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

In-Situ Ksat TestsBorehole TestsBoutwell PermeameterConstant-Head Borehole PermeameterPorous ProbesBAT PermeameterInfiltrometersOpen, Single Ring InfiltrometerOpen, Double Ring InfiltrometerSealed, Single Ring InfiltrometerSealed, Double Ring Infiltrometer

Boutwell Permeameter TestTwo-stage TestMeasures both Khoriz. and Kvert.

Boutwell Permeameter

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)

Boutwell Permeameter TestStage 2:deepen the hole ( Auger or push sampling tube)Calculate: K2Stage 2 terminated when steady conditions are reached

Boutwell Permeameter TestCalculate K2 / K1 Determine m from FigureKh = mK1 Kv = (1/m)K1

Boutwell Permeameter

Stage I:

Stage II: where:

Curves for k1/k2 versus m (L/D = 1.0, 1.6, 2.0)

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

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

Constant Head Borehole PermeameterAssumptions:Soil is homogeneous, isotropic, uniformly soakedboundaries at infinity soil does not swell when wetted

Porous Probes(eg. BAT Permeameter)Probe pushed or driven into soilconstant or falling head tests are performedBAT Permeameter: Student Presentation

Porous Probe Test

Porous Probes(eg. BAT Permeameter)Assumptions:Soil is homogeneous, isotropic, uniformly saturatedboundaries at infinity soil - not smeared across the porous elementsoil suction negligibleisothermal conditions

Infiltrometer Tests

Infiltrometers

Hydraulic Conductivity,

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

Open, Single Ring InfiltrometerAssumptions:Soil is homogeneous and uniformly soakedNo lateral spreading of waterNo volume change due to swelling

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

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

Sealed Single Ring Infiltrometer

Ring Infiltrometer with Mariotte Tubes

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

Sealed Double Ring Infiltrometer

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

Air-entry Permeameter

Air-entry Permeameter

Underdrains or LysimetersLysimeter pan placed underneath the clay linerClay liner built over itKsat calculated based on outflow rate using Darcys Law