3.02 EXCAVATION:
A. GENERAL:
1.
2.
The Contractor shall perform all work of any nature and description required
to accomplish the work as shown on the Drawings and as specified.
Excavations, unless otherwise required by the Engineer, shall be carried only
to the depths and limits shown on the Drawings. If unauthorized excavation is
carried out below required sub-grade and/or beyond minimum lateral limits
shown on Drawings, it shall be backfilled with gravel borrow and compacted
at the Contractor's expense as specified below, except as otherwise indicated.
Excavations shall be kept in dry and good conditions at all times, and all voids
shall be filled to the satisfaction of the Engineer.
In all excavation areas, the Contractor shall strip the surface topsoil layer and
underlying subsoil layer separate from underlying soils. In paved areas, the
Contractor shall first cut pavement as specified in paragraph 3.02 B.1 of this
specification, strip pavement and pavement sub-base separately from
underlying soils. All excavated materials shall be stockpiled separately from
each other within the limits of work.
The Contractor shall follow a construction procedure, which permits visual
identification of stable natural ground. Where groundwater is encountered, the
size of the open excavation shall be limited to that which can be handled by the
Contractor's chosen method of dewatering and which will allow visual
observation of the bottom and backfill in the dry.
The Contractor shall excavate unsuitable materials to stable natural ground
where encountered at proposed excavation sub-grade, as directed by the
Engineer. Unsuitable material includes topsoil, loam, peat, other organic
materials, snow, ice, and trash. Unless specified elsewhere or otherwise
directed by the Engineer, areas where unsuitable materials have been
excavated to stable ground shall be backfilled with compacted special bedding
materials or crushed stone wrapped all around in non-woven filter fabric.
B. TRENCHES:
1. Prior to excavation, trenches in pavement shall have the traveled way surface
cut in a straight line by a concrete saw or equivalent method, to the full depth
of pavement. Excavation shall only be between these cuts. Excavation support
shall be provided as required to avoid undermining of pavement. Cutting
operations shall not be done by ripping equipment.
2. Trenches shall be excavated to such depths as will permit the pipe to be laid at
the elevations, slopes, and depths of cover indicated on the Drawings. Trench
widths shall be as shown on the Drawings or as specified.
3. Where pipe is to be laid in bedding material, the trench may be excavated by
machinery to, or just below, the designated sub-grade provided that the
material remaining in the bottom of the trench is not disturbed.
4. If pipe is to be laid in embankments or other recently filled areas, the fill
2019 Sewer Replacement Project Earthwork
Nashua, NH 02300-4
