See Report for more information and pictures.
- The vibrating plate was not really useful to condense the clay granules.
- We did not remove the sandbags we placed in the beginning as a temporary threshold to
work against. During the overflow tests, this provoked a water jump that could have been
avoided. Actually, knowing now how the clay core behaves, we believe it was not necessary
at all to place those sandbags.
- We are not sure it was necessary to use screed nets between the 20 cm thick layers of clay
granules, since the clay core seemed to be very stable.
- We are not sure it was necessary to fix the first piece of geotextile as we did it. Since the
whole construction did not move at all during the overflow tests, it was probably sufficient to
cover the clay core with a first loose piece of geotextile, stabilised with sand bags.
- We finished the clay core up to approx. 10 cm under the ground level of the dike, in order to
fill the upper part later with a layer of soil and to be able to sow after the so called “flooding”
danger was gone. 10 cm seemed to be insufficient, since the clay core swelled some more
during the overflow tests and the upper surface of the clay core reached the ground level of
the dike. We believe it would have been better to finish the clay core approx. 20 or 30 cm
under the ground level of the dike, and to fill up the gap above with sand bags to obtain a flat surface before putting in place the final geotextile fixed with reinforcement nets. The
sandbags could then be replaced after the storm by an appropriate layer of soil.
- The plugs (with roundels) we used were too small. The self-made anchors of bended Ushaped reinforcement steel on the contrary happened to be very efficient.