In case silt and clay particles are present in considerable amount in the soil sample the analysis of the soil may be done by wet sieving method or wash method
Definition of sieve analysis of soil by wash method
The ratio of the mass of dry soil particles of the same sizes with a total mass of specimen in percentage measure by using the sieve of different standard sizes is known as a sieve analysis test.
- Dry the sample in an oven for removing moisture content because we need the only sample for sieving.
- Take a representative sample about 500 gm of soil by using a riffler or quartering box, when soil contain larger particles (gravels), bigger soil sample will be required.
- Determine the mass of the sample accurately.
- If soil particles are lumped or conglomerated crush the lumped and not the particles using the pestle and mortar.
- wash this dry sample thoroughly on sieve number 200 washing sieve using water until clean water passes through the sieve.
- Dry the sample retained on sieve #200 sieve in an oven because for sieving we need a dry sample.
- Carefully check all the sieves and remove any particles sticking to the sieve mesh.
- Sieves are arranged in the descending order of their sizes with a pan at the bottom.
- Pour the soil from the top and place the cover, put the stack in the sieve shaker and fix the clamps, adjust the time on 10 to 15 minutes and allow the shaker to start.
- The sieving operation shall be conducted by the lateral and vertical motion of the sieves so as to keep the sample moving continuously over the sieve surface.
- The soil particles shall not be turned or manipulated through the sieves by hand.
- Sieving shall be continued until no more than 1-percent by mass of the residue passes any sieve for 60 seconds.
- Remove the sieves from the sieve shaker and carefully weigh the soil retained on each sieve.
- Remove the particles sticking to the sieve mesh and should be included in the weight retained.
- Tabulate the data and calculate the percentage passing as shown in the following table.
Retained weight % = (Retained mass on individual sieve / Total mass of sample) x 100
Cumulative retained weight (%) = Total retained % mass up to the corresponding sieve)
Passing % = 100 – Cumulative retained mass % at respective sieve.
sieve analysis calculation by wash method
The results of the mechanical (sieve) analysis shall be reported as follows:-
Total Sample: (gm) =
Dry wt Before Washing: (gm) =
Dry wt After Washing: (gm) =
Wt passing no 200 after sieving (gm) =
Wt passing no 200 washed. (gm) =
Total wt passing no 200 sieve. (gm) =
|Sieves Sizes||Retained weight||Retained weight %||Cumulative Retained weight %||Passing %||Adjustment|