Earthwork balance and contaminated soil, IL 851 at Kettle Landing

The excavation and embankment quantities in the Earthwork Schedule are summed by segment and material type and checked against the supplemental Preliminary Site Investigation. The project balances on paper, but contaminated suitable earth turns it into a shortage, and no pay item covers the contaminated soil.

IDOT Standard Specifications, Earthwork Schedule at 15% shrinkageSta. 100+00 to 178+00, six segmentsPSI Sep 18, 2026, 22 borings, 52 samplesNAD83(2011) Illinois East (1201), US survey ft; NAVD 88Prepared Nov 5, 2026

Summary

Earthwork balance · Segment 4

Balanced on paper, 2,940 CY short once contamination is counted

The Earthwork Schedule shows a 1,430 CY surplus for the project, 1.8% of embankment. But 3,440 CY of suitable earth in Segment 4, the former storage yard near Sta. 142+60 to 145+60, is impacted, with lead above the TACO Tier 1 residential objective and benzo(a)pyrene above the MAC in SB-14 to SB-16 (PSI Appendix C). That earth is slated for the Segment 5 embankment. With Segments 2 and 6, the base case is 2,940 CY short.

Carry FURNISHED EXCAVATION in the change order request.

Scenarios · Segment 3

The worst case sends 4.0 times as many tons off-site as the base case

The base case is 11,160 tons and the worst case 44,860 tons. 56% of the difference comes from Segment 3, where SB-09 (slag fill, lead 3,100 mg/kg, TCLP lead 7.4 mg/L) and SB-10 are 617 ft apart with no boring in between. The boring log cites utilities and traffic.

Additional borings between the two will show how much of the range is real.

Bid schedule · Section 669

No pay item covers contaminated soil: a potential $823,000 change order in the base case

The bid schedule has no NON-SPECIAL WASTE DISPOSAL or HAZARDOUS WASTE DISPOSAL items. Disposal, hauling and furnished excavation, less disposal already paid under existing items, come to $823,000 in the base case, $2.11 million in the alternative and $4.25 million in the worst case.

Give notice of a differing site condition. The quantities and proposed pay items are in the tool.

Earthwork balance and contaminated soil by scenario

Pick a scenario or change the assumptions. The plan strip shows the roadway with the borings and the zones counted as contaminated; the profile shows excavation depth and contaminated intervals. Click a segment or a boring to see the Earthwork Schedule rows, plan sheets and boring log.

Scenario
Bump up near next limit
0Earthwork balance
0Contaminated soil, in place
0Off-site disposal
0Potential change order

Top band: plan of the excavation width with the borings. Bottom band: profile; gray is excavation from the cross sections, color is contaminated soil counted in the scenario. Blue marks above the roadway show stretches between impacted borings with no sample.

Earthwork balance by segment

Embankment CY. Usable excavation is suitable earth × 0.85 (15% shrinkage) and rock × 1.20. Contaminated suitable earth is deducted.

Contaminated soil by class

Scenario comparison

At the selected unit weight and swell factor.

Source for the selected item

Proposed change order items

The bid schedule has no pay items for regulated substances. The items below use IDOT pay item names; quantities follow the selected scenario.

Sources and method

Sources

  • IL851_Bid_Schedule.xlsxSchedule of prices with earthwork pay items in CU YD142 pay items
  • IL851_Plans_Kettle_Landing.pdfEarthwork Schedule (sheet 14), plan and profile (sheets 21–26), cross sections (sheets 61–79)96 sheets
  • PSI_IL851_Kettle_Landing_2026-09-18.pdfSupplemental Preliminary Site Investigation: boring location plan (Figure 3), boring logs (Appendix B), lab reports (Appendix C)88 pages
  • IL851_Special_Provisions.pdfContract special provisions; no regulated-substance provision included64 pages
  • Disposal_Quotes_2026.pdfTipping fees and haul rates for a Subtitle D landfill and a permitted hazardous waste facility5 pages

Method

  1. Earthwork Schedule rows were summed by segment and material: suitable earth used in embankment and waste earth (EARTH EXCAVATION), peat undercut (REMOVAL AND DISPOSAL OF UNSUITABLE MATERIAL), rock (ROCK EXCAVATION) and embankment from the cross sections.
  2. The balance follows the furnished excavation formula in the Standard Specifications: embankment minus excavation × (1 − shrinkage), with 15% shrinkage for earth and a 1.20 factor for rock.
  3. Each sample was classed against the Maximum Allowable Concentrations of 35 Ill. Adm. Code 1100, Subpart F (lead 107 mg/kg, not location-specific; benzo(a)pyrene 2.1 mg/kg for a populated area in an MSA county outside Chicago), the TACO Tier 1 residential ingestion objective for lead of 400 mg/kg (35 Ill. Adm. Code 742, Appendix B, Table A) and the TCLP lead limit of 5.0 mg/L for characteristic hazardous waste (D008).
  4. Extent along the road: in the base case each impacted boring gets a zone of at most the buffer and at most half the distance to the next boring. The alternative counts the full distance between two impacted borings at the lower class for each interval. The worst case runs out to the next clean boring, at most twice the buffer, and counts the distance between impacted borings at the higher class.
  5. Depth: to the bottom of the deepest impacted sample. Where a boring is not delineated, the added depth applies. Everything is capped at the excavation depth from the cross sections, computed every 5 ft across the excavation width.
  6. Tons are in-place CY × unit weight. Loads are the larger of tons/22 and loose CY/24 for a semi end dump. Cost is disposal plus haul plus furnished excavation for the shortage, less disposal already paid under existing items.

Assumptions and limitations

  • Soil above the MAC but within TACO is not counted as reusable unless the reuse box is checked. Reuse as embankment in the right-of-way needs the Engineer's approval and must be suitable. Classes follow Article 669.05 of the IDOT Standard Specifications (2022): soil above the most stringent MAC but within TACO Tier 1 residential may not go to a CCDD facility or an uncontaminated soil fill operation; where it cannot be used in the right-of-way it is priced here as landfill disposal under NON-SPECIAL WASTE DISPOSAL (Article 669.05(a)(5)).
  • Article 669.05(c) also lets such soil be handled under Article 202.03. Whether IDOT pays for it as non-special waste disposal or as ordinary surplus should be confirmed with the IDOT district environmental unit.
  • Bumping a sample up near the next limit is a scenario assumption, not a measurement. TCLP was run on 5 samples only; a bump to hazardous needs a measured TCLP result.
  • The MAC values assume the site is a populated area in an MSA county. A different location class changes the benzo(a)pyrene limit. The MAC table used is Illinois EPA’s 2012 compilation; the location class and any later changes should be confirmed with Illinois EPA’s CCDD program before disposal is planned.
  • Prices are 2026 quotes: $38/ton landfill disposal, $185/ton hazardous waste disposal, $520 and $1,850 per load haul, $18.00/CY furnished excavation and a $6.00/ton deduct for disposal already paid. Price levels should be checked against current local rates before the cost is used, and the 1.20 rock factor is the estimate’s own and should be confirmed by the estimator.
  • Soil disposal analysis, monitoring, stockpiling and groundwater handling are not priced.
  • Surplus suitable earth in one segment is assumed to be usable in another. Haul within the project is not included.