Earthwork
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Transcript of Earthwork
![Page 1: Earthwork](https://reader033.fdocuments.net/reader033/viewer/2022042615/563db7c1550346aa9a8da1f5/html5/thumbnails/1.jpg)
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HIGHWAY ENGINEERING
EARTHWORKS, CROSS-SECTIONS
AND MASS HAUL DIAGRAMS
OBJECTIVES
• ROUTE SELECTION – Estimation of cut and fill locations and quantities in order to approximately balance these values as a basis for selecting alternative routes and making preliminary costs.
• CONSTRUCTION – preparation of detailed earthwork quantities to establish economical haul distances, acquire borrow pit and disposal areas and to conduct cost and tender estimates.
a pit created to provide
earth that can be used as
fill at another site
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PRESENTATION OUTLINE
• Earthworks and Preliminary Route Selection
• Earthwork Analysis
• Cross-sections types
• Estimating volumes
• Shrinkage
• Location of cross-sections
• Earthworks tabulations
• Mass-Haul Diagrams
Earthworks and Preliminary Route Selection
Base mapping
Horizontal alignments
Vertical alignment (profile or longitudinal section)
Controls and constraints
Evaluation
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Earthworks and Preliminary Route Selection
Plan View
Profile View
Earthwork Analysis
Take cross sections (typically 50 - 200 m)
Plot natural ground level
Plot proposed grade profile
Indicate areas of cut and fill
Calculate volume between cross sections
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Cross-Sections Types
Cross-Section Area
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Cross-Section Area Example
= 53.68 + 45.88 + 131.57 + 19.47 – 16.00 – 45.70 = 188.90
Cross-Section Area
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Estimating Volumes
Average End Area Method
The area between the existing ground and proposed ground is calculated at each cross section.
The area between two consecutive cross sections is averaged.
This area is multiplied by the distance between two cross sections.
Estimating Volumes
Where:V = volume (m3)A1, A2 and A3 = area of end sections (m2)L = length between end sections (m)
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Shrinkage
Material volume increases during excavation (presence of air voids)
Volume decreases during compaction
This difference is defined as 'shrinkage'
Varies with
o soil type
o fill height
o cut depth
Location of Cross Sections
Sufficient to adequately estimate the earthworks
Hilly, undulating terrain requires more than flat terrain
Usually minimum of 20 m in rolling terrain (interval)
Possibly 100 to 200 m in flat terrain (interval)
Most highway departments have standardized intervals
More frequent spacing may be required at specific locations –e.g: at end and near bridges, culverts, etc.
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Mass Haul Computation
Usually in a tabular format with the following columns :
Station or distance Area of cross section • Excavation (cut) • Embankment (fill)
Average cross section area• Excavation• Embankment
Volume• Excavation• Embankment
Excess (+ for embankment, - for excavation) Mass Haul Ordinate
* cross-sections interval shall be within 15 m to 30 m, especially in the mountainous and hilly terrain areas.
Sample of cross section – cut area
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Sample of calculation
Shrinkage : 10%
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Stn/ Dist.
A REA(sq. m)
Shrinkage Average Area(sq. m)
Volume(cu. m)
EXCESS (EXC/EMB)
MassCurve
OrdinateEXC EMB EMB+10% EXC EMB EXC EMB
6 10 0
150 5 40
300 156 0
450 5 140
600 5 14
750 5 45
900 72 0
Stn/ Dist.
A REA(sq. m)
Shrinkage Average Area(sq. m)
Volume(cu. m)
EXCESS (EXC/EMB)
MassCurve
OrdinateEXC EMB EMB+10% EXC EMB EXC EMB
1050 107 0
1200 5 14
1350 5 34
1500 5 43
1650 5 40
1794 11 0
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Mass-Haul Ordinate