نوع مقاله : مقاله پژوهشی
عنوان مقاله English
نویسندگان English
The Mosul Dam is one of the most important earth-and-rockfill dams in the region. It is constructed on a karstic foundation composed of gypsum, anhydrite, dolomite and limestone formations. The solubility of the foundation materials, reservoir-water infiltration, fluctuations in reservoir level, and variations in hydrostatic and pore-water pressures contribute to the complexity of the dam’s geotechnical behaviour and settlement pattern. This study aimed to develop an intelligent management model for monitoring and predicting settlement in the Mosul Dam based on structure–water–foundation interaction. Accordingly, a two-dimensional cross-sectional model of the dam was simulated using the finite-element method and coupled stress–pore-pressure analysis in FLAC2D and ABAQUS. The modelling considered the effects of dam geometry, geotechnical properties of the constituent materials, reservoir-level fluctuations, drawdown rate, pore-water pressure, seepage, and mechanical and hydraulic boundary conditions.The results demonstrated that the dam exhibits an asymmetric settlement pattern, with the greatest settlement occurring on the downstream side. In the ABAQUS model, downstream settlement reached 36.1 mm, whereas upstream settlement was estimated at 23.8 mm. This difference was primarily attributed to the steeper downstream slope, variations in material stiffness, and the non-uniform distribution of pore-water pressure. Moreover, rapid reservoir drawdown at a rate of 2–5 m/day increased the maximum settlement from 28.3 to 41.7 mm and reduced the time required to reach 90% of the ultimate settlement from 60 to 15 days. Analysis of reservoir-level variations showed a substantial nonlinear decrease in the settlement rate within the elevation range of 320–310 m. Accordingly, an elevation of 310 m may be considered a critical management level for controlling the settlement process. At this elevation, the settlement rate decreased to approximately 0.5–0.6 mm/day. A comparison of the results obtained from the two software packages indicated satisfactory agreement, with a maximum settlement difference of approximately 1.5 mm, a consolidation-time difference of approximately three days, and a residual pore-pressure difference of approximately 5 kPa. The findings indicate that controlling the drawdown rate, simultaneously monitoring settlement and pore-water pressure, and incorporating critical reservoir elevations into operational decision-making are essential requirements for the safe management of the Mosul Dam.
کلیدواژهها English