Question For an inorganic soil, the following grain-size analysis is given:Sieve No.        % Passing4                       10010                      9020                      6440                      3880                      18200                    13For this soil, LL = 23% and PL = 19%. Classify the soil according to:a. The AASHTO soil classificationb. The Unified soil classification system

Step 1Given Data:Data for grain-size analysis is given:Sieve No.        % Passing4                       10010                      9020                      6440                      3880                      18200                    13For this soil, LL = 23% and PL = 19%.To Find Out:Classify the soil according to:a. The AASHTO soil classificationb. The Unified soil classification system Step 2Solution:Sieve No.        % Passing          Corresponding size for the Sieve No.4                       100                             4.76 mm                                                                                                      10                      90                              2.00 mm20                      64                              0.841 mm40                      38                              0.420 mm80                      18                              0.177 mm200                    13                              0.074 mmNow,(a) The AASHTO soil classification:Soil is divided based on the Group Index (GI).GI = 0.2a + 0.01bd + 0.005cawhere,a=(75μm passing-35) b=(75μm passing-15)c=(wL-40)d=(Ip-10)Here, 75μm passing =13% (sieve no 200) from the table aboveIp=Plasticity Index=(wL-wp)Ip=(23-19)=4Calculation of a,b,c,d-a=(13-35)=Negative value⇒a=0b=(13-15)=Negative value⇒b=0c=(23-40)=Negative value⇒c=0d=(4-10) =Negative value⇒d=0Now,GI = 0.2a + 0.01bd + 0.005caPutting the values:GI = 0.2×0 + 0.01×0 + 0.005×0GI=0GI values                 Soil Type--------                      Excellent0-1                             Good2-4                             Fair5-9                             Poor10-20                        very PoorHence, The given soil is GOOD (GI=0)  Step 3(b)The Unified soil classification system:From the given data in the question, we conclude that-100% particles pass through Sieve No 4 i.e. 4.76 mmAlso, Only 13% particles passes through Sieve No 200 i.e. 0.074mm=75 micron meter.Size of Sand is 75 micron meter to 4.75 mmHence, the given soil is a Coarse grained soil - SANDFINAL ANSWERS:(a) AASHTO- The given soil is GOOD (GI=0)(b) USCS- Coarse grained soil - SAND ...