2017-05-30
TRIME
®
-PICO IPH Version 2_0
Page 17
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. %.
At a water content of 25 vol. % the error would be 5 vol.-%.
At very high water contents (50 vol. %) errors may reach 10 vol. %.
In the case of a water filled gap under conditions of saturation the gap error would be
much smaller.
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 then has to be
accepted, and measurements immediately after installation are not recommended.
Problems can also arise in swelling and shrinking soils, since cracks develop especially along the
access tubes.
