Question

Q3.Table overleaf (Q3) indicates a levelling survey carried out to establish existing ground levels along the centre line of a proposed road.  

1. Determine the reduced levels using the height of plane of collimation (HPC) method.

2. Find misclosure (if any) and carry out the usual mathematical checks to determine if this misclosure is due to errors in computation.

3. Distribute the actual misclosure and obtain the corrected reduced levels.  

Bonus :

4. Using paper provided to you, sketch the longitudinal section along the existing ground profile from chainage 0 – 100 m.

5. Assuming that the level of the proposed road centre line to be sloping 2% upwards from chainage 0 at an elevation of 77.000 m, plot the proposed road on your sketch and clearly indicate where CUTS and FILLS are required.

Back sight (m)	Intermediate sight (m)	Fore sight (m)	HPC (m)	Reducel Level (m)	Correction (m)	Corrected RL   (m)	Remarks
1.011							TBM1 = 78.000 m
	1.938						Chainage point 0 m
	2.701						Chainage point 10 m
4.587		1.492					Change Point
	0.906						Chainage point 20 m
	2.010						Chainage point 30 m
	3.242						Chainage point 40 m
1.412		2.757					Change Point
	2.220						Chainage point 50 m
3.018		1.212					Change Point
	0.211						Chainage point 60 m
	0.786						Chainage point 70 m
	1.806						Chainage point 80 m
	2.879						Chainage point 90 m
	3.584						Chainage point 100 m
		4.016					TBM2 = 78.560 m

Answer 1