Question

A field soil sample from a cylindrical borehole shown below was collected from field and oven- dried in the lab. Following are the available data. (Assume G, 2.65) Weight of soil sample (Ib) Weight of over-dried soil sample (Ib) 61.85 55.15 Fill-in the Table below for the soil sample: Volume of the hole (in) Unit Weight (lb/t) Moisture Content, w (%) Dry Unit Weight (lb/ft) Void Ratio, e Saturation, S (%) Porosity, n (%) Air Content, A (%) Saturated Unit Weight (lb/ft Effective/Bouyant Unit Weight (b/ft) D 9" Soil Cylinder Sample H 14"

Answer 1

Volume of hole = pi/4 D^2 H = pi/4 times 9^2 times 14 = 290.64 in^3 = 0.515 ft^3. Unit wt (lb/ft^3) = 61.85/0.515 = 120.097 Moisture count (w%) = wt of water/water solids times 100 = 61.85 - 55.15/55.15 times 100 = 12.149 tildeequal to 12.15% Dry unit wt (r_a) r_dry = r_bulk/1 + w = 120.097/1 + 0.1215 = 107.086 lb/ft^3 void ratio(e) = 0.056 + 0.112/0.347 = 0.424 saturation (s) = V_w/V_v times 100 = 0.112/0.056 + 0.112 times = 66.67% porosity (eta) = e/1 + e = 0.424/1.424 = 32.62% Air content A(%) = V_a/V_v = 0.056/0.056 0.112 times 100 = 33.33% saturated unit wt = r_sat = (c_1 + se)r_w/1 + e = (2.56 + 1 times 0.484)/(1 + 0.484) times 6 = 126.71 lb/ft^3 Bouyant unit wt = (r_sub) = r_sat - r_w = 126.71 - 60 = 66.71 lb/ft^3