EXCAVATION Flashcards
Is any man-made cut, cavity or depression in any earth surface that is formed by earth removal.
Excavation
Is a narrow excavation where the depth is greater than its width, and the width measured at the bottom is not greater than 15ft
Trench
Hazards of excavation
Falls
Underground facilities
Vehicular Traffic
Confined Space Condition
Soil Collapse
Working Surface
Principal Causes of Soil Collapse
Steep cutting angle
Superimposed load
Shock and Vibration
Water pressure
Drying
2 types of Soil Collapse
Sliding
Toppling
Most Stable:Clay
Type A
Medium Stability:Silt and unstable rock
Type B
Least stable:Grabel, Loamy Sand, Submerged Soil, soil from which water is freely seeping
Type C
Slope of Type A
3/4:1 or 53
Slope of Type B
1:1 or 45
Slope of Type C
1 1/2:1 or 34
Prevention of Soil Collapse
Shoring and Timbering
sheet Piles
Plate Lining System
Box Type
Shielding
Walls of every excavation over __meter deep shall be supported by adequate shoring
1 meter
In minimum berm, it should be not less than ___ of the depth of the excavation
May be reduced to not less than ___ provided that materials are stable, shoring and barriers are present
1/3
1meter
Sloped Protected with sod, seed, shrubs or ground cover
Berm
For falls, barricades of at least ___ high should be provided.
1 meter
___ should be posted to prevent the public from going near the excavation
Signs
In surface Crossing of trenches, what should be provided?
walkways and bridges
In surface Crossings of Trenches a minimum clear width of ___ and standard___
20 inches, rails
In surface crossing of trenches a minimum of __ past the surface edge
24inches
In vehicular traffic provide workers with ____ or other suitable garments marked with reflectorized materials
warning vest
Excavation shall be kept free of __ at all times
water
Muddy area, workers should be provided with ___ to reduce the hazard of slipping
boots
Hazardous atmosphere in confined space condition shows Oxygen
<19.5% or >23.5%
