7. Underground work

Driven by the development of urbanized areas or by technical imperatives, underground construction is on the increase: tunnels, underground stations, storage areas, reservoirs, etc.

When working on loose soils, lime reduces the water content of extracted materials (also known as "pickling products"), increases their consistency and makes them easier to remove (or reuse).

Also, when tunnels are bored by tunnel boring machines (TBMs), the voussoirs required to hold the earth in place are placed in advance. Hydrated lime is used in the composition of tamping mortars (figure 12 ) used to fill the space between the voussoirs and the drilled wall to ensure the stability of the tunnel tube. When these mortars contain fly ash, lime plays...