3.3 COMPACTION TRIALS(a) Before commencing the formation of embankments, the Contractor shall submit in writing tothe Engineer for approval his proposals for the compaction of each type of fill material to be used in the Works. The proposals shall include the relationship between the types of compaction equipment, and the number of passes required and the method of adjusting moisture content. The Conừactor shall carry out full scale compaction trials on areas not less than 10 m wide and 50 m long as required by the Engineer and using his proposed procedures or such amendments thereto as may be found necessary to satisfy the Engineer that all the specified requirements regarding compaction can be consistently achieved. Compaction frials with the main types of fill material to be used in the Works shall be completed before work with the corresponding materials will be allowed to commence.(b) If during construction of the Works, the character and properties of the fill material change, the Contractor shall carry out further full scale compaction trials and submit the results to the Engineer for approval.(c) Throughout the periods when compaction of earthwork is in progress, the Contractor shall adhere to the compaction procedures found from compaction trials for each type of material being compacted, each type of compaction equipment employed and each degree of compaction specified.3.4 COMPACTION OF EMBANKMENT MATERIAL(a) Unless otherwise specified in the Drawings or otherwise regulated, the Contractor shall compact the filling materials on all embankment layers of filling embankment deeper than 500 mm below sub grade level to a uniform density not less than 95 percent of the required density according to the Testing Process of Determining density by the sand-cone method (22 TCN333-06 II-A) at a moisture content approved by the Engineer to be suitable for such density.(b) Embankment layers at the depth of 500 mm or less below subgrade level and materials scarified to designated depth below subgrade in cut section shall be compacted to a uniform density of not less than 98 percent of the required density according to the Testing Process of Determining density by the sand-cone method (22 TCN333-06 II-A) at a moisture content within the range of 3% less than optimum moisture content to 1% more than optimum moisture content. The optimum moisture content shall be defined as the moisture content at which the maximum dry density is obtained when the soil is compacted.(c) Unless otherwise specified in the Drawings or otherwise regulated, the Contractor shall compact the shoulder filling materials to a uniform density level not less than 95 percent of the required density according to the Testing Process of Determining density by the sand-cone method (22 TCN333-06 II-A) at a moisture content approved by the Engineer to be suitable for such density.(d) The Contractor shall during progress of the Work, make density tests of compacted material in accordance with 22 TCN 333-06. If the result of any test shows that the density is less than the required density the Contractor shall rectify the work. The test shall be made to the full depth of the layer at locations as directed by the Engineer, but which shall not be more than 200 m apart. For backfill around structures or in culvert trenches, at least one test per complete layer of backfill placed shall be carried out. In embankments, at least one test shall be performed in every 500 cubic meters of material placed.(e) The maximum dry density shall be adjusted in accordance with TCVN 4202-95 .(f) At least one group of three in-situ density tests shall be carried out for each 200 m3 of each layer of compacted fill. Tests shall be made to the full depth of the layer. For backfill around structures or in culvert trenches, at least one test per complete layer of backfill placed shall be carried out.3.5 COMPACTION EQUIPMENTCompaction equipment shall be capable of obtaining compaction requirements without detrimentallyaffecting the compacted material. The equipment shall be a modern, efficient compacting unitapproved by the Engineer. The compacting units may be of any type, provided they are capable of compacting each lift of material as specified3.6 PROTECTION OF EARTHWORKS DURING CONSTRUCTIONDuring the construction of the roadway, the embankment shall have sufficient camber to provide drainage from the road of any rainfall and the earthworks shall be maintained in such condition that it will be well drained at all times. Side ditches or gutters shall be so constructed as to avoid damage to embankments by erosion.
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