3 Surveying - 1 Notes
3 Surveying - 1 Notes
3 Surveying - 1 Notes
in
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UNIT I
1.
2.
3.
Plane surveying
Geodetic surveying
b. Secondary classification
(i)
(ii)
(iii)
(iv)
4.
Sl.No
.
1.
Plane surveying
Geodetic surveying
2.
3.
4.
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5.
6.
For a given short length (PQ=PR), draw a right angle triangle. Its base (PR)
and height (PQ) are equal. A short length is divided into a number of parts by using the
principle of similar triangles in which like sides are proportional.
Thus,
1-1 represents 1/10 PQ
9-9 represents 9/10 PQ
8.
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9.
(a)
(b)
(c)
(d)
2.
Engineer's Chain
It is 66 feet long and
divided in to 100 links.
1 link = 1 feet.
Measurements are in feet
and decimals.
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14. Draw a neat sketch to show : Base line, Check line, Tie line, offset.
1.
Base line.
4. offset.
16. What are the instruments used for setting out right angles to a chain
line ?
(i)
Cross staff.
a.
Open cross staff
b.
French cross staff
c.
Adjustable cross staff
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(i)
(ii)
900.
Perpendicular offset
Oblique offset
19. What are the stages of fieldwork in chain surveying ? Or What are the
steps involved in chain survey ?
1. Reconnaissance : It is the preliminary inspection of the area to be surveyed.
2. Marking and fixing Survey lines.
3. Running Survey lines.
4. Taking Offsets.
20. Sketch the conventional signs to represent the following : Wall with gate,
Railway single line, pond, wire fencing.
Object
Wall with gate
Railway single line
Pond
Wire fencing
Conventional signs
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21. What are the different tape corrections ?
1.
2.
3.
4.
5.
(ii)
Chain or tape.
Passometer.
Pedometer
Odometer
Speedometer.
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UNIT II
COMPASS SURVEYING AND PLANE TABLE SURVEYING
1.
2.
(ii)
3.
Define : (a).
True meridian :
The line or plane passing through the geographical North Pole, South Pole and any
point on the surface of the earth, is known as true meridian or geographical meridian.
True meridian at a point is constant.
True bearing :
The angle between the true meridian and a survey line is known as true bearing or
Azimuth of the line.
(b) Magnetic meridian and Bearing.
Magnetic meridian :
Magnetic meridian at a point is the direction indicated by freely suspended, properly
balanced and unaffected magnetic needle at that point.
Magnetic Bearing :
The angle between the magnetic meridian and a survey line is known as magnetic
bearing or bearing of the line. It changes with time.
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In whole circle bearing system (WCB), the bearing of the line is measured with
magnetic north in clockwise direction. It varies from 00 to 3600.
In Quadrantal bearing system (O.B or R.B) the bearing of the line is measured
eastward or westward from north or south, whichever is nearer. The directions can be
either clockwise or anticlockwise. It varies from 00 to 900.
5. Convert the whole circle bearing into reduced bearing: 50o, 176o, 210o,
232o, 150o, 760,
310o, 2420.
Prismatic
(i) The reading is taken with a
u
help of prism provided at the eye
slit
(ii) Sighting and reading taking
can be done simultaneously from
one position of the observer
2.
rveyors compass
S
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BB=FB + 1800
9. The fore bearing of line AB is 15502525". Identify the back bearing of the
line AB in quadrantal system.
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= FB+1800
=15502520"+1800
= 335025'20"(WCB)
=N(3600-33502520")W
=N240 34' 40" W
10. Define and distinguish between magnetic dip and magnetic declination.
Magnetic dip:
Due to the magnetic influence of the earth, the needle does not remain in the
balanced position. This inclination of the needle with the horizontal is known as the dip
of the magnetic needle. To balance the dip of the needle, a rider (brass of silver coil) is
provided along with it.
Magnetic declination:
The magnetic meridian of a place is variable one due to some local attractive
forces. Therefore, the true meridian and the magnetic meridian at the place do not
coincide. The horizontal angle between the magnetic meridian and the true meridian is
known as magnetic declination.
11. The magnetic bearing of a line is 480 24. Calculate the true bearing if the
magnetic declinations are 5038 East and 5038 west.
True bearing = Magnetic bearing + Eastern magnetic declination
= 48024 + 538
True bearing = Magnetic bearing Western magnetic declination
= 48024-5038
= 42046.
12. The magnetic bearing of a line is S 28030E. Calculate the true bearing if the
magnetic declination are 5038 East and 5038 West.
Convert the reduced bearing into Whole circle bearing
Magnetic bearing
= S 28030E. (RB)
=1800-28030
=1510300.
True bearing = Magnetic bearing + Eastern magnetic declination
=151030+7030
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=159000. (WCB)
=S(1800-159000)E (RB)
=S210E.
True bearing = Magnetic bearing Western magnetic declination
=151030 7030
=144000 (WCB)
=S(1800-144000)E (RB)
=S360E
13. What is local attraction? What are the sources of local attractions?
Local attractions is a term used to denote any influence, such as magnetic
substances, which prevents the needle from pointing to the magnetic north in a given
locality.
The source of local attractions are: magnetite in the ground, wire carrying electric
current, steel structures, rails, underground iron pipes, chain etc.
Sl.No.
Closed traverse
Open traverse
1.
2.
3.
Check
Sum of interior angles =(2n-4)90
Sum of exterior angles = (2n+4)90
Where, n =number of sides of the
traverse.
15. What is plane table surveying? When is it preferred? Write its principle.
Plane tabling is the graphical method of surveying is which the field observations
and plotting proceed simultaneously.
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It is mainly suitable for filling the interior details between the control station and
also in magnetic areas.
The main principle of plane table surveying is that the lines joining the points on
the plane table are made to lie parallel to the corresponding lines joining the points on the
ground while working at each station.
Radiation
Intersection
Traversing
Resection
(i)
Resection after orientation by compass.
(ii)
Resection after orientation by back sighting
(iii)
Researching after orientation by three point problem.
a.
Mechanical method (Tracing paper method)
b.
Graphical method (Bessels method)
c.
Lehmans method (Trial and error method)
(iv) Resection after orientation by two point problem.
Instrumental error
Errors of plotting.
Errors due to manipulation and sighting.
1.
2.
3.
4.
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UNIT III
LEVELLING AND APPLICATION
1. Define Levelling. What are the uses of leveling?
Levelling is a branch of surveying, the object of which is; (i) To find the
elevations of given points with respect to a given or assumed datum, and (ii) To establish
points at a given elevation or at different elevations with respect to a given or assumed
datum.
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Dumpy level
Tilting level
Quick setting level.
Y-level
Reversible level.
Automatic level.
Lazer level.
8.
9. Define and distinguish between Back sight and Fore sight in the process
of fly Levelling.
Sl.No.
1.
2.
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10. Explain the theory of direct leveling.
It is the branch of leveling in which the vertical distances with respect to a
horizontal line may be used to determine the relative difference in elevation between
two adjacent points. Steps involved:
HI=known RL (BM)+BS
RL=HI FS
11.
Sl.No.
Reciprocal
1.
2.
It is used when:
(i) two points are a large
distance apart.
(ii) The difference in elevation
between two points is large
(iii) Some obstacles intervenes
between the points.
It is used when:
(i) The instrument cannot be set
Between the two points due to an
obstruction such as a valley, river,
etc.
(b)
(c)
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13.
Sl.N .
o
1.
2.
3.
4.
5.
14. Write the formula for curvature correction, refraction correction and
combined correction.
Curvature correction Cc=0.07849d2 (negative)m
Refraction correction = Cr = 0.01121 d2 (positive)m
Combined correction C = Cc Cr = 0.06728 d2 (negative)m.
Note : d is to be substituted in Km, while the corrections will be in m.
15.
(iii)
Instrumental error
a.
Error due to imperfect adjustment
b.
Error due to sluggish bubble.
c.
Error due to movement of objective slide.
d.
Error due to defective joint.
e.
Error due to incorrect length of staff.
(ii)
Natural error
a.
Earths curvature
b.
Atmospheric refraction
c.
Variations in temperature
d.
Settlement of tripod
e.
Wind vibrations.
Personal errors
a.
Mistakes in manipulation.
b.
Mistake in staff handling.
c.
Mistake in reading the staff
d.
Errors in sighting.
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16.
17.
Define sensitivity of a bubble. State any two factors affecting the same.
The sensitiveness of a bubble is defined the angular value of one division of the
bubble tube. It means the capability of showing small angular movements of the tube
vertically. It can be increased by:
1. Increasing the internal radius of the tube.
2. Increasing the diameter of the tube.
3. Increasing the length of the tube.
4. Decreasing the roughness of the walls.
5. Decreasing the viscosity of the liquid.
20.
1.Contour lines are closed curves. They may either within the map itself or
outside the map depending upon the topography.
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21.Sketch the contours for a (a) hillock (b) lake (c) A ridge line (d) A valley
line.
22.
march.
4.Longitudinal and cross section can be drawn along any direction to know the
nature of the ground.
23.Write the different formulae to calculate the area of the irregular plate.
1. By computations based directly on the field measurements:
(i)
(ii)
(iii)
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24. How do you calculate the capacity of the reservoir from the contour map?
From the contour map, the capacity of the reservior is calculated by the following
formula.
1. Trapezoidal rule = (Ao+An + A1+A2+A3+ .. An-1)d.
2
2. Primsoidal rule = [(ao+An) + 4 (A1+A3+.An-1) +
2(A2+A4+ ..An-2)] d/3
Ao, A1, A2, A3, An = Areas enclosed by successive contours.
d=contour interval.
UNIT IV
THEODOLITE SURVEYING
1.Define: Theodolite surveying. What are the uses of a theodolite?
Theodilite surveying is a branch of surveying, in which the theodolite is accurate
instrument used for the measurement of horizontal angles, vertical angels. It can also be
used for various purpose such as laying off horizontal angles, locating points on a line,
proloning survey lines, establishing grades, determining differences in elevation, etc.
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In Micrometer theodolite micrometers are fitted to read the angels.
6.
7.
1.
2.
3.
10. Name the two methods of measuring horizontal angles using a theolite.
When each method is advantageously used?
The two methods :
(i)
(iii)
Repetition method
Reiteration method (Direct method)
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The method of reiteration is preferred in triangulation, where a number of angles
may be required at one point by the instrument.
The method of repetition appears to be better, it is more time consuming and even
many repetitions may yield ordinary results.
11.
(L)2 + (D)2
L = sum of latitudes
D = sum of departures.
The direction of closing error.
Tan = D / L
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14. Define : Balancing. What are the methods used to balancing the traverse?
The term balancing is generally applied to the operation of applying corrections to
latitudes and departures. So that L = sum of latitudes = 0;D = sum of departures=0.
This applied only for closed traverse.
Methods used to balanceing (adjusting) the traverse:
1. Bowditchs rule
2. Transit rule
3. Graphical method
4. Axis method
Where,
L
D
L
I
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17. What is closed traverse? What are the two checks applicable in this case?
When the lines from a circuit, which ends at the starting point, it is known as
closed traverse.
Check:
(i)
Sum of interior angles =(2n-4) 90
(ii)
Sum of exterior angles = (2n+4)90
Where, n=number of side of the traverse.
19. What are the methods used to find the elevations of the points in the case of
inaccessible points?
1. Single plane method
2. Double plane method
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UNIT V
ENGINEERING SURVEYS
1. Why curves are necessary in the alignment of a highway/ railway? List the
various types of curves.
During the survey of the alignment of a road, railway, canals, etc. the direction of
the line may change due to some unavoidable situations. When two straights of highway
or rail way are at some angle to each other, a curve is introduced between them to avoid
an abrubt change in direction and to make the vehicle move safely, smoothly and
comfortably.
Types of curves.
1. Horizontal curve provided in the horizontal plane.
a. Simple curve
b. Compound curve
c. Reverse curve
d. Transition curve.
2.Vertical curve provided where two straight lines of different gradient interest
in the vertical plane.
a. Summit curve
b. Sag curve
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4. State the relationship between the radius of a curve and the degree of the
curve.
If the chord length is 30m, R=1719/D
If the chord length is 20m, R=1146/D
Where, R = Radius of a curve
D = Degree of the curve
6. Define : Setting out of curves (Curve ranging). What are the methods used
for setting curves?
Setting out of curves means the location of various points along the curve and
joining the same to obtain the actual curves.
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7. What is Sight distance in highways? Which factors affect if?
Sight distance may be defined as the minimum distance two vehicle moving along
a curve, when the driver of one vehicle can just see the other vehicles ahead on the road.
The factors affecting the sight distance are
(i)
Height of the line of the sight of the driver
(ii)
Grade or longitudinal slope of the curve
(iii)
Speed of the vehicle
(iv)
Co efficient of friction
(v)
Efficiency of the break.
12. What are the aims when undertaking setting out operation?
1.
2.
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16 Mark Questions
1. Describe the different kinds of chains used for linear measurements.
2. Explain the two common systems of bearings.
3. What are the sources of errors in compass survey?
4. Explain the different operations involved in working with plane table.
5. Explain the radiation and intersection methods of plane tabling.
6. What are the characteristics of contours?
7. Explain the temporary adjustments for a dumpy level.
8. Explain the special methods of spirit leveling
9. Briefly explain the different methods of adjusting a traverse
10. With a neat sketch show the different parts of a simple circular curve
11. What is meant by 3-4-5 rule? How this is applied to a single roomed building?
12. Explain the two basic principles of surveying.
13. Explain with neat sketches the various methods to chain across the river.
14. State the merits and demerits of plane table surveying.
15. With neat sketches explain in detail about Lehmans rules.
16. Describe the process of repletion and reiteration in horizontal angle measurement.
17. Explain with neat sketches the different types of horizontal curves.
18. What is a vertical curve and why it is provided? Also, show with neat sketches
different types of vertical curves.
19. Describe the different types of corrections applied in linear measurement using a
tape.
20. Explain with neat sketches any two instruments for setting out right angles to a chain
line.
21. What is a planimeter? Explain how the volume of a reservoir could be determined
through contour surveying.
22. Explain any two linear methods of setting out circular curves.
23. Tabulate the differences between a prismatic compass and a surveyors compass.
24. Write a detailed note on Gales Traverse Table
25. With a neat sketch explain the various parts of a prismatic compass. Explain how the
graduations are marked and why.
26. Explain the different steps in chain surveying.
27. What are the different methods of locating contour?
28. Explain the procedure for setting out of a tunnel.
29. What is two-point problem? Explain how it is solved.
30. Discuss in brief the surveys carried out at various stages of a new highway project
and the purpose of each one of them.
31. What are the different instruments used in chain surveying? Explain the use of each
with neat sketches.
32. Draw a neat sketch of a modern tilting level and mark it salient parts.
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