Soil A For a given soil the following are known Percent pass

Soil A: For a given soil, the following are known: Percent passing No. 4 sieve 92% Percent passing No. 200 sieve = 48% LL-30 PI=8 Classify the soil using the Unified Soil Classification System. Give the group symbol and the group name. Group symbol: Group name:

Solution

Soil    %Passing No.200 %Passing No.4                  LL           PI     PI equation of A-line[0.73(LL-20)]

A              48 < 50                   92                 30 <50            8                 7.3 < 8 So, Clay C

         (So, Fine Grained soil)                        (So, L)

B              40 < 50                 60                26 <50       4                 4.38 > 4 So, Silt M

        (So, Fine Grained soil)                                          (So, L)

C             76 > 50                           99 > 50                       60           32

        (So, Coarse Grained soil)         since 99 > 50

                                                    So, Gravel(G) and

                                                     Fines=1% <5%

                                                   So, either well graded (W) or poorly graded (P)
                                                 

Conclusion:

Soil    Group Symbol Group Name

A          CL                      Inorganic Clays with Low Plasticity.

B          ML                     Inorganic Silt with Slight plasticity.

C         GW or GP           Well graded Gravels or Poorly Graded Gravels.