LAB MANUAL 3SieveAnalysis

LAB MANUAL 3SieveAnalysis - CIVE 310 Soil Mechanics Sieve...

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22 CIVE 310 Soil Mechanics Sieve Analysis Section Assigned Due Monday Before Lab: Read this Handout
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23 SIEVE ANALYSIS Grain Size Analysis In order to classify a soil for engineering purposes, one needs to know the distribution of the size of grains in a given soil mass. There are 3 methods used to determine the grain size distribution of soils. 1) Sieve analysis - for soils consisting primarily of particles > 0.074 mm (soils with grain sizes mostly > #200 sieve) 2) Hydrometer analysis - for soils consisting primarily of particles < 0.074 mm (soils with grain sizes mostly < #200 sieve) 3) Combined analysis - perform both sieve and hydrometer analysis on mixed soils Why do we need to do a grain size analysis? 1) For basic information - needed for soil classification 2) For quality assurance in: a) aggregate production plants b) for fill materials c) for sand filters d) for concrete production A grain size distribution is a statistical distribution. Quantities of the same sizes found in a random lab soil sample will generally be found in the field. The American Society for Testing and Materials specifies standard procedures for tests. ASTM D 422 is the test specification number for the grain size distribution tests. Specification ASTM D 421 provides the standard practices for the dry preparation of soil samples. A random sample can be selected by quartering or splitting (Figure 1). Sieving the Sample 1) Hand Sieving a) could use wire-mesh screens placed in frames b) usually use very large opening sizes down to about 25 &m in size
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24 c) could also use standard 8"-diameter, 2"-deep sieves which are portable and easily used by hand 2) Mechanical Sieving a) use a Ro- Tap machine with a stack of sieves (Figure 2) b) seven sieves and a pan at the bottom (Figure 3) What do we do with the data we obtain? The results of mechanical analyses are generally presented on semilogarithmic plots known as particle-size distribution curves . From these curves we can determine 3 basic soil parameters: 1) The effective particle sizes (i.e. - D 10 = 10% finer diameter) 2) The Coefficient of Uniformity 3) The Coefficient of Curvature (or Gradation) A construction of these calculations can be found in Example 1. Coefficient of Uniformity
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This note was uploaded on 04/03/2008 for the course CIVE 310 taught by Professor Iforget during the Spring '08 term at Drexel.

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LAB MANUAL 3SieveAnalysis - CIVE 310 Soil Mechanics Sieve...

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