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5.0
GEOTECHNICAL DESIGN EXAM REVIEW QUESTIONS
WITH DETAILED VERIFIED ANSWERS (100% CORRECT
ANSWERS) /ALREADY GRADED A+
Quiz: What are indicator piles. and how do they benefit the foundation
design process?
Ans: Indicator piles are prototype piles that are constructed before the
production piles. These prototype piles
are typically evaluated using pile driving analyzers, load tests, or other
means to evaluate their load
capacity. The results of these evaluations are then used to guide the design
and construction of the
production piles. In many cases, the indicator piles also are used to support
the structure.
Quiz: Many engineers believe the only disadvantage to over designing
pile foundations is the additional cost of
the pile materials. However, there is another important consequence of
over design which can significantly
affect construction cost and may even make the foundation
impossible to build. What is this consequence and how can it be
avoided?
Ans: In addition to increasing materials costs, over designed piles are
more difficult to install, thus increasing
labor and equipment costs. In some cases, the additional labor and
equipment costs, as well as the
,associated delays in the construction schedule, can be dis proportionally
large compared to the additional
capacity gained. These unnecessary costs and delays can be avoided by
more precise designs and by the used of the various techniques of
verification and redesign during construction. These measures help
assure the as built foundation has sufficient capacity and
performance, without being excessively over designed.
Quiz: Under what circumstances would you most likely require integrity
testing of newly-constructed drilled
shaft foundations?
Ans: Integrity testing is especially important when using the slurry method
of construction.
Quiz: Explain the difference between the active, at-rest, and the
passive earth pressure conditions.
Ans: The at-rest pressure is that which acts on a wall that has not
experienced any lateral displacement or
rotation. In other words, it reflects the horizontal stresses that were present in
the undisturbed ground. The active pressure is that which acts on a
wall that has moved a sufficient distance away from the back fill to
fully mobilize the shear strength of the soil. The passive pressure is that which
acts on a wall that has
moved a sufficient distance into the back fill to fully mobilize the shear
strength of the soil.
Examstudy - Stuvia US
, Quiz: Which of the three earth pressure conditions should be used to
design a rigid basement wall? Why?
Ans: A rigid basement wall should be designed using at-rest pressure
because it has not moved enough to
develop the active condition.
Quiz: A pre-stressed concrete pile is being driven into a saturated
cohesive soil with a hammer blow count of 17 blows per foot of pile
penetration. Unfortunately, the pile driving rig breaks down before the
pile reaches
the required depth of penetration, resulting in a 15-hour delay. Once
the rig is repaired, pile driving
resumes but the blow count is now 25 blows per foot. Explain the
primary reason for this change in blow
count.
Ans: Driving of the pile caused large shear stresses in the soil. Since the soil
was a saturated cohesive soil,
positive pore pressures were generated during driving and therefore
decreased the effective stress and
both the end bearing and side friction compared to static loading. During the
delay, the soil had time to
dissipate some of the excess pore pressure generated during driving and the
affected soil was able to
consolidate. The decrease in pore pressure and the consolidation increased
the soil strength and thereby
Examstudy - Stuvia US
In today's fast-paced educational landscape, students need reliable resources to excel in their studies.
5.0
GEOTECHNICAL DESIGN EXAM REVIEW QUESTIONS
WITH DETAILED VERIFIED ANSWERS (100% CORRECT
ANSWERS) /ALREADY GRADED A+
Quiz: What are indicator piles. and how do they benefit the foundation
design process?
Ans: Indicator piles are prototype piles that are constructed before the
production piles. These prototype piles
are typically evaluated using pile driving analyzers, load tests, or other
means to evaluate their load
capacity. The results of these evaluations are then used to guide the design
and construction of the
production piles. In many cases, the indicator piles also are used to support
the structure.
Quiz: Many engineers believe the only disadvantage to over designing
pile foundations is the additional cost of
the pile materials. However, there is another important consequence of
over design which can significantly
affect construction cost and may even make the foundation
impossible to build. What is this consequence and how can it be
avoided?
Ans: In addition to increasing materials costs, over designed piles are
more difficult to install, thus increasing
labor and equipment costs. In some cases, the additional labor and
equipment costs, as well as the
,associated delays in the construction schedule, can be dis proportionally
large compared to the additional
capacity gained. These unnecessary costs and delays can be avoided by
more precise designs and by the used of the various techniques of
verification and redesign during construction. These measures help
assure the as built foundation has sufficient capacity and
performance, without being excessively over designed.
Quiz: Under what circumstances would you most likely require integrity
testing of newly-constructed drilled
shaft foundations?
Ans: Integrity testing is especially important when using the slurry method
of construction.
Quiz: Explain the difference between the active, at-rest, and the
passive earth pressure conditions.
Ans: The at-rest pressure is that which acts on a wall that has not
experienced any lateral displacement or
rotation. In other words, it reflects the horizontal stresses that were present in
the undisturbed ground. The active pressure is that which acts on a
wall that has moved a sufficient distance away from the back fill to
fully mobilize the shear strength of the soil. The passive pressure is that which
acts on a wall that has
moved a sufficient distance into the back fill to fully mobilize the shear
strength of the soil.
Examstudy - Stuvia US
, Quiz: Which of the three earth pressure conditions should be used to
design a rigid basement wall? Why?
Ans: A rigid basement wall should be designed using at-rest pressure
because it has not moved enough to
develop the active condition.
Quiz: A pre-stressed concrete pile is being driven into a saturated
cohesive soil with a hammer blow count of 17 blows per foot of pile
penetration. Unfortunately, the pile driving rig breaks down before the
pile reaches
the required depth of penetration, resulting in a 15-hour delay. Once
the rig is repaired, pile driving
resumes but the blow count is now 25 blows per foot. Explain the
primary reason for this change in blow
count.
Ans: Driving of the pile caused large shear stresses in the soil. Since the soil
was a saturated cohesive soil,
positive pore pressures were generated during driving and therefore
decreased the effective stress and
both the end bearing and side friction compared to static loading. During the
delay, the soil had time to
dissipate some of the excess pore pressure generated during driving and the
affected soil was able to
consolidate. The decrease in pore pressure and the consolidation increased
the soil strength and thereby
Examstudy - Stuvia US
