ESTIMATION OF
EARTHWORKS IN
CONSTRUCTIONS
Prepared by Aldrin Justado
SOIL CONDITIONS
• There are three principal conditions
or states in which earthmoving
material may exist:
1) Bank
2) Loose
3) Compacted
SOIL CONDITIONS
Figure 1.0 Typical Soil Volume Change during Earthmoving
SWELLING
A soil increases in volume when it is excavated
because the soil grains are loosened during
excavation and air fills the void spaces created.
SWELLING
Find the swell of a soil that weighs 1661
kg/m3 in its natural state and 1186 kg/m3
after excavation.
SWELLING 40%
SHRINKAGE
When a soil is compacted, some of the air is
forced out of the soil's void spaces.
SHRINKAGE
Find the shrinkage of a soil that weighs 1661
kg/m3 in its natural state and 2077 kg/m3 after
compaction.
EARTHWORKS-CUT
AND FILL ESTIMATIONS
BY SECTION METHOD
STA. 0+000
5.25
5.4
6.2
7.5
6.7
STA. 0+100
5.2
5.46
7
7.9
6.78
STA. 0+200
4.8
4.9
4
3.6
2.8
STA. 0+300
5.2
5.46
7
7.9
6.78
Assign the depth at each corner or segment
intersection a weight according to its location
(number of segment lines intersecting at the
point).
• interior points (intersection of four segments)
are assigned a weight of FOUR
• exterior points at the intersection of two
segments are assigned a weight of TWO
• corner points are assigned a weight of ONE.
The figure below shows the topographic map of a certain lot. The soil that
weighs 17386.38 BCM after excavation and 21584.65 BCM after compaction.
An excavator has a bucket capacity of 30CM and an output of 1220 m3/day.
Its operation consist of the cycle: a) excavation time (45 s); b) travel time
(4min); c) dumping time (30s). Assume an overall efficiency factor for the
excavator = 90% and 8-hours working days. Determine the following:
a)
Bank Cubic Meter (BCM)
b)
Swell Percentage (%)
c)
Loose Cubic Meter (LCM)
d)
Shrinkage Percentage (%)
e)
Compacted Cubic Meter (CCM)
f)
No. of days to complete the job.
g)
No. of excavator required.
STA. 0+000
5.25
5.4
6.2
7.5
6.7
STA. 0+100
5.2
5.46
7
7.9
6.78
STA. 0+200
4.8
4.9
4
3.6
2.8
STA. 0+300
5.2
5.46
7
7.9
6.78
ANSWERS AND SOLUTIONS
The figure below shows the topographic map of a certain lot. The soil that
weighs 17386.38 BCM after excavation and 21584.65 BCM after compaction.
An excavator has a bucket capacity of 30CM and an output of 1220 m3/day.
Its operation consist of the cycle: a) excavation time (45 s); b) travel time
(4min); c) dumping time (30s). Assume an overall efficiency factor for the
excavator = 90% and 8-hours working days. Determine the following:
a)
Bank Cubic Meter (BCM) = 19368.72 cu. meter
b)
Swell Percentage (%) = 11.4 %  Factor = 1.1140
c)
Loose Cubic Meter (LCM) = 21576.75408 cu. meter
d)
Shrinkage Percentage (%) = 10.27 %  Factor = 1.1027
e)
Compacted Cubic Meter (CCM) = 21357.88754 cu. meter
f)
No. of days to complete the job. = 9 days
g)
No. of excavator required. = 2 Nr