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In-Situ Hydraulic Conductivity Tests for Compacted ClayRef :
Daniel, D.E., In-Situ Hydraulic Conductivity Tests for Compacted
Clay, Journal of Geotechnical Engineering, Vol.115, No.9, September
1989.
In-Situ Tests Borehole and Porous Probe DevicesInfiltrometers
and Lysimeters
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In-Situ Ksat TestsBorehole TestsBoutwell
PermeameterConstant-Head Borehole PermeameterPorous ProbesBAT
PermeameterInfiltrometersOpen, Single Ring InfiltrometerOpen,
Double Ring InfiltrometerSealed, Single Ring InfiltrometerSealed,
Double Ring Infiltrometer
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Boutwell Permeameter TestTwo-stage TestMeasures both Khoriz. and
Kvert.
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Boutwell Permeameter
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Boutwell Permeameter TestStage 1:drill a holeplace a casing in
the hole seal the annular spaceperform falling head testcalculate
k1continue test until steady conditions are reached(a few days-2
weeks)
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Boutwell Permeameter TestStage 2:deepen the hole ( Auger or push
sampling tube)Calculate: K2Stage 2 terminated when steady
conditions are reached
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Boutwell Permeameter TestCalculate K2 / K1 Determine m from
FigureKh = mK1 Kv = (1/m)K1
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Boutwell Permeameter
Stage I:
Stage II: where:
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Curves for k1/k2 versus m (L/D = 1.0, 1.6, 2.0)
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Boutwell Permeameter TestAssumptions:Soil is homogeneous and
uniformly soakedPorewater pressure=0 at base ( Stage 1 ) and the
center of uncased section ( Stage 2 ) effects of soil suction is
negligible no volume change
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Constant Head Borehole PermeameterConstant water level
maintained in boreholeMeasure q, rate of flow needed to maintain
constant water levelcalculate K: - based on theoretical solutions -
based on statistical regression analysis results -see original
reference for details
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Constant Head Borehole PermeameterAssumptions:Soil is
homogeneous, isotropic, uniformly soakedboundaries at infinity soil
does not swell when wetted
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Porous Probes(eg. BAT Permeameter)Probe pushed or driven into
soilconstant or falling head tests are performedBAT Permeameter:
Student Presentation
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Porous Probe Test
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Porous Probes(eg. BAT Permeameter)Assumptions:Soil is
homogeneous, isotropic, uniformly saturatedboundaries at infinity
soil - not smeared across the porous elementsoil suction
negligibleisothermal conditions
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Infiltrometer Tests
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Infiltrometers
Hydraulic Conductivity,
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Open, Single Ring InfiltrometerSimplest type of
infiltrometerRing is embedded in trench that is sealed with
bentonite groutCalculate rate of infiltration:I = Q/AtCalculate
K:K=I/iwhere i= (H+Lf+f)/Lf
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Open, Single Ring InfiltrometerAssumptions:Soil is homogeneous
and uniformly soakedNo lateral spreading of waterNo volume change
due to swelling
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Open, Double Ring InfiltrometerWorks on the same principle as
the open, single ring infiltrometer except that there are two
infoltrometer rings in this test apparatusInfiltration rates from
inner ring used for calculation of KsatOuter ring limits lateral
spreading of water
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Sealed, Single Ring InfiltrometerWorks on the same principle as
the open, single ring infiltrometer except that the infiltrometer
ring is sealed to minimize evaporative lossesFlow rate measured by
a small stand pipe or by using a Mariotte systemSimilar device
Air-Entry Permeameter
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Sealed Single Ring Infiltrometer
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Ring Infiltrometer with Mariotte Tubes
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Sealed, Double Ring Infiltrometer (SDRI)Two infiltrometer rings
with sealed inner ring and open outer ringFlow rate from inner ring
measured by weighing a small flexible bag filled with water
(attached to inner ring)Eliminates evaporative losses, and error
due to volume changes in water due to temperature changes
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Sealed Double Ring Infiltrometer
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Air Entry PermeameterSealed infiltrometer ring (about 60 cm in
diameter)Conducted in two stagesStage I: rate of infiltration
determined from falling head test or constant head test (Mariotte
bottle)Stage II: valve to the flow measuring device closed,
negative pressure measured on vacuum gage
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Air-entry Permeameter
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Air-entry Permeameter
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Underdrains or LysimetersLysimeter pan placed underneath the
clay linerClay liner built over itKsat calculated based on outflow
rate using Darcys Law