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collector streets and all building structures except one and two family dwellings, garages, <br />carports, and outbuildings for one and two family development. <br />Small Project: Examples of small projects are: (a) a utility excavation no more than <br />five (5) feet deep and less than 300 feet long; and (b) road reconstruction, rehabilitation, <br />widening, or extension of less than 300 feet of road in an area with established infrastructure <br />(roads, utilities). Small projects can also include sidewalk construction in an area with <br />established infrastructure. <br />Soil Description and Classification: In the Eugene/Springfield area, soil units are <br />Quaternary in age (younger than 1.64 My). Soil units include fluvial deposits (alluvium) and <br />slope deposits (colluvium). PDS (Partly Decomposed State) and CDS (Completely <br />Decomposed State) rock, although exhibiting characteristics of a soil, should not be <br />classified as a soil unit for the purpose of geological and geotechnical investigation and <br />design reports. Soil materials are described and classified on the basis of ASTM or <br />AASHTO tests for the following properties: origin: whether residual; colluvial, or <br />transported; gradation: measured or estimated grain size distribution; angularity/roundness <br />of visible soil particles; color; measured or estimated in-place moisture content; Atterberg <br />1"units: liquid limit, plastic limit, plasticity index of the -40 fraction; relative density ifnon- <br />plastic or below the plastic limit; consistency if above the plastic limit; Expansion Index; <br />and, Unified Soil Classification System designation, determined by: gradation and Atterberg <br />limits (ASTM D-2487, UBC 18-1 or equivalent) or the Visual Manual Procedure (ASTM. <br />D-2488 or equivalent). <br />Soil Disturbance: Excavation and/or fill activities that displace the natural ground <br />elevation by more than one (1) foot. <br />Undisturbed Sample: A soil sample that has relatively unaltered in-situ particle <br />structure and contains all of the soil components in their in-situ amounts, configuration, <br />orientation, and degree of saturation. <br />Uniform Area: An area of land: <br />(1) That has a single topographic feature (e.g. flat area, uniformly sloping <br />area) without surface indications of changes in the subsurface (soiUrock stratigraphy, <br />relative position of the water table); <br />(2) For which published information indicates that rock and soil types <br />over the azea of the project have similar physical properties for purposes of design; <br />and <br />(3) For which there is no significant variation in vegetation, such as, but <br />not limited to wet spots with sedges. <br />Units: Rock-, Soil-, Fill-Units. Elements in the geologic stratigraphy of the site <br />which affect the planning, engineering, and construction of the project. Units should be <br />unequivocally identifiable in the field by qualified professionals and mapable at an <br />appropriate scale (e.g. 1" =10'). <br />(1) A rock unit consists of a single rock type of similar origin, which <br />may be present in differing states of decomposition. The engineering properties of <br />the various states of decomposition aze likely to be significantly different. In general, <br />a decrease of weathering and increase in strength can be expected with depth within <br />a single rock unit, although exceptions to this rule aze frequent; <br />(2) A soil unit consists of soil materials naturally present at a site, with <br />Administrative Order - 3 <br />rladminordlrules102geotech 1 ao.wpd(09/05/02) <br />