4849 SPIRE LN 2023 Geotech Report 2025-10-15

Proposed Remedial Excavation: 4849 Spire Lane, Everett, WA December 8.2022 Also mapped near the site are outwash channels of the stratigraphically older Vashon advance outwash. This unit is a well -sorted sand and gravel that was deposited by streams near the advancing ice sheet. This soil unit has been glacially overridden, and as such, typically ranges from dense to very dense. The borings reviewed for.this evaluation and our test pit exploration generally encountered what we interpreted to be fill soil, above a dense poorly graded sand with silt, that we interpreted to be the Vashon advance outwash mapped near the subject site. SOIL CONDITIONS For a detailed description of the subsurface conditions encountered at each exploration location, please refer to the summary exploration logs provided in Appendix A and Appendix B. The stratigraphic contacts indicated on the logs represent the approximate depth to boundaries between soil units. Actual transitions between soil units may be more gradual or occur at different elevations. The descriptions of groundwater conditions and depths are likewise approximate. The following is a generalized description of the soils encountered in the test pit and previous boring logs. Unit 1— Fill and Relic Topsoil: Our test pit exploration encountered up to about 21/2 feet of medium dense, silty sand above an approximate 1-foot of dark brown silty sand to sandy silt, which we interpreted to be fill soils above relic topsoil based on their reworked texture and presence of organic material. These are likely soils disturbed during past grading or earthwork activities associated with construction of the residence. Unit 2 — Vashon Advance Ouhvash: Below the fill and relic topsoil, the test pit encountered a poorly -graded sand with some silt. Based on our probing, the digging action of the excavator, and no caving encountered in the test pit, we interpret this unit as the advance outwash unit of the Vashon Stade mapped near the project site. This soil unit was encountered to the termination depth of 12 feet below grade in our test pit and up to 35 feet below grade in the previous direct push probes advanced at the site. Our subsurface descriptions are based on the conditions encountered at the time of our exploration. Soil conditions between the exploration locations may vary from those encountered. The nature and extent of variations between our exploratory locations may 22-389_4849 spire lane everett_ipt.docx Page 4 PanGEO, Inc.