Understanding Balancing in a Corridor Mass Haul

Use the Auto-Balance Mass Haul or Balance Mass Haul at Grade Point commands to determine the vehicles required to move material between balance points. In a Mass Haul Diagram, a balance point is the point where the usable ordinate crosses the zero cumulative volume line. At this point the amount of cut equals the amount of fill. Haul ranges are used in the balancing process to determine the amount of material that is moved economically (free haul) and the amount of material that will incur additional costs to move (over haul). The Haul range typedetermines if the vehicle is used to balance material along the alignment, from offsite to the alignment or from the alignment to offsite.

A mass haul can be balanced:

Automatically; Use the Auto-Balance Mass Haul command to apply haul ranges at all grade points.
Manually; Use the Balance Mass Haul at Grade Point command to apply haul ranges at selected grade points along the alignment. Balancing manually gives control over the order in which the material is moved.

Balancing different materials

You can balance the total usable and unusable ordinates that are a combination of all material types OR individual material ordinates. It is recommended that you balance individual materials when there are multiple cut and fill materials in the mass haul. This is particularly important when viewing the volume breakdown of materials imported, borrowed, wasted and exported in a specific balance.

In the Auto-Balance Mass Haul or Balance Mass Haul at Grade Point pane, selecting All Materials in the Material list will balance every individual material type but not the total usable or unusable ordinates. The ordinates available for balancing depend on the generic fill setting in the Mass haul properties. If Generic Fill is set to Yes the total usable and unusable ordinates OR the individual material ordinates can be balanced. If Generic Fill is set to No only the individual materials can be balanced.

Note: If you have balanced an individual material and decide you need to balance the total usable and unusable ordinates, you must clear all balances before the usable and unusable ordinate is available in the Material list.

Balancing a mass haul

A mass haul graph is is balanced by running a horizontal line from grade points until the:

length of the line reaches the haul range limit
line reaches another grade point
line reaches the zero balance line on the graph

The haul range with the smallest limit is used first providing the Haul range type is suitable. For more information on suitable haul range types see Create a Haul Range. When the haul range limit is reached the next smallest suitable haul range is used. The process continues until all material is balanced or the largest haul range limit has been reached. The remaining material is overhaul.

The unbalanced areas of the graph appear in the Warnings Unbalanced Material section of the balance line report. If overhaul exists:

existing earthmoving vehicles can be used to balance the remaining material at a higher cost
different earthmoving vehicles that can economically haul larger distances can be used
additional borrow and waste sites can be added to reduce the distance material needs to be moved along the alignment.

Only haul ranges with types alignment to offsite, offsite to alignment or general can be used to balance against vertical lines caused by import, export, borrow, waste, processing sites or haul.

When a mass haul analysis has been balanced:

Balance lines appear on the Mass Haul Diagram showing the movement of material for each haul range.
A symbol appears on the Mass Haul Diagram indicating the direction material is moved.
Balance numbers appears on the Mass Haul diagram indicating the order material is moved.

A balanced Mass Haul Diagram shows:

The amount of over haul in the mass haul analysis
The volume of material moved by each vehicle
The direction in which the material is moved
The average distance the material is moved

The volume remaining between the balanced ordinate and the zero balance line in the Mass Haul Diagram is the amount of over haul. You can reduce the amount of over haul by adding additional vehicles (haul ranges) to your project.

The volume cut off by the balance line is the material that can be economically moved by a vehicle with the specified haul range. This area contains an equal amount of excess cut and excess fill (the earthworks can be balanced by moving the material within the station range).

To view the properties of the balance line, right-click the balance line in the Mass Haul Diagram, and select Properties. The following balance line properties appear:

Balance Line Property	Description
Name	The name given to the haul range. This is likely to be the machine that will be moving the material.
Type	The circumstances when the haul range is used to balance material.
Cut Range	The station range where there is excess cut material
Fill Range	The station range where there is excess fill/a deficit of material
Haul Range	The distance the vehicle used to transport the cut and import material can travel before additional costs are incurred
Average distance	The average distance cut and import material is being hauled along the alignment; this is the distance between the centroid of the cut section and the centroid of the fill section.
Cut	The total amount of material cut within the cut range and the fill range. The volume is in its compacted state. If the balance is on a usable ordinate then the volume is usable only. If the balance is on an unusable ordinate then the volume is unusable only.
Import	The total amount of usable material (compacted) entering the cut range and the fill range. This includes material imported, borrowed, processed or hauled from other parts of the alignment.
Fill	The total amount of fill material (compacted) required within the cut range and the fill range. The volume is a compacted amount.
Export	The total amount of usable material (compacted) exiting the cut and fill range. This includes material exported, wasted, sent to processing sites or hauled to other parts of the alignment.
Total	The total amount of material being added to or removed from the mass haul analysis within the cut range and the fill range. This is a compacted amount. Total = Cut (compacted) + Import or Total = Fill + Export or Total= Balance + Cross Haul + No Haul
Cross Haul	The amount of usable cut material (compacted) being moved across the alignment and used as fill (between two cross sections). This is material that does not need to be hauled along the alignment.
No Haul	This is material that will not be hauled along the alignment. No haul occurs when usable material is imported or borrowed and then immediately exported or wasted.
Balance	The amount of material being moved along the alignment and used to balance other sections Balance = Total – Cross Haul – No Haul

In the materials group of the balance line properties, view the breakdown of different materials cut from the surface or imported within the station range.

Use the Balance Line Report to view the movement of material in the mass haul analysis. To clear balance lines, run the Clear Balance Line command.