بررسی خصوصیات ژئوتکنیکی رسوبات ته‌‌نشین‌شده در مخزن سد لتیان با استفاده از اندازه‌گیری میدانی

نوع مقاله : مقاله پژوهشی

نویسندگان

1 کارشناس ارشد مهندسی ژئوتکنیک و آب، دانشکده مهندسی عمران، دانشگاه تربیت دبیر شهید رجایی، لویزان، تهران، ایران

2 استادیار، دانشکده مهندسی عمران، دانشگاه تربیت دبیر شهید رجایی،تهران

3 دانشیار گروه مهندسی ژئوتکنیک و آب، دانشکده مهندسی عمران، دانشگاه تربیت دبیر شهید رجایی، لویزان، تهران

4 استادیار گروه مهندسی ژئوتکنیک، دانشکده فنی، دانشگاه گیلان، رشت، ایران

چکیده

هدف از این تحقیق بررسی و تحلیل نتایج حاصل از آزمایشات فیزیکی بر روی نمونه­های رسوب برداشت شده از مخزن سد لتیان در استان تهران می­باشد. پس از انجام عملیات پیمایش و بازدید از مخزن سد لتیان، 8 نقطه مهم جهت برداشت نمونه سطحی تعیین شد و بر روی این رسوبات آزمایش­های متداول مکانیک خاک شامل دانه­بندی، وزن مخصوص و سه محوری جهت تعیین پارامترهای مقاومتی خاک و تحکیم انجام شد. نتایج تحقیق حاضر نشان داد که با نزدیک شدن از لبه­های مخزن سد به سمت دیواره سد، درصد رطوبت خاک به میزان بیش از 2 برابر افزایش می­یابد. علت این موضوع ریزدانه­تر شدن اندازه دانه­های خاک است بطوریکه درصد رس و لای موجود در نزدیکی محور سد، بیش از 89 درصد بوده است. با توجه به نتایج آزمایش تراکم و با استفاده از معادلات تجربی مشخص شد که بعد از گذشت 100 سال از ته­­نشست رسوبات در مخزن سد لتیان، جرم مخصوص ظاهری خشک رسوبات برابر با 128/1گرم بر سانتیمتر مکعب خواهد شد. همچنین، با توجه به نتایج آزمایشات سه محوری مشخص شد که مقادیر چسبندگی و زاویه اصطکاک داخلی در نهشته­های مخزن(خاک) سد لتیان به ترتیب برابر با مقادیر 51/0 کیلوگرم بر سانتی­مترمربع و °1/26 می­باشد.

کلیدواژه‌ها


عنوان مقاله [English]

Study on Geotechnical Properties of Sediment Deposited in Latian Dam Reservoir Using Field Measurements

نویسندگان [English]

  • Omid Asiaei 1
  • Mojtaba Karimaei Tabarestani 2
  • Abolfazl Soltani 3
  • Meghdad Payan 4
1 Msc Graduated, Civil Engineering Department, Shahid Rajaei Teacher Trainig University, Lavizan, Tehran, Iran
2 Assistant Professor, Civil Eng. Department, Shahid Rajaee Teacher Training University, Tehran, Iran
3 Associate proffesor, Civil Engineering Department, Shahid Rajaei Teacher Trainig University, Lavizan, Tehran, Iran
4 Asisstant proffesor, Engineering Department, Gillan University, Rasht, Iran
چکیده [English]

This study aims to investigate and analyze the results of geotechnical experiments on sediment samples taken from the Latian Dam reservoir in Tehran province. After the site visit, eight important stations were identified for surface sediment sampling, and on these sediments, common soil mechanics tests such as grain size analysis, determination of specific gravity, consolidation, compaction, and triaxial were performed to determine soil resistance and consolidation parameters. The present study results showed that by approaching the dam wall, soil water content increased by more than two times. This is due to the smaller size of the soil grains so that the percentage of clay and silt near the dam wall was more than 89%. According to the compaction test results and empirical equations, it was found that after 100 years of sediment deposition in the Latian dam reservoir, the dry density of the sediment will be equal to 1.128 g/cm3. In addition, from the triaxial test results, it was found that the cohesion and internal friction angle parameters of the sediments were equal to 0.51 kg/cm2 and 26.1°, respectively.

کلیدواژه‌ها [English]

  • Latian dam
  • reservoir sedimentation
  • geotechnical properties
  • triaxial test
  • compaction test
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