1.0 Introduction
The construction of embankments shall be subjected to the areas where the road center line considerably deviates from the existing road center line and this work shall consist of top soiling, placing of embankment materials and compaction. Embankment construction under special conditions would be carried out as specified in the technical specification.
2.0 Abbreviation
QAE – Quality Assurance Engineer.
SE – Site Engineer
TO – Technical Officer.
QAS – Quality Assurance System.
ME – Materials Engineer (Contractor).
TS – Technical Specification
3.0 Resources Allocation
3.1 Man power
• Site Engineer-01
• Technical Officer-01
• Supervisor-01
• Flagmen -02
• Skilled labors-04
• Unskilled labors-06
• Operators-As required
3.2 Equipment & Tools
• Back-hoe loader-01
• Motor Grader-01
• Vibrating roller-01
• Water bowser -01
• Water pump
• Dump trucks
• Level instrument
• Mortar pans
• Mamoties
• Pick axes
• Crow-bars
• Wheel barrows
• Shovels
• Buckets
• Water barrels
• Safety boots
• Safety Helmets
• Safety Gloves
• Traffic signs
• Blinking Lights
• Barricade boards
• Traffic cones
• Direction boards
3.3 Materials
• Embankment material-type I
• Embankment material-type II
4.0 Quality Control Procedures
4.1 Sampling and testing
The materials Engineer would take the samples from the excavated materials to check weather those materials are suitable or unsuitable for backfilling and the results of the test would be forwarded to the Engineer for approval.
Excavated Soil:
Samples of soil would be taken from the locations where the embankment construction is carried out and those samples would be placed in a polythene bag providing identification tag. All required tests would be carried out in the materials testing laboratory according to the frequencies specified in the technical specification to confirm wether the material is suitable for back filling or not.
Filling Material:
Filling materials as embankment type 1 and type 2 would be found from the borrow pits or from any other excavation. Those materials would be tested as specified in the technical specification prior to the application by taking samples according to the required frequency.
Each layer of those materials would be tested for the required degree of compaction by the method stipulated in the BS 1377. The minimum degree of compaction to be achieved is 95 % of the MDD for the top 150 mm layer and 93% for the remainder of the embankment.
4.2 Inspection Check list
To ensure that the all activities being performed with the expected quality, an inspection check list would be filled by QAE or the respective QA inspectors in case of preconstruction, during construction. The inspection check list shall include the specific requirements, safety and environmental measures.
4.3 Dimension Control
Embankment construction would be carried out according to the designed cross sections. The required slope and length of the excavation would be properly maintained during construction and those requirements would be checked with the inspection check list.
5.0 Methodology
5.1 Preparation of the existing surface for embankment construction.
• Limits of the embankment construction would be identified form the approved drawings given by the Engineer.
• The Surveyor would set out the lines of embankment fill and reference levels would be marked on pegs as directed by the SE and would be notified to the Engineer for approval. The center line would be referenced before commencement of the work.
• All top soil would be removed by using a manual mean or a suitable mechanical devise to an average depth of 150mm and would be disposed to a suitable disposal location by using dump trucks.
• The existing surface would be compacted using a 5-10 ton roller with 4-6 passes or 3 ton roller with 12-20 passes depending on the width of the area.
Methodology Flow Chart
5.2 Embankment filling.
• Embankment filling would be commenced after approval of the borrow pits and the material by the Engineer.
• The borrow materials would be transported to the site by the Dump trucks and stock piled in separate lots as Type I and Type II. If the requirement of embankment material is in small quantities, it will be supplied to the site directly. If it is in larger quantities it will be stock piled at a well-drained area and it will be kept covered to prevent it getting wet. Inspections would be carried out irrespective of quantity.
• Filling embankment would be carried out in bench style. Benching of sloping surfaces would be carried out manually to 150mm height or as directed by the Engineer in each step, before starting to fill the material.