Soils exam 1

Water are the three phases in a phase diagram
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application of wroad compaction/roadworkapplication of unit weightcalculate soil weight/stress (pipeline)application of dry unit weightsoil compactionapplication of saturated unit weightsoil weight/stressDefinition of Geologythe study of materials and processes that form the earthRock CycleIgneous metamorphic sedimentaryBasic rock charactersDark in color little silica but may contain iron, magnesium decomposed to fine-grained soils (silt and clay)acidic rock characteristicslight in color higher silica in lower minerals decompose to sandy/gravely soilsPhysical Weatheringreduce particle size no change in chemical weathering make the coarse fraction of soil, gravel sand and silt thermal stress mechanical stress expose more surface for chemical weatheringChemical WeatheringReduction in form from chemically breaking down the parent materials and the parents change into something else. Form the fine fraction of soil and clay Processes: Acidic Reduction Hydration Oxidation CarbonizationCommon Clay MaterialsSilicon Tetrahedrons Aluminum Octahedrons these combine to form the claysMakeup of Silicon Tetrahedronsone Silicon and four Oxygen - drawMakeup of Aluminum Octahedronsone Aluminum and six hydroxides or oxygensCommon clay typesKaolinite Montmorillonite IlliteKaoliniteOne silica sheet and one alumina sheet thickness=0.72nm layers bounded by hydrogen not affected by water Draw structureMontmorilloniteOne alumina sheet between two silica sheets thickness=0.96 nm bonded by weak Van der Waals forces Very affected by water, can absorb enough that particle may separate Draw structureilliteOne alumina sheet between 2 silica sheets thickness=0.96 nm bonded by potassium ions large water holding capacity Draw StructureDispersed structureaccomplished by presence of K and Na that form thick DDLFlocculated StructureFloat around - accomplished by presence of Ca and H that suppresses DDLDiffused Double LayerClay minerals repeal each other due to net negative charges on the surface Attract cations (+) in the soil moisture to obtain electrical equilibrium conditions Because of net positive charge water charges are attracted and bond to the cation Distance from clay particle surface to limit attraction is DDLDDL for Dispersed StructureNon isotropic; different properties in different directions permeability high in the horizontal direction shear strength low in the horizontal direction low cation concentrationDDL for Flocculated StructureIsotropic; same properties in different directions Low permeability High shear strength occur when cation concentration is highhow is soil formedfrom the weathering of rockshow is clay formedwhen air or moisture comes in contact with rocks/soilFluvial Deposittransportation by water for rivers and streamsLacustrine Deposittransportation by water for lake depositsMarine Depositstransportation by water for seawaterGlacial Depositstransportation by water for snowWhat is sieve analysis?Determines particle size and distribution by separation of grains on a graded series of wire screensCu is the ...Uniformity CoefficientCc or Cz is the...Coefficient of CurvatureList 5 Atterbergs limitsLiquid Limit Plastic Limit Shrinkage Limit Sticky limit Cohesive LimitPI=...LL-PLGravel abbreviation and typeG, coarse aggregateSand abbreviation and typeS, coarse aggregateClay abbreviation and typeC, fine aggregateSilt abbreviation and typeM, fine aggregateWell-grade abbreviationWPoorly graded abbreviationPClayey soil appreviationCHigh plasticity abbreviationHLow plasticity abbreviationLHow do classifications startBy determining the amount passing the #200 sievepassing #200 sieve is ≥50%, then..soil is fine grained soil C&Mpassing #200 sieve is <50%, then..soil is coarse grained soil G&S30% plus No. 200 meansmeans the amount retained from the #200 sieve i.e. if percent passing is 70% then percent retained is 30%