). This testing and sampling procedure consists of driving a standard 2-inch outside 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 recorded, and the total number of blows struck during the final 12 inches is recorded as the Standard Penetration Resistance, or"blow count" (N value). If a total of 50 blows are struck within any 6- inch interval,the driving is stopped and the blow count is recorded as 50 blows for the actual 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 logs describe the vertical sequence of soils and materials encountered in each boring, based primarily upon our field classifications and supported by our subsequent laboratory examination and testing. Where a soil contact was observed to be gradational, our logs indicate the average contact depth. Where a soil type changed between sample intervals, we inferred the contact depth. Our logs also graphically indicate the blow count, sample type, sample number, and approximate depth of each soil sample obtained from the boring, as well as any laboratory tests performed on these soil samples. If any groundwater was encountered in a borehole, the approximate groundwater depth, and date of observation, is depicted on the log. Groundwater depth estimates are typically based on the moisture content of soil samples,the wetted portion of the drilling rods, the water level measured in the borehole after the auger has been extracted, or through the use of an observation well. The boring logs presented in this appendix are based upon the drilling action, observation of the samples secured, laboratory test results, and field logs.The various types of soils are indicated as well as the depth where the soils or characteristics of the soils changed. It should be noted that these changes may have been gradual, and if the changes occurred between sample intervals, they were inferred.