Category Archives: Civil Experiments

Grain size analysis

Grain size analysis


To determine the percentage of soil retained on each sieve.

Requirement of test:-

Grain size analysis can be used to predict soil water movement but also used in the design of filters for earth dams and to determine suitability of soil for road construction, air field etc.


  1. Balance.
  2. I.S. sieves as per I.S. 460-1962.
  3. Rubber pestle and mortar.
  4. Mechanical sieve shaker (if available).


  1. For soil samples of soil retained on 75 micron I.S. sieve. The proportion of soil sample retained on 75 micron I.S. sieve is weighed and recorded weight of soil sample is as per I.S. 2720.
  2. I.S. Sieves are selected and mesh sieves arranged vertically in increasing order.
  3. The soil sample is separated into various fractions by sieving through above sieve in the same order.
  4. The weight soil retained on each sieve is recorded.
  5. The moisture content of soil if above 5% it is to be measured and recorded.
  6. No particle of soil sample shall be pushed through the sieve.



S.NO. I.S. sieve number or size in mm(opening size) Wt. retained in each sieve (gm.) % age retained on each sieve Cumulative % age retained on each sieve % finer remarks
 1. 4.75
 2. 4.00
 3. 3.36
 4. 2.40
 5. 2.00
 6. 1.46
 7. 1.20
 8. 0.60
 9. 0.30
 10. 0.15
 11. 0.075

Now draw graph between %finer( on y-axis) and particle size diameter in mm( on x-axis). The graph is known as grading curve. Now calculate particle size diameters from graph which are designated as D10, D30 and D60(10%, 30% and 60% finer respectively).

Pile load Testing in Soil Mechanics

Pile load test is generally used for determining the load carrying capacity of pile. The setup generally made of two anchor piles and an anchor girder or a reaction girder provided at their top. The test pile is provided between the anchors piles in which the foundation piles are to be installed. The test pile should be at least three times of width or 2.5m clear from the anchor piles.

  • The test load is done with the help of hydraulic jack resting on the reaction girder. The pile movement is generally measured with respect to a fixed reference mark.
  • The test is conducted after a rest period of 3 days after the installation in sandy soils and a period of 1 month in silts and soft clays. The load is applied in equal increments of about one-fifth of the estimated allowable load.
  • The settlements are recorded with the help of three dial gauges. Each stage of the loading is maintained till the rate of movement of the pile top is not more than 0.1 mm per hour for sandy soils and 0.02 mm per hour for clay soils.
  • The test piles are loaded until ultimate load is reached. The obtained results are plotted in the form of load-settlement curve. The ultimate load can be clearly obtained by load settlement-curve approaching vertical.

Field Density Test(Sand Replacement Method)

Field Density Test

Sand Replacement method


Determine the in-situ density (in g/cm3 or kg/cm3) of natural or compacted soils using sand replacement method.

Necessity of test:-

The field density of natural soil is needed for the determination of bearing capacity of soils, for the purpose of stability analysis of slopes, for the determination of pressures on underlying strata for calculation of settlement and the design of underground structures.


  1. Sand pouring cylinder of 3 lits/16.5 lit capacity.
  2. Tool for excavating holes:-scraper.
  3. Cylindrical calibrating container with an internal diameter of 100 mm/200 mm and an internal depth of 150mm/250 mm fitted with a flange 50 mm /75 mm wide an about 5mm surrounding the open end.
  4. Balance machine up to an accuracy of 1g.
  5. Glass plate about 450 mm/600 mm square and 10 mm thick.
  6. Suitable non-corrodible air-tight containers.
  7. Oven maintaining temperature between 105°C to 110°C .
  8. Natural sand passing 1mm I.S Sieve and retained on 600 micron I.S Sieve.
  9. Metal tray having hole—50mm deep and 300mm/450mm square with a 100mm/200mm diameter hole in the center.


Calibration of the cylinder

  1. Fill the sand pouring cylinder with clean sand so that the level of the sand in the cylinder is within about 10 mm from the top, find out the initial weight of the cylinder plus sand (w1) and this weight should be maintained constant throughout the test for which the calibration in used.
  2. Allow the sand of volume equal to that of the calibrating container to run out of the cylinder by opening the shutter, close the shutter and place the cylinder on the glass plate. Open the shutter and allow the sand to run out . When no faster movement of sand takes place in the cylinder close the shutter and remove the cylinder carefully weigh the sand collected on the glass plate. Its weight (w2) gives the weight of sand filling the cone portion of the sand pouring cylinder.

Repeat this step at least three times and take the mean weight (w2).

Put the sand back into the sand pouring cylinder to have the same initial constant weight (w1).

Determination of bulk density of soil

  1. Determination the volume (v) of the calibrating container be filling it with water to the brim. Check this volume by calculating from the measured internal dimensions of the container.
  2. Place the sand pouring cylinder centrally on the top on the calibrating container making sure that constant weight (w1) is maintained. 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 weight (w3).

Determination of dry density of soil In-place

  1. Approximately 60 sq cm of area of soil to be tested should be trimmed down to a level surface, approximately of the size of the container. Keep the metal tray on the level surface and excavate a circular hole of volume equal to that of the calibration container. Collect all the excavated soil in the tray and find out the weight of the excavated soil (ww). Remove the tray, and place the sand pouring cylinder filled to constant weight (w1) so that the base of the cylinder covers the hole concentrically. Open the shutter and the 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 weight (w3).
  2. Keep a representative sample of the excavated soil for water content determination.

Observations and Calculations:-

Number of Samples
S.NO.                    Sample Details                         calibration 1 2 3
1. Mean weight of sand in cone (of pouring cylinder) (w2) in gms
2. Volume of calibrating container (v) in ml
3. Weight of sand (+ cylinder) before pouring (w3) in gms
4. Mean weight of sand (+cylinder) after pouring (w3) in gms
5. Weight of sand to fill calibrating containers( wα = w1 – w3 – w2 ) in gms
6. Bulk density of sand γs = wα/v gms/cc
Number of Samples
S.NO. Measurement of Soil Density 1 2 3
1. Determination No
2. Weight of wet soil from hole (ww) in gms
3. Weight of sand (+ cylinder ) before pouring (w1) in gms
4. Weight of sand (+ cylinder ) after pouring (w4) in gms
5. Weight of sand in hole (wb = w1 – w4 – w2 ) in gms
6. Bulk densityγb= (ww/wb)× γs gms/cc
7. Water content container No.
8. Weight of soil for water content determination of gms
9. Weight of oven dried soil in gms
10. Water content ‘w’ %
11. Dry densityγd =     γb                gms/cc



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Determination of moisture content

Determination of moisture content


Determine the natural moisture content of the soil sample.

Definition:-It is the ratio of weight of the water to the weight of solids in soil mass and it is generally expressed in percentage and usually done to get the state of soil in field.


  • Container
  • Electric oven to maintain temperature between 105°C to 110°C.
  • Desiccator
  • Weighing machine


  • Weight the container with lid as W1.
  • Take sample in container and weigh with lid W2.
  • Remove lid and keep container in oven maintaining temperature between 105°C to 110°C for a period of 14 to 16
  • Now weigh the constant weight (W3) of container with lid and dry soil sample.


S.No. Weight(in gms) Sample Nos.
1. Weight of container with lid(W1)gms 1 2 3 4
2. Weight of container with lid and wet soil(W2)gms        
3. Weight of container with lid and dry soil(W3)gms        
4. Percentage of moisture





Result: – The natural moisture content of soil sample is __________