Numerical modeling on treatment of mylonitization and fracture belt in dam foundation

A nonlinear 3-D numerical modeling was carried out for investigating the stress-deformation status of the gravity dam and the influence of fracture belt on stability of dam foundation in a hydropower project.Based on the comparison of numerical computational results of different treatments a scheme for reinforcing the dam foundation was proposed.It is found that the uneven displacement of the mylonitization and fracture belt results in the occurrence of high tensile stress at the toe of the dam and greatly affects the stress status of the dam. The proposed treatment including keeping the configuration of the dam toe as a vertical surface,excavating an oblique pit of the fracture belt with 5m depth and filling with concrete with height 3m to 5m.By adopting this treatment the tensile stress region at dam toe was greatly reduced and the stress was decreased by 2/3.This effectiveness of this measure and the stability of the dam are verified by the computational result of strength reserve coefficient method.