میزان رسوب در ستون‌های زهکش ماسه‌ای بعد از انجام زهکشی در خاک

نوع مقاله : مقاله کامل پژوهشی

نویسندگان

گروه خاک، دانشکده مهندسی عمران، دانشگاه سمنان

چکیده

یکی از مسائل مرتبط با ستون‌های زهکش بحث انسداد در آن‌ها می‌باشد. در ستون‌های زهکش به ­دلیل ورود ذرات ریزدانه از خاک اطراف به داخل ستون زهکش، منافذ به مرور مسدود می‌گردند. در این تحقیق چهار ستون زهکش به­ کمک سلول ساخته شده مورد آزمایش قرار گرفت، که شامل ستون‌های تک­ مصالح و ستون‌های مخلوط می‌باشند. بر روی هر نمونه، 8 آزمایش انجام شده. مصالح مورد استفاده در این ستون‌ها شامل 3 اندازه ماسه به قطر میانگین 5/0، 75/0 و 1 سانتی‌متر است. به ­منظور بررسی عملکرد میزان رسوب، خاک با آب مخلوط شده، که درصد اختلاط این ریزدانه با آب 0، 5، 5/7 و 10 درصد از وزن آب است. در تمام آزمایش‌ها جریان آب، با هد 1 متر وارد ستون‌های زهکش شده و پس از عبور از ستون از آن خارج شده است. نتایج آزمایش‌ها نشان می‌دهد میزان رسوب در ستون‌های زهکش، به نوع جنس مصالح، نسبت تخلخل مؤثر، نسبت تخلخل غیر مؤثر، نسبت تخلخل اولیه، اصطکاک بین مصالح داخل ستون با ریزدانه مخلوط در آب، حفرات در سطح مصالح، زبری و شکل هندسی مصالح می‌باشد. رسوب در ستون‌های زهکش باعث کاهش نسبت تخلخل، کاهش عبور جریان، افزایش اصطکاک داخلی و ایجاد پل‌های ارتباطی بین ریزدانه و در نتیجه انسداد و از بین رفتن عملکرد زهکشی ستون می‌شود. دانه­ بندی خاک قبل و بعد انجام آزمایش نشان­ دهنده‌ این است که ذرات عبوری از الک 200 به ­طور کلی از نمونه‌ها عبور کرده و بیشترین وزن ذرات رسوب کرده، ذرات بزرگتر از 5/0 میلی‌متر می‌باشد.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

The Amount of Sediment in Sand Drainage Columns after Drainage in the Soil

نویسندگان [English]

  • Amirhossein Pashaie
  • Adel Asakereh
  • Abdolhossein Haddad
Civil Engineering Department, Semnan University, Semnan, Iran
چکیده [English]

Historically for geotechnical engineers, the design and construction of structures on soft soil sediments has been a challenge. The ability to serve and limit the conditions as well as the cost and time program is considered. To meet these requirements, many types of construction methods are available. For example, replacing soft soil with other materials, reinforcing embankment, using lightweight filling materials, prefabricated vertical drainage and overhead or suction to accelerate consolidation, stage density, use of stone columns or different options from cement and cement mixture The soil is like a deep mixing or candle with reinforced reinforcement. Among all existing construction methods, the use of stone columns in soft soil is one of the most common things to reduce session and improve stability and freight capacity. However, when the stone columns are installed in very soft soils, it results in excessive clay pouring into the inner parts of the stone columns and reduces its stone column bearing capacity as well as its drainage capacity (Almeida, 2019). The stone column obstruction has been widely reported and its obstruction on the amount of soft soil improved with the stone columns is visible (Tai and Zhou, 2019) The use of stone columns is a popular technique in improving land with fine soil that can easily Reduce drainage and time of consolidation, as well as increased hardness and shear resistance (Indraratna, 2017). Vertical drainage, such as prefabricated drainage, sand drainage, stone columns and pebbles that are commonly used to accelerate or increase soil resistance. Many previous studies have reported that the area of the impact and resistance of the well causes excess water pressure in the soft soil to be improved with drainage (Nguyen, 2020). The stone column contains empty space or pores. The microphones are attached to the surface of the pores, through which penetrating water flows. Studies show that hydrodynamic or colloidal force is generally responsible for separating the microphones from the pores (Survi and Kousik, 2018). Stone columns create drainage paths due to high permeability (Weber et al., 2010).

کلیدواژه‌ها [English]

  • Drainage columns
  • Void ratio
  • Sedimentation
  • Permeability
  • Slurry

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نشریه مهندسی عمران و محیط زیست دانشگاه تبریز
دوره 53.3، شماره 112 - شماره پیاپی 112
پاییز 1402
آذر 1402
صفحه 37-45

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