Landslide and excavation support

A landslide rarely has one cause. Several usually combine: weak clayey layers with low residual strength, a groundwater table raised by a wet season or a burst water main, the toe of the slope cut away by an excavation, or undercutting by a river or the sea.

Investigation therefore starts by establishing the mechanism — the position of the slip surface, the groundwater regime, the history of movement. A stabilisation design without that stage is an expensive guess.

Depending on the mechanism we use reinforced counterfort embankments at the toe, anti-landslide structures of piles and anchors, gabion retaining walls and reinforced fills. For deep excavations in urban settings we design cast-in-place reinforced concrete piles and anchor systems.

Experience along the Black Sea coast over recent decades shows that most drainage works have had the expected effect and improved slope stability — while expensive groynes against marine abrasion often fail to solve the problem. In many cases the decisive factor is the raised groundwater table, not the abrasion.

Drainage — tunnel galleries, horizontal borehole drains, large-diameter shafts — is therefore an integral part of our solutions rather than an addition to them.