Undertake a practical levelling survey using the levelling equipment provided by your college. a. A levelling survey for a proposed sewer is to be carried out to establish the invert levels at various...

Undertake a practical levelling survey using the levelling equipment provided by your college.

a. A levelling survey for a proposed sewer is to be carried out to establish the invert levels at various chainage points for the sewer. Select the equipment needed to perform the levelling survey. Working in groups of three, peg out a straight line a minimum of 40 m long over undulating land. This represents the line of a proposed sewer. Set out pegs or arrows at regular intervals to take account of the changes in the slope of the ground. Establish a suitable point for a TBM and using this, undertake a level survey of the ground marked by the pegs using an optical or digital level.

b. Carry out the levelling survey in the field and all necessary arithmetic and accuracy calculation checks to determine the ‘Reduced Levels’ of the points on the ground that have been marked out. Use one of the two available methods for booking levels. Remember in your group to take turns in holding the staff and taking/booking the readings. From your field notes and booking sheet produce a long section in a standard format showing the variation of ground level with chainage.

c. The new sewer that is to be constructed starts from a point at the end of the line, with a reduced level of 1 m below the existing ground level at that point. Calculate the invert levels of all the chainage points survey along the ground assuming that the sewer falls at gradient of 1 in 40. Add the reduced levels of the invert of the sewer to the long section produced previously in a standard format.

d. Undertake further levelling work.