Rock + Dam Analysis

To improve monitoring of the Bin El Ouidane dam, built in 1952, Itasca Consultants SAS (Ecully, France) was asked by INGEMA to conduct a FLAC3D analysis of the behavior of the "dam + rock" system with respect to seasonal temperature variations and water level changes in the reservoir. The dam was constructed with independent cantilevers, later grouted to make the arch monolithic. For each set of model parameters (water level in the reservoir and air temperature) corresponding to one particular moment in time, new pore pressures and heat fluxes between the dam and the air, on one hand, and the dam and the water, on the other, were calculated. These phenomena affect the mechanical behavior of the dam, as shown in the graph below, which depicts radial and tangential pendulum displacements from September 1998 to August 2004. The resulting thermo-hydromechanical model was calibrated using measurements available since the dam's construction and is capable of predicting its future behavior. Future normal and abnormal behavior of the dam can be determined by comparing the simulated motions and measured ones.

Figure 3. Agreement is seen between the measured and modeled pendulum displacements.