Question

12) of 7.5.km. What for overhaut, if the rate for overhaut in lor an average 2.2 Refer to Table 2-1 Plot the mass haul d 2 km long road Assume no shrinkage (a) Draw the haul directions, and Comment on the balance of material and cut and fill sections on the mass haul diagramme (15) Table 2-1: Cut and fill areas sectional cut area 100 600 10008 1100 1200 1300 1400 1600 1700 1800 1900 2000 (b) Recalculate the mass haul diagramme quantities, but assume a shrinkage factor of 92%. What is the balance of material remaining? Must this material be spoiled or hauled to site (12) from a borrow pit?

Please help with 2.2 (a) and (b)

Answer 1

Here's the excel sheet containing the mass haul diagram in terms of cumulative cross sectional area (m²) with chainage:

And here's the Mass haul diagram with directions of hauling (marked with arrows) and cut and fill sections:

CHAINAGE CUT AREA (m2) FILL AREA (mA2) CUMULATIVE AREA 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 -13 12 9 24 32 38 47 45 40 32 24 2 2

We can see that at the end of the Mass haul diagram, we are left with -2 m² of balance which means we need to borrow that much form a borrow pit nearby.

Mass diagram 60 50 40 30 4 45 38 32 24 24 20 15 - Mass diagram 6 -2 2000 1000 1500 2500 -8 -10 -20 -30 -13 -1 -22

Now, due to the shrinkage factor, 0.92, the fill sections will get compacted and the earth required to fill those sections will be increased by a factor of 1/0.92 = 1.087. Therefore, the new Mass haul diagram will look like:

8111 037 834 121 2527800 4443221 73008 - 25 14777653 D07 74 89500000000025 8897 6 89500000000025 8897 6 00009 12 7 9 9 8 6 63 0000 0000 1234 6789 1234 6789


Mass Haul Diagram (Corrected fill) 50.00 4.2.91 36.09 40.00 37.48 30.00 22.09 20.00 13.09 10.00 -- Cumulative Area 4.09 2.70 0.00 2.91 1000 1500 28083 2500 10.00 14.91 18.48 -20.00 23.91 30.00

We can clearly see that now, the requirement of earth is 8.17 m² due to shrinkage. The borrow pits aren't necessarily nearby to the project sites. Also, sometimes, the terrain makes it difficult to haul earth from a borrow pit to the work site. Therefore, spoiling is the better option.

Thank you. Upvotes are appreciated.