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Theodolite and Its Uses

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AmitKumar8151

This document discusses the uses of a theodolite in mine surveying. It describes how a theodolite can be used to measure horizontal and vertical angles, determine magnetic bearings, prolong survey lines, and conduct traverses. Key uses include measuring angles between points, determining elevations, setting horizontal lines, and establishing grades. A theodolite is a precise surveying instrument useful for laying out surveys, locating points, and establishing curves in mine sites.

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NATIONAL INSTITUTE OF TECHNOLOGY RAIPUR DEPARTMENT OF MINING ENGINEERING A TERM PROJECT USES OF THEODOLITE IN MINE SURVEY-II PREPARED BY: AMIT KUMAR ROLL NO. 18121008 B.TECH. MINING ENGINEERING 5TH SEMESTER UNDER GUIDANCE OF: PROF. B.R. PARATE ASSOCIATE PROFESSOR DEPARTMENT OF MINING ENGINEERING
ACKNOWLEDGEMENT I would like to express my special thank of gratitude to respected Prof. B.R. Parate sir and T. Sai Kumar sir for their guidance, help and useful suggestion and give us opportunity to do this project on Uses of Theodolite (Mine survey II).
INDEX CONTENTS 1. INTRODUCTION ...........................................................................................4 2. USES OF THEODOLITE ..................................................................................5 2.1Measurement of Horizontal angle .............................................................5 2.2Measurement of Vertical Angle .................................................................6 2.3 Magnetic Bearing with Theodolite............................................................7 2.4 Using a theodolite as a level .....................................................................8 2.5 Prolonging a straight line ..........................................................................8 2.6 Traversing with theodolite........................................................................9 CONCLUSION ...................................................................................................10 REFERENCES.....................................................................................................10
THEODOLITE 1. INTRODUCTION: - The theodolite is the most precise instrument designed for the measurement of horizontal and vertical angles with considerable accuracy and it has wide field usefulness in surveying such as laying off horizontal angles, locating points on line, prolonging survey lines, establishing grades, determining difference in elevation, setting out curve. Theodolite may be classified as 1. Transit theodolite 2. Non-transit Theodolite Parts of the Theodolite: -
2. USES OF THEODOLITE: - the various uses of theodolite are the following: 2.1 Measurement of Horizontal angle: An angle between any two points within the same horizontal plane. ordinary method to measure horizontal angle <AOB. A B O a. Set up the theodolite at station point O and level it accurately. b. Set the Vernier A to the zero or 3600 of the horizontal circles. Tighten the upper clamp. c. Loosen the lower clamp. Turn the instrument and direct the telescope towards A to bisect it accurately with the use of tangent screw. After bisecting accurately check the reading which must still read zero. Read the Vernier B and record both the readings. d. Loosen the upper clamp and turn the telescope clockwise until line of sight bisects point B on the righthand side. Then tighten the upper clamp and bisect it accurately by turning its tangent screw. e. Read both Verniers. The reading of the Vernier a which was initially set at zero gives the value of the angle AOB directly and that of the other Vernier B by deducting 1800 . The mean of the two Vernier readings gives the value of the required angle AOB. f. Change the face of the instrument and repeat the whole process. The mean of the two Vernier readings gives the second value of the angle AOB which should be approximately or exactly equal to the previous value. g. The mean of the two values of the angle AOB, one with face left and the other with face right, gives the required angle free from all instrumental errors.
2.2 Measurement of Vertical Angle: A vertical angle is an angle between the inclined line of sight and the horizontal. It may be an angle of elevation or depression according as the object is above or below the horizontal plane. To Measure the Vertical Angle of an object A at a station O: a. Set up the theodolite at station point O and level it accurately with reference to the altitude bubble. b. Set the zero of vertical Vernier exactly to the zero of the vertical circle clamp and tangent screw. c. Bring the bubble of the altitude level in the central position. d. The line of sight is thus made horizontal and Vernier still reads zero. e. Loosen the vertical circle clamp screw and direct the telescope towards the object A and sight it exactly by using the vertical circle tangent screw. f. Read both Verniers on the vertical circle, The mean of the two Vernier readings gives the value of the required angle. g. Change the face of the instrument and repeat the process. The mean of the two Vernier readings gives the second value of the required angle. h. The average of the two values of the angles thus obtained, is the required value of the angle free from instrumental errors.
For measuring Vertical Angle between two points A &B: a. Sight A as before and take the mean of the two Vernier readings at the vertical circle. Let it be 留. b. Similarly, sight B and take the mean of the two Vernier readings at the vertical circle. Let it be 署. c. The sum or difference of these readings will give the value of the vertical angle between A and B according as one of the points is above and the other below the horizontal plane. or both points are on the same side of the horizontal plane Fig b & c 硫. 2.3 Magnetic Bearing with Theodolite To find the bearing of a line AB as shown in fig. below a. Set up the instrument over A and level it accurately. b. Set the Vernier to the zero of the horizontal circle. c. Release the magnetic needle and loosen the lower clamp. d. Rotate the instrument till magnetic needle points to North. Now clamp the lower clamp with the help of lower tangent screw. Bring the needle exactly against the mark in order to bring it in magnetic meridian. At this stage the line of sight will also be in magnetic meridian.
e. Now loose the upper clamp and point the telescope towards B. With the help of upper tangent screw ,bisect B accurately and read both the verniers .The mean of the two readings will be recorded as magnetic bearing of line. f. Change the face of the instrument for accurate magnetic bearing of the line and repeat. the mean of the two values will give the correct bearing of the line AB. 2.4 Using a theodolite as a level if the theodolite is in perfect adjustment, it can be used as a levelling instrument. The theodolite is levelled with respect to the altitude level. When the bubble of the altitude level is in centre and the Vernier reading of the vertical circle is zero, the line of sight is horizontal. Then the instrument can be used as a level the back sight (B.S.) is taken on the staff held at B.M. and the height of the instrument is determined. The staff is then shifted to the point whose elevation is required, and a foresight (F.S.) is taken. Thus, R.L. = B.M. + B.S. - F.S. However, a theodolite should not be used as a levelling instrument as far as possible. The accuracy attained is generally less than with a good dumpy level or tilting level. 2.5 Prolonging a straight line There are two methods of prolonging a given line such as AB: (1) Fore sight method, and (2) Back sight method. a. Set up the theodolite at A and level it accurately. Bisect the point B correctly. Establish a point C in line beyond B approximately by looking over the top of the telescope and accurately by sighting through the telescope. b. Shift the instrument to B, take a fore sight on C and establish; point D in line beyond C.
c. Repeat the process until the last point (Z) is established. Note: For this method, the instrument must be in perfect adjustment. a. Set up the instrument at B and level it accurately. b. Take a back sight on A. c. Tighten the upper and lower clamps, transit the telescope and establish a point C in the line beyond B. d. Shift the theodolite to C, back sight on B, transit the telescope and establish a point D in line beyond C. e. Repeat the process until the last point (Z) is established. Note: This method also requires the instrument to be in perfect adjustment. When the line is to be prolonged with high precision or when the instrument is in imperfect adjustment, the process of double sighting or double reversing, is used. Suppose the line AB is to be prolonged to a point Z. 2.6 Traversing with theodolite A traverse is a series of connected lines whose lengths and directions are measured in the field Different methods of Traversing, 1. Traversing by included angles 2. Traversing by deflection angles. Sum of the measured interior angles should equal (2N 4) right angles. The sum of the measured exterior angles should equal (2N + 4) right angles. where N is number of sides of the traverse. The algebraic sum of the deflection angles should equal 360属.Consider the right-hand deflection angles as positive, and left-hand ones as negative.
fig. closed traverse Fig. open traverse CONCLUSION There are vast uses of theodolite in surveying. Above mentioned uses of theodolite are the main. There are several uses are like in triangulation, correlation and joint boundary survey, Tacheometric observations, calculation of area; determination of true north, longitude and latitude; setting out the curves etc. REFERENCES Mine surveying and levelling By S. Ghatak. /neharajpl/theodolite-surveying-89057990 https://www.engineeringenotes.com/surveying/theodolite- surveying/use-of-theodolite-in-surveying-theodolite-surveying- surveying/14061

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Theodolite and Its Uses

  • 1. NATIONAL INSTITUTE OF TECHNOLOGY RAIPUR DEPARTMENT OF MINING ENGINEERING A TERM PROJECT USES OF THEODOLITE IN MINE SURVEY-II PREPARED BY: AMIT KUMAR ROLL NO. 18121008 B.TECH. MINING ENGINEERING 5TH SEMESTER UNDER GUIDANCE OF: PROF. B.R. PARATE ASSOCIATE PROFESSOR DEPARTMENT OF MINING ENGINEERING
  • 2. ACKNOWLEDGEMENT I would like to express my special thank of gratitude to respected Prof. B.R. Parate sir and T. Sai Kumar sir for their guidance, help and useful suggestion and give us opportunity to do this project on Uses of Theodolite (Mine survey II).
  • 3. INDEX CONTENTS 1. INTRODUCTION ...........................................................................................4 2. USES OF THEODOLITE ..................................................................................5 2.1Measurement of Horizontal angle .............................................................5 2.2Measurement of Vertical Angle .................................................................6 2.3 Magnetic Bearing with Theodolite............................................................7 2.4 Using a theodolite as a level .....................................................................8 2.5 Prolonging a straight line ..........................................................................8 2.6 Traversing with theodolite........................................................................9 CONCLUSION ...................................................................................................10 REFERENCES.....................................................................................................10
  • 4. THEODOLITE 1. INTRODUCTION: - The theodolite is the most precise instrument designed for the measurement of horizontal and vertical angles with considerable accuracy and it has wide field usefulness in surveying such as laying off horizontal angles, locating points on line, prolonging survey lines, establishing grades, determining difference in elevation, setting out curve. Theodolite may be classified as 1. Transit theodolite 2. Non-transit Theodolite Parts of the Theodolite: -
  • 5. 2. USES OF THEODOLITE: - the various uses of theodolite are the following: 2.1 Measurement of Horizontal angle: An angle between any two points within the same horizontal plane. ordinary method to measure horizontal angle <AOB. A B O a. Set up the theodolite at station point O and level it accurately. b. Set the Vernier A to the zero or 3600 of the horizontal circles. Tighten the upper clamp. c. Loosen the lower clamp. Turn the instrument and direct the telescope towards A to bisect it accurately with the use of tangent screw. After bisecting accurately check the reading which must still read zero. Read the Vernier B and record both the readings. d. Loosen the upper clamp and turn the telescope clockwise until line of sight bisects point B on the righthand side. Then tighten the upper clamp and bisect it accurately by turning its tangent screw. e. Read both Verniers. The reading of the Vernier a which was initially set at zero gives the value of the angle AOB directly and that of the other Vernier B by deducting 1800 . The mean of the two Vernier readings gives the value of the required angle AOB. f. Change the face of the instrument and repeat the whole process. The mean of the two Vernier readings gives the second value of the angle AOB which should be approximately or exactly equal to the previous value. g. The mean of the two values of the angle AOB, one with face left and the other with face right, gives the required angle free from all instrumental errors.
  • 6. 2.2 Measurement of Vertical Angle: A vertical angle is an angle between the inclined line of sight and the horizontal. It may be an angle of elevation or depression according as the object is above or below the horizontal plane. To Measure the Vertical Angle of an object A at a station O: a. Set up the theodolite at station point O and level it accurately with reference to the altitude bubble. b. Set the zero of vertical Vernier exactly to the zero of the vertical circle clamp and tangent screw. c. Bring the bubble of the altitude level in the central position. d. The line of sight is thus made horizontal and Vernier still reads zero. e. Loosen the vertical circle clamp screw and direct the telescope towards the object A and sight it exactly by using the vertical circle tangent screw. f. Read both Verniers on the vertical circle, The mean of the two Vernier readings gives the value of the required angle. g. Change the face of the instrument and repeat the process. The mean of the two Vernier readings gives the second value of the required angle. h. The average of the two values of the angles thus obtained, is the required value of the angle free from instrumental errors.
  • 7. For measuring Vertical Angle between two points A &B: a. Sight A as before and take the mean of the two Vernier readings at the vertical circle. Let it be 留. b. Similarly, sight B and take the mean of the two Vernier readings at the vertical circle. Let it be 署. c. The sum or difference of these readings will give the value of the vertical angle between A and B according as one of the points is above and the other below the horizontal plane. or both points are on the same side of the horizontal plane Fig b & c 硫. 2.3 Magnetic Bearing with Theodolite To find the bearing of a line AB as shown in fig. below a. Set up the instrument over A and level it accurately. b. Set the Vernier to the zero of the horizontal circle. c. Release the magnetic needle and loosen the lower clamp. d. Rotate the instrument till magnetic needle points to North. Now clamp the lower clamp with the help of lower tangent screw. Bring the needle exactly against the mark in order to bring it in magnetic meridian. At this stage the line of sight will also be in magnetic meridian.
  • 8. e. Now loose the upper clamp and point the telescope towards B. With the help of upper tangent screw ,bisect B accurately and read both the verniers .The mean of the two readings will be recorded as magnetic bearing of line. f. Change the face of the instrument for accurate magnetic bearing of the line and repeat. the mean of the two values will give the correct bearing of the line AB. 2.4 Using a theodolite as a level if the theodolite is in perfect adjustment, it can be used as a levelling instrument. The theodolite is levelled with respect to the altitude level. When the bubble of the altitude level is in centre and the Vernier reading of the vertical circle is zero, the line of sight is horizontal. Then the instrument can be used as a level the back sight (B.S.) is taken on the staff held at B.M. and the height of the instrument is determined. The staff is then shifted to the point whose elevation is required, and a foresight (F.S.) is taken. Thus, R.L. = B.M. + B.S. - F.S. However, a theodolite should not be used as a levelling instrument as far as possible. The accuracy attained is generally less than with a good dumpy level or tilting level. 2.5 Prolonging a straight line There are two methods of prolonging a given line such as AB: (1) Fore sight method, and (2) Back sight method. a. Set up the theodolite at A and level it accurately. Bisect the point B correctly. Establish a point C in line beyond B approximately by looking over the top of the telescope and accurately by sighting through the telescope. b. Shift the instrument to B, take a fore sight on C and establish; point D in line beyond C.
  • 9. c. Repeat the process until the last point (Z) is established. Note: For this method, the instrument must be in perfect adjustment. a. Set up the instrument at B and level it accurately. b. Take a back sight on A. c. Tighten the upper and lower clamps, transit the telescope and establish a point C in the line beyond B. d. Shift the theodolite to C, back sight on B, transit the telescope and establish a point D in line beyond C. e. Repeat the process until the last point (Z) is established. Note: This method also requires the instrument to be in perfect adjustment. When the line is to be prolonged with high precision or when the instrument is in imperfect adjustment, the process of double sighting or double reversing, is used. Suppose the line AB is to be prolonged to a point Z. 2.6 Traversing with theodolite A traverse is a series of connected lines whose lengths and directions are measured in the field Different methods of Traversing, 1. Traversing by included angles 2. Traversing by deflection angles. Sum of the measured interior angles should equal (2N 4) right angles. The sum of the measured exterior angles should equal (2N + 4) right angles. where N is number of sides of the traverse. The algebraic sum of the deflection angles should equal 360属.Consider the right-hand deflection angles as positive, and left-hand ones as negative.
  • 10. fig. closed traverse Fig. open traverse CONCLUSION There are vast uses of theodolite in surveying. Above mentioned uses of theodolite are the main. There are several uses are like in triangulation, correlation and joint boundary survey, Tacheometric observations, calculation of area; determination of true north, longitude and latitude; setting out the curves etc. REFERENCES Mine surveying and levelling By S. Ghatak. /neharajpl/theodolite-surveying-89057990 https://www.engineeringenotes.com/surveying/theodolite- surveying/use-of-theodolite-in-surveying-theodolite-surveying- surveying/14061