ASBOG - Engineering Geology Exam Questions with Correct Answers
6 views 0 purchase
Course
PG - Professional Geologist
Institution
PG - Professional Geologist
Strain - Answer-An alteration in the shape or volume of a soil related to stress. It is calculated as the ratio of the new shape compared to the original shape
Effective Stress - Answer-The total amount of stress placed on a soil minus the pore-water pressure
Normal Stress - Answer-The compon...
ASBOG - Engineering Geology Exam
Questions with Correct Answers
Strain - Answer-An alteration in the shape or volume of a soil related to stress. It is
calculated as the ratio of the new shape compared to the original shape
Effective Stress - Answer-The total amount of stress placed on a soil minus the pore-
water pressure
Normal Stress - Answer-The component of total stress that acts perpendicular to the
plane.
Shear stress - Answer-The component of total stress that acts parallel to any point in
question.
Dilatancy - Answer-Tendency of a material to increase in volume when subjected to a
shape change. Assume a closed-packed structure from an open-packed structure
Quick Condition - Answer-Tendency of some soils that lack cohesion to allow water to
flow rapidly between grains and to liquefy the material. Soil does NOT possess
significant bearing capacity
Elastic Modulus - Answer-Measure stiffness in a material (bulk, shear, Young's(Elastic))
Triaxial Test - Answer-Test for mechanical properties of deformable solids.
Direct Shear test - Answer-Measure shear strength when sample is surrounded
withstand subjected to mechanical stresses.
Unconfined compressive strength test - Answer-Similar to triaxial but without external
confining pressure.
Consistency - Answer-General amount of cohesion in soil particles
Critical void ratio - Answer-Void ratio of soil that stays the same even during shearing
events.
Mohr circle - Answer-Graph showing stresses that act on a single point on a plane. The
x-axis - normal stress. Y-axis - shear stress
Seepage - Answer-The flow of a fluid through soil pores.
4-inch diameter; three lifts; 25 blows by 5.5 lb hammer; falling 12-inches - Answer-
Proctor Test
,five lifts; 10lb hammer; 18-inches - Answer-Modified Proctor Test
Differentiate between the three different types of modulus: bulk
(incompressibility) modulus, shear (rigidity) modulus, Young's
(elasticity) modulus. - Answer-There are three different kinds of modulus, or ways to
measure the
stiffness of the material:
• bulk modulus (K; otherwise known as incompressibility
modulus): a measure of a substance's resistance to uniform
compression. It is defined as the pressure increase needed
to affect a given relative decrease in volume
• shear modulus (G; also known as rigidity modulus): refers
to the deformation of a solid when exposed to a force
parallel to one of its surfaces as its opposite face is exposed
to an opposing force. This will cause an object that is
shaped like a rectangular prism to be deform into a
parallelpiped
• Young's modulus (E; also known as the modulus of
elasticity): a measure of the stiffness of a given material.
Defined as the ratio, for small strains, of the rate of change
of stress with strain
Define the terms used to describe volume changes in soils:
dilatancy, dry strength, quick condition. - Answer-The following terms are used to
describe volume changes in soils:
dilatancy: the tendency of a material to increase in volume
when subjected to a shape change. Also refers to material
which can assume a close-packed structure from a openpacked
structure
• dry strength: the resistance that a dry soil possesses to
being crushed. A soil that is composed of clays and gravels
will have relatively high dry strength
quick condition: the tendency of some soils that lack
cohesion to allow water to flow rapidly between grains and
to liquefy the material. Such a soil does not possess
significant bearing capacity. Bearing capacity is the ability
of soils to support the loads imposed by buildings or
structures
Distinguish between the following types of tests: direct shear test,
triaxial test, unconfined compressive strength test. - Answer-The following tests are
designed to quantify engineering parameters
of soils:
• triaxial test: a common method to measure the mechanical
properties of many deformable solids. The test is used for
, soil, sand, clay, and other granular material. Test involves a
cylinder of soil which is subjected to uniform fluid pressure
from all sides. After being checked for deformation, the
sample is then subjected to a vertical load. Drainage
conditions are controlled
• direct shear test: laboratory tests to measure the shear
strength of soil in which the soil or rock sample is
surrounded with sand and subjected to a series of
mechanical stresses which are analyzed by computer. The
sample is normally saturated before the test is run, but can
be run at the in-situ moisture content
• unconfined compressive strength test: similar to a triaxial
test but without external confining pressure applied
Discuss the terms used to describe soil grain size: well-graded, gap
graded, effective size, coefficient of curvature, coefficient of
uniformity. - Answer-The following terms are used to describe the grain size of soil:
• well-graded soil: soil or unconsolidated sediment consisting
of particles of several different sizes and having a uniform
or equal distribution of particles from coarse to fine. A
graded sand or sandstone containing coarse, medium, and
fine particle sizes is an example
• effective size: corresponds with the weight percentage of
material equal to a certain size amount. Measures the
distribution of grain sizes; for example, a grain with an
effective size of D3o would be finer than 70% of the other
grains in the sample
• gap-graded soil: any soil that is missing distinct particle
size ranges.
• coefficient of curvature (Cc): a measure of the curve on a
grain size distribution plot
• coefficient of uniformity (Cu): a measure of the degree to
which grain sizes are uniform. Found by determining the
ratio of particle sizes
Define the following terms related to soil strength investigations:
bearing capacity, consistency, critical void ratio, Mohr circle, Mohr Coulomb
equation. - Answer-The following terms are related to soil strength investigations:
• bearing capacity: the maximum load per unit area that a
particular soil can be subjected to before it collapses.
Bearing capacity is the ability of soils to support the loads
imposed by buildings or structures
• consistency: the general amount of cohesion in soil
particles
• critical void ratio: the void ratio of soil that stays the same
even during shearing events
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through EFT, credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying this summary from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller lectknancy. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy this summary for R344,62. You're not tied to anything after your purchase.
