Observations and Calculations
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Diameter of ring (mm) =
Area of ring (mm2), A =
Height of ring (mm), H =
Mass of ring (g) =
Specific gravity of solids, Gs =

Before Test
Mass of ring + wet soil (g) =
Initial moisture content (%), wi =
Initial height of specimen (mm), Hi =

After Test
Mass of ring + wet soil (g) =
Mass of dry soil (g), Ws =
Final moisture content (%), wf =
Height of solids (mm),
Total change in height (mm)
=
Final height of specimen (mm), Hf =

After any stage
Height of specimen (mm), H =
Void ratio at increased pressure,
Degree of saturation (%),
Void ratio at initial pressure, e0 =

 Table 1: Time - settlement data for different pressure intensities Date Start time Pressure intensity (kg/cm2 ) p1 p2 p3 p4 Elapsed time (t) (min) Dial gauge readings and compression Reading Comp. (mm) Reading Comp. (mm) Reading Comp. (mm) Reading Comp. (mm) 0 0 0.25 0.5 1 1 2.25 1.5 4 2 6.25 2.5 9 3 12.25 3.5 16 4 20.25 4.5 25 5 36 6 49 7 64 8 81 9 100 10 169 13 256 16 361 19

 Table 2: Calculation of e, av and mv Applied pressure p (kg/cm2) Final dial readings (mm) Change in height of sample (mm) Height of sample (mm) Void ratio Coefficient of compressibility (cm2/kg) 1+e0 Coefficient of volume compressibility(cm2/kg) (1) (2) (3) (4) (5) (6) (7) (8) (9) 0 0.1 0.2 0.4 0.8 1.6 3.2 6.4

1. Calculate the void ratio at the end of each pressure increment, and plot void ratio vs. pressure variation on simple graph paper. Determine coefficient of compressibility and coefficient of volume compressibility for each increment.

2. Plot void ratio vs. log pressure, and obtain compression index and preconsolidation stress (maximum past pressure).

3. For each pressure intensity, plot compression vs., and determine t90 by square root of time fitting method. Also construct a semilog plot of compression vs. time on log scale, and determine t50 by logarithm of time fitting method.

4. Calculate values of coefficient of consolidation (cv) for each pressure intensity applied to the specimen.

From square root of time fitting method,

From logarithm of time fitting method,

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