Q & Answer - What are the different types of Engineering surveys under taken before construction of a new line/ Explain their scope and significance.

Q. What are the different types of Engineering surveys under taken before construction of a new line/ Explain their scope and significance.

Ans.- Different types of Engineering surveys –

Reconnaissance Survey -

Rough and rapid survey with or with out instrument of one or more routs for a proposed line is called Reconnaissance Survey. Approximate heights and distances are collected using instruments such as prismatic compass, hand level and range finder.

SURVEYING

General purpose of Surveying –The main object of surveying is the preparation of  maps or plans which are the basis in planning and design of engineering project such as route location of railway line, roads and water supply scheme. To locate correct position of any point in horizontal and vertical plane. 

Definition of Survey : Operation of making such measurements that the relative

position of various features, natural or Artificial on the surface of the earth can be exhibited in their correct Horizontal and vertical relationship.

SURVEYING - Normally determining position in Horizontal plane is called surveying. Art of making measurement and determining the position of point in horizontal plane. Surveying is done by various instruments such as surveyor’s chain, compass, measuring tape, ranging rods, pegs etc.

LEVELLING - The art of determining relative altitudes of points on the surface of the earth or beneath the surface of earth is called LEVELLING. Determining the position of point in vertical plane. Determining relative heights or depth is called levelling.

For execution of Engineering Projects it is very necessary to determine elevations of different points along the alignment of proposed project.Other applications are :

i) Taking rail levels existing before track renewals to finalise final rail level profile including vertical curves.

ii) Initial ground levels for earthwork calculations.

iii) Levels for measurement of earthwork.

iv) Measurement of ballast etc.