IMKO TRIME-FM, Руководство пользователя

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Note that the necessity of a close contact between access tube and material is vital for reliable
measurements and that the tubes should be installed by our recommended method.
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For example at an assumed water content of 15 vol. % an air gap of 1 mm around the whole length
of the tube would result in an underestimation of 1 - 2 vol. %.
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At a water content of 25 vol. % the error would be 5 vol.-%.
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At very high water contents (50 vol. %) errors may reach 10 vol. %.
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In the case of a water filled gap under conditions of saturation the gap error would be much smaller.
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Problems may arise, however, in very inhomogeneous soils and when drilling under very dry
conditions. For these soils other drilling methods are recommended (e. g. pre-boring with an
Edelman auger, washing mud into the cavity around the tube). Losses in accuracy must then be
accepted, and measurements immediately after installation are not recommended.
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Problems can also arise in swelling and shrinking soils, since cracks develop especially along the
access tubes.
2.3 Measuring experiences
The new TRIME technique was thoroughly tested in the field and compared both to neutron probe
measurements and thermo gravimetrically determined values.
Figure 3: Comparison of TRIME measurements and gravimetric water content determination for a clayey soil.
Figures 5 and 6 show a comparison of water content determinations for a loess and for a heavy clay,
made with a neutron probe (Wallingford), the TRIME-T3 probe, and the gravimetric method. In contrast
to the neutron probe, which is not suitable for measurements near the surface due to radiation losses
to the atmosphere, TRIME has no problem at all to measure directly at the soil surface.