Aquaculture Engineering

Unit 7- Earth work calculations

Methods used to calculate volume of earthwork

Longitudinal slope and cross slope
The slope of the ground along a given line is known as the longitudinal slope. On the other hand slope of the ground perpendicular to the given line is known as the cross slope or transverse slope. A ground having a cross slope is also known as side long ground. In flat country the cross slope is usually negligible. In a hilly terrain the cross slope is usually significant.

Note: Unless otherwise specified we should always assume that cross slope is zero.

Formation in cutting and filling

For a trapezoidal section cutting or filling, areas of the section is given by

Where,
A = Area of the section
B = Width of the section
Y = Depth of cut or height of bank
K = Slope of the section
Usually slope of the section is considered only horizontal to vertical. When ever the side slope is not clearly specified we shall assume the given side slope has horizontal to vertical.
For instance a side slope is 2:1 i.e., H = 2 V=1 . . . K=2
Side Slope is 3:2 means H=3 V=2 K = 1.5. . . . 1.5 H =1V