The purpose of this civil work method of statement is to define the procedures to ensure that the proposed materials and workmanship to be used at the site are complying with the condition / requirements as stipulated in the project earthwork specifications.
Method statement covers the requirements for all earth works up to and including the preparation of formation level.
This method statement is to be adopted during earthwork activities for widening and strengthening of highways.
The method statement describes the controlling elements during the excavation of earthworks.
Below is list of necessary equipment’s for the earth work activities.
- Dump Truck
- Service Vehicle for General Workers
Health and Safety Requirements
Conditions and precautions listed in the project specifications shall be followed as minimum.
All staff involved in the project shall be inducted on the safety, health and environmental issues associated with the work.
Only trained personnel with relevant experience shall be allowed to handle machinery.
Appropriate safety signboards, barriers and lighting and other safeguards shall be provided as required by the nature of and location of the works.
The works related to the earthworks shall be carried out in accordance with the project health & safety requirements.
All field personnel will use PPE safety requirements like safety shoes, helmets, cover all, dust mask etc. as required.
Work Methodology for the Earth Work
SETTING OUT: Prior to any commencement of any physical works, a professional land surveyor shall be appointed to carryout demarcation works and establish bench marks on site. Upon obtaining all the necessary survey data, a joint survey to check existing ground levels shall be carried out with the consulting engineers.
PREPARATION OF SITE: When any material is disposed outside the site, the disposed material shall be graded to a neat appearance and shall not obstruct natural drainage or cause damage to highways or property. All precautions shall be taken to prevent any erosion of the soil on the affected areas. All unsuitable material and surplus suitable material shall be run to spoil in tips approved by the Engineer.
EXCAVATION OF CUTTINGS:
The excavation of cutting shall be carried out in accordance with the relevant approved drawings and to the levels, widths and heights shown thereon.
Hauling of material from cuttings or the importation of fill material to the embankment or other areas of fill shall proceed only when sufficient compaction plant is operating at the place of deposition to ensure compliance with the specification requirements.
Any excess depth excavated below the formation level exceeding tolerance of 300mm shall be made good by backfilling with suitable material of similar characteristic of that removed and compacted in accordance with specifications.
Excavation for Site Levelling and Soil Replacement
Finish level shall be recorded in accordance to survey practice and jointly inspected in the presence of Engineer.
The side slopes of cuttings and embankments shall be as per the approved drawings.
Removal of Unsuitable Material and Soft Spots
If during the progress of the work the soil encountered has characteristics, as determined by tests conducted under the direction of the Engineer, that render it unsuitable for incorporation in the road embankment, the Contractor shall excavate and remove such unsuitable material to the extent directed by the Engineer.
Where Contractor finds isolated soft spots during excavation, this material shall be removed to the extent directed by the engineer.
No excavated suitable material shall be removed from the site without the approval of the engineer.
Should the Contractor permitted to remove suitable material to suit his operational procedure then he shall make good any consequent deficit of fill material arising there from.
Where the excavation reveals a combination of suitable and unsuitable material the excavation shall, unless otherwise agreed with the Engineer, shall be carried out in such manner that the suitable materials area excavated separately for use in the works without contamination by the unsuitable material.
The hauling of excavated material to areas of fill shall proceed only when sufficient spreading and compacting plant/equipment are operating at the place of deposition to ensure placing and compaction.
Unsuitable excavated material shall be removed and carted away to an approved area after approved by the Engineer.
Excavating High Level Areas: The Contractor shall excavate high level areas in all materials including rock for the full width of the road construction down to the top of the required sub grade.
Excavation in rock may be carried out by a tracked bulldozer and ripper or by the use of blasting with explosives or any other method approved by the engineer.
After it has been established that the excavated material is rock and after the area where such rock exists has been defined, the Contractor shall incorporate the rock in the embankment.
Excavation for Pits and Trenches
All trenches and pits under roads shall, where possible, be excavated, backfilled and compacted before road construction commences.
The sides of the excavation shall be adequately supported at all times.
Trenches and pits shall be kept free of water.
Trenches for pipes or ducts shall be excavated to the levels and gradients indicated in the contract documents.
Filling Requirements & Procedure
Filling low-level areas shall be to the level of sub grade as designated.
After completion of clearing and grubbing, the Contractor shall carry out the necessary leveling in order to control the thickness of the layers of fill.
The existing natural ground shall be scarified in place to a minimum depth of 75mm for the full width of the embankment.
Scarified material shall be leveled and compacted to a minimum of 95% maximum dry density.
Where an existing embankment is being widened, the existing embankment slope shall be trimmed and compacted into benches of minimum width 1m and depth 500mm before placing and compacting each layer of new embankment material unless otherwise directed by the engineer to suite particular circumstances.
Contractor shall not proceed with filling and compaction any subsequent layer before testing and securing the approval of the engineer for the previous layer.
Each fill thickness shall not exceed 250mm.
Forming of Embankments and Other Areas of Fill
In areas of shallow filling, where after the removal of top soil, before embankment construction is compacted, the surfaced of the ground shall be graded and compacted.
Embankments and other areas of fill shall be formed of suitable material.
All earthworks material placed in or below embankments, below formation level in cuttings or elsewhere in the works shall be deposited and compacted as soon as practicable after excavation in layers of thickness not exceeding 250mm.
Embankments shall be built up evenly over the full width unless otherwise indicated and shall be maintained at all times with a sufficient camber and a surface sufficiently even to enable surface water to drain readily from them.
During the construction of embankments, construction traffic or water erosion shall be made good.
Compaction of embankments and other areas of fill shall be undertaken to the requirements of specifications.
The embankments shall be constructed to sufficient width to permit adequate compaction at the edges before trimming back.
Placing & Compaction of Embankments & Other Fills
Earth fill on the embankments shall be spread so as to produce uniform distribution and gradation of the earth fill throughout.
Cluster of rock, which would interfere with proper compaction, will not be permitted.
The earth fill shall be placed in continuous, approximately horizontal layers over the length being constructed for the full width of the embankment.
Material which has been compacted to a dry density less than required or at a moisture content outside the tolerable range shall be removed or reworked and re-compacted until the required properties are achieved.