A pictorial case history of lateral rock creep in an open cut into the Niagara Escarpment rocks at Hamilton, Ontario

Excavation of an open trench to a total depth of 10–13 m including a 5.5 m penetration into the Eramosa Member of the Lockport dolomite formation resulted in an estimated 5–10 cm of lateral rock movement towards the excavation with slippage clearly defined at bedding planes and joints as illustrated in the accompanying photographs. The movements observed are the visual manifestation of release of high locked-in lateral stresses characteristic of rocks of the Niagara escarpment. If movement is not allowed, very high stresses are ultimately transferred to any rock encased structures.