Q 1 Two existing manholes, A and B are to be connected by a sewer. The plan length AB is 140.000m

The line of the sewer was established by means of pegs at 20m intervals. The peg tops were levelled by taking a run of levels starting on TBM1 and finishing on TBM2. The results are shown in Table Q.1. The excavation for the sewer is to be monitored using profiles and a 2.5m traveller.
(a) Draw up a suitable level book page and reduce the levels carrying out relevant arithmetic checks. (10)
(b) Calculate the gradient of the pipe. (3)
(c) Calculate the required heights of the profiles above the tops of the pegs. (4)
(Total 17)
BS IS FS Distance from
Manhole A Remarks
1.926 TBM1
(RL 95.249 AOD)
2.989 0 Invert manhole A
1.744 20 Top of Peg 1
1.308 1.873 40 Top of Peg 2
1.481 60 Top of Peg 3
1.746 80 Top of Peg 4
0.924 2.088 100 Top of Peg 5
1.062 120 Top of Peg 6
1.598 140 Invert Manhole B
2.206 TBM 2
(RL 93.240m AOD)
Table Q 1

Q.2
An anti-clockwise closed traverse 9, 10, 11,12,9 was used as the controlling framework for a topographical survey of a small area of ground.
Table Q.2 provides details of the horizontal angle measurements recorded on two faces during the traverse stage, along with the computed horizontal distances.
Instrument
Station Target
Station Face 1
Hor. Angle Face 2
Hor. Angle Line Mean
Distance
9 12
10 00°00’00?
100°08’20? 179°59’58?
280°08’14? 9-10 60.025m
10 9
11 00°00’00?
50°56’54? 180°00’05?
230°56’46? 10-11 21.134m
11 10
12 00°00’00?
131°07’41? 179°59’56?
311°07’40? 11-12 49.995m
12 11
9 00°00’00?
77°46’38? 180°00’06?
257°46’45? 12-9 18.512m
Table Q.2
The W.C.B. of the line 9-10 was determined accurately as 71°10’34? with the coordinates of 9 being 1039.712m E, 1022.578m N.
(i) Determine the mean horizontal angle recorded at each instrument station. (7)

(ii) Using Worksheet Q.2 complete and adjust the traverse. (8)

(iii) Comment on the accuracy of the results. (2)

(Total 17)

Q3
Four corners V,X,Y and Z of a proposed Telephone mast base are to be set out initially from Station “A” by angle and distance and then checked by intersection from station “D”.
The stations and the detail points are all based on the same coordinate system and are given in the table below.

Station Easting Northing
A 1000.000 1000.000
D 984.396 994.269

Detail points
V 994.478 999.223
X 994.478 1000.723
Y 991.478 1000.723
Z 991.478 999.223
1) Describe with full calculations a method of setting out the 4 points. (9)
2) Describe a method of checking the position of the points again showing all working.
(7)
Total (16)