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Pure fine and middle sand (Ss)
Material: packed quartz sand particle size: 0.1 bis 0.3 mm, soil type: sandy sand (S: 100%, U: 0%, T:
0%), site: Bodenphysikalisches Labor, TU Braunschweig, evaporation: 1.4 mm/d, temperature: 22°C
Description of the measuring process
The measurement process is typical of sand with narrow particle size distri-
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bution and without fines
The tension rise spontaneously immediately after the start of measurement,
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until they reach a level that corresponds to the bubble point. In this case it
is about 50 cm (pF 1.7).
The tensio shafts run for a long time completely in parallel, and differ only
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around a hydrostatic pressure difference of 2.5 hPa.
After draining the main pore portion the tensio shaft value of the upper ten-
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sio shaft rises extremely steep. The failure of the tensio shaft is now very quick.
The lower tensio shaft is at the end of the measurement still completely
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unaffected by the extreme dehydration front, the difference of water ten-
sions is very high.
Hydraulic conductivities can be calculated only for a short period of time.
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The measurement is completed due to the failure of the upper tensio shaft
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after removal of 35% water
89 | Addendum
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