SOILS AND FOUNDATIONS Lesson 04 667 Geotech Design...SOILS AND FOUNDATIONS Testing Experience ......

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Transcript of SOILS AND FOUNDATIONS Lesson 04 667 Geotech Design...SOILS AND FOUNDATIONS Testing Experience ......

  • SOILS AND FOUNDATIONSSOILS AND FOUNDATIONS

    Testing

    Experience

    Theory

    Lesson 04Lesson 04Chapter 4 Chapter 4 Engineering Description, Classification and Engineering Description, Classification and

    Characteristics of Soils and RocksCharacteristics of Soils and Rocks

  • TopicsTopics

    gg Topic 1 (Section 4.0, 4.1)Topic 1 (Section 4.0, 4.1)-- Engineering description of soilsEngineering description of soils

    gg Topic 2 (Section 4.2)Topic 2 (Section 4.2)-- Engineering classification of soilsEngineering classification of soils

    gg Topic 3 (Section 4.3, 4.4, 4.5) Topic 3 (Section 4.3, 4.4, 4.5) -- Engineering characteristics of soilsEngineering characteristics of soils

    gg Topic 4 (Section 4.6)Topic 4 (Section 4.6)-- Engineering description of rock and rock mass Engineering description of rock and rock mass

    classificationclassificationgg Topic 5 (Section 4.7)Topic 5 (Section 4.7)

    -- Subsurface profile developmentSubsurface profile development

  • Engineering Description, Engineering Description, Classification and Characteristics Classification and Characteristics

    of Soils and Rocks of Soils and Rocks

    Lesson 04 Lesson 04 -- Topic 1Topic 1Engineering Description of SoilsEngineering Description of Soils

    (Section 4.0, 4.1)(Section 4.0, 4.1)

  • Learning OutcomesLearning Outcomes

    ggAt the end of this session, the participant will At the end of this session, the participant will be able to:be able to:-- Compare soil, rock and intermediate Compare soil, rock and intermediate

    geomaterialsgeomaterials ((IGMsIGMs))-- Contrast identification, description and Contrast identification, description and

    classificationclassification-- Perform engineering description of soilPerform engineering description of soil

  • Rock, Soil and IGMRock, Soil and IGM

    ggWhat is Rock?What is Rock?ggWhat is Soil?What is Soil?ggWhat is Intermediate What is Intermediate GeoMaterialGeoMaterial (IGM)?(IGM)?

  • Identification, Description and Identification, Description and Classification of SoilsClassification of Soilsgg IdentificationIdentification

    -- Process of determining the components of a given soil, Process of determining the components of a given soil, e.g., gravel, sand, silt, clay, etc.e.g., gravel, sand, silt, clay, etc.

    gg DescriptionDescription-- Process of estimating the relative percentage of each Process of estimating the relative percentage of each

    component of soilcomponent of soil-- Description includes identificationDescription includes identification

    gg ClassificationClassification-- Laboratory based process of grouping Laboratory based process of grouping geomaterialsgeomaterials with with

    similar engineering characteristics into categoriessimilar engineering characteristics into categories

  • Soil DescriptionSoil Description

    ggSystematic naming of individual soils in both Systematic naming of individual soils in both written and spoken formswritten and spoken forms

    ggASTM D 2488, AASHTO M 145ASTM D 2488, AASHTO M 145ggSoil Soil decriptiondecription is used in the field during is used in the field during

    logginglogging

  • Soil DescriptionSoil Description

    ggApparent consistency (e.g., soft, firm)Apparent consistency (e.g., soft, firm)ggWater content (e.g., dry, moist)Water content (e.g., dry, moist)ggColor Color ggMain soil type (e.g., Sand)Main soil type (e.g., Sand)ggDescriptive term for main soil type (e.g., fine, Descriptive term for main soil type (e.g., fine,

    medium, coarse, wellmedium, coarse, well--rounded)rounded)ggParticleParticle--size distribution (e.g., uniform, wellsize distribution (e.g., uniform, well--

    graded)graded)

  • Soil DescriptionSoil Description

    gg Plasticity adjective (e.g., high, low)Plasticity adjective (e.g., high, low)gg Soil texture (e.g., rough, smooth, waxy)Soil texture (e.g., rough, smooth, waxy)gg Descriptive term for minor soil Descriptive term for minor soil type(stype(s) (e.g., with, ) (e.g., with,

    some, trace, etc.)some, trace, etc.)gg Minor soil type name with y (e.g., Minor soil type name with y (e.g., siltysilty))

    -- If fineIf fine--grained minor component 12%grained minor component 12%gg Descriptive adjective with if fineDescriptive adjective with if fine--grained grained

    component is between 5 and 12%component is between 5 and 12%gg Inclusions (e.g., concretions, cementation)Inclusions (e.g., concretions, cementation)gg Geological name (e.g., Holocene, Jurassic)Geological name (e.g., Holocene, Jurassic)

  • Soil DescriptionSoil DescriptionExamplesExamplesggFineFine--grained soilsgrained soils

    -- Soft, wet, gray, high plasticity CLAY, with f. Sand Soft, wet, gray, high plasticity CLAY, with f. Sand (Alluvium)(Alluvium)

    ggCoarseCoarse--grained soilsgrained soils-- Dense, moist, brown, Dense, moist, brown, siltysilty mm--ff SAND, with f. SAND, with f.

    Gravel to c. Sand (Alluvium)Gravel to c. Sand (Alluvium)

  • Apparent Density of CoarseApparent Density of Coarse--Grained Grained Soils (Table 4Soils (Table 4--1)1)

    N60 Apparent Density Relative Density, %

    0 4 Very loose 0 20

    >4 - 10 Loose 20 40

    >10 - 30 Medium dense 40 70

    >30 - 50 Dense 70 85

    >50 Very Dense 85 100

    The above guidance may be misleading in gravelly soils.

  • N60 ConsistencyUnconfined Compressive

    Strength, qu, ksf (kPa)Results of Manual Manipulation

    8>400Cannot be imprinted by fingers or

    difficult to indent by thumbnail.

    Note that N60-values should not be used to determine the design strength of fine grained soils.

  • Water ContentWater Content

    Description Conditions

    DryNo sign of water and soil dry to touch

    MoistSigns of water and soil is relatively dry to touch

    WetSigns of water and soil definitely wet to touch;

    granular soil exhibits some free water when densified

  • Particle Size DefinitionParticle Size DefinitionDescribing Size DistributionDescribing Size DistributionggTable 4Table 4--44

    ggTable 4Table 4--55

  • Simple Tests for Soil TypeSimple Tests for Soil Type-- CoarseCoarse--Grained SoilsGrained SoilsggFeel and smear testsFeel and smear testsggSedimentation testSedimentation testggVisual characteristicsVisual characteristics

  • Simple Test for Soil Type Simple Test for Soil Type -- FineFine--Grained SoilsGrained SoilsggShaking (Shaking (dilatancydilatancy) test) testggDry strength testDry strength testggThread testThread testggSmear testSmear test

  • Field Methods to Describe PlasticityField Methods to Describe Plasticity(Table 4(Table 4--6)6)

    Plasticity Range Adjective Dry Strength Smear Test

    Thread Smallest Diameter, in

    (mm)

    0 Nonplastic none - crumbles into powder with mere pressuregritty or

    rough ball cracks

    1 - 10 low plasticity low - crumbles into powder with some finger pressurerough to

    smooth1/4 1/8(6 to 3)

    >10 - 20 medium plasticity

    medium - breaks into pieces or crumbles with considerable finger pressure

    smooth and dull

    1/16(1.5)

    >20 - 40 high plasticity

    high - cannot be broken with finger pressure; spec. will break into pieces between thumb and a hard surface

    Shiny 0.03(0.75)

    >40 very plasticvery high - cant be broken

    between thumb and a hard surface

    very shiny and waxy

    0.02(0.5)

  • Highly Organic SoilsHighly Organic Soils

    gg Dark gray and black (sometimes dark brown)Dark gray and black (sometimes dark brown)-- Not all dark colored soils are organicNot all dark colored soils are organic

    ggWhen exposed to air, color of sample surface When exposed to air, color of sample surface changes from darker to lighterchanges from darker to lighter-- Pull apart sample to verify darker color insidePull apart sample to verify darker color inside

    gg Characteristic odorCharacteristic odorgg FriableFriablegg SpongierSpongiergg DO NOT CONFUSE TOP SOIL WITH ORGANIC DO NOT CONFUSE TOP SOIL WITH ORGANIC

    SOILS OR PEATSOILS OR PEAT

  • Minor Soil TypesMinor Soil Types

    ggTrace (between 1 to 12%)Trace (between 1 to 12%)ggSome (between 12 to 30%)Some (between 12 to 30%)

  • InclusionsInclusions

    ggDescribed using withDescribed using withggExamplesExamples

    -- With With petroluempetroluem odorodor-- With organic matterWith organic matter-- With foreign matter (roots, bricks, etc.)With foreign matter (roots, bricks, etc.)-- With shell fragmentsWith shell fragments-- With micaWith mica-- With With parting(sparting(s), ), seam(sseam(s) etc. of (give soils ) etc. of (give soils

    complete description)complete description)

  • Layered SoilsLayered Soils(Table 4(Table 4--7)7)gg PartingPartinggg SeamSeamgg LayerLayergg StratumStratumgg PocketPocketgg LensLensgg VarvedVarvedgg OccasionalOccasionalgg FrequentFrequent

  • Geological NameGeological Name

    ggPotomac Group FormationPotomac Group FormationggYorktown FormationYorktown FormationggCoconino SandstoneCoconino Sandstone

  • Learning OutcomesLearning Outcomes

    ggAt the end of this session, the participant will At the end of this session, the participant will be able to:be able to:-- Compare soil, rock and intermediate Compare soil, rock and intermediate

    geomaterialsgeomaterials ((IGMsIGMs))-- Contrast identification, description and Contrast identification, description and

    classificationclassification-- Perform engineering description of soilPerform engineering description of soil

  • Any Questions?Any Questions?

    THE ROAD TOUNDERSTANDING

    SOILSAND

    FOUNDATIONS