METHODOLOGY / PROCEDURE OF EARTH / SOIL EXCAVATION AND BACK FILLING

WORK METHODOLOGY / PROCEDURE OF EXCAVATION AND BACK FILLING

EXCAVATION IN SOIL

Ø    The area to be excavated should be inspected properly for presence of any underground services from ground tale-tell signs like route marker, vent pipes, Manhole cover, depression along trench etc. or from as built drawings.

Ø     Excavation layout to be marked on the ground with reference to latest revision of approved drawing keeping in mind working space, side slope etc. with help of survey dept. may be taken if required

Ø    Excavation in a particular unit for foundation etc. to be started only after establishment of Finished Ground Level (FGL) for the area through area grading.

Ø    During area grading, top soil, black cotton soil or unsuitable soil should be removed in advance before excavation in suitable soil which is fit for reuse.

Ø    Any underground service line, cables or other obstacles found during excavation shall be identified by proper description, location, dimensions, below grade elevation and same shall be informed to concerned authority.

Ø    Suitable side slope and steps to be provided during excavation depending on type of soil and depth of excavation for stability of excavated pit.

Ø    Final excavation level should be free from loose soil, soft patch etc. before laying PCC to avoid any settlement of completed structure.

Ø    In case of excess excavation below the required level the same should be filled with suitable soil.

Ø    Excavation will in slope manner.

DISPOSAL OF SEEPAGE WATER.

Ø    In case ground water table is above the bottom of excavation, there will be entry of seepage water within the excavated area. A sump at a suitable location within the excavated area to be maintained from which water to be pumped out to keep the excavated area workable and safe. 

Ø    In case of deep excavation at high ground water table volume of seepage water may be substantial. In such a situation well point dewatering may be adopted.

Ø    Location for disposal of seepage water to considered in advance to avoid water logging of nearby area.

DISPOSAL OF EXCAVATED MATERIAL

Ø    Different types of excavated material should be kept or disposed separately depending on their type and usage. Like;

a) Top soil or black cotton soil which may be used for landscaping work,

b) Good quality soil or moorum for filling (i.e. tested and approved),

c) Unsuitable soil, debris can be used only in landfill area shall be kept or disposed separately without mixing up with each other.

Ø    Disposal area to be decided in advance, if required in consultation with client to identify areas where no facility is expected to come in near future, to avoid re-handling.

BACK FILLING

Ø    Back filling material over which some structure will rest shall be compacted in advance for its suitability.

Ø    Back filling around foundation with excavated material (pre-approved wherever applicable) shall be taken up after any specialized coating (if required) and UG piping and cabling (if any).

Ø    Back filling activity should be carried in layers with watering and compaction (hand or mechanical means as required depending upon requirement).

Ø    Field compaction test may be carried out as per project requirment..