Excavation , Compaction & Grading Flashcards
If ground water is encountered during pipe trench excavation, the trench bottom must be stabilized by:
Over Excavating approximately 12” and filling to grade with gravel
____ is the largest size aggregate used for structural fill
12”
A typical drainage trench should be at least ____ wide and at least ___ below the pipe
18” wide, 12” below
A 6:3 slope means
3- foot rise or drop for every 6 feet of horizantal distance or a 6 foot rise orr drop for evey 3 feet of horizantal distance
Material excavated from the trench and piled adjacent to it, mut be maintained so that the toe of the slope is a minimum ___ from the edge of trench
2 feet
Damp proofing prevents?
penetration of moisture through the foundation wall in below-grade applications
What is the minimum clearance required under all portions of pipe?
6 inches
Underpinning is used when?
An excavation goes below foundations of the existing structure
When filling unsuitable areas a general rule of thumb for dirt to aggregate is?
Figure one cubic yard of dirt for every 2 tons of aggregate used.
Coarse grain soils have ___ % dry weight of the consituent material retained on the no. 200 sieve.
50%
Trench excavation in advance of pipe laying must not exceed ____ feet in length
150 feet
For maximum compaction, material backfilled into a trench should be placed with ___ lifts
6 inch lifts
Asphalt is sprayed at a rate of?
0.10 to 0.15 gallons per yard
Minimum allowance in compaction?
90%
Cut and fill
Cut (c) = lower than the ref. point
Fill (f) = higher than the ref. point
