UGT IL-2700 User manual

Manual
Hood Infiltrometer
IL -2700

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Content
1. Introduction ......................................................................................................................... 3
1.1 Scope of supply ....................................................................................................................... 4
2. Introduction ......................................................................................................................... 6
3. Underlying theoretical principles........................................................................................... 7
4. Methodology of the experimetal procedure .......................................................................... 8
4.1 Infiltration tests with different water tensions....................................................................... 8
4.2 Infiltration tests with identical water tensions ....................................................................... 9
5. Technical Parameters, Set Up and Operation ...................................................................... 10
5.1 Technical Specifications......................................................................................................... 10
5.2 Assembly and operation of the Hood Infiltrometer.............................................................. 10
6. Test procedure.................................................................................................................... 12
6.1 Preparation of the Hood Infiltrometer.................................................................................. 12
6.2 Setting up the Hood Infiltrometer......................................................................................... 12
6.3 Filling the hood...................................................................................................................... 13
6.4 Choosing the effective water tension ................................................................................... 13
6.5 Measuring the infiltration rate.............................................................................................. 14
6.6 Bubble point (BP) of the soil.................................................................................................. 14
6.7 Soil Tensiometer.................................................................................................................... 15
7. Infiltration Measurement with the tension infiltrometer...................................................... 15
8. Calculation of hydraulic conductivity ................................................................................... 16
9. Micrologger IL-2700 ............................................................................................................ 17
9.1 Features................................................................................................................................. 17
9.2 Technical Data ....................................................................................................................... 17
9.3 General guidelines for operation .......................................................................................... 18
9.4 Measurement ........................................................................................................................ 19
9.5 Remarks for the configuration of a measurement ................................................................ 19
9.6 Calibration ............................................................................................................................. 20
9.7 Configuring the measurement interval /Starting a measurement........................................ 20
9.8 Options menu........................................................................................................................ 21
9.9 Menu structure...................................................................................................................... 21
10. Software IL2700 GUI........................................................................................................ 27
10.1 Reading out Data................................................................................................................... 28
11. Notes.............................................................................................................................. 31
12. References ...................................................................................................................... 32

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1. Introduction
Thank you for choosing the hood infiltrometer IL -2700. This manual can help you understand
the IL-2700 features.
The hood infiltrometer is designed to measure the hydraulic conductivity of soils in virtually
saturated areas in field studies. No additional contact layer nor preparation of the soil surface
is necessary on the measurement area. This does not only save labor time but also enables
the measuring of the infiltration and the conductivity under completely natural conditions in
a destruction-free manner. The effective increase in pressure on the soil surface can be freely
selected between zero and a vacuum up to the bubble point of the soil.
There are several ways to contact UGT if you need a quote or product information please
contact
Email: [email protected]
For any technical assistance or feedback or in case of problems with your product please con-
tact
Email: [email protected]
We look forward to your inquiries or questions and are with pleasure at your disposal.Phone:
+ 49 (0) 33432 –89 575
Fax:
+ 49 (0) 33432 –89 573
If contacting us by email or fax, please include as part of your message your instrument serial
number, your name, address, phone, and a description of your problem or question.
Please read these instructions before operating your hood infiltrometer to ensure that it per-
forms to its full potential.

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1.1 Scope of supply
Infiltration vessel with scale for manual level recording
1
and pressure sensor for electronic level recording
*
Handheld instrument IL-2700
1
*
Read out software IL-2700
1
*
U-tube manometer with field tripod
1
Infiltration hoods
2
Restriction ring for sand compaction
1
Funnel
1
Pipette ball
1
Transport case
1
Optional Equipment: Tension chamber
* only supplied with electronic data acquisition / IL-2700

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List of abbreviations
a
Arc radius of circular source area
[L]
F
Source area of infiltration
[L2]
h
Hydraulic pressure head
[L]
Hk
Height of Infiltration chamber
[L]
Hs
Waterlevel in standpipe
[L]
kf
Saturated hydraulic conductivity
[L/T]
ku
Hydraulic conductivity
[L/T]
LDP
Bubblepoint
[L]
Q
Steady-state flow
[V/T]
q
Ratio of two source areas
-
rs
Effective radius of the infiltration area
[L]
T
Submersion depth of the air intake pipe
[L]
t
Time
[T]
Us
Negative pressure at U-tube manometer
[L]
Us(le)
Waterlevel in left limb of the U-tube manometer
[L]
Us(ri)
Waterlevel in right limb of the U-tube manometer
[L]
Usmax
Maximum pressure at U-tube manometer
[L]
vB
Infiltrationrate into soil
[L/T]
Z
Waterlevel in infiltration chamber
[L]
α
Gardner co-efficient
[L-1]
π
Number pi
-

Umwelt-Geräte-Technik GmbH | Eberswalder Str. 58 | D-15374 Müncheberg | Tel.: [phone] - 89 575 | www.ugt-online.de Page 6 of 32
2. Introduction
The Hood Infiltrometer IL-2700 (Fig. 1) is used for measuring the soil hydraulic conductivity
near saturation in field tests. Infiltration starts from a closed hood filled with water and stand-
ing on the ground. The circular surface under the hood is directly covered with water and acts
as the source area of infiltration flow. There is no need for providing a contact layer on the
measuring surface or any preparation of the soil. Only the vegetation has to be cut short
enough, to not influence the hood.
The hydraulic pressure head in the water volume under the hood is controlled by a MARIOTTE
water supply system. The effective pressure head on the soil surface can be chosen freely
between zero and a negative pressure up to the bubble point (air permeation value) of the
soil. That pressure head is measured precisely by means of a supplemental U-tube manome-
ter.
An additional soil tensiometer measures the water tension in a defined soil depth and hence
enables the exact determination of the hydraulic gradient for the recent water flow.
It is advisable to calculate the hydraulic con-
ductivity from the steady-state infiltration
according to WOODING (1968) as determined
in the course of the test.
Two hoods with an infiltration area ratio of
approximately 1:2 are available for the infil-
tration test.
An additional infiltration chamber together
with the MARIOTTE water supply system
makes up a regular tension infiltrometer en-
abling infiltration tests up to about 60 hPa
irrespective of the bubble point of the soil.
The data for the flowrate can also be collected with a pressure sensor and the micrologger
IL-2700 and read out to a PC and evaluated using the IL-2700 software
Fig. 1: Hood Infiltrometer IL-2700 in measuring position

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3. Underlying theoretical principles
Hydraulic conductivity kuas a function of water tension hin soils or other open-pored materi-
als near saturation can be described according to GARDNER (1958):
).( h
fu ekk


(1)
kf- saturated hydraulic conductivity
h - hydraulic pressure head (pos. In overpressure range)
α - Gardner-Koeffizient
Such approach allows an analytical solution for a large number of two- and three-dimensional
flow processes. It is the regular basis for the interpretation of test results with the infiltrome-
ter systems common so far.
According to WOODING (1968), the following applies to the steady-state flow Q(volume/time)
from a circular infiltration area (radius a) into the infinite soil:
)
4
1(
2a
kaQ u 


(2)
For experimental determination of kf and  , the infiltration test can be run with different wa-
ter tensions (hydraulic pressure heads) or the infiltration gets fed from source areas with dif-
ferent radii for equal water tensions. However, infiltration from different source areas makes
sense only in largely homogeneous soils.

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4. Methodology of the experimetal procedure
4.1 Infiltration tests with different water tensions
The Hood Infiltrometer allows the infiltration test at different water tensions up to the bubble point
of the soil or the membrane below the infiltration chamber (radius a).
For neighboring values of the chosen water tensions (h1, h2) applies according to equations (1), (2):
)
4
1(
1
2
1a
ek
a
Qh
f






(3)
)
4
1(
2
2
2a
ek
a
Qh
f






(4)
By way of division we get:
)(
)ln(
21
2
1
hh Q
Q

 
(h1, h2 < 0)
(5)
And for the hydraulic conductivities we get:
)
4
1(
)( 2
1
1
a
a
Q
hk






(6)
)
4
1(
)( 2
2
2
a
a
Q
hk






(7)
To run an infiltration test with a water tension lower than the bubble point use the infiltra-
tion chamber to make up a tension infiltrometer. Mind the influence of the contact mate-
rial between soil and tension chamber, as here the “series connection” from contact mate-
rial and soil will become effective.

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4.2 Infiltration tests with identical water tensions
On infiltration with identical water tensions from infiltration hoods with different radii ap-
plies for the respective flow rate:
When choosing the source areas with a ration of (10) we get:
12 FqF 
 
2
aF  
(10)
)1(
)1(4
2
1
1
2
1
Q
Q
qa
Q
Q
q





(11)
Now ku and  can be determined for an unknown soil using (11), (8) and (1). As different
soil sections are effective in each test run, soil inhomogeneities will sometimes lead to in-
valid results. In such experiments, equation (11) should be used only for representative
means of the infiltration rates of the infiltration hoods under review.
)
4
1(
)(
1
2
1
1
a
a
Q
hk






(8)
)
4
1(
)(
2
2
2
2
a
a
Q
hk






(9)

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5. Technical Parameters, Set Up and Operation
5.1 Technical Specifications
Tension area:
0 … bubble point with hood
0 … 60 hPa with tension chamber
Tension measurement:
U-tube manometer
Resolution 0.1 hPa
Infiltration measurement:
Differential pressure sensor 0 - 70 mbar
Resolution 1 mm water column
Conductivity range of the soil
10-3 m/s to 10-7 m/s
5.2 Assembly and operation of the Hood Infiltrometer
A hood [2] with circular base is standing directly on the soil surface. The space under the hood
is filled with water, hydraulic pressure head getting controlled through a MARIOTTE water
supply system [5, 6, 7]. Water-saturated fine sand is used to seal the edge of the hood against
the soil up to an outer ring [1]. Such sealing will be effective only if the pressure in the water
volume under the hood is negative. The negative pressure can be adjusted freely from zero
up to the bubble point (air permeation point). The soil pore system on the measuring surface
will remain absolutely undisturbed.
When setting up the test system, first the overflow chamber [3] under the hood has to be
filled –well controlled - with water. Upon overflow of that chamber begins the volume under
the hood gets filled with water and the infiltration into the soil starts. The enclosed air is piped
into the air volume of the infiltration reservoir [5] through the vent pipe [10].
Attention!
For unstable soils or non-structured sands the soil surface under the overflow chamber
should be prevented from flushing out applying a rag.
After the air escape hose has been closed [V2, V3], the water volume under the hood remains
in steady-state. Now the infiltration flow is delivered directly from the infiltration reservoir of
the MARIOTTE water supply system from where the reading can be taken of a scale (filling
height).