1(a)
Critically define the terms void ratio, porosity and water content with phase diagram.

4 M

1(b)
Derive the relation \( \gamma _{d}=\dfrac{G.\gamma w}{1+e} \) with usual notations.

6 M

1(c)
In an earthen embankment under construction, the bulk unit weight is 16.5kN/m

^{3}at water content 11%. If the water content has to be increased to 50%, compute the quantity of water to be added per cubic meter of soil. Assume no change in void ratio. Also determine 'e' at this water content taking G = 2.65.
10 M

2(a)
Define relative density of sand and list its importance in geotechnical engineering.

4 M

2(b)
Describe consistency of soil. List and define consistency limits.

6 M

2(c)
The following results are obtained by conducting liquid limit test on clayey soil in the laboratory:

Plot flow curve. Determine Liquid limit, Toughness index. Assume plastic limit = 20%.

No. of blows (N) : | 34 | 23 | 18 | 12 |

Water content (W%): | 44.6 | 49.4 | 51.4 | 55.6 |

Plot flow curve. Determine Liquid limit, Toughness index. Assume plastic limit = 20%.

10 M

3(a)
Explain with the help of typical particle size distribution curve, well graded, poorly graded and gap gtaded soil.

4 M

3(b)
With the neat sketch, explain structure of clay minerals.

6 M

3(c)
Following results are obtained from the laboratory tests conducted on two soil samples :

Show the positions of these soils on plasticity chart and classify as per I.S. system.

Soil sample | A | B |

Liquid limit | 85% | 45% |

Plastic limit | 50% | 12% |

Show the positions of these soils on plasticity chart and classify as per I.S. system.

10 M

4(a)
Derive the relation between co-efficient of permeability and percolation with usual notations.

7 M

4(b)
Explain Quick - sand phenomena and list its importance during construction.

5 M

4(c)
A falling head permeater accommodates a soil sample of 6cm length and 500cm

^{2}in area. The permeability of sample is expected to be 1 × 10^{-4}cm/sec. Head of water in the standpipe falls from 30cm to 10cm in 40 minutes. Determine the size of the stand pipe which should be used.
8 M

5(a)
Explain sensitivity and thixotropy of clayey soil.

4 M

5(b)
List the factors affecting shear strength of soil.

4 M

5(c)
A direct shear test results are obtained as follows :

Determine shear parameters graphically. Also draw Mohr's circle corresponding to second test result and report major and minor principal stresses.

Normal stress (kN/m^{2}) : |
100 | 200 | 300 |

Shear stress (kN/m^{2}) : |
130 | 185 | 240 |

Determine shear parameters graphically. Also draw Mohr's circle corresponding to second test result and report major and minor principal stresses.

12 M

6(a)
List the factors affecting compaction of soil and explain any 2 in detail.

5 M

6(b)
List and explain various types of field compaction equipments.

5 M

6(c)
The results of standard compaction test conducted in the laboratory are tabulated as follows:

Find MDD and OMC with usual notaions by plotting comoaction curve. Also draw ZAVD -line assuming G = 2.65.

Water content% : | 5.00 | 10.00 | 14.00 | 20.00 | 25.00 |

Bulk density kN/m^{3} |
17.70 | 19.80 | 21.00 | 21.80 | 21.60 |

Find MDD and OMC with usual notaions by plotting comoaction curve. Also draw ZAVD -line assuming G = 2.65.

10 M

7(a)
State the assumptions of one - dimensional Terzaghi's theory of consolidation. Also write standard / general differential one - dimensional consolidation equation with usual notation.

8 M

7(b)
Explain with neat sketch, determination of co-efficient of consolidation by square - root of time fitting method.

6 M

7(c)
A layer of soft clay is 6m thick and lies under newly constructed building. The weight of sand overlying the clayey layer produces a pressure of 260 kN/m

^{2}and this new construction increases the pressure by 100kN/m^{2}. If the compression index is 0.5, compute settlement of soil layer given water content 40% and G = 2.65.
6 M

8(a)
Critically discuss limitations of direct shear test.

4 M

8(b)
Explain Vane shear test with neat sketch along with relations.

6 M

8(c)
A vane apparatus test. A torque of 45N-m was applied at which failure took place. Subsequently, vane instrument rotated rapidly, so as to get reolded soil sample. This remolded soil was sheared at a torque of 18 N-m. Then calculate sensitivity of clayey soil.

10 M

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