Question 1 |

With reference to the compaction test conducted on soils, which of the following is INCORRECT ?

Peak point of the compaction curve gives
the maximum dry unit weight and optimum
moisture content. | |

With increase in the compaction effort, the
maximum dry unit weight increases. | |

With increase in the compaction effort, the
optimum moisture content decreases. | |

Compaction curve cross the zero-air-voids
curve. |

Question 1 Explanation:

Line of optimum

100% saturation line or zero void line.

Compaction curve never crosses the zero-air-voids curve.

100% saturation line or zero void line.

Compaction curve never crosses the zero-air-voids curve.

Question 2 |

An uncompacted heap of soil has a volume of 10000 m^3 and void ratio of 1. If the soil is compacted to a volume of 7500 m^3, then the corresponding void ratio of the compacted soil is __________. (round off to one decimal place)

0.2 | |

0.8 | |

0.5 | |

0.1 |

Question 2 Explanation:

\begin{aligned}
(V_S)_{\text{heap}}&=(V_S)_{\text{compacted soil}}\\
\left ( \frac{V_T}{1+e} \right )_{\text{heap}}&=\left ( \frac{V_T}{1+e} \right )_{\text{compacted soil}}\\
\frac{10000}{1+1}&=\frac{7500}{1+e}\\
e&=0.5
\end{aligned}

Question 3 |

OMC-SP and MDD-SP denote the optimum moisture content and maximum dry density obtained from standard Proctor compaction test, respectively. OMC-MP and MDD-MP denote the optimum moisture content and maximum dry density obtained from the modified Proctor compaction test, respectively. Which one of the following is correct?

OMC-SP \lt OMC-MP and MDD-SP \lt MDD-MP | |

OMC-SP \gt OMC-MP and MDD-SP \lt MDD-MP | |

OMC-SP \lt OMC-MP and MDD-SP \gt MDD-MP | |

OMC-SP \gt OMC-MP and MDD-SP \gt MDD-MP |

Question 3 Explanation:

\begin{array}{r} \mathrm{OMC}-\mathrm{SP} \gt \mathrm{OMC}-\mathrm{MP} \\ \mathrm{MDD}-\mathrm{SP} \lt \mathrm{MDD}-\mathrm{MP} \end{array}

Question 4 |

Following statements are made on compacted soils, wherein DS stands for the soils compacted on
dry side of optimum moisture content and WS stands for the soils compacted on wet side of
optimum moisture content. Identify the incorrect statement.

Soil structure is flocculated on DS and dispersed on WS. | |

Construction pore water pressure is low on DS and high on WS. | |

On drying, shrinkage is high on DS and low on WS. | |

On access to water, swelling is high on DS and low on WS. |

Question 5 |

Two series of compaction tests were performed in the laboratory on an inorganic clayey soil
employing two different levels of compaction energy per unit volume of soil. With regard to the
above tests, the following two statements are made.

I The optimum moisture content is expected to be more for the tests with higher energy.

II The maximum dry density is expected to be more for the tests with higher energy.

The CORRECT option evaluating the above statements is

I The optimum moisture content is expected to be more for the tests with higher energy.

II The maximum dry density is expected to be more for the tests with higher energy.

The CORRECT option evaluating the above statements is

Only I is TRUE | |

Only II is TRUE | |

Both I and II are TRUE | |

Neither I nor II is TRUE |

Question 5 Explanation:

Optimum moisture content of the soil decreases with increase compactive efforts.

There are 5 questions to complete.