Backfilling sewer work

 Backfilling  sewer work 

A . general
The Contractor shall perform all excavations quickly to minimize disruption to the public. Filling trenches on roads and paved / tiled areas is usually performed using similar materials excavated in situ in which the trench is building or structure chosen materials. Special padding is used if designated or managed . When the excavation is close to the existing structure to flow, where some of the later works can be built on or near or in emergency situations may require the contractor to fill with concrete.

Two . selected fill
The packaging material can be selected from part of the site selection methods may include sieving to remove large particles or hand or classification methods of soil classification and testing of property on the machine floor. The filling with the chosen material is performed as defined below.
a cohesive soils
Cohesive Soils are placed in layers not exceeding 200 mm ( compacted thickness ) and compacted so that along each - dry density layer positioned in situ is at least 95 % of the maximum density determined by dry land BS 1377 Part 4: Test 3.5 , as appropriate . "

The use of nuclear densitometer to determine the scope must comply with the requirements of the local authorities concerned .
If the tests show that the site specified compaction can be achieved with layers of more than 200 mm thick compacted approval may be given to the thicker layer of replacement, but not exceeding 250 mm , providing the plant used is used for assays. The moisture content of the soil can be determined on the ground by the method of test gas pressure calcium carbide (fast ) according to ASTM D4944 standard . All calibration and testing will be performed by accredited by the relevant local authority laboratory.
b - granular soils
Granular soils are placed in layers not exceeding 200 mm ( compacted thickness ) and compacted by the intermediate layer so that each placed in situ dry density is not less than 95 % of the maximum dry density determined by BS 1377 part 4 : Test 3.5 or 3.6 on the same floor as necessary.
If the tests show that the site specified compaction can be achieved with layers of more than 200 mm thick compacted approval may be given to the thicker layer of replacement, but not exceeding 250 mm , providing the plant used is used for assays.
Unless otherwise humidity is maintained and if necessary change the permitted enter 2% of the optimum moisture content methods.
For draining granular soils that have not clearly defined optimum moisture content , compression is performed to obtain a relative density of at least 95% if necessary. During the compaction of the soil was wet as I can