mass haul

Question 1

what is a mass haul diagram

Answer 1

a mass haul diagram is a graphical plot of the accumulated earthworks volume resulting from cut and fill operations versus distance along a highway construction project. The diagram show the amount of surplus or defecit at any given station.

commonly cut vols are adjusted for shrinkage or swell before being entered into mass haul computations.

Question 2

notes

Answer 2

• positive slope is cut
• negative slope is fill
• a peak occurs at a change from cut to fill (grade point)
• a valley occurs at a change from fill to cut (grade point)
• balance point is where the mass haul line crosses the balance line. earthworks are balanced between the two balance point stations.
• TOTAL MASS HAUL = area between the mass haul line and the balance line. units are m^3*m of m^3km, eg “mass haul = 9000m^3km” for a project

Question 3

free haul and overhaul

Answer 3

• if a mass haul diagram is above the balance line then haul moves from left to right and the distance for hauling is determined from a local horizontal balance line
• usually the first 300m of haul is free, included in contract price. EW’s moved in this category are ‘free haul’. remaining distance on the local balance line is then paid for at an additional ‘over haul’ price

mass haul has two components, free haul and overhaul. to construct the free haul and overhaul diagram by balance point,
- shift mass haul line above the balance line to the right
- shift mass haul line below the balance line to the left
both shifts are the free haul distance

Question 4

some definitions

Answer 4

free haul distance: the limit to which the contractor is expected to haul excevated material at no additional cost
free haul amount: the material hauled within the free haul distance
over haul amount: the material hauled beyond the free haul distance
borrow pit: a location at a specific station where additional fill material is added to the project (borrow material)
spoil pit: location where surplus excevated material is removed from the project

Question 5

grade point method

Answer 5

from grade points, the length of the free haul distance parallel to the balance line is dropped so that the ends touch the mass haul line. the area between the ends of the line is free haul, everything else is overhaul.