In Plain English
Quick Answer
Large-scale digging over a wide area to lower the entire site grade — used for basements and below-grade construction.
Definition
Definition
Large-scale excavation of soil and rock over a broad area to lower an entire site's grade, as opposed to trench or pit excavation. Mass excavation is used for basements, underground parking, below-grade construction, and site grading. It typically employs large equipment such as scrapers, bulldozers, and articulated dump trucks and is priced per cubic yard removed.
Context
Why It Matters in Bidding
Mass excavation is priced per cubic yard and dominated by equipment production rates and haul logistics, so estimators must analyze soil type, swell and shrink factors, and disposal distance rather than just bank-volume quantities. Misjudging unsuitable soils, rock, dewatering, or off-site haul costs can swing earthwork bids dramatically, and these high-volume operations carry major schedule and cash-flow implications.
Example
Example
For a below-grade parking structure, the estimator calculates 25,000 bank cubic yards, applies a swell factor for hauling, then prices excavator and dump-truck production rates plus a 12-mile round-trip haul to the disposal site.
See Also
Related Terms
FAQ
Questions Contractors Ask
How is mass excavation priced in an estimate?
It is priced per cubic yard based on equipment production rates—excavators, scrapers, dozers, and haul trucks—matched to soil conditions and haul distance. Estimators convert bank volume using swell factors for loose hauled material and shrink factors for compacted fill, then layer in mobilization, dewatering, and disposal or stockpile costs.
What hidden costs are commonly missed in mass excavation bids?
Unsuitable soil removal, rock excavation, dewatering, shoring near property lines, off-site haul and tipping fees, and erosion-control measures are frequent omissions. Geotechnical reports should be reviewed closely, since unanticipated rock or groundwater can multiply unit costs. Many contractors qualify their bid with assumptions about subsurface conditions to manage this risk.
What is the difference between mass excavation and trench excavation?
Mass excavation lowers grade over a broad area with high-production equipment and lower unit costs, while trench excavation is narrow, slower, and pricier per yard due to confined work, shoring, and bedding. They use different productivity factors and should be estimated as separate items rather than blended into one earthwork rate.
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