How use soil in laboratory.

Question.

            Define liquid limit and plastic limit. How do you calculate plasticity index ? How many strokes are specified for rolling the thread of soil when determining plastic limit ? And how many revolution per second when determining liquid limit ?

Answer .

       Liquid limit is the water content in which the soil mass has a capacity to Flow as a liquid . It is in between the liquid and plastic state the rate is 2 revolution per second . Plastic limit is the water content in which the soil mass can be molded without crumbling . It is in between plastic and semi-solid state . The rate is 80 to 90 strokes per minute . 

Question .

        Could we used for embankment material ? 

Answer .

      Yes , by plating. It is a method of covering or confining of unstable fills with a suitable , stable material. 

Question .

          What are the test you run to Determine the suitability of a subgrade material ?

Answer .

          A -  Sieve analysis 

          B -  Atterberg test

          C -  Proctor test 

          D -  C.B. R. test 

          E -  Field density test 

Question .

       What are the basic test normally caried out to determine soil characteristics and conditions ?

Answer .

         A -  C.B.R. test

         B -  Sieve analysis 

         C -  Atterberg test 

Question .

       How di you determine the shear strength of a soil ?

Answer .

       By tri-axial test . The basic principles is that a cylindrical soil specimen in first encased ina thin rubber membrane and subjected to fluid pressure around the cylindrical surface . The lateral pressure is held constant while an axial load is applied and until failure occurs .

Question .

        What type soil are well suitable for subgrade ? 

Answer .

    A_1_a , A_1_b  ,   A_2_4

Question .

     What do you mean by type A , AA , AAA in the compaction of soil ? 

Answer .

       Type A - compacted density of a soil shall be equal or greater then 90% of maximum density or 70% of relative density .

     Type AA - compacted density of a soil shall be equal or greater then 95% of maximum density or 74% of relative density 

    Type AAA - compacted density of a soil shall be equal or greater then 100% of maximum density or 78% of relative density .

        To be continue.....