土的工程绪论土的工程 (14).pdf

1.3.2 Particle size distribution curves of soilEffective size d10Continuous size d30Average size d50Constrained size d60Particle size/mmParticle size distribution curvesParticle size distribution curvesd10d30d50d60Percentage smaller/%Effective sized10Continuous size d30Average size d50Constrained size d60Coefficient of uniformity:represents the slope of the curveCu=d60/d10 Coefficient of curvature:represents the continuity of the curveCc=d302/(d10d60)The characteristics and the engineeringsignificance of particle size distributioncurves can be expressed quantitatively.Basic conceptsWhen Cu5 or 10 and Cc=13:Well-grained soil;Otherwise:Poor-grained soil.Cu=166.7Cc=2.96Cu=2.25Cc=0.84Cu=18.0Cc=0.88Particle size/mmPercentage smaller/%土力学土力学Soil MechanicsSoil MechanicsProf.Prof.H.J.LiaoH.J.LiaoPhysical state of water in voids:Liquid water,gaseous water and solid waterMineral crystallization water and chemically bound waterUsually only changed under high temperature or long-term heating conditions,not included in the calculation of the water content.Bound waterStrong bound water and weakly bound waterFreedom waterGravity water and capillary waterPore water in soilFree gasIt is communicates with the atmosphere,when the soil layer is compressed under loading,the gas is easily to escape.Entrapped airExists in fine-grained soil and isolated from the atmosphere,thecompressibility will be increased and the permeability decreasedunder loading,so that the soil body difficult to compact completely.Toxic gas and flammable gasTrigger geological disaster.Pore air in soilStatementStatement:Thanks for some pictures and materials fromthe Internet used in this courseware only for teaching.