CMP 305 Final exam with 100% correct
answers 2024
Site Investigation: Necessities for planning construction techniques - ANSWER-
Site Access, Type of construction equipment, ground water, surface water
development
Documents for Evaluating the site - ANSWER- Soil Maps, topographic maps,
aerial photographs, USGS topographic quadrangle maps
Info obtained from soil profile - ANSWER- uniform soil conditions, number of
borings and bore spacing, type - size - weight of structure
Bore spacing for road work, one story building, multi story - ANSWER- Road -
500-1000'
one story - 100-200'
multi story - 50-100'
How far down does boring depth have to be? - ANSWER- until suitable soil
bearing capacity is found and depth of ground water(if needed)
Direct Exploration - ANSWER- Uses Test pit method, pit or trench, visual
inspection, limited depth 15-20', equipment: backhoe or excavator.
Advantages of Direct exploration - ANSWER- view soil profile(type and color)
obtain undisturbed sample
Disadvantages of Direct exploration - ANSWER- limited depth, ground water may
limit depth, safety(soil caving in)
Devices for in-place soil testing - ANSWER- Pocket penetrometer(TSF), torvane,
thumb penetration
, Semi-direct exploration - ANSWER- Auger Drilling
Auger Types - ANSWER- Solid Auger: dry regions, auger removed for
sampling(hole will collapse), Hollow Auger: sampling thru the auger, faster taking
samples, (split barrel, shelby tube).
Rotary Drill - ANSWER- auger with clay slurry, slurry moves soil up, slurry
stabilizes the sides of the drill hole
Cone Penetrometer - ANSWER- Holland, US & Canada, pushed into the ground,
records readings in different sections. Adv: provides a continuous record of test
results used for engineering properties for the entire profile
Geophysical Testing - ANSWER- Road work, fast, quick results, less expensive.
Seismic refraction and electrical resistance.
Seismic refraction - ANSWER- velocity of seismic wave transmitted through soil.
greater density - faster waves.
Drilled Samples - ANSWER- Disturbed samples
why do we sample - ANSWER- use for grain size analysis, liquid limits, plastic
limits and plastic index
Testing with Undisturbed samples - ANSWER- Split barrel, shelby tube or test pit
Split barrel or standard penetration test(SPT) - ANSWER- tube used to collect soil
sample at the bottom of the test hole. pass through the hollow tube auger,
measurement - resistance to penetration
Split barrel Specs.
OD, Length, Sample OD, Hammer wt., Drop height - ANSWER- OD=2",
Length=30", Sample OD 1 5/8", hammer wt.= 140#, Drop height=30"
how does Standard Penetration Test work - ANSWER- sampler is driven for 3
consecutive 6" increments. Count number of blows per 6" increments, Blow
count summation(take last two sets of numbers)
Shelby Tube dimensions - ANSWER- Dia. 2-5", Length 4"