Explain fundamental concepts relating to soil fabric, formation, and mineralogy, Slides of Geotechnical Engineering

Download Explain fundamental concepts relating to soil fabric, formation, and mineralogy and more Slides Geotechnical Engineering in PDF only on Docsity! Grain Size Analysis Sources: Soil Mechanics – Laboratory Manual,B.M. DAS (Chapters 4 & 5) Soil Properties, Testing, Measurement, and Evaluation, C. Liu, J. Evett  Grain size Analysis  Chapter 4: Mechanical Method (Sieve Analysis)  Chapter 5: Hydrometer Method Class Outlines Sieve Analysis  ASTM D 421  Applicable for soils that are mostly granular with some or no fines  The U.S. No. 200 sieve (0.074mm or 0.0029in) is the smallest sieve size typically used in practice  Small size is 500g (why?) Sieve Analysis (Cont.) Sieve Analysis (Cont.)  3/8”, ¼” sieves is the size of the opening  No.10 sieve …. has 10 apertures per linear inch  Use sieves No. 3/8”, No.4, No.10, No.40, No.140 & No.200 Hydrometer Analysis  ASTM D422  This method is generally used to determine the particle- size distribution for soils with small grain sizes < 0.075 mm (No. 200)  The lower limit of the particle size determined by this procedure is about 0.001mm  In the lab we will use ASTM 152-H Hydrometer (?)  This method is based on Stoke’s law “The larger the grain size, the greater its settling velocity in a fluid”  The sample size is 50g passing #10 (why?) waterofityvisDv ws cos:; 18 )( 2      Hydrometer Analysis (Cont.) L =30 Hydrometer Test (Cont.)  A Hydrometer reading of 30 means that there are 30 g of soil solids in suspension per 1000cc of soil-water mixture at a temperature of 200C  Take reading at 15, 30, 60 seconds then at 2, 5, 15, 30 and 60 minutes Hydrometer Test (Calculation - pp 30)  R – Hydrometer reading (col 2)  Rcp – corrected hydrometer reading for calculation of percent finer (col 3) Rcp = R + FT – Fz  Percent finer (col 4) =  RcL - Corrected reading for determination of effective length (col 5) & Find L from Table 5-1 pp 26 RcL = R + Fm  Determine D = s cp W Ra a = correction for Gs see Table 5-3 pp 30 Assume Gs = 2.65 (min) )( t cmL A  Notes from:  CE 3121: Geotechnical Engineering Laboratory Abdulrahman Alhabshi  Civil Engineering - Texas Tech University