Earthworks engineering

Published on 14 February 2008
Excavation in progress (all rights reserved)

Earthworks engineering involves the following operations:

• Surface stripping - Replacement of failed area

• Pre-infill improvements

• Excavation of rubble

• Infilling or stock/spoil piling of rubble

• Improvements after excavation

• Upper earthworks components

• Subgrade - Regulation of subgrade

• Subsoil and top soil

• Surface drainage - Roadbed drainage

Actual earthworks engineering operations will begin with removal of the subsoil and top soil which will either be set aside in long piles down the sides or in spoil heaps so that it can be reused later to cover the bank sides and heaps of unsuitable materials.

In infill areas of poor load bearing capacity, the unsuitable materials will be excavated and replaced by suitable ones. Other enhancement techniques may be used, such as vertical drainage, dynamic compaction and ballasted columns...

Large areas of rubble are excavated using various work stations and transported for use as infill or for spoil heaps if they are superfluous to requirements or unsuitable.
The embankments of rubble are improved as required, if they show signs of being unstable.
In unconsolidated strata, these improvements would be in the form of trenches, groins or drainage curtains.
In rocky ground they would involve use of pinning, grillage or shotcrete.

The upper part of the earthworks will be formed from selected materials, then the subgrade will be laid down consisting either of processed materials or of ancillary materials.
Fine regulation of the roadbed will now follow.

The banks will be covered with soil and this will be turfed to prevent it from eroding.
Drainage of the roadbed now takes place.