Civil Engineering - Estimating and Costing - Discussion

The number of neutrons will be 6 so the total number becomes 6 + 6 is equal to 12.

99.25+(2.75/30)*x = 100+(x+30)/120.

By solving it x=12m from chainage 6 towards ch. 7, so answer will be (6+12).

It is (6+8) chains.

Please, explain this.

Actually, none of the answers is correct.

From calculations, we get that the formation line intersects the ground surface at a distance of 12m from chainage point 6. (let us call this point 'X').

Also, when chainage is represented as (A+B) chains, it refers to "A chains" and "B links".

Since the distance between consecutive chainage points is 30m, we can say that a 30m metric chain is used for chaining and a 30m chain has 150 links, each 20cm (or 0.2m) long.

So, number of links between the points '6' and 'X' = (distance between points '6' and 'X') / (link length).
= (12)/(0.2)
= 60.

Hence, the correct way of representing the point 'X' is (6+60) chains.

I think the correct answer is 6+14 chains.

Gradient given is 1:120
So for 30m rise of = (1/120*30),
= 0.25 m.

RL of formation level @6 chain = 100.0 + 0.25.
= 100.25 m.
RL of formation level @7 chain = 100.25+ 0.25
=100.5 m.

So difference = 102-100.5 = 1.5.

By similar triangles -
(1/x) = 1.5/(30-x)
X = 12.

So the answer is (6+12) chains.

I think the answer is (6+8) chains.

Thanks for your explanation @Gance.