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Reg No.:_. Name:
APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY
V SEMESTER B.TECH DEGREE EXAMINATION(R&S), DECEMBER 2019
Course Code: CE305

Course Name: GEOTECHNICAL ENGINEERING - II
Max. Marks: 100 Duration: 3 Hours

PARTA
Answer any two full questions, each carries 15 marks. Marks
1 a) Differentiate between isobar and pressure bulb. Give one practical example to (7%)
highlight the significance of pressure bulb.
0) What is meant by passive state of plastic equilibrium of soils? Give two field (7൭)
situations [with sketches] where passive mechanism develops.
2 ஐ Critically differentiate between Boussinesq’s theory and Westergaard’s theory. (712)

b) A retaining wall supports a backfill with the following properties: Upper layer: (714)
angle of internal friction=30°; unit weight=17KN/m* ; thickness=2m. Lower
layer: angle of internal friction=35°; unit weight=19KN/m’; thickness=4m. Find
the total lateral earth pressure, if the retaining wall tends to move towards the
backfill.

3 8) Compute the vertical stress at a depth of 1.5m vertically beneath the centre of 2 (714)

circular ring type of footing (width of ring=2m; internal diameter=S5m) subjected
to a uniform pressure of 175KPa.

b) An excavation is to be carried out in a soil with angle of internal friction=30°; (712
cohesion=10KPa. unit weight =20 KN/m*. Find the maximum stable depth up to
which excavation can be carried out without failure.

PART B
Answer any two full questions, each carries 15 marks.

4 a) State the assumptions of Terzaghi’s bearing capacity theory. (712)
b) State the functions of any 5 elements of a well foundation. (712)

5 ച Estimate the net ultimate bearing capacity of a circular footing of 2.5m diameter (712)
placed at 1.5m depth, in a lateritic soil (cohesion=48KPa; unit weight
=18KN/m’). Bearing capacity factors are Nc=10, Nq=3, Ny=1.5.

b) How can the allowable bearing capacity of rafts on clay be estimated? (712)

6 9) Mention any three causes of differential settlement. Suggest any three measures (7൭)
for reducing the same.

b) Design a combined footing for 2 columns, if size of both columns are: (716)
350mmX350mm; Column loads=1800KN and 1200kKN; C/c distance between
columns=4m. Clear spacing beyond the outer face of the ۱12001180 column=
0.175m. Safe bearing capacity of soil=219kPa.

PART 6
Answer any two full questions, each carries20 marks.

7 ஐ A circular concrete pile of diameter 500mm is installed in a clay stratum having (10)