土的工程绪论土的工程 (12).pdf

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1、Soil MechanicsSoil MechanicsChapter 1:Basic characteristics and engineering classification of soilsSoil Mechanics-chapter1Outline of Chapter 1IntroductionSoil generationSoil composition and phase relationshipsParticle size analysisDensity properties for granular soilsPlasticity properties of soilsSo

2、il compactionEngineering classification of soilsSoil Mechanics-chapter1Soil CompositionSoil is an un-cemented or weakly cemented accumulation of mineral particles formed by the weathering of rocks,the void space between the particles containing water and/or air.In soil(and in most rock),voids exist

3、between particles,and the voids may be filled with a liquid,usually water,or a gas,usually air.Different from structure-steel and concrete etc highly cemented materials and man-made.1.3.1 Soil Composition and Phase RelationshipsSoil Mechanics-chapter1Soil particlesVoid spaces(liquid+gasliquid+gas)So

4、lid particlesSolid particles(Soil)(Soil)WaterWaterAirAirPhase diagramsPhase RelationshipsSoil Mechanics-chapter1ParticlesAir and waterThree-phase composition Three-phase material=solids+liquid+gasAs a result,soils are often referred to as a three-phase material or system(solids+liquid+gas)Soil Mecha

5、nics-chapter1two-phase:dry soil=solid soil particles+pore air fully saturated soil=solid soil particles+pore waterthree-phase:partially saturated soil=solid soil particles+pore water+pore airSoil Mechanics-chapter1Particle size analysisThe particle size analysis of a soil sample involves determining

6、 the percentage by mass of particles within the different size ranges.Particle sizes in soils can vary from over 100mm to less than 0.001mm.Soil Mechanics-chapter1Two tests(a)Sieving test(b)Sedimentation testTest MethodsThe particle size distribution of a coarse-grained soil canbe determined by the

7、method of sieving.The particle size distribution of a fine-grained soil or the fine-grained fraction of a coarse-grained soil can be determined by the method of sedimentation.Soil Mechanics-chapter1Sieving testSoil MechanicsStatement:Thanks for some pictures and materials fromthe Internet used in this courseware only for teaching.