نوع مقاله : یادداشت فنی
نویسندگان
1 دانشکده ی مهندسی عمران و محیط زیست - دانشگاه صنعتی امیرکبیر
2 دانشکده ی مهندسی عمران و محیط زیست، دانشگاه صنعتی امیرکبیر
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Monitoring and \ evaluating \ earth-rock fill dams in different \ stages of their
lifetime including \ construction \ impounding, rapid drawdown and earthquake
occurrences \ are important for \ improvement of dam \ monitoring, safety control and stability. Historically, earthquakes have \ caused severe damages and human
losses. The destruction of infrastructures, such as dams, is of high concern
because of financial and human losses caused by water flowing downstream into
densely populated human settlements. Based on the world's earthquake data, rock
fill dams showed different behaviors under earthquake conditions, ranging from
minor damage and deformation to complete destruction. In the present study the
Gotvand dam, one of the largest rock fill dams in Iran has been focused on. In
this study, the largest dams' cross-section was modeled and evaluated using two
dimensional finite- element software, FLAC4.0. The back analyses results
compared with data collected from instrumentation and characterized materials'
properties exactly. In numerical analysis, regarding the nonlinear nature of
geo-mechanic materials such as soil, the Mohr-Columb constitutive rule and the
hardening- softening models used to simulate the material behavior in
foundation and dam body respectively. Under elastic conditions, the main
assumptions include; 1) increasing the internal friction angle with increasing
the plastic strain; 2) dependence of material's elastic modulus and dilation
angle on confining pressure; 3) bulk modulus of water dependence in a medium
tension stress of the elements during the construction and first impounding to
estimate the pore water pressure correctly and saturation collapse simulation
during the first impounding. The model was ran for five years after impounding
until it reached a steady state. The Mohr-Columb nonlinear constitutive model
through Massing-Finn rules was used to simulate the nonlinear and hysteretic
behavior of soil and rock materials under earthquake condition. The dynamic
analysis is performed to predict the displacement of the Gotvand dam under the
maximum credible earthquake (MCE) condition. The type of acceleration time
history and the magnitude of input acceleration are also investigated to
predict the dynamic behavior of the dam including deformations on the design
based earthquake (DBE), the maximum design earthquake (MDE), and MCE. The
maximum settlement of the dam core due to application of the Manjil earthquake
is equal to 1.94 meters, and the maximum horizontal deformations are 1.30 and
1.19 meters in upstream and downstream shells, respectively. The results showed
that the dam deformations were highly influenced by the magnitude of the
earthquakes and the acceleration time history.
کلیدواژهها [English]
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