This document summarizes geotechnical tests performed on soil samples collected from a site. In-situ density, Atterberg limits, sieve analysis, and permeability tests were conducted. Based on the results, the soil was classified as poorly graded sandy soil (SP) according to the Unified Soil Classification System. Permeability values indicated the soil is clayey. No water table was observed during borehole drilling. Previous studies estimated the bearing capacity of soil in the area to be about 1 ton per square foot.

2. Haider Ali Jafferi
Civil Engineer
Hyderabad, Sindh

3. Introduction:
Geotechnical investigations are performed to
obtain information on the physical properties of
soil and rock underlying the site to design
earthworks and foundations for proposed
structures, and for repair of damages to
earthworks and structures ,caused by subsurface
conditions

5. Site Plan

6.  In-situ Soil Density by Core Cutter Method
 Atterberg Limits
 Sieve Analysis
 Soil Classification by USCS
 Permeability of soil by Constant Head Method

7.  Apparatus Used:
 Standard: ASTM D2937
 Significance:
 Field Work:
 Soil excavated up to a depth of 3 ft.
 The core cutter is driven inside the soil with the
help of hammer.
 Soil is trimmed around the core cutter and core
cutter is removed.

8.  Lab Observations:
Internal dia of core cutter = 4 in
Height of core cutter = 5 in
Core cutter cross sectional area =πd2/4 = 12.56 in2
Mass of empty core cutter = 1383.8 g = 3.044 lbs
Mass of core cutter + soil = 3017.7 g = 6.639 lbs
Mass of soil =6.639 – 3.044 = 3.595 lbs
Volume of core cutter = 62.8 in3
Bulk density = ρb= M2 –M1/V = 1588.1907 kg/m3
Dry density = ρd= ρb/1 + m.c = 1489.5202 kg/m3

9.  Apparatus Used:
 Standard Reference: ASTM D-422
 Significance:
 Field Work:
 Bore holes are drilled with the help of earth augers.
 Holes were drilled at 3 ft interval up to 12 ft and
disturbed samples of the soil were collected.
 Soil samples were collected in the bags and were
transported to the lab for laboratory tests and
observations.

10.  LABORATORY OBSERVATIONS:
 Sieves were arranged in the order and were tightly held
on the sieve shaker.
 About 500 g of soil disturbed soil sample of depth 3 ft
was placed on the top sieve (sieve no 4).
 Sieve shaker was then turned on and sieves were
shaken for 5 minutes

11. Gradation Test Results:
 Sample # 1 (3 ft.)
Cu=4.8
Cc=1.5
So soil is Poorly Graded (SP)
 Sample # 2 (6 ft.)
Cu=3.28
Cc=1.2
So soil is Poorly Graded (SP)

12.  Sample # 3 (9 ft.)
Cu=2.9
Cc=1.0
So soil is Poorly Graded (SP)
 Sample # 4 (12 ft.)
Cu=2.65
Cc=1.1
So soil is Poorly Graded (SP)

13.  Standard Reference: ASTM D431
 Significance:
 Liquid Limit:
 Apparatus Used:
 Lab Work:
 Soil sample was passed through sieve no. 40.
 Water was added to the taken soil sample gradually in
order to make a paste.
 The soil paste was filled in the Cassagrande apparatus, and
blows were applied.
 No of blows were counted and a graph was made to
determine the intermediate value of m.c at standard 25
blows.

14.  Lab Observations:
 Sample # 1 (3 ft.)
Trial A:
No of blows = 31
M.C = 29.5 %
Trial B:
No of blows = 23
M.C = 33.5%
 Sample # 2(6 ft.)
Trial A:
No of blows = 23
M.C = 32.8 %
Trial B:
No of blows = 30
M.C = 33.5%

15.  Sample # 3(9 ft.)
Trial A:
No of blows = 27
M.C = 26.7 %
Trial B:
No of blows = 21
M.C = 29.6%
 Sample # 4(12 ft.)
Trial A:
No of blows = 22
M.C = 29.9 %
Trial B:
No of blows = 30
M.C = 27.2%

16.  Sample # 1 (3 ft.)
Trial A:
M.C = 21.3 %
Trial B:
M.C = 23.1%
 Sample # 2 (6 ft.)
Trial A:
M.C = 12.5%
Trial B:
M.C =17.6 %
 Sample # 3 (9 ft.)
Trial A:
M.C = 19.3 %
Trial B:
M.C = 16.7%
 Sample # 4 (12 ft.)
Trial A:
M.C = 17.7 %
Trial B:
M.C = 19.3%

17.  Apparatus Used:
 Significance:
 Lab Work:
 Soil was passed through sieve # 200.
 Soil sample was filled in Permeameter in three fills and
were properly tampered.
 Time period was noted for the water to discharge, in
order to carry out important calculations.

18.  Laboratory Observations:
h = 41.5 in
L = 7.5 in
Q = 20 ml = 0.02 L
t = 2:30 hr = 9000 sec
A = 75.42 cm2 = 11.69 in2
K = Q L/A h t
K = 5.325 x 10-9 cm/sec

19.  In-situ Field Density:
 Bulk Density= 1588.19 kg/m3
 Dry Density = 1491.01 kg/m3
For well graded soil, Cu >6
1 < Cc <3
The results of experiment shown that the soil type was “poorly
graded sandy soil” and its symbol is “SP”.
For permeability, if Vale of K is less than 0.0001, than the soil
will be clayey other wise will be sandy.
Our result of experiment was 5.325 x 10^-9, and soil type came
out to be clayey.

20.  The foundation designing mainly depends upon the
bearing capacity of soil.
 During the test, no water table was intercepted during
the bore holes.
 The previous geotechnical studies shown that the
bearing capacity of the soil in this vicinity is about 1
ton per square feet.