Ranchi University 2010-2nd Sem B.E Geo Informatics III B.TechRegular s, GEO TECHNICAL ENGINEERING (Civil Engineering - Question Paper

III B.Tech II Semester Regular Examinations, April 2010
GEO tech. ENGINEERING
(Civil Engineering)
Time: three hours Max Marks: 80
ans any 5 ques.
All ques. carry equal marks
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1. (a) Differentiate ranging from residual and transported soils.
(b) An undisturbed specimen of clay was tested in the laboratory and the subsequent
outcomes were found. Specific gravity of solids is 2.70, wet and dry masses of
the specimen are 210 g and 125 g respectively. Assuming the wet specimen to
be:
i. 100% saturated and
ii. 75% saturated, determine:
A. total volume,
B. void ratio and
C. porosity of the specimen. [6+10]
2. (a) Write the notes on Indian Standard Classification of coarse grained soils.
(b) define the hydrometer method of particle size analysis of soils. [6+10]
3. (a) explain the factors that influence the value of coefficient of permeability of a
soil.
(b) A soil sample 90 mm high and 6000 mm2 in cross-section was subjected to
a falling head permeability test. The head fall from 500 mm to 300 mm in
1500 sec. The permeability of the soil was 2.4×10-3 mm/s. Determine the
diameter of the stand pipe. [8+8]
4. (a) Define: total stress, effective stress and neutral stress as applied to soils.
(b) elaborate the corrections to be made to the phreatic line? And how the identical
is carried out.
(c) What is a flow net? State its properties and applications. What is the volume
of seepage ranging from 2 successive flow lines and equipotential lines? [4+4+8]
5. A water tower has a circular foundation of 10m diameter. If the total weight of the
tower, including foundation is 2.5 × 104 kN, compute the vertical stress a depth of
3.0m beneath the foundation level. Also compute stress at 1.5m depth. [16]
6. The subsequent are outcomes of standard compaction test performed on a sample of soil:
Water content (%) five 10 14 20 25
Bulk density (kN/m3) 17.7 19.8 21 20.8 20.6
Plot the water content - dry density curve and find the optimum water content
and maximum dry density. compute the water content necessary to completely
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Code No: V3201/R07 Set No. 1
saturate the sample at its maximum dry density, assuming no change in the quantity.
Take G = 2.7. [16]
7. (a) discuss why there is a significant time lag in the settlement of clay soils but
not in sandy soils.
(b) discuss in sequence, the occurrences that take place when a saturated clay
deposit undergoes consolidation. [8+8]
8. A series of undrained shear box tests (area of box = 3600mm2) were carried out on
a soil with the subsequent outcomes.
Normal Load (N) Shear force at failure (N)
90 70
180 90
270 117
(a) Determine the cohesion and angle of friction of the soil with respect to total
stresses.
(b) If a 30 mm diameter, 72 mm long sample of the identical soil was tested in
a triaxial machine, with a cell pressure 270 KN/m2. What would be the
additional axial load at failure, if the sample shortened by 6.3 mm?
(c) If the soil was tested in an unconfined compression apparatus, at what value
of compressive stress, would failure be expected? [16]
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Earning:   Approval pending.