# GATE Questions & Answers of Compaction in laboratory and field conditions

## What is the Weightage of Compaction in laboratory and field conditions in GATE Exam?

Total 8 Questions have been asked from Compaction in laboratory and field conditions topic of Soil Mechanics subject in previous GATE papers. Average marks 1.38.

The compression curve (void ratio, e vs. effective stress, ${\sigma }_{v}^{\text{'}}$) for a certain clayey soil is a straight line in a semi-logarithmic plot and it passes through the points (e = 1.2; ${\sigma }_{v}^{\text{'}}$ = 50 kPa) and (e = 0.6; ${\sigma }_{v}^{\text{'}}$ = 800 kPa). The compression index (up to two decimal places) of the soil is ______

An undisturbed soil sample was taken from the middle of a clay layer (i.e., 1.5 m below GL), as shown in figure. The water table was at the top of clay layer. Laboratory test results are as follows:

 Natural water content of clay : 25% Preconsolidation pressure of clay : 60 kPa Compression index of clay : 0.50 Recompression index of clay : 0.05 Specific gravity of clay : 2.70 Bulk unit weight of sand : 17 kN/m3

A compacted fill of 2.5 m height with unit weight of 20 kN/m3 is placed at the ground level.

Assuming unit weight of water as10 kN/m3, the ultimate consolidation settlement (expressed in mm) of the clay layer is ____________

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?

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

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

In a compaction test, G, w, S and e represent the specific gravity, water content, degree of saturation and void ratio of the soil sample, respectively. If ${\gamma }_{w}$ represents the unit weight of water and ${\gamma }_{d}$ represents the dry unit weight of the soil, the equation for zero air voids line is

Deposit with flocculated structure is formed when

Compaction by vibratory roller is the best method of compaction in case of