Akademik Veri Yönetim Sistemi
Uluslararası Katılımlı IV. Ulusal Baraj Güvenliği Sempozyumu, Elazığ, Türkiye, 9 - 11 Ekim 2014, ss.151-159
The rapid drawdown condition is a
critical limit state for many dams, levees, and natural slopes along waterways.
This condition occurs when the water level adjacent to a slope drops rapidly
relative to the time required for water pressures to dissipate in the slope. As
the water level falls, the total stresses in the slope are reduced, and the
soil is in a state of undrained unloading. At the same time, the stabilizing
effect of the water at the slope surface is removed, and shear stresses
increase. Unloading from drawdown will cause a decrease in pore pressures
within the embankment. At the same time, the increase in shear stress may
either raise or lower pore pressures. These pore pressure responses are stress
dependent and are difficult to accurately predict. Since the soil’s shear
strength is directly related to the pore pressure, the appropriate strengths
for rapid drawdown are hard to evaluate.
This paper presents an investigation of a dam slope stability during rapid
drawdown. For this purpose, a coupled transient seepage and deformation
analyses (including consolidation), together with the stability analysis, were
performed using numerical analyses for submerged slopes. Nonlinear
elasto-plastic behavior of the slope soil is taken into account while analysis
of the generation and dissipation of pore pressure is carried out.