CONSTRUCTION ON FROZEN SALINE GROUNDS OF THE ARCTIC COAST OF EURASIA

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• CONSTRUCTION ON FROZEN SALINE GROUNDS OF THE
  ARCTIC COAST OF EURASIA

A. Brouchkov 2004
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Wetland of Northern Russia
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Frozen saline soils definition
It is offered to define frozen saline soils as
soils containing of 0.05 salts
Long-term strength of adfreezing for concrete and
marine sand at -3C
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Frozen saline soils distribution
Distribution of frozen saline soils in the
Arctic blue - marine type yellow - continental
type
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Two major types of frozen saline soils
Synchronous type
Marine deposits saline pore solution
Frozen saline soils
Freezing
Continental and marine deposits affected by sea
level raise and by sea water saturation
Asynchronous type
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Features of salinization

• Salinization normally is changed within the
  limits of 0.05-2
• Sea salts composition is common
• Active layer, except for slopes and coasts, does
  not contain salts
• Salinization changes with depth as a rule,
  salinization increases until 10-15 m

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Redistribution of salts during freezing
marine silt

sand
Results of freezing of saline soils left - water
content (1) and salinization (2) of marine silt
after experimental freezing right - water
content (1) and salinization (2) of marine sand
after freezing on Amderma foreland
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Change of water and salt content long-term
experiments
Water content distribution in the marine silt 1
initial under influence of temperature
gradient (on the left -2.7?, on the right
-2.2?) after 2 - 1 year 3 - 3 years 9 months
4 - 11 years
Salinization distribution in the marine silt at
the temperature 3?? 1 - initial 2 after 7
months 3 after 11 years of experiment
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Change of cryogenic structure under temperature
gradient long-term experiments
(a)
(b) (c)
(d)
The character of a cryogenic structure of samples
of marine frozen saline silt (a) before and (b)
6 months, (c) 5 years and (d) 11 years after the
beginning of experiment cold side (-2.7C) at
the top, warm side (-2.2C) at the bottom
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Change of salt content with time
Mechanism of salt transfer in the layer of
seasonal temperature changes distribution of
temperature in winter (left) and summer (right)
time and water and salt flows. Winter water and
salt flow is directed to active layer where salts
are washed during the summer. Summer water and
salt flow cause a salt collection at some depth
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Salt distribution in frozen soils with depth
Frozen marine silt deposits in Amderma
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Distribution of salts with depth
a
b
Soil salinization for a marine and coastal
deposits of late Pleistocene (III2-4) of the
Central and Southern Yamal (1) and Northern Yamal
(2) b marine and lagoon Holocene deposits
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Distribution of salts with depth
Salinization a marine Paleogene deposits (mP)
of Tazovsky peninsula (mP) b marine and
glacial deposits (II2-4) of Nothern Yamal (1),
Central and Southern Yamal (2), Gidan (3),
Tazovsky peninsula (4), Ob-Pur area (5) c
marine and coastal deposits of Late Pleistocene
(the same legend as for b)
a
b
c
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Cryogenic structure of frozen saline soils
Cryogenic structure of frozen saline marine silt
Salinization and total water content of frozen
marine Pleistocene silts of Yamal peninsula
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Unfrozen water content in frozen saline soils
Unfrozen water content in marine silt at
salinization Dsal 0.5
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Creep of frozen saline soils
Strains of marine sand at -2?, salinization
Dsal0.5 under uniaxial stress of 0.01 MPa and
water content (W) of 0.3, 0.5 and 0.7
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Long-term creep of frozen saline soils
Long-term strains of marine frozen saline silt
under constant uniaxial stress of 0.1 MPa, at -
3? salinization Dsal0.5 specimens are
numbered
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Long-term strength of frozen saline soils
Long-term strength found in the ball test of
marine silt at -2?, salinization Dsal0.5
chemical composition of salts is different
Long-term strength of frozen saline soils under
constant uniaxial stress at -2?, salinization
Dsal0.2
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Mechanical properties of frozen saline soils
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Testing of stability of frozen saline bases
Test Soils Bearing capacity according CNR, kN Bearing capacity according tests of piles, kN
1 Sand up to 4 m, then sandy silt T-2?C, salinization 0.1 410 310
2 Sandy silt with T-2?C, salinization 0.1-0.2, water content 30-50 810 680
3 Sandy silt, T-3.5?C, salinization 0.6-0.9, water content 30-50 640 290
Results of tests of concrete piles in frozen
saline deposits by static loading in Amderma
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Settlements of pile high school in Amderma
Settlements of building n. 21, Polyarnay St. in
Amderma (Velli, 1977)
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Deformations of buildings on frozen saline soils
in the Arctic coast
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Deformations of buildings on frozen saline soils
in the Arctic coast
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Deformations of buildings on frozen saline soils
in the Arctic coast
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Deformations of buildings on frozen saline soils
in the Arctic coast
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Deformations of pipelines on frozen saline soils
in the Arctic coast
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Deformations of buildings in Amderma
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Statistic of damages
Town Total deformation rate,
Amderma, Kara sea coast 40
Anadyr 20
Salekhard and Labytnangi Above 10
Dikson, Kara sea coast 33
Tiksi, Laptevs sea coast 22
Pevek, 50
Yakutsk, Lena river valley 27
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New apartment building of light materials
constructed in nineties in Amderma
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Conclusion
1. Frozen saline soils are widely distributed
along the Arctic coast and are characterized by
low bearing capacity. Chemical composition of
salts is important frozen deposits of the marine
type have the lowest strength. Ice normally plays
a bearing role. 2. Salts change creep
capabilities of soil creep rate decreases with
time, as confirmed by long-term experiments
lasting 12 years. 3. Almost half of all
buildings along the Russian Arctic cost have been
damaged, and the major reasons for the damages
were the following underestimating of the
influence of salinization of soils uncontrolled
heat emission due to water leaking and snow
redistribution. Existing construction regulations
concerning bearing capacity calculations of
frozen saline soils need to be reviewed.