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APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY
FOURTH SEMESTER B.TECH DEGREE EXAMINATION, APRIL 2018

Course Code: CE208
Course Name: GEOTECHNICAL ENGINEERING I (CE)

Max. Marks: 100 Duration: 3 Hours
(Graph sheets may be supplied on request) PART A
Answer any two full questions, each carries 15 marks Marks
1a) The wet unit weight of a clay sample is 18.8kKN/m? at 20% water content. What (5) is the
degree of saturation?
b) An embankment of 10ന്‌ volume is to be constructed with a soil having a void
(10)
ratio of 0.8 after compaction. There are three borrow pits marked A, B and C
having soils with void ratios of 0.9, 1.5 and 1.8 respectively. The cost of
excavation and transporting the soil is Rs. 25, Rs 0.23 and Rs. 0.18 per ‏تر‎
‎respectively. Calculate the volume of soil to be excavated from each pit. Which
borrow pit is most economical?
2 य) What are the index properties of soil? Why are they important? (5)
0) A partially saturated clay weighs 113.4 gm in its natural state and 93.4g in its (10) dry
state. If specific gravity is 2.65, find out the void ratio, porosity, degree of saturation,
Ywet, Yd aNd Ysat. Size of the clay is 3.7 cm in dia. and 7.5 cm ht.
3 a) What are the different corrections applied to hydrometer reading? (5)
b) Ina hydrometer analysis 50 ഉ of soil was mixed in water to form 1000ml (10)
uniform soil suspension. The corrected hydrometer reading after a lapse of 60mts
from the start of sedimentation was 1.010 and the corresponding effective depth
was 108 mm. Determine the effective diameter corresponding to 60mts reading
and percentage of particles finer than this size. G= 2.7 viscosity of water is 0.001
Ns/m?
PART B
Answer any two full questions, each carries 15 marks
4+ a) Explain the effect of capillarity on effective stress. (5)
b) A bed of sand consists of three horizontal layers of equal thickness. The (10)
magnitude of the coefficient of permeability for both upper and lower layer is 07
‘mm/s and for the middle layer, it is 6x10mm/s. what 15 the ratio of the
average permeability of the bed in the horizontal direction to that in vertical

direction.

5 a) List the demerits of direct shear test. (5) b) The following data refers to a CU test on a
normally consolidated clay. (10)

Compute the total stress and effective shear strength parameters.

Sample no Cell pressure Deviator stress Pore pressure
(kPa) (kPa) (kPa)
1 100 130 48
2 300 485 140

3 500 645 290