Physical Modeling of Seismic Response of Makhool Dam Subjected to the Halabja Earthquake

Abstract

Earth dam can be considered as the most ancient type of embankment dam that can be constructed with natural materials such as natural soils, rocks, clay and gravel. Zone earthfill dam is typically composed of two main parts: central core and shell that is filled with gravel and rock to strengthen the stability of the whole body of dam. Many reasons can cause the failure of an earth dam including hydraulic failure, structural failure and seepage failure. Earthquake failure can be considered as a structural failure, therefore, it is important to study the dynamic response of earth dam during the earthquake. This paper presents a seismic analysis on zone-earth dam subjected to earthquake excitation by using a shaking table with dimensions (170×150) cm, on which maximum acceleration, pore-water pressure, and displacement were calculated. The Makhool dam is considered as a case study that is located on Tigris River in Iraq with total length 3670 m. The physical model was simulated using a scale of 1:400 that fit the dimensions of the container (100×50×60) cm and subjected the model to the Halabja earthquake, with a magnitude of 7.3 (Richter scale) according to the Iraq Meteorological Organization and Seismology. Three values of earthquake (0.04 g, 0.06 g, and 0.08 g) were used with a time of 10 seconds, and the parameters were calculated on two nodes on the physical model. Pore-water pressure increases with an increase in the value of the earthquake and is larger at the dam base than the dam crest. Additionally, the displacement can be increased, which weakens the dam soil and affects the stability of the dam. The value of x-acceleration will be reduced at the end of the earthquake, which means the input acceleration affects soil properties.