running sand

English

Noun

running sand (uncountable)

1. (construction) Saturated sand which flows into an excavation or void due to water pressure.
   • 1946 January and February, “Notes and News: Demolition of Rhydyfelin Viaduct”, in Railway Magazine, page 53:

     During the construction of the viaduct, the sinking of the caissons in the river bed caused much difficulty to the engineer and contractors, as a bed of running sand was encountered; in consequence, the expenditure for these foundations proved almost prohibitive.