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General Design and Construction of Earth and Rock-Fill Dams


Quiz Questions

1.Dams are a critical and essential part of the Nation’s infrastructure for the storage and management of water in watersheds.
True
False
2. An earth dam is composed of suitable soils obtained from borrow areas or required excavation and compacted in layers by mechanical means.
True
False
3.What does FEMA stand for?
Federal Emergency Management Agency
Functional Emergency Management Agency
Federal Emergency Management Association
None of the above
4.The term freeboard is applied to the vertical distance of a dam crest above the maximum reservoir water elevation adopted for the spillway design flood.
True
False
5.The treatment of an earth foundation under a rock-fill dam should be substantially the different as that for an earth dam.
True
False
6.The design of dams on earth foundations is based on the in situ shear strength of the foundation soils.
True
False
7.Where cutoff or drainage trenches extend below the water table, a complete dewatering is necessary to prepare properly the foundation and to compact the first lifts of embankment fill.
True
False
8.Seepage control is necessary to prevent excessive uplift pressures, instability of the downstream slope, piping through the embankment and/or foundation, and erosion of material by migration into open joints in the foundation and abutments.
True
False
9.Some of the methods for seepage control in embankments are
Flat slopes without drains
Embankment zonation
Vertical (or inclined) and horizontal drains
All of the above
10.The most positive method for control of under-seepage consists of excavating a trench beneath the impervious zone of the embankment through pervious foundation strata and backfilling it with compacted impervious material.
True
False
11.When a complete cutoff is not required or is too costly, an upstream impervious blanket tied into the impervious core of the dam may be used to minimize under seepage.
True
False
12.When a complete cutoff is not required or is too costly, relief wells installed along the downstream toe of the dam may be used to prevent excessive uplift pressures and piping through the foundation.
True
False
13.What does figure 7-1illustrate about?
(Refer Pg 7-4)
Typical embankment sections, earth dams (Prompton and Alamo Dams)
Rock Dams
Earth Dams
None of the above
14.Horizontal cracking may be caused by tensile stresses related to differential embankment and/or foundation settlement.
True
False
15.Cracking develops within zones of tensile stresses within earth dams due to differential settlement filling of the reservoir, and seismic action.
True
False
16.Longitudinal cracks do not provide continuous open seepage paths across the core of the dam, as do transverse and horizontal cracks, and therefore pose no threat with regard to piping through the embankment.
True
False
17.Densities obtained from field compaction using conventional tamping or pneumatic rollers and the standard number of passes of lift thickness are about different to or slightly greater than maximum densities for the standard compaction test.
True
False
18.Adequate slope protection must be provided for all earth and rock-fill dams to protect against wind and wave erosion, weathering, ice damage, and potential damage from floating debris.
True
False
19.If the dam’s foundation consists of compressible soils, the outlet works tower and conduit should be founded upon or in stronger abutment soils or rock where less settlement and horizontal spreading will occur and where the embankment is lower.
True
False
20.Contractor quality control (CQC) is the construction contractor’s system to manage, control, and document his own, his supplier’s, and his subcontractor’s activities to comply with contract requirements.
True
False