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SANCOLD Conference 2017: Stability Analysis of a Concrete Gravity Dam Tongue Wall

By RO Cassells, GD Roberts. ARQ Consulting Engineers, Pretoria, South Africa.

A concrete gravity dam tongue wall comprises a concrete structure that transitions from the concrete gravity spillway section of a dam, to the non-overflow earthen embankment section. The stability analysis of a concrete gravity dam tongue wall is affected by lateral earth loads imposed on it due to the embankment fill, and a specific analysis methodology is not generally defined. The magnitude of the active and passive lateral earth load acting on the tongue wall is directly related to the deflection of the structure under such loading.

This paper discusses how active and passive lateral earth loads were applied by progressive mobilisation of wedge forces in the fill, and proposes a defined methodology for the stability evaluation of tongue walls.