Exercise #1 By performing a mechanical grain size analysis on a soil sample, you have obtained the following measurements:

Draw a gradation curve (on the semi-log plot below) based upon the above measurements.  In addition, determine the coefficients of uniformity and of curvature for this soil sample.  [Note:  To be scientifically accurate, the units of weight should be in Newtons or Pounds.  However, soil engineers in the U.S. often misuse the terminology between weight and mass in the SI system of units.  The correct relationship between mass and weight follows the formula W=mg where W is the weight in Newtons, m is the mass in kilograms, and g is the acceleration due to gravity and is equal to 9.8 m/s².]

Exercise #2: Consider a soil sample that has the same grain size data as the sample in exercise #1.  After performing an Atterberg Limits test on this sample (the part that passes a No. 40 sieve), you find the liquid limit is 25% along with the plastic limit being equal to 15%.  Determine the soil classification (or group symbol) according to USCS. Describe each step in using the USCS chart. In other words, what criteria does the soil satisfy when moving from the left to the right in the chart.

Soil Properties

Exercise #3: (Soils in Construction textbook, pg 33, problem #1)  A 5 lb soil sample was taken from a fill.  The volume of the hole from which the sample was taken was 0.044 ft³.  The sample weighed 4.4 lb after oven drying.  It was determined that the specific gravity of the soil was 2.65.  Compute:

a) The unit weight of the fill.
b) The dry unit weight.
c) Void ratio.
d) Porosity.
e) Degree of saturation.
f) Unit weight of the fill if all the voids were filled with water.

Exercise #4:  A moist soil has a total unit weight of 16.4 kN/m³ and a water content of 6%.  Assuming that the dry unit weight is to remain constant, how much water , in liters per cubic meter, must be added to increase the water content to 10 percent?