Analysis on long term stress and deformation of high concrete face rockfill dam in narrow valley

A creep model describing the long term displacement of rockfill is proposed based on the analysis result of settlement records of several existing concrete face rockfill dams and large-scale triaxial creep test for rockfill of the Jiudianxia Dam. The model is applied to carry out the 3-D stress-deformation analysis for the 133 m high Jiudianxia rockfill Dam, located at a narrow valley. The influences of 3-D effect and creep on long term stress-deformation characteristics of the dam are investigated. The result shows that the arch effect formed by the banks of narrow valley exists and reduces the settlement and stress of the dam. The dam body on the right side which has a less steep bank than the left side moves more significantly towards the center of the valley. The arch effect also reduces the bending and settlement of the concrete slabs resulted in the failure of the joints or slipping of slab. The slabs at upper part of the dam in valley canter region may be broken due to extrusion pressure. The creep effect increases the possibility of extrusion failure of the slabs along the direction of dam axis. The reservoir water pressure may cause the extension deformation when the deflection of slabs takes place, but the extensive stress may be reduced due to the deformation of post creep of the dam.