Investigation of heave in billings shale by mineralogical and biogeochemical methods

A building founded on Billings Shale has suffered nearly 4 in. (10 cm) of heave to its basement floor slab. The heaved zone was thought to be associated with a fault zone in the shale, near which the rock was fractured and contained extensive pyrite intrusions. Investigations have shown the heave to be due to the weathering of the pyrite in the presence of autotrophic bacteria. Factors creating a favorable environment for this complex weathering process are discussed.La dalle de b\ue9ton au sous-sol d'un b\ue2timent fonde sur un schiste de la formation Billings a subi pr\ue8s de 4 po. (10 cm) de soul\ue8vement. On a cru que la zone de soul\ue8vement provenait d'une zone failleuse dans le schiste pr\ue8s de laquelle la roche \ue9tait fractur\ue9e et contenait des intrusions importantes de pyrite. L'\ue9tude a montr\ue9 que le soul\ue8vement est attribuable \ue0 l'alt\ue9ration de la pyrite en pr\ue9sence de bact\ue9ries autotrophes. L'article discute des facteurs qui procurent une ambiance favorable \ue0 ce proc\ue9de complexe d'alt\ue9ration.Peer reviewed: NoNRC publication: Ye