Chapter 2 - Earthmoving materials & operations

Question 1

Describe the process of earthmoving

Answer 1

Excavation -> Loading -> Hauling(moving) -> Placing(Dumping) -> compaction -> Grading & Finishing

Question 2

Describe how efficiently manage earthmoving

Answer 2

1) Accurate estimation of job quantity & conditions
2) Proper selection of equipment
3) Competent job management

Question 3

What are the criteria to select equipment?

Answer 3

1) The ability of it to perform the work
2) Out of the options available, the one maximizing profit
3) Possible future use
4) Availability of the equipment, parts and service
5) The effect of equipment downtime on other construction operations
* Equipment downtime - The amount of time that equipment isn’t operating

Question 4

What is the basic relationship of production?

Answer 4

Volume per cycle x cycles per hour = production

Volume per cycle - Nominal capacity of the equipment
Cyles per hour - including efficiency. 60(min/hr)/ cycle time (min)

Question 5

What is the cost per unit production formula

Answer 5

Equipment cost ($/hr) / Equipment (production/hr)

Question 6

What characteristics of soil and rock the constructor should know about?

Answer 6

1) Volume-change characteristics
2) Methods of classification
3) Field identification

Question 7

Describe the different volume-change characteristics (Bank, loose compacted and their units)

Answer 7

Bank: Material in its natural state before disturbance(“in-place”). BCY/BCM
Loose: Excavated or loaded material. LCY/LCM
Compacted: Material after compaction. CCY/CCM

Question 8

What are the formulas for swell and shrinkage

Answer 8

Swell (%) = ((Soil density in bank/Soil density in loose) -1) x 100
Shrinkage (%) - (1- (Soil density in bank/Soil density in compaction)) x 100

Question 9

What is the volume of:
1) Spoil bank
2) Spoil pile

Answer 9

1) Bank - Section area X length
2) Pile - 1/3 x base area x height

Question 10

What is the height of:
1) Spoil bank - also what is the base formula
2) Spoil pile - also what is the diameter formula

Answer 10

1) Bank - H=(B x tanR)/2 while B = square root (4V/(L x tanR))
2) Spoil - H=(DxTanR)/2 while D = cube root ((7.64V)/tanR)

Question 11

What Mass diagram provides CMs with?

Answer 11

• The length and direction of the haul
• Location and amount of borrow and waste
  -The average length of the haul

Question 12

What is stripping?

Answer 12

The upper layer of organic material

Question 13

What is the meaning of negative mass ordinate? (The last column in the mass diagram table)

Answer 13

Negative means- More fill than cut up to this point in the project

Question 14

What is the most economical haul distance for each machine type (Dozer, Scraper, Trucks)

Answer 14

Dozers - 0<x<300
Scarper 300<x<5000
Trucks x>5000

Question 15

Mass diagram: If the curve is above the balance line, in which direction is the haul?

Answer 15

The direction of haul is from left to right—lower station value to a higher station value.

• When the curve is below the balance line the haul is from right to left—down stationing.