GEOTECHNICAL ENGINEERING LABORATORY

BCECCE 506

  1. Visual Soil Classification
  2. Specific Gravity using Density Bottle and Pycnometer
  3. Core Cutter Method of Determining In-situ Unit Weight
  4. Sand Replacement Method of Determining In-situ Unit Weight
  5. Sieve Analysis
  6. Hydrometer Analysis
  7. Consistency Limits – Liquid Limit, Plastic Limit and Shrinkage Limit
  8. Constant Head Permeability Test
  9. Falling Head Permeability Test
  10. Standard Proctor Compaction test
  11. Direct Shear Test
  12. Unconfined Compression Test
  13. California Bearing Ratio
  14. Triaxial Test
  15. Consolidation Test
  16. Standard Penetration Test and Static Cone Penetration Test

EXPT. NO: DATE:

VISUAL SOIL CLASSIFICATION

OBJECTIVE: To identify the soil in the field through visual examination and simple field tests.

PROCEDURE:

Visual examination: This is done by taking a representative sample of soil and spreading it on a flat surface or the palm of the hand. Visual examination is carried out with respect to size, angularity, touch and grading. Observe the colour.

Wet and Manipulated Strength Test: to perform this test, take a small quantity of the soil in hand, moisten it if needed and work it with fingers and feel it. If the soil is clayey a soapy touch would be felt; if the soil is sandy a feeling of roughness is experienced and in case of silty soil moisture will come out if it is squeezed in between the fingers. Also clay sticks to the fingers and dries fairly quickly and can be wiped off the fingers easily. This test helps to distinguish the major soil characteristic that is whether the soil is clayey, sandy or silty.

Thread Test: To perform this test take a small quantity of soil, moisten if needed and roll it in between the palms of the hand or on a flat smooth surface into a thread of about 3 mm diameter. If crumbling does not occur, fold the thread and re-roll as before. Repeat the process until the moisture content of the soil has been reduced by drying during manipulation, to the plastic limit, which is indicated by crumbling which occurs as the soil is being rolled. The characteristic of the thread as it approaches the plastic limit affords the means of identification of the soil in the manner.

Dilatancy Test: About 5 cc of soil sample is taken and enough water is added to nearly saturate it. The pat of the soil is placed in the palm of the hand and shaken horizontally, striking vigorously against the other hand several times. The pat is then squeezed between the fingers. The appearance and disappearance of water with shaking and squeezing is referred to as positive reaction. This reaction is quick if water appears and disappears rapidly, slow if water appears and disappears slowly and no reaction if the water condition does not appear to change. The type of reaction is observed and recorded. Fine sands and silts exhibit a quick reaction whereas clays, none to slow.

Dry Strength Test: The prepared soil sample is completely dried in the sun or by air-drying. Its strength is tested by breaking the lump between fingers. Resistance to breaking, termed dry strength is a measure of plasticity and is considerably influenced by the colloidal fraction content of the soil. If the dry sample can be powdered easily, it is said to have low dry strength whereas if considerable finger pressure is required to break the lump, it is said to have high dry strength. A high dry strength is a characteristic feature of clays of high plasticity. Typical inorganic silts have only a slight dry strength. Silty fine sands and silts have practically the same low dry strength but can be distinguished from each other by their feel during powering of the dry sample.

OBSERVATION:

Colour:

Wet and manipulated strength:

Thread test:

Dilatancy:

Dry Strength test:

RESULT:

The type of soil is identified as ______

EXPT. NO: DATE:

DETERMINATION OF SPECIFIC GRAVITY OF SOILBY DENSITY BOTTLE

OBJECTIVE: The main aim of the test is to determine the specific gravity of soil fraction by density bottle.

MATERIALS AND EQUIPMENT REQUIRED: Density bottle of 50 ml or 100 ml capacity with stopper; constant temperature water bath maintaining temperature of 270c, balance sensitive to 0.001 g, vacuum source, wash bottle filled with distilled water.

PROCEDURE:

1) To clean and dry the density bottle, wash it thoroughly with distilled water and allow it to drain.

2) Find the mass of the empty clean bottle (W1) accurate to 0.001 g with its stopper.

3) Take about 10 to 20 g of oven-dried sample in the density bottle. Find the mass of the bottle with the soil and stopper(W2).

4) Put about 10 ml of distilled water in the bottle so that soil is fully soaked and entrapped air is removed. Now weigh the bottle along with soil, water and stopper(W3).

5) Now, empty the bottle and wash it. Fill it completely with water alone. Weigh the bottle containing water alone with its stopper(W4).

6) Repeat steps 3 to 5 and take two more determinations.

TABULATION:

S.NO / Determination no.
Trial 1 / Trial 2
1. / Density Bottle no.
2. / Weight of density bottle (W1) kg
3. / Weight of bottle + dry soil (W2) kg
4. / Weight of bottle + soil + water
(W3) kg
5. / Weight of bottle + water (W4) kg
Specific gravity

CALCULATION:

The specific gravity of the soil is calculated from

G = W2 – W1

(W2-W1) – (W3 – W4)

RESULT:

The specific gravity of the given soil sample is = ______

EXPT. NO: DATE:

DETERMINATION OF SPECIFIC GRAVITY OF SOILBY PYCNOMETER

OBJECTIVE: The main aim of the test is to determine the specific gravity of soil fraction passing IS 4.75 mm test sieve by pycnometer.

MATERIALS AND EQUIPMENT REQUIRED: Pycnometer of 900 ml capacity with a conical brass cup, balance, glass rod, distilled water.

PROCEDURE:

1) Clean the pycnometer by washing it thoroughly with distilled water and allow it to drain.

2) Find the mass of the empty clean pycnometer (W1) along with its stopper.

3) Take about 10 to 20 g of oven-dried sample in the pycnometer. Find the mass of the pycnometer with the soil and stopper(W2).

4) Put about 10 ml of distilled water in the pycnometer so that soil is fully soaked and entrapped air is removed. Now weigh the pycnometer along with soil, water and stopper(W3).

5) Now, empty the pycnometer and wash it. Fill it completely with water alone. Weigh the pycnometer containing water alone with its stopper(W4).

6) Repeat steps 3 to 5 and take two more determinations.

TABULATION:

S.NO / Determination no.
Trial 1 / Trial 2
1. / Pycnometer no.
2. / Weight of pycnometer (W1) kg
3. / Weight of pycnometer + dry soil (W2) kg
4. / Weight of pycnometer + soil + water
(W3) kg
5. / Weight of pycnometer + water (W4) kg
Specific gravity

CALCULATION:

The specific gravity of the soil is calculated from

G = W2 – W1

(W2-W1) – (W3 – W4)

RESULT:

The specific gravity of the given soil sample is = ______

EXPT. NO: DATE:

FIELD UNIT WEIGHT BY CORE CUTTER METHOD

OBJECTIVE: The aim of the test is to determine the dry density and dry unit weight of soil in-place by the core cutter.

MATERIALS AND EQUIPMENT REQUIRED: cylindrical core cutter of steel (13 cm long & 10 cm dia.), steel dolly (2.5 cm high & 10 cm dia.), steel rammer, palette knife, steel rule, spade or pickaxe, straight edge, balance, container for water content determination.

PROCEDURE:

1) Measure the internal dimensions of the core cutter and calculate its volume. Find the weight of the core cutter (without dolly).

2) Expose the small area, about 30 cm square, to be tested and level it. Put the dolly on top of the core cutter and drive the assembly into the soil with the help of rammer until the top of the dolly protrudes about 1.5 cm above the surface.

3) Dig out the container from the surrounding soil, and allow some soil to project from the lower end of the cutter. With the help of the straight edge, trim flat the end of the cutter. Take out the dolly and also trim flat the other end of the cutter.

4) Find the weight of cutter full of soil.

5) Keep some representative specimen of soil for water content determination.

6) Repeat the test at two or three locations nearby and get the average dry unit weight.

TABULATION:

Diameter of core cutter (cm) = Height of core cutter (cm) =

S.No.
1. / Wt. of core cutter (W1) g
2. / Wt. of soil + core cutter (W2) g
3. / Wt. of soil (W2 – W1) g
4. / Volume of core cutter (V) m3
5. / Unit weight of soil (γb) = ((W2 – W1)/V) kN/m3
S.No. / Description
1. / Pycnometer no.
2. / Weight of pycnometer (W1) g
3. / Weight of pycnometer + dry soil (W2) g
4. / Weight of pycnometer + soil + water
(W3) g
5. / Weight of pycnometer + water (W4) g
Specific gravity
Observation No. / 1 / 2 / 3
Container No.
Wt. of container + wet soil g
Wt. of container + dry soil g
Wt. of empty container g
Wt. of dry soil g
Wt. of wet soil g
Water content (w) %
In-situ dry density of the soil
γd = γb / (1+w) kN/m3

RESULT:

The field bulk density of soil γb =

Water content of soil w =

Field density of soil γd =

Void ratio e =

Degree of saturation S (%) =

EXPT. NO: DATE:

FIELD UNIT WEIGHT BY SAND REPLACEMENT METHOD

OBJECTIVE: The object of the test is to determine the dry density of natural or compact soil, in place, by the sand replacement method.

MATERIALS AND EQUIPMENT REQUIRED: Sand pouring cylinder mounted on a pouring core and separated by a shutter, cylindrical calibrating container, 2 metal trays (one with central hole and another without hole), sand, excavating tools, glass plate, balance, oven, water content crucible, etc.

PROCEDURE:

1) Fill the clean closely graded sand in the sand pouring cylinder upto a height 1 cm below the top. Determine the total initial weight of the cylinder and sand (W1). This total initial mass should be maintained constant throughout the tests for which the calibration is used.

2) Allow the sand of volume equivalent to that of the excavated hole in the soil, to run out of cylinder by opening the shutter. Close the shutter and place the cylinder on the glass plate.

3) Open the shutter and allow the sand to run out. Close the valve when no further movement of sand is observed. Remove the cylinder carefully. Weigh the sand collected on the glass surface. Its mass (W2) will give the mass of sand filling the pouring cone. Repeat this step at least three times and take the mean mass (W2). Put the sand back into the cylinder, to have the same constant mass (W1).

4) Determine the volume of the calibrating container by filling it with water full to the brim and finding the mass of water. This volume should be checked by calculating it from the measured internal dimensions of the container.

5) Place the sand pouring cylinder concentrically on the top of the calibrating container, after being filled to the constant weight (W1). Open the shutter and permit the sand to run into the container. When no further movement of sand is seen, close the shutter. Remove the pouring cylinder and find its mass (W3).

6) Repeat step 2 atleast twice and find mean the mean weight W3. Put the sand into the sand pouring cylinder.

7) Expose about 45 cm2 area of the soil to be tested and trim it down to level surface. Keep the tray on the level surface and excavate a circular hole of approximately 10 cm diameter and 15 cm deep and collect all the excavated soil in the tray. Find the weight of the excavated soil (W) of the excavated soil.

8) Remove the tray and place the sand pouring cylinder so that the base of the cylinder concentrically covers the hole. The cylinder should have its constant weight (W1). Open the shutter and permit the sand to run into the hole. Close the shutter when no further movement of the sand is seen. Remove the cylinder and determine its mass (W4).

9) Keep a representative sample of the excavated soil for water content determination.

TABULATIONS:

a)To determine the bulk density of the sand:

Volume of the calibrating cylinder, V m3
Weight of the pouring cylinder filled
with sand, W1 g
Weight of the pouring cylinder + sand (after pouring
in the calibrating container) W2 g
Weight of the sand collected on the glass plate
(weight of the sand filled in the cone) W3 g
Weight of the sand filled in the calibrating container
W = W1 –W2 –W3 g
Bulk unit weight of sand, γb(sand) = W/Vh kN/m3

b) To determine In-situ unit weight of soil:

Weight of the wet soil excavated from the hole W g
Weight of the pouring cylinder + sand (after filling
the hole and the cone) W4 g
Weight of the sand filled in the hole
W’’ = W1 –W4 –W3 g
Volume of the hole, Vh = W’’/ γb(sand) m3
Bulk unit weight of field soil, γb(soil) = W/Vh kN/m3

c) To determine the water content:

Container No.
Wt. of container + wet soil g
Wt. of container + dry soil g
Wt. of empty container g
Wt. of dry soil g
Wt. of wet soil g
Water content (w) %
In-situ dry unit weight of the soil
γd = γb / (1+w) kN/m3

RESULT

The field unit weight of the given sample is =

The water content of the given sample is =

The dry unit weight of the given sample is =

EXPT. NO: DATE:

GRAIN SIZE DISTRIBUTION BY SIEVE ANALYSIS

OBJECTIVE: The object of this experiment is to determine grain size distribution of coarse grained soil by sieving. The test covers both coarse sieve analysis as well as fine sieve analysis.

MATERIALS AND EQUIPMENT: Balance, set of IS sieves: 4.75 mm, 2.36 mm, 1.18 mm, 600 micron, 300 micron, 150 micron & 75 micron, wire brush, mechanical sieve shaker, riffler.

PROCEDURE:

1) The given 1000 g sample is sieved through 4.75 mm sieve.

2) The fraction retained on 4.75 mm sieve is used for coarse sieve analysis.

3) Arrange the IS sieves No. 4.75 mm, 2.36 mm, 1.18 mm, 600 micron, 300 micron, 150 micron & 75 micron in order keeping the sieve of 4.75 mm on the top. Then the soil is allowed passing through the arranged sieve set.

4) The set of sieves is placed in a mechanical sieve shaker.

5) About 10 minutes sieving should be done.

6) The soil fraction retained on each sieve is collected and weighed.

7) The percentage of soil retained on each sieve is calculated.

TABULATION:

S.No. / IS Sieve / Particle
Size (mm) / Weight
Retained (g) / % retained / Cumulative
% retained / % Finer
01 / 4.75
02 / 2.36
03 / 1.18
04 / 0.600
05 / 0.300
06 / 0.150
07 / 0.075
08 / PAN

CALCULATION:

The percentage of weight retained on each sieve is calculated on the basis of total weight of soil sample taken and from these results the percent passing through such of the sieves is calculated.

GRAPH:

The results of the mechanical analysis are plotted to get a particle size distribution curve with the percentage fine as the ordinate and the particle diameter as the abscissa on a logarithmic scale.

RESULT:

The uniformity coefficient and the coefficient of curvature of the given soil sample is ………..

The soil is classified as …………………….. according to ISSCS.

EXPT. NO: DATE:

GRAIN SIZE DISTRIBUTION BY HYDROMETER

OBJECTIVE:

To determine the percentage of various sized particles of soil passing through IS sieve and to plot the gain size distribution curve.

MATERIALS AND EQUIPMENT:

  1. Bouyoucus Hydrometer
  2. Deflocculating agent
  3. Thermometer
  4. Balance 0.01g sensitivity
  5. Stop Watch
  6. Stirrer

THEORY:

The hydrometer method, based on continuous sedimentation principle, whereby a steady fall of particles occurs through a liquid at rest. Particle sizes are determined from stoke’s law which relates velocity of a particle falling through a liquid to the diameter of the particle, the specific gravity of the particle and the viscosity of the liquid. From stoke’s law

Where - Viscosity of fluid in dyne (sec / cm2)

HR – Height of fall in cm

T – time of fall in minutes

D – is the diameter of particle in mm

Stoke’s law assumes that soil particles could be treated as spheres and that soil suspension is of sufficiently low concentration to permit individual settling of sufficiently low concentration to permit individual settling of grains without any interference.

Procedure:

  1. About 50 g of the soil passing through 75 micron sieve is taken in a mixer jar.
  2. An approximate amount of distilled water and the deflocculating agent (sodium hexametaphosphate, 10 percent strength) added to the soil paste.
  3. The mixed suspension is stirred for about 10minutes.
  4. After mixing the suspension is washed with enough distilled water to make up the volume to 1000cc.
  5. By placing the hands over on the open end of the jar and turn gradually upside down and back.
  6. Then the soil particles are allowed to settle.
  7. Immediately the stop watch is started after the hydrometer is gently inserted in int.
  8. The hydrometer readings are observed at 0.25,0.5,1 and 2 minutes without removing the hydrometer. If readings could not be taken accurately at the first time, the test has been repeated.
  9. A suitable meniscus correction is then applied to the hydrometer reading corresponding to different times from start.
  10. In addition to this the dispersion agent correction and temperature corrections are also applied in the hydrometer reading.

TABULATION:

Elapsed time, t, min / Temp. t0C / Observed Hydrometer reading, R / Hyd.Reading corrected for meniscus only / Temp. Correction Ct / Combined correction
C =
Cd +Cm+ Ct / Corrected Hydrometer reading / Effective depth / Particle diameter Dmm / Percent finer (%)

Model calculation:

Temperature correction Ct = 0.005t2-0.018t-1.59 for t<4min

Where t-elapsed time in minutes

Combined correction C = Ct+Cd+Cm

Where Ct – Temperature correctin

Cd – Dispersing agent correction

Cm – meniscus correction

Combined hydrometer reading Rc = R+C

Effective depth HR = -0.27RT+16.97

Where Rt – Hydrometer correction only for meniscus

Particle diameter

Where - Viscosity of fluid in dyne (sec / cm2)

HR – Height of fall in cm

T – Time of fall in minutes

D – Diameter of particle in mm

Gs – Specific gravity of the soil sample

Gw – Specific gravity of water

% Finer(N) =

Where, Gs – Specific gravity of soil sample

Gw – specific gravity of water

W – Weight of the soil sample in grams

Rc –Combined correction for hydrometer reading in cm

GRAPH:

The results of the hydrometer analysis are plotted to get a particle size distribution curve with the percentage fine as the ordinate and the particle diameter as the abscissa.

Result: %Sand, %Silt, %Clay of the given soil sample is

EXPT. NO: DATE:

LIQUID AND PLASTIC LIMIT OF A SAMPLE

OBJECTIVE:

To classify the given fine grained soil based on its plasticity characteristics.

MATERIALS AND EQUIPMENT: Mechanical liquid limit device (Casagrande type), grooving tool, moisture cups, oven, plastic limit plate, soil mixing equipments (porcelain dish, spatula, sqeeze bottle etc.), balance.