Civil Engineering - Estimating and Costing - Discussion

The road is made of two layers:

1. A 15 cm thick concrete layer.
2. A 10 cm thick gravel sub-base layer.

Box cutting is all about how much earth you need to remove, so we only care about the final dimensions of the road profile. So, we need to consider both layers (concrete and gravel) to determine the total depth of the excavation.

1. Calculate the total thickness:
The total thickness is 15 cm (concrete) + 10 cm (gravel) = 25 cm.
We need to convert this to meters: 25 cm = 0.25 m.

2. Calculate the volume:
Volume is calculated by: Length x Width x Height (or Thickness in this case).
Length = 1000 m.
Width = 8 m.
Thickness = 0.25 m.
Volume = 1000 m x 8 m x 0.25 m = 2000 m3.

Therefore, the correct answer is Option D: 2000 m3.

Quantity of cc road = 1000*8*0.15 = 1200 cum.
Quantity of sub-base gravel = 1000*8*0.10 = 800 cum.
Tt. Quantity = 1200 + 800 = 2000 cum.
Formulae for cut-off volume = (1/4)*2000,
= 500 cum.

Box cutting in road crust = 2000-500,
= 1500 cum.
Hence, 1500 cum is the total volume for box cutting in road crust.

Orginal volume = 1000m * 8m * (15cm+10cm),
= 1000 * 8 * 0.25cum,
= 2000 cum.

Cutt-off volume = (1/4) * original volume.
= (1/4) * 2000cum,
= 500cum.

So, Box cutting in road curst = (2000-500).
= 1500cum.

Box cutting means to the excavation of the road so as to fit the road in the excavated portion this is done to make road level with the surrounding, now you have remembered that there is compaction of 6.25cm in gravel in the subbase so remaining total available ht will be 15+3.75cm, and then as usual l*b*h.

Box cutting means the excavation of the road so as to fit the road in the excavated portion this is done to make road level with the surrounding, now you have remembered that there is compaction of 6.25cm in gravel in the subbase so remaining total available ht will be 15+3.75cm, and then as usual l*b*h.

Sub base =10 cm.

And we take base = to or less than about sub base = 10 cm. Total depth of cutting = 20 cm. Therefore, V cutting = 1000 x 8 x .2= 1600m3.

We excavate less than 1600 so the nearest option is 1500. So correct answer is 1500 m3.

The road is 1000m long = 1000m.
The width is 8m = 8m.
The thickness of slab = 0.15m.
Excavation for sub base (10cm thick - 6.25cm compaction) = 3.75cm for gravel.

So,
1000m x 8m x (0.15m + .0375m).
1000m x 8m x 0.1875m = 1500 cubic m.

Orginal volume = 1000m * 8m * (15cm+10cm),
= 1000 * 8 * 0.25cum,
= 2000 cum.

Cutt-off volume = (1/4) * original volume.
= (1/4) * 2000cum,
= 500cum.

So, Box cutting in road curst = (2000-500),
= 1500cum.

Original volume= as you know = 2000.

Cutt off volume= 1/4 of the original volume.
1/4x2000 = 500cum.
So, box cutting in road = 2000 - 500 = 1500 cum.

Original Volume= 1000*8*(0.15+0.10)=2000m3,
Cutoff Volume= Original Volume/4=2000/4=500m3,
Box cutting in road crust= 2000-500= 1500m3.