1. What do you understand by the terrm soil?

Ans:

The tem soil is defined as unconsolidated material composed of solid particles produced by the disintegration of rocks. The void space between the particles may contain air, water or both. The solid particles may contain organic matter.

2. What are the scopes of soil engineering?

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Soil engg has vast applications in civil engg.works:
1. Foundation
2. Retaining structures
3. Stability of slopes
4. Underground structures
5. Pavement design
6. Earthen dams
7. Miscallenous soil problems

3.What is block diagram?

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Block diagram is also known as three phase diagram. It defines the soil mass consists of solid particles which form a prous structures that is filled with air, water, or partly air and partly water

4.What is the difference between soil and solids.

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Soil is the complex material formed of voids, and solid particles whereas Solids is the part of soil represented in a three phase system.

5.What is void ratio and porosity?

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Void ratio: It is defined as the ratio of the volume of voids to the volume of solids. It is represented by e. Porosity: It is defined as the ratio of the volume of voids to the total volume.

6.Give the equation stating the relationship between void ratio and porosity.

Ans:

η = e/1+e and e = η/1-η
(1-η)(1+e) = 1

7. Inter relation between mass and unit weight.

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γ = W/V = M.g/V

8.What is dry unit weight, saturated unit weight, and submerged unit weight.

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Dry unit weight: Weight of solids per unit total volume.
γd = Ws/V
Submerged unit weight: Submerged unit weight per unit total volume.
γ' = Wsub/V
Saturated unit weight: Bulk unit weight when the soil is fully saturated.
γsat = Wsat/V

9.Relation between bulk unit weight, specific gravity, water content, void ratio.

Ans:

γ = γw (G+s.e)/1+e
Γ = γw G. (1+w)/1+e

10.What are the various methods of determination of bulk unit weight and dry unit weight? Explain core cutter method.

Ans:

There are two methods of determining bulk unit weight and dry unit weight:

1. Core cutter method
2. Sand replacement method.
Core cutter method:
1. Measure the inside dimensions of core cutter and calculate its volume.
2. Weigh the core cutter (without dolly) accurate to 1 gm.
3. Clean the top of soil on the site and level it. Dolly placed on the top of the core cutterand drive into the soil
with the help of rammer until about 1 to 1.5 cm of the dolly remains above the surface.
4. Dig out the container which is containing the soil from the ground. Remove the dolly with the help of straight edge,
trim flat, the end of the cutter.
5. Weigh the cutter with full soil and keep representative specimen soil for water content determination. (W2)
6. Repeat the test at two to three locations nearby for getting avg. unit weight.

11. Give the procedure for determination of specific gravity by pyconometer.

Ans:

1. Dry the pyconometer thoroughly and weigh with its cap tightly screwed on W1
2. Unscrew the cap and put in about 200 gm of oven dried soil sample passing 4.75 mm IS sieve and weigh again (W2)
3. Add sufficient water to cover soil about half, full screwed the cap and shake welll, so that soil becomes wet and air shall be removed.
4. Allow the air to remove about 20 minutes, then add more water up to the top of the cap, use glass rod to remove entrapped air.
5. After removing the entrapped air, again chedck the level of water in pyconometer and water vis required to the top of cap and wipe off with dry cloth from outside and take weight as W2.
6. Clean the pyconometer by washing thoroughly with water.
7. Fill the pyconometer with water upto its top, screw on the cap and add the water up to top of the cap.
8. Weigh the pyconometer after drying it on the outside thoroughly (W4)
9. Repeat the test twice.
Calculation:
G = (W2-W1)/(W2-W1)-(W3-W4)

12.Explain the procedure of determination of water content through oven drying method

Ans:

The oven drying method is the method adopted for water content determination and is very accurate method. Classified under IS 2720 (part-2)-1973.
1. The soil sample is collected in an air tight container and weighed as W2 with lid and before that the container is weighed and the weight of the container is noted as W1.
2. The quantity of sample to be taken for the test depends upon the gradation and maximum size of the particles and the degree of wetness of the soil specimen.
3. The soil sample in the container is then dried in an oven for 24 hours at temperature of 110° ± 5°C. and the container is weighed again, noted as W3.
4. Now with the help of the formula the water loss can be calculated, which will give the value for water content.
5. w = [(W2-W1)/(W3-W1)] x 100