Item 102 - Excavation
102.1 Description
This Item shall consist of roadway drainage and borrow excavation, and the disposal of material in accordance with this Specification and in conformity with the lines, grades and dimensions shown on the Plans or established by the Engineer.
102.1.1 Roadway Excavation
Roadway excavation will include excavation and grading for roadways, parking areas, intersections, approaches, slope rounding, benching, waterways and ditches; removal of unsuitable material from the roadbed and beneath embankment areas; and excavating selected material found in the roadway as ordered by the Engineer for specific use in the improvement. Roadway excavation will be classified as "unclassified excavation", "rock excavation", "common excavation", or "muck excavation" as indicated in the Bill of Quantities and hereinafter described.
- Unclassified Excavation. Unclassified excaJation shall consist of the excavation and disposal of all materials regardless of its nature, not classified and included in the Bill of Quantities under other pay items.
- Rock Excavation. Rock excavation shall consist of excavation of igneous, sedimentary and metamorphic rocks which cannot be excavated without blasting or the use of rippers, and all boulders or other detached stones each hqving a volume of 1 cubic meter or more as determined by physical measurements or visually by the Engineer.
- Common Excavation. Common excavations shall consist of all excavation not included in the Bill of Quantities under "rock excavation" or other pay items.
- Muck Excavation. Muck excavation shall consist of the removal and disposal of deposits of saturated or unsaturated mixtures of soils and organic matter not suitable for foundation materials regardless of moisture content.
102.1.2 Borrow Excavation
Borrow excavation shall consist of the excavation and utilization of approved materials required for the construction of embankments or for other portions of the work, and shall be obtained from approved sources, in accordance with Clause 61 , Standard Specifications for Public Works and Highways, Volume I and the following:
- Borrow, Case 1 - Borrow Case 1 will consist of material obtained from sources designated on the Plans or in the Special Provisions.
- Borrow, Case 2 - Borrow Case 2 will consist of material obtained from sources provided by the Contractor.
The material shall meet the quality requirements determined by the Engineer unless otherwise provided in the Contract.
102.2 Construction Requirements
102.2.1 General
When there is evidence of discrepancies on the actual elevations and that shown on the Plans, a pre-construction survey referred to the datum plane used in the approved Plan shall be undertaken by the variations that do' not constitute a safety hazard or an impairment to drainage courses or facilities will be permitted.
A maximum offset of 600 mm will be permitted for a construction working bench at the bottom of each lift for use in drilling the next lower presplitting pattern.
Ditches shall conform to the slope, grade, and shape of the required cross-section, with no projections of roots, stumps, rock, or similar matter. The Contractor shall maintain and keep open and free from leaves, sticks, and other debris all ditches dug by him until final acceptance of the work.
Furrow ditches shall be formed by plowing a continuous furrow along the line staked by the Engineer. Methods other than - plowing may be used if acceptable to the Engineer.The ditches shall be cleaned out by hand shovel work, by ditcher, or by some other suitable method, throwing all loose materials on the downhill side so that the bottom of the finished ditch shall be approximately 450 mm below the crest of the loose material piled on the downhill side. Hand finish will not be required; but the flow lines shall be in satisfactory shape to provide drainage without overflow.
When excavation methods employed by the Contractor leave undrained pockets .tn the rock surface, the Contractor shall at his own expense, properly drain such depressions or when permitted by the Engineer fill the depressions with approved impermeable material.
Material below subgrade, other than solid rock shall be thoroughly scarified to a depth. of 150 mm and the moisture content increased or reduced, as necessary, to bring the material throughout this 1.50 mm layer to the moisture. content suitable for maximum compaction. This layer shall then be compacted in accordance with Subsection 104.3.3
All borrow areas shall be bladed and left in such shape as to permit accurate measurements after excavation has been completed. The Contractor shall not excavate beyond the dimensions and elevations established, and no material shall be removed prior to the staking out and cross-sectioning of the site. The finished borrow areas shall be approximately true to line and grade established and specified and shall be finished, as prescribed in Clause 61, Standard Specifications for Public Works and Highways, Volume 1. When necessary to remove fencing, the fencing shall be replaced in at least as good condition as it was originally. The Contractor shall be responsible for the confinement of livestock when a portion of the fence is removed.
Where excavation to the finished graded section results in a subgrade or slopes of unsuitable soil, the Engineer may require the Contractor to remove the unsuitable material and backfill to the finished graded section with approved material. The Contractor shall conduct his operations in such a way that the Engineer can take the necessary cross-sectional measurements before the backfill is placed.
The excavation of muck shall be handled in a manner that will not permit the entrapment of muck within the backfill. The.material used for backfilling up to the ground line or water level, whichever is higher, shall be rock or other suitable granular material selected from the roadway excavation, if available. If not available, suitable material shall be obtained from other approved sources. Unsuitable material removed shall be disposed off in designated areas shown on the Plans or approved by the Engineer.
Measurement of Unsuitable or Surplus Material shall be the net volume in its original position.
For measurement purposes, surplus suitable material shall be calculated as the difference between the net volume of suitable material required to be used in embankment corrected by applying a shrinkage factor or a swell factor in case of rock excavation, determined by laboratory tests to get its original volume measurement, and the net volume of suitable material from excavation in the original position. Separate pay items shall be provided for surplus common, unclassified and rock material.
The Contractor shall be deemed to have included in the contract unit prices all costs of obtaining land for the disposal of unsuitable or surplus material.
Payment will be made under:
A maximum offset of 600 mm will be permitted for a construction working bench at the bottom of each lift for use in drilling the next lower presplitting pattern.
102.2.6 Excavation of Ditches, Gutters, etc.
All materials excavated from side ditches and gutters, channel changes, irrigation ditches, inlet and outlet ditches, toe ditches, furrow ditches, and such 'other ditches as may be designated on the Plans or staked by the Engineer, shall be utilized as provided in Subsection 102.2.3.Ditches shall conform to the slope, grade, and shape of the required cross-section, with no projections of roots, stumps, rock, or similar matter. The Contractor shall maintain and keep open and free from leaves, sticks, and other debris all ditches dug by him until final acceptance of the work.
Furrow ditches shall be formed by plowing a continuous furrow along the line staked by the Engineer. Methods other than - plowing may be used if acceptable to the Engineer.The ditches shall be cleaned out by hand shovel work, by ditcher, or by some other suitable method, throwing all loose materials on the downhill side so that the bottom of the finished ditch shall be approximately 450 mm below the crest of the loose material piled on the downhill side. Hand finish will not be required; but the flow lines shall be in satisfactory shape to provide drainage without overflow.
102.2. 7 Excavation of Roadbed Level
Rock shall be excavated to a depth of 150 mm below subgrade within the limits .'of the roadbed, and the excavation backfilled with material designated. on the Plans or approved by the Engineer and compacted to the.required density.When excavation methods employed by the Contractor leave undrained pockets .tn the rock surface, the Contractor shall at his own expense, properly drain such depressions or when permitted by the Engineer fill the depressions with approved impermeable material.
Material below subgrade, other than solid rock shall be thoroughly scarified to a depth. of 150 mm and the moisture content increased or reduced, as necessary, to bring the material throughout this 1.50 mm layer to the moisture. content suitable for maximum compaction. This layer shall then be compacted in accordance with Subsection 104.3.3
102.2.8 Borrow Areas
The Contractor shall notify the Engineer sufficiently in advance of opening any borrow areas so that cross-section elevations and measurements of the ground surface after stripping may be taken, and the borrow material can be tested before being used. Sufficient time for testing the borrow material shall be allowed.All borrow areas shall be bladed and left in such shape as to permit accurate measurements after excavation has been completed. The Contractor shall not excavate beyond the dimensions and elevations established, and no material shall be removed prior to the staking out and cross-sectioning of the site. The finished borrow areas shall be approximately true to line and grade established and specified and shall be finished, as prescribed in Clause 61, Standard Specifications for Public Works and Highways, Volume 1. When necessary to remove fencing, the fencing shall be replaced in at least as good condition as it was originally. The Contractor shall be responsible for the confinement of livestock when a portion of the fence is removed.
102.2.9 Removal of Unsuitable Material
Where the Plans show the top portion of the roadbed to be selected topping, all unsuitable materials shall be excavated to the depth necessary for replacement of the selected topping to the required compacted thickness.Where excavation to the finished graded section results in a subgrade or slopes of unsuitable soil, the Engineer may require the Contractor to remove the unsuitable material and backfill to the finished graded section with approved material. The Contractor shall conduct his operations in such a way that the Engineer can take the necessary cross-sectional measurements before the backfill is placed.
The excavation of muck shall be handled in a manner that will not permit the entrapment of muck within the backfill. The.material used for backfilling up to the ground line or water level, whichever is higher, shall be rock or other suitable granular material selected from the roadway excavation, if available. If not available, suitable material shall be obtained from other approved sources. Unsuitable material removed shall be disposed off in designated areas shown on the Plans or approved by the Engineer.
102.3 Method of Measurement
The cost of excavation of material which is incorporated in the Works or in other areas of fill shall be deemed to be included in the Items of Work where the material is used.Measurement of Unsuitable or Surplus Material shall be the net volume in its original position.
For measurement purposes, surplus suitable material shall be calculated as the difference between the net volume of suitable material required to be used in embankment corrected by applying a shrinkage factor or a swell factor in case of rock excavation, determined by laboratory tests to get its original volume measurement, and the net volume of suitable material from excavation in the original position. Separate pay items shall be provided for surplus common, unclassified and rock material.
The Contractor shall be deemed to have included in the contract unit prices all costs of obtaining land for the disposal of unsuitable or surplus material.
102.4 Basis of Payment
The accepted quantities, measured as prescribed in Section 102.3 shall be paid for at the contract unit price for each of the Pay Items listed below that is included in the Bill of Quantities which price and payment shall be full compensation for the removal and disposal of excavated materials including all labor, equipment, tools, and Incidentals necessary to complete the work prescribed in this Item.Payment will be made under:
| Pay Item Number | Description | Unit of Measurement |
|---|---|---|
| 102 (1) | Unsuitable Excavation | Cubic Meter |
| 102 (2) | Surplus Common Excavation | Cubic Meter |
| 103 (3) | Surplus Rock Excavation | Cubic Meter |
| 102 (4) | Surplus Unclassified Excavation | Cubic Meter |
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