土的工程绪论土的工程 (24).pdf
Soil MechanicsSoil MechanicsChapter 1:Basic characteristics and engineering classification of soilsSoil Mechanics-chapter1（4）Void ratio （5）Porositye=Vv/Vs n=(Vv/V)x100(%)Conversion Index(1)e=n/(1-n)n=e/(1+e)Definition:The void ratio is the ratio of thevolume of voids to the volume of solids.The porosity is the ratio of the volume of voids to the total volume of the soil.The eand the nare inter-related as follows:Soil Mechanics-chapter1Conversion Index(2)（6）Degree of saturationSr=(Vw/Vv)x100(%)0 1(completely dry)(fully saturated)Define:The degree of saturation(Sr)is the ratio of the volume of water to the total volume of void space.It is also expressed as a percentage.Soil Mechanics-chapter1（7）Completely dry soil(Sr=0)d=ms/V(kg/m3)or d=dg(kN/m3)（8）Fully saturated soil(Sr=1)sat=(ms+Vvw)/V(kg/m3)or sat=satg(kN/m3)（9）Buoyant=(ms-Vsw)/V(g/cm3)or =g(kN/m3)g=980cm/s2,w=10kN/m3Conversion Index(3)Soil Mechanics-chapter13 measurable parameters(by tests)are:water content w soil density specific gravity dsSoil Mechanics-chapter1How to derive a phase relationship?(a)Using the phase diagram(b)Mathematic operation Remember definition of each parameter!Phase diagramsma=0mwmsmVaVvVVwVsAirWaterSolid particlcs(Solid)MassVolumem=mass，V=volumeds wSoil Mechanics-chapter1/1wdmmmmmVmVVVVVswsswwssswwwsww1,VeVVVsvsv;dmVmVsswssswww1dmVmmswswwssssswdmmmmmVmswwsswwwssswDeducing of phase relationshipsds wSoil Mechanics-chapter1Deducing phase relationships:rsSwde?d drwvwsvrwvsSVVVwVeSVVwedone;!Phase diagramds wSoil Mechanics-chapter1Prove phase relationships mathematically?enn1?From complicated site to simplify:vvvvvsnnVVVVVVVVVVVedone1/1/!Deducing phase relationships:Soil Mechanics-chapter1The above,r and w can be calculated directly by definition(original expression).Example 1.1Given:m=2290g,V=1.15x10-3(m3)ms=2035g,ds=2.68Ask:w,e,n,Srmwmsw2035100%12.5%22902035Vkg mm1.15 101990/2.2933VkN mmg1990 9.819.5/3Soil Mechanics-chapter1The below parameters need to use phase relationships:edwsw1990110.522.68 1.125 1000(1)ene11.52100%34%0.52eSd wrs0.5264.5%2.68 12.5%Soil MechanicsStatement:Thanks for some pictures and materials fromthe Internet used in this courseware only for teaching.
