In some cases, when the strata along or under a cut is
composed of layers of rocks of different hardness, the softer layers get
weathered at a faster rate than the overlying or underlying harder rocks.
This generally results in undermining which might cause slips
or falls of the whole face.
Sometimes, when the top layers are weathered too heavily, the
slope might experience a persistent rock fall or experience debris-fall type of
situation from above.
Ground Water Conditions
It is always- necessary to investigate thoroughly the position
of water table of the area. It is quite likely that a water bearing zone
(aquifer) might be intersecting the base or slopes of an alignment.
Specific care and design would be required for these natural
water conduits. These are always to be taken as weak and hazardous zones in the
It is also known that water exerts important influence on the
beating capacity of the rocks and soil.
Hence when the ground is rich with moisture it would not bear
the design loads, unless these properties of ground have also been determined
in moist conditions. sometimes there is a condition of free flow of
ground-water through the soil.
quite dangerous for the stability of the road surface laid above such soil.