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 ) |
|
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,