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UCE – THIRUKKUVALAI B.E.CIVIL ENGINEERING

CE 6511 SOIL MECHANICS LABORATORY 1

CE 6511 SOIL MECHANICS LABORATORY (REGULATION-2013)

OBSERVATION

FACULTY OF ENGINEERING

DEPARTMENT OF CIVIL ENGINEERING

NAME: ___________________________________

REGISTER NUMBER: ________________________

YEAR/SEM.: _______________________________

ACADEMIC YEAR: __________________________

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UCE – THIRUKKUVALAI B.E.CIVIL ENGINEERING

CE 6511 SOIL MECHANICS LABORATORY / K.KESAVAN. M.E./CIVIL/UCE-T V+ 2

CE 6511 SOIL MECHANICS

LABORATORY (REGULATION-2013)

PREPARED

BY

FACULTY OF ENGINEERING

DEPARTMENT OF CIVIL ENGINEERING


UCE – THIRUKKUVALAI www.vidyarthiplus.com B.E.CIVIL ENGINEERING


CE 6511 SOIL MECHANICS

LABORATORY (REGULATION-2013)

SYLLABUS LIST OF EXPERIMENTS

1. DETERMINATION OF INDEX PROPERTIES: a. Specific gravity of soil solids.

b. Grain size distribution – Sieve analysis.

c. Grain size distribution Hydrometer analysis.

d. Liquid limit and Plastic limit tests.

e. Shrinkage limit and Differential free swell tests.

2. DETERMINATION OF INSITU DENSITY AND COMPACTION CHARACTERISTICS: a. Field density Test. (Sand Replacement Method)

b. Determination of moisture – density relationship using standard Proctor

compaction test.

3. DETERMINATION OF ENGINEERING PROPERTIES: a. Permeability determination. (Constant head and Falling head methods)

b. One dimensional Consolidation test. (Determination of co-efficient of

consolidation only)

c. Direct Shear test in cohesion-less soil.

d. Unconfined compression test in cohesive soil.

e. Laboratory Vane Shear test in cohesive soil.

f. Tri-axial Compression test in cohesion-less soil. (Demonstration only)

g. California Bearing Ratio Test.

Anna University Practical Question paper Specimen*




INDEX SL.NO DATE EXPERIMENTS PAGE NO REMARKS




DETERMINATION OF SPECIFIC GRAVITY OF SOIL SOLIDS

Ex.No.: Date:

Aim: To determine the specific gravity of given soil solids.

Apparatus Required:

x 4.75 mm IS sieve

x Pycnometer

x Distilled Water

x Weighing Balance

x Microwave Oven

Instrument Setup:

Fig.1. (a). IS Sieve (b). Pycnometer

Procedure:

x Dry the pycnometer and weigh it with its cap. (W1)

x Take about 200gmof oven dried soil passing through 4.75mm sieve into the pycnometer and

weigh again (W2).

x Add sufficient de-aired water to cover the soil and screw on the cap.

x Shake the pycnometer well and remove entrapped air if any.

x After the air has been removed, fill the pycnometer with water completely.

x Thoroughly dry the pycnometer from out side and weigh it (W3).

x Clean the pycnometer by washing thoroughly.

x Fill the cleaned pycnometer completely with water up to its top with cap screw on.

x Weigh the pycnometer after drying it on the outside thoroughly (W4).

x Repeat the procedure for three samples and obtain the average value of specific gravity.

Formula: The specific gravity of given soil sample (G) = (𝑊2−𝑊1)

(𝑊4−𝑊1)−(𝑊3−𝑊2)




Where,

W1 - Weight of Empty Pycnometer

W2 - Weight of Pycnometer + Dry soil solid

W3 - Weight of Pycnometer + Dry soil solid+Water

W4 - Weight of Pycnometer + Water

Observation & Tabulation:

Sl.no Sample Wt.(W1) gm Wt.(W2) gm Wt.(W3) gm Wt.(W4) gm Specific Gravity (G) Remarks

Average (G)

Calculation:

The specific gravity of given soil sample (G) = (𝑊2−𝑊1)(𝑊4−𝑊1)−(𝑊3−𝑊2)

Result:

x The specific gravity of given soil solid sample (G) is _______________

Limitations:

x The limitation of specific gravity of soil solid is (G) 2.50 – 2.65 at 27ºC

Viva – Voce:

1. Define: Specific Gravity. 2. What is the limitations of Specific gravity of soil? 3. What are the use of this Experiment? 4. Enlist the methods of water content in soil sample. 5. Difference between specific gravity and bulk specific gravity.

Experiment Demo Link: https://www.youtube.com/watch?v=1pdhk6z1674




DETERMINATION OF GRAIN SIZE DISTRIBUTION – SIEVE ANALYSIS

Ex.No.: Date:

Aim: To determine the grain size distribution of given soil sample by sieve analysis. Apparatus Required:

x A set of IS sieve x Shaker x Tray x Weighing Balance x Microwave oven

Instrument setup:

Fig.2. (a).IS Sieve set (b).Shaker (c). Distribution Process Procedure:

x Weigh 500gms of oven dry soil sample, of which grain size distribution has to be studied. x Take the soil sample into 75μ sieve. x Wash the soil sample keeping it in the sieve. Washing of soil sample means: place the soil

the sieve and gently pour water over the soil so that it wets the soil and remove the fine particles in the form of mud, leaving only the sand and gravel size particles in the sieve.

x Transfer the soil retained in the sieve after washing into a tray. Invert the sieve into the tray and pour water gently so that all the soil particles retained in the sieve are transferred into the tray.

x Keep the tray in the oven for 24 hours at 105ºc to dry it completely. x Weigh the oven dry soil in the tray (W) x The weight of the fine grained soil is equal to 500 – W x Clean the sieve set so that no soil particles were struck in them. x Arrange the sieves in order such that coarse sieve is kept at the top and the fine sieve is at

the bottom. Place the closed pan below the finest sieve.




x Take the oven dried soil obtained after washing into the top sieve and keep the lid to close the top sieve.

x Position the sieve set in the sieve shaker and sieve the sample for a period of 10 minutes. x Separate the sieves and weigh carefully the amount of soil retained on each sieve, This is

usually done by transferring the soil retained on each sieve on a separate sieve of paper and weighing the soil with the paper.

x Enter the observations in the Table and calculate the cumulative percentage of soil retained on each sieve.

x Draw the grain size distribution curve between grain size on log scale on the abscissa and the percentage finer on the ordinate.

Formula:

� Uniformity co-efficient (Cu) = 𝐷60 𝐷10⁄

� Co-efficient of curvature (Cc) = (𝐷302 )

𝐷60𝑋𝐷10⁄

Observation: Weight of the soil taken for testing (W) = Nos of IS sieve = Tabulation:

Sl no Sieve Reading

mm Weight of soil retained gm

% weight retained

Cumulative weight

retained (x)

Percentage finer

(y=100-x) Remarks

Pass Retain

Average




Calculation: (from graph)

� Uniformity co-efficient (Cu) = 𝐷60 𝐷10⁄

� Co-efficient of curvature (Cc) = (𝐷302 )

𝐷60𝑋𝐷10⁄

Graph:

The graph (Semi-log) draw between percentage of finer and size of the sieve.

% of finer

60

10

D60 D10 Particle diameter, mm (log scale)

Result:

x Uniformity co-efficient (Cu) = x Co-efficient of curvature (Cc) = x The finer / coarser percentage (F) =

Viva-voce:

1. What is meant by fineness? 2. How to understand the finer and coarser of soil? 3. Which one is the effective diameter of soil? 4. What are the uses of their tests? 5. What are the limitations of co-efficient of curvature?

Experiment Demo Link: https://www.youtube.com/watch?v=M8cqAjXUhLc




DETERMINATION OF GRAIN SIZE DISTRIBUTION – HYDROMETER ANALYSIS

Ex.No.: Date:

Aim: To determine the grain size distribution of given soil sample by sieve analysis. Apparatus Required:

x Hydrometer x 1000 ml glass cylinder with solution x Evaporating dish x Thermometer x Stop watch x Stirrer

Instrument setup:

Fig.3. (a). Hydrometer (b). Thermometers Procedure:

x Take 50g of dry soil in an evaporating dish, add 100 ml dispersing agent, and prepare a suspension.

x Transfer the suspension into the cup of a mechanical stirrer, add more distilled water and operate the stirrer for three minutes.

x Wash the soil slurry into a cylinder and add distilled water to bring up the level to the 1000 ml mark.

x Cover the open and of the cylinder with a stopper and hold it securely with the palm of the hand. Then turn the cylinder upside down and back upright repeatedly for one minute.

x Place the cylinder down and remove the stopper. Insert a hydrometer and start a stop watch simultaneously. To minimize bobbing of the hydrometer, It should be released close to the reading depth. This requires some amount of rehearsal and practice.

x Take hydrometer readings on to upper rim of the meniscus formed by the suspension and the hydrometer stem after time intervals of periods of 0.5, 1.2 & 4 minutes.

x After the 4 minutes reading, remove the hydrometer slowly, and float it in a second cylinder containing 100 ml dispersing agent and distilled water up to 1000 ml mark.

x Take further reading after elapsed time periods of 8, 15 and 30 minutes and also after 1, 2, 4, 8 and 24 hours. Insert the hydrometer only just before the reading and withdraw immediately after the reading.

x Observe and keep recording the temperature of the soil suspension.




x Shake the solution in the second cylinder thoroughly. Insert the hydrometer and note the meniscus correction which is the reading difference between the top of the meniscus and the level of the solution in the cylinder when observed along the hydrometer stem.

x The composite correction is the difference between the top meniscus reading and value of 1 corresponding to the usual hydrometer calibration temperature of 27ºC. This may be positive or negative.

x Calibrate the hydrometer to establish a relation between any reading and its corresponding effective depth and obtain a calibration plot.

x The effective depth is the distance from the surface of the soil suspension to the level at which the density of the suspension is being measured.

Formula:

x Particle size factor (M) = √ 18𝜇𝛾𝑠−𝛾𝑤

x Percentage finer factor (N) = 𝐺𝑠(𝐺𝑠−1) x (100/W)

Observation: x Mass of dry soil taken (passing 75𝜇) = g. x Specific gravity of soil (G) = x Meniscus correction (Cm) =

Tabulation:

Sl.No Time

(t) min

Hydrometer reading

Effective depth (h) cm

√𝒉𝒕

Particle size in mm

Factor M

Factor N

% of finer

based on mass F

% of finer

based on total mass

Calculation: Total percentage finer = F x % of finer based on total mass.

Graph: The graph between particle size Vs percent finer in semi-log sheet. Result:

x The percentage of finer is ______________ Viva-voce:

1. What are the function of hydrometer? 2. What are the uses of this test? 3. Which one is the best of soil distribution test?

Experiment Demo Link: https://www.youtube.com/watch?v=YsM8XkCH78U




DETERMINATION OF LIQUID LIMIT

Ex.No.: Date:

Aim: To determine the liquid limit of the given soil sample. Apparatus Required:

x Casagrande’s apparatus x Groove tool x 425𝜇 IS seive x Mixing Ceramic Bowl x Sensitive weighing balance x Distilled water

Instrument setup:

Fig.4. (a). Casagrande’s (b). Curve, WC Vs N (c). Soil limit

Procedure: x Adjust the cup of liquid limit apparatus with the help of grooving tool gauge and the

adjustment plate to give a drop of exactly 1cm on the point of contact on the base. x Take about 120gm of an air dried soil sample passing 425μ sieve. x Mix the soil thoroughly with some distilled water to form a uniform paste. x Place a portion of the paste in the cup of the liquid limit device; smooth the surface with

spatula to a maximum depth of 1 cm. Draw the grooving tool through the sample along the symmetrical axis of the cup, holding the tool perpendicular to the cup.

x Turn the handle at a rate of 2 revolutions per second and count the blows until the two parts of the soil sample come in contact with each other, at the bottom of the groove along a distance of 10mm.

x Transfer about 15 gm of the soil sample forming the wedge of the groove that flowed together to a water content bin, and determine the water content by oven drying.

x Transfer the remaining soil in the cup to the main soil sample in the bowl and mix thoroughly after adding a small amount of water.

x Repeat steps 4 – 7 .Obtain at least five sets of readings in the range of 10 – 40 blows. x Record the observations in the Table.




Formula: Flow index (If) = (W1-W2) / log10 (N2-N1) Where, W1 - Water content in % at N1 blows W2 - Water content in % at N2 blows Observation & Tabulation:

Sl.no Description Sample Remarks A B C D

1. Weight of dry soil in g. (w1)

2. Weight of wet soil in g. (w2)

3. Weight of Water W, (w2-w1)

4. Moisture content M (W/w1)

5. Moisture in percentage (%)

Calculation: Water content in = ml.

Flow index (If) = (W1-W2) / log10 (N2-N1)

Toughness index (It) = (plasticity index / flow index)

Graph:

The graph between number of blows Vs water content.

Result:

x The liquid limit of given soil sample =

x The flow index of given soil sample =

x The toughness index of given soil sample =

Viva-voce:

1. What is meant by liquid limit?

2. Define: Atterberg’s limit.

3. Difference between solid and semi solid.

4. Enumerate the difference of liquid and plastic limit.

5. What are the merits of this experiment?

Experiment Demo Link: https://www.youtube.com/watch?v=pM-w_cvk1nA




DETERMINATION OF PLASTIC LIMIT

Ex.No.: Date:

Aim: To determine the plastic limit of the given soil solid sample. Apparatus Required:

x 425𝜇 IS seive x Mixing Ceramic Bowl x Sensitive weighing balance x Distilled water x Glass plate x Microwave oven

Instrument setup:

Fig.5. (a). Plastic limit apparatus. (b). Plastic limit process

Procedure: x Take about 30g of air dried soil sample passing through 425μ sieve. x Mix thoroughly with distilled water on the glass plate until it is plastic enough to be shaped

into a small ball. x Take about 10g of the plastic soil mass and roll it between the hand and the glass plate to

form the soil mass into a thread of as small diameter as possible. If the diameter of the thread becomes less than 3 mm without cracks, it indicates that the water added to the soil is more than its plastic limit, hence the soil is kneaded further and rolled into thread again.

x Repeat this rolling and remoulding process until the thread start just crumbling at a diameter of 3mm.

x If the soil sample start crumbling before the diameter of thread reaches 3mm (i.e when the diameter is more than 3mm) in step 3, it shows that water added in step 2 is less than the plastic limit of the soil. Hence, some more water should be added and mixed to a uniform mass and rolled again, until the thread starts just crumbling at a dia of 3mm.

x Collect the piece of crumbled soil thread at 3mm diameter in an airtight container and determine moisture content.

x Repeat this procedure on the remaining masses of 10g. x Record the observations in Table and obtain the average value of plastic limit.




Formula: Flow index (If) = (W1-W2) / log10 (N2-N1) Where, W1 - Water content in % at N1 blows W2 - Water content in % at N2 blows Observation & Tabulation:

Sl.no Description Sample Remarks A B C D 1. Weight of dry soil in g. (w1)

2. Weight of wet soil in g. (w2)


4. Moisture content M (W/w1)

5. Moisture in percentage (%)

Calculation: Water content in = ml.

Flow index (If) = (W1-W2) / log10 (N2-N1)

Toughness index (It) = (plasticity index / flow index)

Graph:

The graph between number of blows Vs water content.

Result:

x The Plastic limit of given soil sample =

x The flow index of given soil sample =

x The toughness index of given soil sample =

Viva-voce:

1. Define: Plastic limit.

2. Difference between plastic and elastic limit.

3. Difference between plastic and shrinkage limit.

4. Give best an example for liquid, plastic, elastic, shrinkage limits.

5. Define: Plastic index. Experiment Demo Link: https://www.youtube.com/watch?v=97En9_ERZmM




DETERMINATION OF SHRINKAGE LIMIT

Ex.No.: Date:

Aim: To determine the shrinkage limit of the given soil samples. Apparatus Required:

x Shrinkage apparatus x Evaporated dish x Mercury x Sensitive weighing balance

Instrument setup:

Fig.6. (a) Shrinkage limit tools (b). Shrinkage process

Procedure: x About 30 gms of soil passing through 425 micron sieve is taken with distilled water. x The shrinkage dish is coated with a thin layer of Vaseline .The soil sample is placed in the

dish by giving gentle taps. The top surface is surfaced with a straight edge. x The shrinkage dish with wet soil is weighed. The dish is dried first in air and then in oven. x The shrinkage dish is weighed with dry soil. After cleaning the shrinkage dish its empty

weight is taken. x An empty porcelain dish which will be useful for weighing mercury is weighed. x The shrinkage dish is kept inside a large porcelain dish it is filled with mercury and the

excess is removed by pressing the plain glass plate firmly over the top of the dish. The contents of the shrinkage dish are transferred to the mercury weighing dish and weighed.

x The glass cup is kept in a large dish, filled it with over flowing mercury, the excess is removed by pressing the glass plate with three prongs firmly over the top of the cup.

x It is placed in another large dish. The dry soil is placed on the surface of the mercury and submerge it under the mercury by pressing with the glass plate with prongs.

x The mercury displaced by the dry soil pat is transferred to the mercury weighing dish and weighed.




Observation & Tabulation:

Sl.no Description Sample Remarks A B C D 1. Weight of dry soil + dish in g. (w1)

2. Weight of wet soil + dish in g. (w2)


4. Weight of dish in g. (w3)

5. Weight of dry soil in g. W (w1- w3)

6. Water content in ml (W/W)

7. Weight of mercury in g.

8. Volume of wet soil (mercury*)

9. Volume of dry soil

10. Shrinkage limit

Result:

x The shrinkage limit of the given soil sample = x The shrinkage ratio of the given soil sample = x The linear shrinkage of the given soil sample = x The volumetric shrinkage of the given soil sample =

Viva-voce:

1. Define: shrinkage limit 2. Define: shrinkage ratio 3. Define: linear shrinkage 4. Define: volumetric shrinkage 5. Difference between thawing and shrinkage.

Experiment Demo Link: https://www.youtube.com/watch?v=bxh3kMGt9h0




DETERMINATION OF FIELD DENSITY OF SOIL – SAND REPLACEMENT METHOD

Ex.No.: Date:

Aim: To determine the field density of soil at a given location by sand replacement method. Apparatus Required:

x Sand Pouring Cylinder x Calibrating ban x Metal tray with a central hole x Weighing balance x Trowel x Planner

Instrument setup:

Fig.7. (a) Pouring cylinder & tray (b). Pouring process

Procedure: (A). Calibration Of Sand Density:

x Measure the internal dimensions diameter (d) and height (h) of the calibrating can and compute its internal volume V.

x Fill the sand pouring cylinder (SPC) with sand with 1 cm top clearance to avoid any spillover during operation and find its weight (W1)

x Place the SPC on a planner, open the slit above the cone by operating the valve and allow the sand to run down. The sand will freely run down till it fills the conical portion.

x When there is no further downward movement of sand in the SPC, close the slit. x Find the weight of the SPC along with the sand remaining after filling the cone (W2) x Place the SPC concentrically on top of the calibrating can. Open the slit to allow the sand to

rundown until the sand flow stops by itself. This operation will fill the calibrating can and the conical portion of the SOC. Now close the slit and find the weight of the SPC with the remaining sand(W3)

(B). Measurement Of Soil Density: x Clean and level the ground surface where the field density is to be determined. x Place the tray with a central hole over the portion of the soil to be tested.




x Excavate a pit into the ground, through the hole in the plate , approximately 12cm deep (Close the height of the calibrating can ) The hole in the tray will guide the diameter of the pit to be made in the ground.

x Collect the excavated soil into the planner and weigh the soil (W) x Determine the moisture content of the excavated soil. x Place the SPC, with sand having the latest weight of W3, over the pit so that the base of the

cylinder covers the pit concentrically. x Open the slit of the SPC and allow the sand to run into the pit freely, till there is no

downward movement of sand level in the SPC and then close the slit. x Find the weight of the SPC with the remaining sand W4.

Observation & Tabulation: (A). Calibration Of Sand Density: Sl.no Particulars Trial 1 Trail 2 Remark

1. Volume of the calibrating container (V)

2. Weight of SPC + Soil (W1)

3. Wt. of SPC + Soil (W2) After filling conical portion

4. Wt. of SPC + Soil (W3) After filling calibrated can

5. Wt. of soil required to fill cone (Wc) = (W1-W2)

6. Wt. of soil required to fill cone & can (Wcc) = (W2-W3)

7. Weight of soil in calibrating can (Wcc- Wc)

8. Unit weight of sand (Wcc- Wc)/V (B). Measurement Of Soil Density:

Sl.no Particulars Trial 1 Trail 2 Remark

1. Wt.of SPC after filling the hole and conical portion,W4

2. Weight of Soil in the hole and cone (W3- W4)

3. Weight of Soil in the pit (Wp) = (W3- W4) - Wc

4. Volume of soil required to fill the pit (Vp)

5. Weight of soil excavated from the pit (W)

6. Wet unit weight of the soil

7. Dry unit weight of the soil

8. Void ratio / Degree of saturation of soil Result:

x Dry / Wet unit weight of soil = x Void ratio / Porosity / Degree of saturation of the soil =

Experiment Demo Link: https://www.youtube.com/watch?v=C10dklH12W0




STANDARD PROCTOR COMPACTION TEST

Ex.No.: Date:

Aim: To determine optimum moisture content and maximum dry density for a given soil by standard proctor compaction test. Apparatus Required:

x Cylindrical mould with accessories x Rammer x Weighing balance x Measuring jar x Trowel and planner x Microwave oven

Instrument setup:

Fig.8. (a).Proctor compaction tester (b). Compaction process Procedure:

x Take about 3 kg of air dried soil x Sieve the soil through 20mm sieve. Take the soil that passes through the sieve for testing x Take 2.5 kg of the soil and add water to bring its moisture content to about 4% in coarse

grained soils and 8% in case of fine grained soils x Clean and dry and grease the mould and base plate .Weigh the mould with base plate. Fit the

collar. x Compact the wet soil in three equal layers by the rammer with 25 evenly distributed blows

in each layer. x Remove the collar and trim off the soil flush with the top of the mould. In removing the

collar rotate it to break the bond between it and the soil before lifting it off the mould. x Clean the outside of the mould and weigh the mould with soil and base plate. x Remove the soil from the mould and obtain a representative soil sample from the bottom,

middle and top for water content determination x Repeat the above procedure with 8,12,16 and 210 % of water contents for coarse grained

soil and 14,18,22 and 26 % for fine grained soil samples approximately. The above moisture contents are given only for guidance. However, the moisture contents may be selected based




on experience so that, the dry density of soil shows the increase in moisture content. Each trial should be performed on a fresh sample.

Observation: x Diameter of the mould (D) = x Volume of the mould (V) = x Height of the mould (H) = x Weight of the mould (W1) =

Tabulation:

Sl.no Particulars Trial 1 Trial 2

1. Weight of mould + Compacted wet soil in g. (W2)

2. Weight of Compacted Wet soil in g. (W) = (W2-W1)

3. Wet density of soil

4. Empty weight of bin in g. (We)

5. Weight of bin + wet soil in g.(Ww)

6. Weight of bin + dry soil in g. (Wd)

7. Weight of water (w) = (Wd-Ww)

8. Weight of dry soil (Wd-We)

9. Moisture content (W) = (w/(Wd-We))

Graph: Plot the graph between moisture content in X-axis and dry density in Y-axis.

Result: x Optimum moisture content (%) = x Maximum dry density (gm/cc) =

Viva-voce: 1. Define: Dry density. 2. What are the advantage of this test? 3. Difference between sand replacement and core cutter method. 4. Which is the best one to find the density of soil?

Experiment Demo Link: https://www.youtube.com/watch?v=J9S3bv9l7Ic




PERMEABILITY OF SOIL – CONSTANT HEAD METHOD Ex.No.: Date:

Aim: To determine the co-efficient of permeability of the given soil by constant head method. Apparatus Required:

x Permeability apparatus with Accessories x Stop watch x Measuring jar

Instrument setup:

Fig.9. (a). Constant head method setup Procedure:

x Compact the soil into the mould at a given dry density and moisture content by a suitable

device. Place the specimen centrally over the bottom porous disc and filter paper.

x Place a filter paper, porous stone and washer on top of the soil sample and fix the top collar.

x Connect the stand pipe to the inlet of the top plate. Fill the stand pipe with water.

x Connect the reservoir with water to the outlet at the bottom of the mould and allow the

water to flow through and ensure complete saturation of the sample.

x Open the air valve at the top and allow the water to flow out so that the air in the cylinder is

removed.

x When steady flow is reached, collect the water in a measuring flask for a convenient time

intervals by keeping the head constant. The constant head of flow is provided with the help

of constant head reservoir

x Repeat the for three more different time intervals

Formula:

x Co-efficient of permeability of soil (K) = 𝑄𝐿𝐴𝑡ℎ⁄




Where, K – Co-efficient of permeability Q – Quantity of water in sec h – Constant hydraulic head in cm / t – time in sec A, L – Cross sectional area (cm2) and Length (cm) of the soil sample. Observation:

x Length of soil sample (L) = cm x Area of the soil sample (A) = cm2

Tabulation:

Sl.no Hydraulic head in cm

(h)

Time interval in

sec (t)

Quantity of water

collection (cc)

Co-efficient of permeability

(cm/sec) Remark

Result:

x Co-efficient of permeability of the given soil sample is _____________ Viva-voce:

1. Define: Permeability. 2. Define: Seepage. 3. What are the uses of this experiment? 4. Define: Rate of settlement. 5. Difference between dam and embankment.

Experiment Demo Link: https://www.youtube.com/watch?v=dnLLUMW0j3I




PERMEABILITY OF SOIL – FALLING HEAD METHOD

Ex.No.: Date:

Aim: To determine the co-efficient of permeability of the given soil by constant head method. Apparatus Required:

x Permeability apparatus with Accessories x Stop watch x Measuring jar x Funnel

Instrument setup:

Fig.10. Falling head method setup Procedure:

x Compact the soil into the mould at a given dry density and moisture content by a suitable device. Place the specimen centrally over the bottom porous disc and filter paper.

x Place a filter paper, porous stone and washer on top of the soil sample and fix the top collar. x Connect the stand pipe to the inlet of the top plate. Fill the stand pipe with water. x Connect the reservoir with water to the outlet at the bottom of the mould and allow the

water to flow through and ensure complete saturation of the sample. x Open the air valve at the top and allow the water to flow out so that the air in the cylinder is

removed. x Fix the height h1 and h2 on the pipe from the top of water level in the reservoir x When all the air has escaped, close the air valve and allow the water from the pipe to flow

through the soil and establish a steady flow. x Record the time required for the water head to fall from h1 to h2. x Change the height h1 and h2 and record the time required for the fall of head.

Formula:

x Co-efficient of permeability of soil (K) = 2.303 𝑎𝐿 𝐴𝑡 𝑙𝑜𝑔10⁄ (ℎ1/ℎ2)




Where, K – Co-efficient of permeability a – Area of stand pipe in cm2

t – Time required for the head from h1 to h2 in sec A – Cross sectional area (cm2) Q – Quantity of water in sec L – Length (cm) of the soil sample h1 – Initial head water in the stand pipe above the water level in the container in cm h2 – final head water in the stand pipe above the water level in the container in cm

Observation: x Length of soil sample (L) = cm x Area of the soil sample (A) = cm2 x Dia of the stand pipe (D) = cm x Area of the stand pipe (a) = cm2

Tabulation:

Sl.no Initial head in cm (h1)

Final head in cm (h2)

Time interval in sec (t)

Co-efficient of permeability (cm/sec) Remark

Result:

x Co-efficient of permeability of the given soil sample is _____________ Viva-voce:

1. Define: SBC. 2. What are the applications of their experiment? 3. Enlist the properties of soil. 4. Enlist the various types of hydraulic structures. 5. Compare the constant and varying head methods.

Experiment Demo Link: https://www.youtube.com/watch?v=DPWpEG0yuKU




ONE DIMENSIONAL CONSOLIDATION TEST Ex.No.: Date:

Aim: To determine the settlement due to primary consolidation of soil by conducting one

dimensional test.

Apparatus Required: x Consolidometer consisting of specimen ring. x Guide ring x Porous stones x Dial gauges x Stop watch

Procedure:

(a). Preparation of specimen:

Sufficient thickness of the soil specimen is cut from undisturbed sample. The consolidation ring is gradually inserted into the sample. The consolidation ring is gradually inserted into the sample by pressing and carefully removing the material around it. The specimen should be trimmed smooth and flush to the ends of the ring. Any voids in the specimen caused due to removal of gravel or limestone pieces should be filled back by pressing completely the loose soil in the voids. The ring should be wiped clean and weighed again with the soil. Place wet filter paper on top and bottom faces of the sample and two porous stones covering it should be in place. Place this whole assembly in the loading frame. Over the porous stone a perforated plate with loading ball is placed as shown in the figure.

The sample is put for saturation both from top and bottom. After allowing time for saturation the load is applied through the loading frame. The settlement in sample is measured using a dial gauge.

The stepwise procedure for observing reading is as follows: 1. Apply the required load intensity (stress) at which Cv is to be determined. 2. As the loading is applied, the stop watch should be started. 3. Take the readings of the dial gauge at different time interval from the time

of loading and record them in the table.

(i). Square root method: x Record the dial gauge readings at different time interval from the point of loading in x Table. x Plot a graph between √t on X axis and dial gauge reading on Y axis .Where t is time in

minutes. x The curve drawn reflects three components of settlement (i) Immediate settlement or

elastic compression. This will be reflected in the form of steep settlements in a small time interval and a nearly vertical line at the initial portion of the curve represents it.




This is followed by (ii) Primary consolidation curve, which will be nearly a straight line with a reduced sloe. The majority of consolidation will be in this zone. After primary consolidation (iii) Secondary consolidation takes place that is marked by a curve nearly parallel to time axis.

x Draw a straight line through a primary consolidation zone. Identification of primary consolidation zone depends on experience and eye judgment. Extent the straight line to meet Y- axis at Oc. Oc is the corrected zero.

x Draw another straight line through Oc , with a slope equal to 1.15 times the slope of the earlier straight line.

x The Straight line so drawn (with 1.15 times the slope of primary consolidation line) will intersect the originally plotted curve at a point. The X co ordinate of this point will give √t90. Where t90 is the time required for 90% consolidation (in minutes)

x The coefficient of consolidation is calculated as follows Cv = 0.848 H2 / (t90× 60) cm2/sec.

Where, H = length of drainage path (cm) H = half thickness of soil sample for double drainage and H = thickness of soil sample for single drainage t90 = time required for 90% consolidation in minutes.

(ii). Log Method:

x The compression dial readings should be plotted against the log of time and a smooth curve drawn to pass through the points.

x The two straight portions of the curve should be extended to intersect at a point , the ordinate of which gives d100 corresponding to 100% primary compression.

x The corrected zero point ds shall be located by the laying of above point in the neighbor hood of 0.1 minute a distance equal to the vertical distance between this point and one at a time which is four times this value.

x The 50% compression point which is halfway between the corrected zero point and the 100% compression point, shall be marked on the curve and the readings on the time axis corresponding to this point t50, time to 50% primary compression, shall be noted. The readings on the dial gauge reading axis, corresponding to 100% compression gives d100.

x Coefficient of consolidation is calculated as follows Cv = 0.197 H2/ t50.

Observation:

x Diameter of Sample (D) = x Thickness of Sample (t) = x Unit weight of soil (w) =




Tabulation:

Sl.no Time in min. (t) √𝒕 Dial Gauge reading

1. 0.00

2. 0.25

3. 2.25

4. 4.00

5. 6.25

6. 9.00

7. 12.25

8. 16.00

9. 20.25

10. 25.00

11. 36.00

12. 49.00

13. 64.00

14. 81.00

15. 100.00

16. 121.00

17. 144.00

18. 169.00

19. 225.00

20. 256.00

Result: x The Co-efficient of Consolidation of the given soil sample is ____________.

Viva-voce: 1. Define: Consolidation. 2. Difference between Compaction and Consolidation. 3. What are the important of this experiment? 4. Difference between cohesive and cohesion less soil. Give with an example. 5. Define: Compression index.

Experiment Demo Link: https://www.youtube.com/watch?v=3bvevFBNYw0




DIRECT SHEAR TEST IN COHESION-LESS SOIL

Ex.No.: Date:

Aim: To determine the shear strength of given soil sample by Direct shear test.

Apparatus Required:

x Direct shear box x Loading frame (Motor type loader) x Dial gauge x Proving ring x Tamper x Weighing balance x Aluminum container x Spatula

Instrument setup:

Fig.11. Direct shear test setup

Procedure: x Check the inner dimension of the soil container. x Put the test of the s oil container together. x Calculate the volume of the container. x Place the soil in smooth layers (10 mm thick). If a dense sample is desired tamp the soil. x Weigh the soil container the difference of these two is the weight of the soil. Calculate the

density of the soil. x Make the surface of the soil plane. Put the upper grating on stone and loading block on top

of soil. x Measure the thickness of the specimen and apply the desired normal load and remove the

shear pin.




x Attach the dial gauge which measures the change of volume. Record the initial reading of the dial gauge and calibration values.

x Before proceeding to test check all adjustments to see that is no connection between two parts except sand/soil.

x Start the motor, take the reading of the shear force and record the reading. x Take volume change readings till failure and add 5kg/cm2 and continue the test till failure. x Record carefully all the readings. Set the dial gauge zero, before starting the experiment.

Observation: x Least count (LC) = x Proving ring constant = x Dimension of shear box = 60x60 mm x Empty wt. of shear box =

Tabulation: (Normal Stress 0.5 kg/cm2) Gauge

reading Proving ring

reading

Initial reading (div) Shear

deformation (IhxLC)

Vertical deformation

(IvxLC)

Proving initial

reading (Ip)

Shear stress (Ipxarea of the

specimen) Hori. Vert. Hori. (Ih)

Vert. (Iv)

0

25

50

75

100

(Normal Stress 1.5 kg/cm2) Gauge

reading Proving ring

reading

Initial reading (div) Shear

deformation (IhxLC)

Vertical deformation

(IvxLC)

Proving initial

reading (Ip)

Shear stress (Ipxarea of the

specimen) Hori. Vert. Hori. (Ih)

Vert. (Iv)

0

25

50

75

100

Result: x The shear strength of the given soil sample is _____________.

Experiment Demo Link: https://www.youtube.com/watch?v=a3LrPo1mtYA




UNCONFINED COMPRESSION TEST IN COHESIVE SOIL

Ex.No.: Date:

Aim: To the shear parameters of cohesive soil.

Apparatus Required: x Loading frame x Proving ring x Soil trimmer x Evaporating dish x Dial gauge x Weighing balance x Microwave oven x Vernier

Instrument setup:

Fig.12. Unconfined Compression Apparatus

Procedure: (a). Specimen – Undisturbed sample:

x Note down the sample number bore hole number and the depth at which the sample was taken.

x Remove the protective cover from the sampling tube. x Place the sampling tube extractor and push the plunger till a small length of sample moves

out. x Trim the projected sample using a wire saw. Again push the plunger of the extractor till a 75

mm long sample comes out. x Cutout this sample carefully and hold it on the split sampler so that it does not fall. x Take about 10 to 15 g of soil from the tube for water content determination. x Note the container number and take the net weight and measure the diameter at the top,

middle and bottom of the sample and fine the average. x Measure the length of the sample and find the weight of the sample and recorded.




(b). Moulded sample:

x For the desired water content and the dry density calculate the weight of the soil required for preparing a specimen of 3.8 cm dia. and 7.5 cm long.

x Add required quantity of water Ww to this soil. Ww = (WsxW)/100 gm.

x Mix the soil thoroughly with water and place the wet soil in a tight thick polyurethane bag in a humidity chamber and place the soil in a constant volume mould having and internal height of 7.5 cm and internal dia. Of 3.8 cm.

x After 24 he humidity hours take the soil from the a humidity chamber and place the soil in a constant volume mould having and internal height of 7.5 cm and internal dia. Of 3.8 cm.

x Place the lubricated mould with plungers in position in the load frame and apply the compressive load till the specimen is compacted to a height of 7.5 cm.

x Eject the specimen from the constant volume mould and record the correct height, weight and diameter of the specimen.

Test procedure: x Take two frictionless bearing plates of 75 mm diameter and Place the specimen on the

base plate of the load frame. x Place a hardened steel ball on the bearing plate and Adjust the center line of the

specimen such that the proving ring and the steel ball are in the same line. x Fix a dial gauge to measure the vertical compression of the specimen. Adjust the gear

position on the load frame to give suitable vertical displacement. x Start applying the load and record the readings of the proving ring dial and compression

dial for every 5 mm compression. x Continue loading till failure is complete.

Formula:

x Unconfined compression strength of the soil is qu

x Shear strength of the soil = (qu/2)

Where,

qu – Undisturbed soil (or) Moulded soil sample

Observation:

x Specific gravity of soil (G) = 2.71 x Bulk density of soil = x Water saturation = x Degree of saturation = x Diameter of the soil (Do) = x Area of cross section (A) = x Initial length of the sample (Lo) = 76 mm




Tabulation:

Elapsed

time in

min (t)

Compression

gauge

reading in

mm (L)

Strain (e)

(Lx100)/Lo

in %

Area (A)

(Ao/(1-e)

In cm2

Proving

ring

reading in

div.

Axial load

in kg

Compressive

stress (qu)

(load/area)

in kg/cm2

Calculation:

x Unconfined compression strength of the soil is qu

x Shear strength of the soil = (qu/2)

Graph:

Draw the sketch of the failure pattern in the specimen.

Result:

1. Define: UCC. 2. What are the merits of UCC? 3. What are the demerits of UCC? 4. Enlist the various methods of shear parameters. 5. Which one is the best test of shear strength of the soil?

Experiment Demo Link: https://www.youtube.com/watch?v=8hzizh7dB9A




VANE SHEAR TEST IN COHESIVE SOIL

Ex.No.: Date:

Aim: To determine the shear strength of a given soil sample by vane shear method.

Apparatus Required: x Vane shear apparatus x Specimen x Specimen container x Caliper

Instrument setup:

Fig.13 Vane Shear Apparatus

Procedure:

x Prepare two or three specimen of the given soil sample of dimensions of at least 37.5 mm

diameter and 75 mm length in specimen (L/d ratio is 2 to 3)

x Mount the specimen container with the specimen on the base of the vane shear apparatus. If

the specimen container is closed at one end, if should be provided with a hole of about 1

mm diameter at the bottom.

x Gently lower the shear vane into the specimen to their full length without disturbing the soil

specimen. The top of the vanes should be at least 10 mm below the top of the specimen.

Note the readings of the angle of twist.

x Rotate the vanes at an uniform rate say 0.1º/s by suitable operating the torque application

handle until the specimen fails.

x Note the final reading of the angle of twist and Find the value of blade height in cm.

x Find the value of blade width in cm.




Formula:

x Shear strength (S) = T/𝜋(D2H/2+D3/6) Where, S – Shear strength of soil in kg/cm2 T – Torque in cm kg D – Overall diameter of vane in cm T – Spring constant / 180º x difference in degrees.

Observation: x No of vane = x Diameter of vane (D) =

Tabulation:

Sl.no Initial

reading in deg.

Final reading in deg.

Difference in deg.

(dº)

Spring constant in kg cm

(Cs)

T = Cs / 180ºxdº

G = 1/𝝅(D2H/2+D3/6)

Shear stress (S) = TxG in

kg/cm2

Calculation:

x Shear strength (S) = T/𝜋(D2H/2+D3/6) x G = 1/𝜋(D2H/2+D3/6

Result: x The shear strength of given a soil sample is ______________.

Viva-voce:

1. What are the uses of their experiment? 2. Enlist the types of shear failure. 3. How to find out the shear failure? Give an example. 4. How to solve the shear failure? Give an example. 5. Draw the near sketch of various shear failure in soil.

Experiment Demo Link: https://www.youtube.com/watch?v=5AXm6NdoXfw




TRI-AXIAL COMPRESSION TEST IN COHESION-LESS SOIL Ex.No.: Date:

Aim: Since the shear strength of a soil is determined in terms of the total stress in this test (the

total stress being equal to the effective stress plus the pore pressure), the strength depends on the pressure developed in the pore fluid during loading.

Apparatus Required: x Platform Weighing Scale Equipped With A Screw-Jack Activated-Load Yoke; x Deadweight Load Apparatus; x Hydraulic Or Pneumatic Loading Device

Instrument setup:

Fig.14. Tri-Axial Compression test apparatus

Procedure: x Position the specimen in the chamber and assemble the triaxial chamber x Bring the axial load piston into contact with the specimen cap several times to permit proper

seating and alignment of the piston with the cap. x During this procedure, take care not to apply a deviator stress to the specimen exceeding

0.5% of the estimated compressive strength. x If the weight of the piston is sufficient to apply a deviator stress to the specimen exceeding

0.5% of the estimated compressive strength: the piston should be locked in place above the specimen cap after checking the seating and alignment; and left locked until application of the chamber pressure.

x Place the chamber in position in the axial loading device.




x Carefully align the axial loading device, the axial load-measuring device, and the triaxial chamber to prevent the application of a lateral force to the piston during testing.

x Attach the pressure-maintaining and measurement device. x Fill the chamber with the confining fluid to a predetermined level. x Adjust the pressure-maintaining and measurement device to the desired chamber pressure

and apply pressure to the chamber fluid. x If the axial load-measuring device is located outside the triaxial chamber, the chamber will

produce an upward force on the piston that will react against the axial loading device. In this case, start the test with piston slightly above the specimen cap, and before the piston comes in contact with the specimen cap, measure and record the initial piston friction and upward thrust of the piston produced by the chamber pressure. Later correct the measured axial load, or adjust the axial load-measuring device to compensate for the friction and thrust.

x If the axial load-measuring device is located inside the chamber, it will not be necessary to correct or compensate for the uplift force acting on the axial loading device or for piston friction.

x In either case, record the initial reading on the deformation indicator when the piston contacts the specimen cap.

x Approximately 10 minutes after the application of chamber pressure (see Note 1) begin to apply the axial load to produce axial strain at a rate of approximately:

� 1%/minute for plastic materials � 0.3%/minute for brittle materials that achieve maximum deviator stress at

approximately 3–6% strain. x At these rates, the elapsed time to reach maximum deviator stress will be approximately 15

–20 minutes Graph:

Fig.15.Mohr’s Diagram

Result:

x The tri-axial compression test were studied. Experiment Demo Link: https://www.youtube.com/watch?v=x9IEALyQcI0




CALIFORNIA BEARING RATIO TEST

Ex.No.: Date:

Aim: To determine the strength of the given soil sample.

Apparatus Required:

x Mould x Steel Cutting collar x Spacer Disc x Surcharge weight x Dial gauges x IS Sieves x Penetration Plunger x Loading Machine

Instrument setup:

Fig.16. CBR apparatus

Procedure: x Normally 3 specimens each of about 7 kg must be completed so that their compacted

densities range from 95% - 100% generally with 10, 30 and 65 blows. x Weigh of empty mould. x Add water to the first specimen and after compaction remove he collar and level the surface. x Take sample for determination of moisture content. x Weight of mould + compacted specimen and place the mould in the soaking tank for 4 days. x Take other samples and apply different blows and repeat the whole process. x After 4 days measure the swell reading and find % of swell. x Remove the mould from the tank and allow water to drain. x Then place the specimen under the penetration piston and place surcharge load of 10 lb. x Apply the load and note the penetration load values. x Draw the graph the penetration Vs penetration load.




Tabulation:

Penetration in mm

Proving ring reading

Piston load in lb

Area of piston in in2

Penetration stress in psi

Graph: Graph of penetration Vs load.

Result:

x The strength of the soil sample is ________ Experiment Demo Link: https://www.youtube.com/watch?v=8mdSmB3CtZM




ANNA UNIVERSITY EXPECTED PRACTICAL QUESTION PAPER*

ANNA UNIVERSITY::CHENNAI – 600 025 B.E/B.Tech DEGREE PRACTICAL EXAMINATIONS Nov/Dec 2016

Fifth Semester Regulation 2013

CE 6511 SOIL MECHANICS LABORATORY Time: 3 Hrs Max.mark: 100

1. Determination of specific gravity of soil solids. (100) 2. Determination of grain size distribution by Sieve analysis method. (100) 3. Determination of grain size distribution by Hydrometer method. (100) 4. Determination of Liquid and Plastic limit of given soil sample. (100) 5. Determination of Shrinkage limit of given finer soil sample. (100) 6. Determine the dry density of soil in given location by Field density test.

a) Core cutter method (50) b) Sand replacement method (50)

7. Determination of moisture-density relationship by compaction. (100) 8. Determination of soil properties by using Constant head method. (100) 9. Determination of permeability of given soil by varying head method. (100) 10. Determination of co-efficient of consolidation by 1D test. (100) 11. Determine the properties of given cohesive-less soil by shear test. (100) 12. Determine the strength of given sample by UCC. (100) 13. Determine the shear strength of given soil by Vane shear test. (100) 14. To conduct the CBR for given soil sample. (100) 15. Determine the fineness of given dry soil sample. (100) 16. To find the value of (G) in given solid particles. (100) 17. To find the percentage of moisture in given soil by Atterberg’s limit. (100) 18. Draw a shear envelope diagram by using any one shear strength test. (100) 19. Determine the value of soil by one D consolidation test. (100) 20. To conduct the field density test for given soil sample. (100)

Allocation of mark:

Sl.no Aim & Apparatus

Procedure &

Formula

Observation &

Tabulation Calculation

Drawing &

Graph Result Viva Total

1. 15 25 15 15 10 10 10 100 Note: * - Specimen copy.


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