SECTION 03100 - COMMON EXCAVATION

SECTION 03100 - common excavation
TABLE OF CONTENTS
SECTION 03100 - common excavation
Description
Common Excavation shall consist of all excavation within the limits of the right-of-way except Structural Excavation, which shall be in accordance with Specification section 03200.
Common Excavation shall include the removal, handling and proper utilization or disposal of all excavated materials and shaping of excavation and preparation of exposed surface of excavation for the entire length of the roadway and approaches, in accordance with Specification requirements and the lines, levels, grades, dimensions and cross-sections shown on the Drawings and/or as required by the Engineer.
General
A pre-construction survey shall be undertaken by the Contractor under the control of the Engineer to serve as a basis for the computation of the actual volume of the excavated materials.
All excavations shall be finished to reasonably smooth and uniform surfaces. No materials shall be wasted without authority of the Engineer. Excavation operations shall be conducted so that material outside of the limits of slopes will not be disturbed. Prior to excavation, all necessary clearing and grubbing in that area shall have been performed in accordance with Specification section 02100. 
Conservation of Topsoil
In accordance with the provisions of Specification section 02100, suitable topsoil encountered in excavation and on areas where embankment is to be placed shall be removed to such extent and to such depth as the Engineer may direct. The removed topsoil shall be transported and deposited in storage piles at locations approved by the Engineer. The topsoil shall be completely removed to the required depth from any designated area prior to the beginning of regular excavation or embankment work in the area and shall be kept separate from other excavated materials for later use. No separate payment for the top soil excavation shall be made if the excavation is in the area covered under clearing and grubbing.
Use of Excavated Material
All suitable material removed from the excavation shall be used (unless otherwise directed by the Engineer) for the formation of the embankment, subgrade, shoulders, slopes, bedding, surcharge and backfill for structures, and for other purposes shown on the Drawings or as directed by the Engineer.
Any material surplus to these requirements, or any material declared in writing by the Engineer to be unsuitable, shall be disposed of by the Contractor outside the right-of-way or as directed by the Engineer in accordance with the provisions of these Specifications, and shall be considered as Waste Material. 
Removal of Unsuitable Material
Materials below the natural ground surface in embankment areas and in excavation areas below the grading plane or other limits shown on the Drawings or as designated by the Engineer, that is unsuitable for the planned use, shall be excavated and disposed of off site.
Unsuitable Material shall include:
Materials containing detrimental quantities of organic material, such as grass, roots and sewage.
Highly organic soil such as peat and muck.
Soils with liquid limit exceeding 50% and plasticity index exceeding 35%.
Soils with a natural water content exceeding 50%.
Soil with very low natural density, 800 kg/m3 or lower.
Highly expansive soil having an Activity value greater than 1.0 or degree of expansion classified by AASHTO T 258 as “Very High” or Extra High”. The Activity Value shall be measured as the ratio: Plasticity Index (AASHTO T90)/Percent Clay Size (AASHTO T 88).
Materials having hazardous chemical or physical properties.
Soil that cannot be properly compacted in accordance to Specification requirements as determined by the Engineer.
When so directed in writing by the Engineer, the Contractor shall remove material unsuitable for use in the embankment and shall dispose of it.
Where the excavation reveals a combination of suitable and unsuitable materials the Contractor shall unless otherwise agreed by the Engineer, carry out the excavation in such a manner that the suitable materials are excavated separately for use in the Works without contamination by the unsuitable materials.
When unsuitable material below sub-grade level in cut or below embankment foundation level is ordered to be removed, the soil left in place after the removal of the unsuitable material shall be compacted, to a depth of 20 cm, to a density of 90 percent of the maximum dry density determined according to AASHTO T99. Payment for such compaction shall be included in the unit rate for Common Excavation.
Dimensional Tolerances
Finished grades, lines and formations after excavation shall not vary from those specified by more than 20 mm at any point.
Finished excavated surfaces that are exposed to surface run-off water shall be sufficiently smooth and uniform, and have sufficient slope, to ensure the free drainage of the surface without ponding.
Excavation classification
All Common Excavation, regardless of its nature (soil, gravel, rock, etc.) will be in a single unit price for payment. No allowance will be made for classification of different types of material encountered.
Measurement and Payment
Method of Measurement
The Contractor shall, after clearing and grubbing, make topographical survey of the area and submit the surveyed cross section and profile maps to the Engineer for his review. The actual excavation volume shall be computed by the Contractor, and subject to the Engineer’s approval from the average cross section areas bounded by the ground lines after clearing and grubbing, the designed slope lines, and top planes of subgrade.
The quantity of Common Excavation to be paid for shall be the number of cubic meters of material acceptably excavated in accordance with specification requirements and approved by the Engineer, based on field measurements. The material shall be measured in the original position in the natural ground after Site Clearing
The measurement for payment shall include unavoidable excavation due to slides when considered by the Engineer to be not attributable to carelessness of the Contractor.
No payment will be made for the excavation from unapproved design changes.
All excavation will be in a single unit price for payment regardless of its nature or geological classification.
Where the Engineer orders the use of material obtained from Common Excavation for the execution of other works (such as stone masonry or aggregates for pavement or concrete) the Common Excavation shall not be paid for separately but shall be considered as a subsidiary obligation of the Contractor covered under the unit rates paid for the other works in which the material is employed.
Basis of Payment
The work measured as provided above shall be paid for in accordance with applicable Unit Prices as indicated on the Bid Price Schedule. The price and payment shall be full compensation for all work involved in performing excavation including excavating, removal, haulage, placing and compaction or satisfactory disposal of roadway excavation, for shaping and completion of all surfaces and for furnishing all labor, materials, tools, equipment and incidentals to complete the work to the limits and as otherwise shown on the Drawings and as required in accordance with the Specifications and/or as directed by the Engineer.
Pay Item
Description
Unit
03100-1
Common Excavation
m3