2382282
Construction Issues in Periglacial Environments
- Permafrost
- Melting
- Train tracks can be uprooted by
thawing of the ground below of by the
process of frost heave.
- The Qinghai-Xiang
railroad in China was
constructed to cross a
large permafrost area. To
prevent heat from the
track melting the
permafrost and making
the ground unstable it
was elevated. High
bridges were constructed
and crushed rock used to
insulate the ground.
- The Qinghai-Xiang
railroad in China was
constructed to cross a
large permafrost area. To
prevent heat from the
track melting the
permafrost and making
the ground unstable it
was elevated. High
bridges were constructed
and crushed rock used to
insulate the ground.
- Roads can buckle
as a result of
uneven thawing or
frost heave.
- The use of gravel beds
to isolate roads and
the permafrost is
practiced in
permafrost areas to
prevent permafrost
from melting. Some
structures can be up to
3m high.
- Roads are painted white to
reduce the amount of heat
they absorb from exposure to
the sun, therefore reducing
the melting effect.
- The use of gravel beds
to isolate roads and
the permafrost is
practiced in
permafrost areas to
prevent permafrost
from melting. Some
structures can be up to
3m high.
- Subsurface pipes
can be ruptured
as the permafrost
melts and the
ground fluctuates
and becomes
unstable.
- Pipes are placed above ground.
- Large transport pipes such as the
Trans-Alaska Pipeline are built as
separate components therefore if there
is movement sections of the pipe can
be closedand any potential leak
contained.
- Sealed tubes of ammonia are placed within
stantions. As the ammonia heats up it rises
within the tube. Once at the top it is cooled by
the passing cold air, it then sinks back to the
bottom of the tube. this cooling cycle helps to
negate the warming effect of the pipeline.
- Pipes are designed to move slightly in
accordance to fluctuations in the permafrost
layer and to also survive seismic events.
- Sealed tubes of ammonia are placed within
stantions. As the ammonia heats up it rises
within the tube. Once at the top it is cooled by
the passing cold air, it then sinks back to the
bottom of the tube. this cooling cycle helps to
negate the warming effect of the pipeline.
- Pipes are placed above ground.
- Flooding can
occur as the
permafrost layer
melts. This could
create mass
flooding or
ponding of
surface water in
depressions.
- Preventative
measures are in
place to prevent
permafrost melt
and subsequent
flooding. Gravel
is used as a base
as an insulator
but also due to
its high drainage
capacity to
prevent excess
water ponding.
- Preventative
measures are in
place to prevent
permafrost melt
and subsequent
flooding. Gravel
is used as a base
as an insulator
but also due to
its high drainage
capacity to
prevent excess
water ponding.
- Subsidence
can occur as
the ground
thaws at
different rates
and becomes
unstable.
- Homes and buildings are built on
raised steel frames to isolate the
heat they generate to prevent the
permafrost layer from melting.
The gap between the building and
the ground allows cool air to
negate the heating effect of the
building.
- Homes and buildings are built on
raised steel frames to isolate the
heat they generate to prevent the
permafrost layer from melting.
The gap between the building and
the ground allows cool air to
negate the heating effect of the
building.
- Mass Movement can occur as
permafrost melts and ground
becomes unstable. it can also be a
by-product of the addition of eexcess
water to the system.
- Steps are taken to ensure
permafrost stays frozen to
reduce the risk of melt
induced mass movement.
- Steps are taken to ensure
permafrost stays frozen to
reduce the risk of melt
induced mass movement.
- Train tracks can be uprooted by
thawing of the ground below of by the
process of frost heave.
- Freezing
- The process of
frost heave is
when
groundwater is
frozen by the
permafrost layer,
and expands,
effectively
heaving the
ground above it.
- Gravel beds used in
construction are also used
because of its drainage capacity
therefore reducing the amount
of water in the sediment and
reducing the rick of frost heave.
- Gravel beds used in
construction are also used
because of its drainage capacity
therefore reducing the amount
of water in the sediment and
reducing the rick of frost heave.
- Subsurface
pipes carrying
water can freeze.
- Many pipes are placed above ground.
- Pipes are well insulated
to prevent freezing.
- Many pipes are placed above ground.
- The presence of
permafrost means the
ground is impenetrable
due to the ice.
- Due to the impenetrable
ground many buildings are
raised and built on the surface.
- In some cases the ground is fully
thawed and the building
constructed. The heat from the
building or the activities taking
place ensures that the ground
does not re-freeze.
- Due to the impenetrable
ground many buildings are
raised and built on the surface.
- The process of
frost heave is
when
groundwater is
frozen by the
permafrost layer,
and expands,
effectively
heaving the
ground above it.
- Melting
- Access
- Seasonal permafrost
melt can create
marshland and
unstable ground. This
can mean some areas
become inaccessible as
it is impossible to
construct roads in
these conditions.
- In the winter ice roads are constructed to cross these areas.
- In the winter ice roads are constructed to cross these areas.
- Seasonal permafrost
melt can create
marshland and
unstable ground. This
can mean some areas
become inaccessible as
it is impossible to
construct roads in
these conditions.
- Resource Extraction
- Impenetrable ground
- Drilling for resources
can cause permafrost to
melt.
- Drilling platforms are
constructed on concrete
plinths to isolate them from
the ground. This also helps
stabilise the heavy
machinery.
- Specialised drilling fluid is
created with a lower freezing
point to prevent problems with
extraction.
- Drilling platforms are
constructed on concrete
plinths to isolate them from
the ground. This also helps
stabilise the heavy
machinery.
- Impenetrable ground
- Climate
- High Altitude/Thin Air
- In the Tibetan plateau the
permafrost is at a high altitude
therefore posing a risk to
workers. To negate this issue
many workers were sourced
from these areas where they
have been pre-exposed to this
environment. There are also
guidelines in place to ensure
safe working conditions and
regulated breaks and health
checks.
- In the Tibetan plateau the
permafrost is at a high altitude
therefore posing a risk to
workers. To negate this issue
many workers were sourced
from these areas where they
have been pre-exposed to this
environment. There are also
guidelines in place to ensure
safe working conditions and
regulated breaks and health
checks.
- Extreme Temperatures
- People
- Mandatory safety equipment
and warm clothing are standard
requirements for all construction
jobs in extreme temperatures.
Regular breaks and warm
environments should be available
to all employees in the
workplace.
- Machinery
- In extreme temperatures machinery may
not perform well. To prevent this
specialised equipment is developed such as
drilling liquids that have a lower freezing
point then normal to ensure smooth
running of equipment.
- In extreme temperatures machinery may
not perform well. To prevent this
specialised equipment is developed such as
drilling liquids that have a lower freezing
point then normal to ensure smooth
running of equipment.
- Maintenance
- Adverse weather conditions may
mean access for maintenance can
be restricted. This is solved by
providing a high standard of work
initially and maintenance work
conducted when possible.
- Adverse weather conditions may
mean access for maintenance can
be restricted. This is solved by
providing a high standard of work
initially and maintenance work
conducted when possible.
- People
- High Altitude/Thin Air
- Amenities
- Lack of available extractable
freshwater. In areas of
permafrost minerals in the
groundwater tend to become
extremely concentrated in
the water above the ice
thereofre making it
unsuitable for human
consumption.
- Water is transported into the area. Either by pipes or in bottled form.
- In some areas
groundwater is
available as a
result of taliks in
the permafrost.
- Water is transported into the area. Either by pipes or in bottled form.
- Water within pipes can freeze.
- Overland pipes
- Well insulated pipes.
- Overland pipes
- Lack of available extractable
freshwater. In areas of
permafrost minerals in the
groundwater tend to become
extremely concentrated in
the water above the ice
thereofre making it
unsuitable for human
consumption.
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