LECTURE 8-COFFERDAMS CAISSONS EXAM QUESTIONS

PDF Download LECTURE 8-COFFERDAMS & CAISSONS EXAM QUESTIONS Actual Qs and Ans - Expert-Verified Explanation -Guaranteed passing score -49 Questions and Answers

-Format: Multiple-choice / Flashcard

Question 1: suitable for steeper slope, either dumped or hand packed

Answer:

rock fill embankments facts (2)

Question 2: height and weight increased causing sinking

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open caisson construction step 3 Question 3: costly, sunk with aid of compressed air, provides dry working chamber, slow rate of sinking, regulations are applied

Answer:

Pneumatic caisson facts (5)

Question 4: narrow, sluggish, low, moderate

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Earth fill embankments are suitable for _______ and _______ rivers. Suitable for ____ and ______ head of water.

Question 5: Used in conditions that are more than 20 m deep.

Answer:

Caisson fact 3:

Question 6: clay, dry

Answer:

Earth fill embankment fact: ______ is suitable for ____ construction

Question 7: caisson is firmly bedded on rock

Answer:

open caisson construction step 4

Question 8: box, open, pneumatic

Answer:

Caisson types (3)

Question 9: seepage

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hand packed rock-fill problem

Question 10: steel, dikes, timber, puddle walls/clay, timber cribs, concrete

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cofferdam materials/types (6)

Question 11: fly ash can be dumped on outer surface

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Avoiding seepage Question 12: Permanent structure used when loading conditions require access to deep founding levels and/or resistance to large cross forces.

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Caisson fact 1:

Question 13: driven, riverbed, U, braced, strength, stability

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Steel sheets are _____ into ______ to form cut off usually a ____ or flat section. _____ for increased _____ and ______.

Question 14: provide a drainage ditch

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solution to erosion in sand embankments Question 15: excavation commenced using a grab bucket mucking out inside the caisson

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open caisson construction step 2 Question 16: Massive hollow structures which sink into soil under own weight. Uses in bridge support, wharves and pumping stations.

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Caisson fact 2:

Question 17: 20 m depth, most common, great strength, high salvage value.

Answer:

steel sheet piling facts (4)

Question 18: open, excavation, proceeds, constant, height, water, pumped

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_____ caissons permit _____ or other work to be carried out inside. It will sink down any depth into the soil as excavation ______ once the ground condition is ______. Sections can be added on top to increase ______ and _____ can be ______ out.Question 19: 7-8 m depth, 2 rows of timber sheeting 5-6 m apart, filled with impervious materials, clay acts as water barrier, economical at 6 m depths due to simplicity

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puddle wall facts (5) Question 20: caissons, foundations, directly, inside, marine, excavating, difficult

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_____ are often used as ______ either being _____ used of after work is undertaken ______. Can be used in _____ environments or on land for foundations if _____ conditions are ______.

Question 21: volume of air supply, caisson sickness, the bends, structural integrity, man management

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Pneumatic caisson regulations (5)

Question 22: shoe, cutting, edge, face, larger, skin

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Bottom of caisson is fitted with a _____ or ______ ______ which projects beyond the ____ of the caisson allowing the shoe to cleave a hole ______ than the caisson and reduces ____ friction.

Question 23: seepage, rock, water, tightness

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_____ will carry fly ash in the interslices of the _____. A fair degree of _____ ______ will be attained.

Question 24: flow strength, wave action, tide or groundwater range

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factor: water conditions (3)

Question 25: pile driving hammer, crane, steel sheets, barges, H-piles and/or wide flange beams for wales and stringers

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Items needed to install cofferdams (5)

Question 26: water jets or bentonite as lubrication

Answer:

two ways of reducing skin friction

Question 27: land or in water

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factor: area to be protected

Question 28: Box caisson

Answer:

Open at top, closed at bottom, floated into place with ballast and its filled with appropriate material, water may be pumped first. Hollow caissons can be used to house equipment. When they are filled they can be used as foundations.