WORK PLANS - Laserfiche WebLink

Home Browse Search

Soil Classification Standard Operating Procedure SWE-FSOP-201;Revision 0 Ahtna Southwest Environmental Operations particles sized between the coarsest and finest grains. A poorly-graded (P) sand or gravel consists predominately of one size or has a wide range of sizes with some intermediate sizes missing. Soils that have characteristics of two groups are given boundary classifications using the names that most nearly describe the soil.The two groups are separated by a slash.The same is true when a sand could be well or poorly-graded.Again,the two groups are separated by a slash. Soil description should be concise and stress major constituents and characteristics for fine-grained, organic, or coarse-grained soils. 4.1.2 Field Descriptions Content of soil descriptions in the field should be based on requirements to support project objectives, utilizing criteria and nomenclature modified from ASTM D2488. Description categories may include, but are not limited to: • Group Name. Name assigned to a particular lithology based on granular content, grading, and percentage of fines (specific grain sizes), described in the sections above. • Group Symbol.USCS symbol corresponding to the group name,e.g.,sandy silt(SM)or well-graded sand (SW). • Color. The basic color of the soil, as well as staining or color change resulting from oxidation/reduction. MunsellT"' soil color charts are commonly referenced for basic soil color. • Moisture Content.The amount of soil moisture is described as dry, moist,or wet. Note saturated conditions and when groundwater is encountered. • Relative Density/Consistency. An estimate of density of a fine-grained soil or consistency of a cohesive soil, usually based on standard penetration tests. An approximation of density/consistency can be determined by ease of penetration of the sample by thumb and/or fingers. • Particle (Grain) Size Distribution. An estimate of the percentage and grain-size range of each of the soil's subordinate constituents with emphasis on clay-particle constituents. This description may also include a description of grain/particle angularity. This parameter is critical for assessing the hydrogeology of the site. • Soil Texture and Structure. Description of arrangement of particles into aggregates and their structure. This description includes joints, fissures, slickened sides, bedding, veins, root holes, debris, organic content, and residual or relict structure, as well as other characteristics that may influence the movement or retention of water or contaminants. • Odor. Odor is described from a warm, moist sample. The odor should only be described if it is organic or unusual. An organic odor will have a distinctive decaying vegetation smell. Unusual odors (petroleum product, chemical, and the like) should also be described. 4.1.3 Example Description Below is an example for an interval from 7.2 feet (')to 9.1' below ground surface: Poorly-graded sand(SP), light yellowish-brown (10YR 6/4), moist to 8.5; saturated below 8.5; loose- to medium-dense, —85%fine-grained sand with trace amount of medium-grained sand, —15%silt, thin (-1-2mm)bedding, oxidation/reduction color change to black below 8.5',-hydrocarbon-like odor. Page 6 of 11