Rajiv Gandhi Proudyogiki Vishwavidyalaya 2007 B.E Civil Engineering Geotechnical engineering 1 - Question Paper

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Geotechnical engg

Total No. of Questions : 8 ] [ Total No. of Printed Pages : 2

- B. E. (Seyenth Semester)

EXAMINATION, Nov.-Dee,, 2007 (Civil Engg. Branch)

GEOTECHNICAL ENGINEERINGI (CE-704)

Time: Three Hours -Maximum Marks : 100 Minim um Pass Marks : 35

.Note : Attempt any five questions. All questions carry equal , marks.. Assume suitable data wherever necessary.

1. (a) Explain the plasticity chart used in Indian standard soil

- classification system. ' 10

(b) Explain a method of determining the grain size

^{1 distribution of bohesionless soils. 10}

2. (a) Draw at least three different types of grading curves

with'neat sketches. Discuss their properties. 10

(b) A fully saturated clay sample has. a volume of 0* 18 X 10³m³ and weighs 3-14 N. .If the specific gravity of the soil grains is 2*6, find the void ratio, porosity, moisture content, and unit weight. . 10

3. (a) What is Darcys law ? Give its limitation. 10' (b) What is flow net ? Describe its uses. ^<VS\ 10

i

4. (a) Describe a laboratory method to determine coefficient

of consolidation. 10

(b) The porosity of a sample of sand in the loose state was 54% and in dense state 38%. Find out the critical hydraulic gradient in both the states. If the specific gravity of the soil was 2*60 what will be the saturated' and submerged unit weight in kN/rn³ ? 10

5. (a) State advantage and disadvantage of direct shekr lest

and triaxial compression test. L 10

(b) Explain Progressive Failure. In what test do you observe this phenomenon ? 10

6. (a) Describe the Swedish method of slope stability analysis

cl. d jjui dy coiiesive soil. 10

(b) Discuss the stability of infinite slopes in cohesionless and cohesive soil 10

7. (a) Develop the expression for coefficient of earth

pressure in active state, in passive case and in state of rest, 10

(b) A 1.0 metre deep vertical cut is to be made through a cohesive soil of mass specific gravity 2*i gm/cc. Calculate the total pressure on timber sheeting which will be used to restrain the cut faces. 10

8. Write short notes on any four of the following : 5 each

(i) Factors affecting permeability of soil

(ii) .Unconfined compression test

(iii) Rare shear test

(iv) Arching of soils

(v) Formation of soils

CE 704