Estimation of Earthwork Cut and Fill Volumes

This assignment involves estimating cut and fill volumes of four grids provided on topographical plan of a given site. The cut and fill volumes are calculated using four-corner method. The general procedure is to determine the proposed and existing levels at each corner of the four grids. The difference between existing and proposed level is determined at each of the four corners and then averaged. The average cut or fill depth is then multiplied by the area of the grid to get the cut or fill volume of that particular grid.

Running head: ESTIMATING EARTHWORK CUT AND FILL VOLUMES
Estimation of Earthwork Cut and Fill Volumes
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ESTIMATING EARTHWORK CUT AND FILL VOLUMES 2
Estimation of Earthwork Cut and Fill Volumes
This assignment involves estimating cut and fill volumes of four grids provided on
topographical plan of a given site. There is an assumption that an average of 250 mm of topsoil
has to be unearthed on the site before any construction work can start. This means that the four
grids will have an obligatory cut depth of 250 mm. This cut may have been recommended so as
to make the ground more stable after realizing that the topsoil as it is may not provide the
required ground or surface stability for the structure to be built on it. The cut and fill volumes are
calculated using four-corner method. This method is also referred to as grid method. The general
procedure is to determine the proposed and existing levels at each corner of the four grids. The
difference between existing and proposed level is determined at each of the four corners and then
averaged. The average cut or fill depth is then multiplied by the area of the grid to get the cut or
fill volume of that particular grid (Engineers Daily, 2014). The proposed elevations are
determined by finding the average of multiple topographical elevations provided by J.L.
Richards & Associated Limited.
For example, calculation of proposed elevation for corner 1 of grid 1 is as follows:
91.565+91.597+ 91.590+91.694
4 =91.612m
The calculation of elevation difference at the corners of the four grids is shown in Table 1 below
Table 1: Calculation of elevation difference
Elevation difference (Existing level – proposed level
Corner Grid #1 Grid #2 Grid $3 Grid #4
Corner 1 91.612 m – 91.77 m
= -0.158 m
91.667 m – 91.81 m
= -0.143 m
91.657 m – 91.85 m
= -0.193 m
91.60 m – 91.70 m
= -0.100 m
Corner 2 91.667 m – 91.81 m
= -0.143 m
91.657 m – 91.85 m
= -0.193 m
91.785 m – 91.89 m
= -0.105 m
91.642 m – 91.75 m
= -0.108 m

ESTIMATING EARTHWORK CUT AND FILL VOLUMES 3
Corner 3 91.728 m – 91.83 m
= -0.102 m
91.762 m – 91.87 m
= -0.108 m
91.848 m – 91.91 m
= -0.062 m
91.612 m – 91.77 m
= -0.158 m
Corner 4 91.762 m – 91.87 m
= -0.108 m
91.848 m – 91.91 m
= -0.062 m
91.804 m – 91.95 m
= -0.146 m
91.667 m – 91.81 m
= -0.143 m
The values obtained in the table above are then used to determine average depth of each grid.
Since the difference between existing level and proposed level at each corner is negative, it
means that the volume in each grid is fill. The calculation of average depth, area and cut/fill
volume for each grid is as shown in Table 2 below
Table 2: Calculation of cut and fill area, average height and volume
Sketches Ordinate
s
Area Average
Ht.
Volume
Cut Fill
Grid #1
Area: 40 m x 40 m
Avg . Fill depth=0.158+ ( 0.143 ) + ( 0.102 ) + ( 0.108 )
4
= 0.128 m
1,600 m2 0.128 m 204.8 m3
Avg. cut depth = 0.25 m 1,600 m2 0.25 m 400 m3
Grid #2
Area: 40 m x 40 m
Avg . Fill depth=0.143+ ( 0.193 ) + ( 0.108 ) + ( 0.062 )
4
= 0.127 m
1,600 m2 0.127 m 203.2 m3
Avg. cut depth = 0.25 m 1,600 m2 0.25 m 400 m3
Grid #3

ESTIMATING EARTHWORK CUT AND FILL VOLUMES 4
Area: 40 m x 40 m
Avg . Fill depth=0.193+ ( 0.105 ) + ( 0.062 ) + ( 0.146 )
4
= 0.127 m
1,600 m2 0.127 m 203.2 m3
Avg. cut depth = 0.25 m 1,600 m2 0.25 m 400 m3
Grid #4
Area: 40 m x 40 m
Avg . Fill depth=0.100+ ( 0.108 ) +0.158+ ( 0.143 )
4
= 0.127 m
1,600 m2 0.127 m 203.2 m3
Avg. cut depth = 0.25 m 1,600 m2 0.25 m 400 m3
The summary showing total cut and fill volumes of different grids is shown in Table 3 below
Table 3: Total cut and fill volumes
Grid Number Fill Volume Cut Volume
Grid Number 1 204.8 m3 400 m3
Grid Number 2 203.2 m3 400 m3
Grid Number 3 203.2 m3 400 m3
Grid Number 4 203.2 m3 400 m3
Total 814.4 m3 1,600 m3
The calculations above show that the volume of cut is greater than the volume of fill. Looking at
these values, it shows that there will be surplus soil on site. Knowing cut and fill volumes
(earthwork) helps the contractor to plan where to dispose the surplus soil (New Building Material

ESTIMATING EARTHWORK CUT AND FILL VOLUMES 5
& Construction World, 2012). If the cut soil meets the required properties of fill material, it can
be used as fill before disposing the surplus soil material.
Works Cited
Engineers Daily. (2014, April 1). Calculation of Cut and Fill Using the Grid Method. Retrieved from
Engineers Daily: http://www.engineersdaily.com/2014/04/calculation-of-cut-and-fill-using-grid-
method.html
New Building Material & Construction World. (2012, September 24). Construction Site Earthwork
Calculation. Retrieved from NBM&CW: https://www.nbmcw.com/equipments/surveying-
testing-equipments/29427-construction-site-earthwork-calculation.html