Under the pavement: the beach?
A famous Situationist International slogan by Guy Debord, also translated as: "Under the paving stones, the beach". But has anyone really tried to test this hypothesis? In reality the urban soil under the pavement is more complex than that. And fortunately the ever present roadworks enable us to study urban soil in detail.
Urban soil layers
At the moment the quay of the 4e Westwagenhof is being restored. The soil has been dug up to a depth of only 1 meter. This no archaeological level, it cannot be older than a few years. But already interesting soil patterns can be observed.
There are 4 layers here, or more. But I'm sure about these ones:
- the paving stones (200*100 mm) - useful for scale
- dry sand - it probably dried during the roadworks
- wet sand - it also could have a relationship with the ground water level
- dark clay - might be more than one layer
|The transition between dry and wet sand.||The transition between the sand and the clay.|
I'm learning the craft on-the-fly, without any theoretical preparation. So I make all the stupid mistakes. For example ... I only took a soil sample from the heap of sand that had been dug out of the hole. And I took only the sand. In hindsight the clay layer would have been much more interesting because it is older.
Where I took the sample. Not good.
Soil analysis attempt
Weight = 47 grams (using my digital kitchen scales)
Volume = 33 cubic centimeters (estimated by measuring the height in the container)
Density = 1.4 grams / cubic cm
The density of dry sand = 1400 - 1600 kg / cubic m - so this fits the range perfectly.
I thought I had a spare tea-sieve, but right now I can't find it.
There are a few "concretions" clumps of sand in a cement-like matrix. The chalk might come from the mortar in the canal walls. Or maybe the sand has been used before on some building site.
Scientifically the experiment is worthless. But poetically it makes you aware of the urban underground and it's unfathomable history. It also highlights the variety of underground soil mixtures, colors and textures. To be continued.