Learning Objectives:

• Gain an understanding of the various laboratory and field tests used in civil engineering, including their purposes and applications.
• Differentiate between laboratory tests conducted in controlled environments and field tests conducted on construction sites.

Some sample lab and field tests include:

• The California Bearing Ratio (CBR) test is a standardized test used to evaluate the mechanical strength of subgrade soils and their suitability for road construction and pavement design.
• Sp. gravity of solids : Pycnometer Method: The Pycnometer Method is a laboratory technique used to determine the density and specific gravity of soil and aggregate materials. It is an essential test in geotechnical and materials engineering.
• Sp. gravity of solids : Density Bottle Method The specific gravity of solids is a measure of the relative density of a solid material compared to water. The Density Bottle Method is a laboratory technique used to determine the specific gravity of soil and other solid materials.
• Dry-Density of Soil: Water replacement method: Dry Density ($\rho_d$) represents the mass of dry soil per unit volume. It is typically expressed in grams per cubic centimeter (g/cm$^3$) or pounds per cubic foot (lb/ft$^3$). Dry density of soil samples is essential for geotechnical engineering, construction materials testing, and compaction quality control.
• In-Situ Dry Density: Sand replacement method

Solved Example: 9072-01

In order to obtain a good quality of undisturbed soil the area ratio of the sampling tube should be:

A. 8%

B. 16%

C. 24%

D. 32%

Correct Answer: A

Solved Example: 9072-02

Shelby tube is one of the most widely used devices for:

A. Drilling rocks and cobbles

B. Measuring effective stress

C. Wash borings

D. Collecting undisturbed soil samples

Correct Answer: D

Solved Example: 9072-03

The type of soil sample collected using wash boring technique is:

A. Representative

B. Zero-representative

C. Undisturbed

D. Zero disturbed

Correct Answer: B

Solved Example: 9072-04

Auger boring is suited for which of the following exploratory strata?

A. Partly saturated sands, silts and medium to stiff cohesive soils

B. All types of soils and rocks except fissured rocks

C. Practically all types of soils except hard and cemented soil or rock

D. All types of soils and rocks except loose sands and soft sticky clays

Correct Answer: A

Solved Example: 9072-05

Undisturbed soil samples are obtained by:

A. Thick-walled samplers

B. Direct excavations

C. Thin-walled samplers

D. Augers

Correct Answer: C

Solved Example: 9072-06

What should be the minimum depth of exploration below an isolated footing?

A. Equal to width of footing

B. One and half times the width of footing

C. Three times the width of footing

D. Three times the depth of footing

Correct Answer: B

Solved Example: 9072-07

The degree of disturbance of the sample collected by the sampler is expressed by a term called the 'area ratio'. If the outer diameter and inner diameter of the sampler are D$_o$ and D$_i$ respectively, the area ratio is given by:

A. $\dfrac{{D_o^2 - D_i^2}}{{D_i^2}}$

B. $\dfrac{{D_o^2 - D_i^2}}{{D_i^2}}$

C. $\dfrac{{D_o^2 - D_i^2}}{{D_o^2}}$

D. $\dfrac{{D_i^2 - D_o^2}}{{D_o^2}}$

Correct Answer: A

Solved Example: 9072-08

For sampling saturated sands and other soft and wet soils satisfactorily, the most suitable soil sampler is:

A. Open drive thin-walled sampler

B. Standard split-spoon sampler

C. Stationary piston sampler

D. Rotary sampler

Correct Answer: A

Solved Example: 9072-09

Los Angeles testing machine is used to conduct:

A. Attrition test

B. Impact test

C. Abrasion test

D. Crushing strength test

Correct Answer: C