Concrete face rockfill dam located on deformed foundation: stress-strain state

Гидротехническое строительство

Concrete face rockfill dam (CFRD) located on soil foundation has a composite structure of the seepage control facility. It includes three elements: the dam concrete face, the seepage control cuttoff wall (CW) in the foundation and the concrete apron connecting them. There is an urgent task to study workability and stress-strain state (SSS) of the seepage control facility as a whole structure as well as each element separately. Method. The SSS analysis of an abstract dam with the aid of numerical modeling was conducted to solve this task. A 100 m high CFRD located on a 100 m thick foundation layer was considered. Analyses were conducted for several alternatives of foundation soils with deformation modulus from 40 to 5000 МPа. Results. The analyses showed that the SSS of the dam on the soil foundation drastically differs from the SSS of the dam on the rock foundation. The concrete face and the cuttoff wall are subject to considerable compressive longitudinal forces. Due to bending deformations in CW and the concrete apron, considerable tensile stresses may occur. Conclusions. A number of recommendations was formulated for providing strength of the elements of the composite seepage control facility of the dam on soil foundation. To provide strength of the concrete face it is necessary that the deformability of the dam soil be close to the foundation soil. To provide CW with strength, it is recommended use the material with rigidity of no more than by 2–3 times greater than the foundation soil rigidity. The most vulnerable element of the structure of the composite seepage control facility is the concrete apron. To avoid cracking in it, it should be cut by transversal joints to form separate slabs.