10930 HOLLY DR Geotech Report 2025-08-08

Helix Design Group,Inc.—Greenwood Heating&Air Conditioning,Everett,WA April 22,2022 Geotechnical Engineering Report Z0219 Improvement plans involve the clearing/stripping/grading of the subject property, and the construction of a one-story, 10,000-sf warehouse building adjoined to a two-story, 5,000-sf office building towards the central portion of the property. The new structures will be encircled by extensive asphalt pavements for drive lanes and parking facilities to support 50 to 60 vehicles. Site produce stormwater will be retained onsite if feasible, with the northeast corner of the property being reserved for stormwater management. 2.0 EXPLORATORY METHODS We explored surface conditions at the project site on March 15,2022,and subsurface conditions at the project site on March 25, 2022. Our exploration and evaluation program comprised the following elements: • Surface reconnaissance of the site, • Three exploratory test pit excavations (designated TP-1 through TP-3), excavated on March 25,2022, and • A review of published geologic and seismologic maps and literature. Table 1 (below) summarizes the approximate functional locations and termination depths of our subsurface explorations,and Figure 2(attached)depicts their approximate relative locations. The following sections describe the procedures used for excavation of test pits. TABLE 1 APPROXIMATE LOCATIONS AND DEPTHS OF EXPLORATIONS Termination Exploration Functional Location Depth (feet) TP-1 ±135 ft south-southeast of the northern corner of the project site 5 TP-2 ±140 ft east of western property line and±80 north of the southern property line 4 TP-3 ±80 ft west of eastern property line and±40 south of the northern property line 4 The specific number and locations of our explorations were selected in relation to the existing site features, under the constraints of surface access, underground utility conflicts, and budget considerations. It should be realized that the explorations performed and utilized for this evaluation reveals subsurface conditions only at discrete locations 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 begun. If significant variations are observed at that time,we may need to modify our conclusions and recommendations contained in this report to reflect the actual site conditions. 2.1 Test Pit Procedures Our exploratory test pits were excavated with a rubber-tracked mini-excavator operated by an excavation contractor under subcontract to MGI. An engineering geologist from our firm observed the test pit excavations, collected soil samples, and logged the subsurface conditions. Migizi Group,Inc. Page 2 of 16