INDEX. SR NO NAME OF THE PRACTICALS Page No. Measuring the bearing of traverse lines, calculation of included angles and check.

Transcription

1 INDEX SR NO NAME OF THE PRACTICALS Page No 1 Measuring the bearing of traverse lines, calculation of included angles and check. 1 2 To study the essential parts of dumpy level & reduction of levels 3 To Study fly, differential, profile & Check leveling 4 To study and use the plane table survey by radiation and intersection method To measure direct angle, deflection angle and magnetic bearing of line by using thedolite To measure horizontal and vertical angle between two points using theodolite To measure horizontal angle by repetition& group of angle in a horizon i.e. reiteration To determined distance and reduce level of elevation point by Tachometric observations Project No.1 Profile leveling Project No.2 Block Contouring Project No.3 Theodolite Traversing 19

2 PRACTICAL NO: 1 Aim : measuring the bearing of traverse lines, calculation of included angles and check. Apparatus: Prismatic compass, pegs, ranging rods etc Theory: Definition: Surveying which involves series of connected lines is known as traversing The sides of traverse are known is known as Traverse legs. In traversing with a compass free or loose needle method is employed to determine direction of survey line. The compass is setup at each of the successive station and fore & back bearing of each line is determined All the readings are noted in field book. Each of the line is observed independently & errors are calculated, compensated. The field work consists of primary survey, marking of stations, running of traverse lines. Pick up all the details & note down in field in Systematic manner. Traverse stations should be selected that I) They are visible from each other II) They are as long as possible. III) The line joining them are as near the boundaries & objects To be located as possible S.No Station point Line Fore bearing Back bearing Difference Correction at Station Corrected fore bearing Corrected Back Included Angle Correction Corrected Angle

3 PRACTICAL NO: 2 Aim:- To study the essential parts of dumpy level & reduction of levels. Apparatus:- Dumpy level, tripod stand, leveling staff etc. Theory:-The dumpy level is a simple and compact instrument; the telescope is rigidly fixed to its supports it can be rotated about its longitudinal axis. Level tube is permanently placed so that axis lies in same vertical plane. A focusing screw near the eye piece provided to get clear image of the object and to bisect cross hair. Bench mark: - It is point of known elevation. It is used either as a starting point or as a check point before closing. Axis of telescope: - It is line joining the object, optical centre of the glass to the centre of the eye piece. Line of collimation (Line of sight):- It is line joining intersection of cross hair to the optical centre of the glass. FIGURE: - Parts of dumpy level: - 1. Tripod: - The tripod consists of three legs, lower ends of it fitted with steel shoes. 2. Leveling head: - It consists of two parallel triangular plates to supports the foots screws. 3. Foot Screws: - It is provided between trivet and tribatch, by turning the screws the tribatch can be raised or lowered to bring bubble tube at the centre. 4. Telescope: - It consist of an object glass and eye piece on opposite end, a diaphragm is fixed with the telescope just in front of eye piece. 5. Bubble tube: - Two bubble tubes one longitudinal and one cross bubble provided right angles to each other. The bubble is brought to the centre with the help of foot screws. 6. Compass: - A compass is provided just below the telescope for taking magnetic bearing of a line required. Reduction of levels H.I method:- The reduced level of the line of collimation is said to be the height of the instrument. In this system height of the line of collimation is found out by adding back side reading to the R.L of bench mark on which BS is taken. Then RL of intermediate points and the change point are obtained by subtracting the respective staff reading from the height of instrument (HI). To find new HI of change point BS is taken on last point.

4 Observation Table: Station point Chainage BS IS FS RL of collimation point(hi) Remark Result: Level Difference between A & B is..

5 PRACTICAL NO: 3 Aim: To Study fly, differential, profile & Check leveling. Apparatus: Dumpy level, leveling staff, Cross staff, Chain, Compass& pegs, ranging rodetc. Fly leveling: Leveling is done to calculate RL of a particular point from the known bench mark e.g. In fig showing R.L of particular point is A is calculated by taking back sight on BM & F.s on A. Differential Leveling: This condition of leveling is applied when the points are far apart & they are not intervisible. To find level difference between two points A & B First level instrument is set up at O 1 with bubble tube At centre, taking staff at A. Calculating HI for taking level at C. Leveling is shifted to O 2 new HI is calculated by taking BS at C& RL of D point is calculate By taking FS at D. Then again instrument is shifted at O 3, RL of B Is calculated in previous manner. Then difference in level between A & B is calculated i.e. Level difference between A & B Check leveling: - To check the leveling operation i.e. accuracy of leveling at the end each work. Level lines are run, returning to initial or starting point to view work done on each day. Actual aim of check leveling is to check difference between two points in alternate route. Profile Leveling: - This leveling operation is done to obtain the accurate out line of surface of ground i.e. To find RL of points at a particular known distance. AB & BC line of alignment, RL of A is calculated by fly leveling. The instrument is set at O 1 as per easily to take level. The chain is stretch between AB & BC at a fix distance from A on line AB levels is taken. For cross section leveling a distance section are depend upon taken at 5 mm or 10 mm, 15 mm are depend upon sight. As per requirement, level is shifted between O 1 & O 2. When alignment is changing two C.S. is taken i.e. one parallel to first alignment & one perpendicular to next alignment.

6 PRACTICAL NO: 4 AIM:- To study and use the plane table survey by radiation and intersection method. Theory: Plane tabling is a graphical method of surveying in which field book and plotting are done simultaneously. It is most suitable for filling in detail about between the stations previously fixed by triangulation. It is particularly adopted on small scale or medium scale marking in which detail is required for graphical survey. Accessories for plane table survey: 1) Drawing board-made up of well-seasoned wood such as teak or pine and its size is 40x30 cm to 75x60cm. It is mounted on midpoint after levelling about interior axis. 2) Alidade- Alidade consists of brass or metal or wood straight edge or ruler about 50cm long line levelled edge. It is used for sighting the object to the located point. 3) Trough compass- A trough compass or circular box compass with magnetic needle at centre is used for measuring north direction on drawing sheet. 4)U-fork Once the line of fork/plumb bob is attached and upper arm is same what to indicate which point on table is vertically over the station point on ground. 5) Bubble Tube: There is a bubble in the tube when the bubble comes exactly in the centre of the tube then indicates that the bubble corner is exactly horizontal to ground. Methods of plane table surveying: 1. Radiation: In this method point is located on plan by drawing a ray from plane table stat. to the point and plotting to scale along the ray. The distance measured from station to the point. This method is suitable for small area which can be commanded from a single station. Procedure 1) Select point P such that all points to be located visible from it. 2) Set up the table at P and after levelling it clamp the board. 3) Using U-fork selected point P is traversed to table. 4) Mark direction of magnetic meridian with the help of trough compass right top corner of sheet. 5) Centring the alidade on P and sight point.a to B, C, D, etc. and draw rays on table along fiducial edge with chisel pointed pencil. 6) Measure distance PA, PB, PC, PD by chain or tape. 7) Taking suitable scale plot these distances on sheets.

7 Fig: Radiation Method 2. Intersection method- In this method point is fixed on plan by the intersection of rays drawn from the two instrument stations. The line joining these stations is called base line. It is suitable when distances are very large and having observations between them. Procedure- 1) Select two points P& Q in a commanding position so that they are easily accessible 2) First centre table at P and select point p on paper so that p point is exactly over P point and Mark direction of magnetic meridian with the help of trough compass right top corner of sheet. 3)when the alidade pivoted on the p, sight Q & other objects A, B& C etc to be located Using fiducial edge of the alidade draw rays towards points. 4) Measure distance between PQ and set it off to scale along the ray drawn to Q thus fixing the position of q on sheet. 5) Shift the table and set up it at Q.Set up q point exactly over Q on ground &level it Again sight all points from Q 6) The intersection points are required points to be plotted.

8 7) Place the alidade along qp & orientation done by Back sighting. 8) Alidade Touching q, sighting same object & drawing rays.intersection of Rays drawn from p& q gives position of A,B and Con sheet.

9 Practical No: 5 Aim: - To measure direct angle, deflection angle and magnetic bearing of line by using thedolite Apparatus: - Transit thedolite, ranging rod, pegs etc. (1)Direct Angle: The angle measured clockwise from preceding line to the following line. They may vary 0 to 360. Procedure:- - Set up the thedolite at O and level it accurately set vernier A to Loose the lower plate and take back sight on A. - Loose upper plate rotate telescope clockwise and bisect B exactly read both vernier. Plunge the telescope turns the instrument about its outer axis and take back sight on A the reading on vernier A will be same as in Step 1. - Loose the upper plate, turn the telescope clockwise and again bisect B exactly. - Read both verniers. The reading will be twice the previous, <AOB will be obtain by dividing the final reading by 2. Station Object Face A B Initial Final Initial Final A B Face angle (2) Deflection Angle:- Deflection angle is the angle which the survey line makes with the prolongation of preceding line. Procedure:-

10 - Set up the theodolite at B and level it accurately. - With both plates clamp the vernier A reading take back sight on A. Plunge the telescope to direct the line of sight AB. Loosen the upper plate and turn the telescope clockwise to take fore sight C. Read both verniers. The mean of two verniers reading gives the approximate value of deflection at B &clamp upper clamp. - Loosen the lower clamp and turns the telescope horizontally to back sight on A. The vernier will read the same reading as in step 4 and telescope transited. Plunge the telescope and unclamped the plates and again bisect C. Read both verniers. Find the mean of final readings. Thus the deflection angle is doubled and hence one half of its average value given accurate value of deflection angle at B. Fig: Deflection Angle Observation Table: Station Object Face A B Initial Final Initial Final A B Face angle (3)Magnetic Bearing:- The angle which a line makes with the magnetic meridian is called a magnetic bearing of a line. Procedure:- For measuring hearing through compass or tabular compass is attached to theodolite.

11 Set the vernier A to of the horizontal circle after setting theodolite over 0 and level it. Loosen the lower clamp magnetic needle is then realized to swing on pivot of compass. Rotate the instrument till needle roughly point to the north by using lower tangent screw and correct direction of magnetic needle is obtain. - Loose the upper clamp and direct the telescope towards A and bisect it exactly by using upper clamp and upper tangent screw. Read both verniers. - Change the face and repeat the process. The average of two values gives correct bearing of line AB. Observation Table: Fig magnetic Bearing of line : Station Object Face A B Initial Final Initial Final A B Face angle Result: Direct angle between A & C=. Deflection Angle between A & C=.. Magnetic Bearing of a line OA

12 PRACTICAL NO: 6 Aim: - To measure horizontal and vertical angle between two points using theodolite. Apparatus: - Transit theodolitetripod, ranging rod, pegs etc. (1)Measurement of horizontal angles:- Procedure:- - Set the theodolite over 0. Take make the vernier at To set the reading at loose the upper plate till zero of vernier plate coincide with lower horizontal circle at 0. - Turn the telescope to bisect ranging rod at P using clamp screw to exact bisect P point. - Now unclamp the upper plate and turn the telescope in clockwise direction to bisect ranging rod at R is bisected, clamp upper plate. - Read both reading, vernier A gives reading directly, vernier B reading detecting from Change the face to repeat the process, mean of the face reading gives <POR. Station Object Face A B Initial Final Initial Final A B Face angle

13 (2) Measurement of vertical angle: To measure the vertical angle of an object P - Set up the instrument over station O and level it carefully with respect to altitude bubble. - By means of vertical circle clamp and tangent screw, set 0 of the vertical circle exactly to 0 of the circle. - Bring the bubble of the altitude level to the centre of its run by means of foot &clip screw. The line of sight is thus made horizontal. - Loose the vertical circle clamp and direct the telescope in vertical plane towards the object P, and bisect exactly using vertical tangent screw. - Read both the verniers C and D, the mean of two readings gives angle for that face. - Change the face and repeat the above process, and get the face reading. - The average of two face values gives exact value of required vertical angle. Observation Table: Station Object Face A B Initial Final Initial Final A B Face angle

14 PRACTICAL NO: 7 Aim:- To measure horizontal angle by repetition& group of angle in a horizon i.e. reiteration. Apparatus:- theodolite, pegs, ranging rod etc. Repetition Method:- Theory:- 1. Set up instrument at O with face left or right. 2. Make the vernier A at to vernier B at with upper clamp to lower unclamp. 3. Bisect A point exacting by using lower clamp screw. 4. Unclamp the upper, clamp to lower screw. Clamp rotate clockwise bisect B 5. After bisecting B point make upper clamp to lower unclamp and read both the verniers. 6. Swing the telescope towards A clockwise by leaving verniers unchanged. Using lower tangent screws i.e. initial reading is final reading of first round. 7. Apply the same procedure as per A for bisecting B swing the telescope towards A. 8. After three rounds face is changed same three rounds are taken on changed face. Average reading is calculated in each face. of two faces is final reading. Observation Table: Station Object Face A B Initial Final Initial Final A B Face angle

15 Reiteration Method: It is preferred when several angles is to be taken at a particular points i.e. horizon is closed. Theory:- 1. Set up the instrument over o to make vernier at by clamping upper clamp screw to a lower clamp screw. 2. Direct the telescope at point A i.e. initial point bisect it accurately using lower clamp screw. 3. Losing the upper plate and clamping lower rotate clockwise to bisect B point by clamping upper screw. Read both verniers the mean of two verniers reading gives < AOB. 4. Similarly bisect C to point take down readings. 5. Finally closed horizon by sighting the referring object A i.e. vernier reading Change face take down another sets of readings. Observation Table: Station Object Face A B Initial Final Initial Final A B Face angle Result : Repetition angle between A & B is. Reiteration angle at a horizon is.

16 PRACTICAL NO: 8 Aim:- To determined distance and reduce level of elevation point by Tachometric observations. Apparatus:- tachometer, leveling staff, pegs, etc. Theory:- There are two constants i.e. multiplying constant (K), and additive constant(c) these are computed by taking observations. Procedure:(tachometric constants) - Measure a line OA 10 m long on a fairly level ground with a steel tape and fixed pegs along a distance of 5m. - Set up the instrument over O, obtained the staff intersect by taking stadia reading on the staff truly vertical on each peg. - On substituting values of D and S in equation D=KS+C, we get a equation when showed in pairs and get the values of k and C. Observation Table: Distance 5m Staff Upper Lower Staff Intercept

17 10m 2)Measurement of RL and distance. - Set up the instrument at O, do all the temporary adjustment. - Bisect the staff station at a vertical angle Ø. - With the help of staff intersect and Ø, distance between instrument and staff station is determined by D=KS.Cos2Ø+C.Cos Ø - V=D.tan Ø. - The RL of a staff station is determined by = RL of inst. Axis+V-h - Ø may be angle of elevation or depression. Station Point O Staff station P Vertical angle Staff Upper Middle Lower H.I Result: R.L of P point is.. Distance of P point from station is

18 Project No: 1 Aim:- To carry out profile leveling to determine undulation of ground surface along a predetermined line which is center line of Road, canal or pipe line etc. Procedure:- 1. Let AB be the line of section stations marked on the ground at every 20 or 30 meters. 2. The level is set on firm ground so that large no. of points can be commanded on the line. 3. A back sight is taken on BM to determine the reduced level of the plane of collimation. 4. The staff reading is taken on the staff stations marked. When it is found necessary to shift the instrument on account of length of sight exceeding 100m or owing to the irregularities the staff men select a suitable change points as for sight is taken on it. 5. The instrument is then shifted and set on new point and BS is taken on C.P to find elevation of the read plane of collimation. 6. The RL of various plane are determined by height. Of instrument method or rise and fall method. The finally profile is plotted on a sheet. Stati on Distance Bearing Collimation point Left Centre Right Back Fore BS IS FS Reduced levels Remarks

19 Project No: 2 Aim:- To perform Block Contouring. Theory:- This method is suitable for when the area is not very extensive. In this method the area is divided into series of the squares and the corners of the squares are marked with the pegs. The size of square varies from 5 m to 2 m side depending upon the nature of ground and contour interval. The square need not to be same size throughout. Each separate square is pegged out. The elevation of the ground at the corners of the square are determined with a level. Intermediate points within the square may be taken when required and may be located on the diagonals of the squares or by the measurement from the corners. The system of square is plotted and near each corner is written its elevation. The corner lines are the interpolated in the usual way.

20 Project No: 3 Aim :- To perform Theodolite traversing. Procedure:- In running traverse ABCD the theodolite is set up over the first station A and bearing of line AB is measured. The angle DAB is then measured by taking a back sight on preceding station and fore sight on forward station B. Turning the telescope clock wise, the mean of two vernier reading gives the required angle DAB. Face left and face right observation should be made to eliminate the instrumental error. The theodolite is moves to each of the successive stations B, C etc, and angles ABC, BCD, CDA are measured. The line AB, BC, CD are measured with chain or tape and offset necessary to locate the details and recorded in field book.