2. EARTH WORK
2.1 Scope of Work
Earth work consists of
excavation, back filling and disposal of surplus Material. Work of this section
includes all measures and materials required to
design supply, support, use, construction, removal of earth work.
The ground shall be excavated
to the lengths, widths and exact depths required for the construction of the
works. The contractor shall examine any unsuitable or weak ground material,
standards of which are given below and shall report the situation in writing to
the Engineer before executing concrete or any other Works.
if the surface of
a subgrade is found to be unstable or to include any type of refuse subject to
removal in the opinion of the Engineer, the contractor shall excavate and remove
such unsuitable Material to the width and depth required by the Engineer. Any
excavation to a level lower than that indicated on the drawings shall be
compensated for filling with concrete mix (1:4:8)
or with other material as
directed by the Engineer at the contractor's expense.
Due weather to
negligence or error on the part of the contractor or at the request of the
Engineer owing to an unstable sub grade, the contract price shall be deemed to
cover the whole cost of all excavation, inclusive of replacement with suitable
Material, necessary in what so ever typo of earth or ground conditions
encountered, e.g. earth With boulders, hard pan , rock, old concrete foundation,
roadways, paved areas, etc.
All excavation works shall be kept dry and clean
in order that work may not be affected or interfered with by water entering the
excavation. The contractor shall pump out all water which may occur or be
brought into the excavation employing such equipment as engines, pumps pipe
work, chutes and other necessary devices to keep the water level below the
bottom of the permanent works during the period required by the Engineer, Raised
water shall be conveyed away in such manner as not to cause any nuisance or
injury to the occupants of adjacent properties or sites. If pumping is required
f it shall be carried out continuously and my not be stopped without the
permission of the Engineer .
Excavated material, approved by the Engineer for
re-use for filling shall be selected, loaded and hauled to the specified
location for temporary stockpiling. Excavation materials containing brushy roots
or other vegetable materials shall be classified as unsuitable for fill.
sides of excavation shall be supported as necessary to Maintain a vertical face
and to prevent fall or slip of any nature at any - time during the duration of
excavation and back filling works. The contractor shall be responsible for the
design, supply, fixing and removal of the shoring, sheet piling or any works
required to support the side of the excavation.
It is also the contractors
responsibility to protect existing structures and utilities from damage or
interruption of services due to excavation work .
2.3 Disposal of Surplus
The contractor shall
be responsible for all surplus soil of excavated material not suitable for
re-use . The Engineer my require the contractor to transport such surplus to a
disposal area and /or my instruct the contractor to dispose of the surplus to a
disposal area to be procured by the contractor himself - This shall all be
carried out by the contractor at no extra expense to the employer.
2. 4 Filling
2. 4. 1 Backfilling
Excavation shall not be
backfilled until such structures and properties as drainage, insulation pipes,
construction details, and water tightness have been inspected, tested and
approved by the Engineer .
All available precaution shall be taken during
back filling to ensure that the pipes, insulation and construction details are
not damaged. All backfill material shall be approved and free from vegetable or
organic material, mud, refuse, boulders, rock , stones of over 15 cm and other
materials which, in the opinion of the Engineer, are unsuitable.
shall be carried out in such away and to such a generous depth as to ensure that
the final surfaces after settlement and compaction conform to the levels
indicated in the Drawings and specifications .
2. 4. 2 Compaction
Compaction of fill
(under ground pipes and those buildings or structures where concrete fill is not
c quir required).
All soil fill material used shall be thoroughly compacted
by mechanical means until the specified degree of compaction is obtained. The
filling Material shall be approved by the Engineer and placed in even layers of
a depth not greater than 30cm . A power driven roller of least 10 tons shall
make at least 10 trips for each layer unless otherwise specified.
effort shall be made to compact the fill material at its optimum moisture
content for compaction. In any case, the dry density of compacted soil shall not
be less than 95% of the value obtained in a standard laboratory test. When spade
will not permit the use of rollers, other types of approved equipment shall be
used to achieve the same degree of degree of compaction specified. Filling and
compacting around pipes, cables and conduits shall be done by hand using
selected Materials to depth of the least 50cm above such pipes, cables and
2. 5 Hard Core
indicated on the drawings or directed by the Engineer, broken brick, hard stone
or gravel free from vegetable matter and lump of clay shall be laid on the
compacted subgrade to a thickness of 80mm.
2.6 Protection Against
Selected appropriate anti-termite method approved by the Engineer
shall be executed in accordance with the local procedures and Manufacturers
instruction on the excavation bottom surface and the materials used for filling
or backfilling and to the sores.