تعیین ضرایب ثابت معادلات ون گناختن-معلم و گاردنر با استفاده از یک معادلۀ آماری تخمین نفوذپذیری غیر اشباع خاک

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشجوی کارشناسی ارشد مهندسی آب گرایش سازه‌های آبی دانشگاه تهران

2 دانشیار گروه سازه‌های آبی دانشگاه تهران

3 استادیار گروه سازه‌های آبی دانشگاه بوعلی سینای همدان

چکیده

اطلاعات لازم در خصوص مقدار نفوذپذیری یک خاک در طراحی پروژه‏های عمرانی، به‌خصوص سازه‏های هیدرولیکی، اهمیت بسیار زیادی دارد. تعیین مقدار آن برای خاک‏های غیر اشباع در آزمایشگاه به صرف زمان طولانی و هزینة زیاد نیاز دارد. بنابراین ترجیح داده می‏شود با روش‏های غیر مستقیم، مانند منحنی مشخصة آب‏خاک، به تعیین آن اقدام شود. این روش‏های غیر مستقیم ضرایب ثابتی دارند که برای تعیین آن‌ها به داشتن اطلاعات خاصی از منحنی مشخصة آب‏خاک، نظیر رطوبت در نقطة اشباع خاک و رطوبت باقی‌مانده، نیاز است. در پژوهش حاضر ابتدا با بررسی یک مدل آماری، که تابع رطوبت اشباع و باقی‌مانده نیست، ضرایب نفوذپذیری غیر اشباع خاک محاسبه شدند که دارای همبستگی مناسب با مدل‏های مشهور در این زمینه بود. سپس، ضرایب ثابت تعدادی از معادلات تخمین نفوذپذیری به کمک این رابطة آماری تعیین شدند. نتایج حاکی از دقت بالای مدل پیشنهادی جهت تعیین این ضرایب بود.

کلیدواژه‌ها

عنوان مقاله [English]

Determination the Constant Parameters of Van Genuchten-Mualem and Gardner’s Equations Using a Statistical Model to Estimate the Permeability in Unsaturated Soil

نویسندگان [English]

  • Mohammad Mahdi Kholousi 1
  • Ali Raeisi Estabragh 2
  • Saeid Gohari 3
1 Graduate Student, University College of Agriculture and Natural Resources, University of Tehran
2 Associate Professor, University College of Agriculture and Natural Resources, University of Tehran
3 Assistant Professor, University College of Agriculture and Natural Resources, University of Tehran
چکیده [English]

Availability of accurate information regarding permeability of soil is needed in planning for the development projects, especially hydraulic structures. Laboratory determination of unsaturated permeability of soil involves high costs and is very time taking. Therefore, it is preferred to determine it using such indirect methods as making use of soil-water characteristic curve. These indirect methods are of constant parameters the determination of which needs such special information of soil water characteristic curve as residual and saturated water contents. Through initially examining a statistical model ( not a function of residual and saturated water contents) the  permeability coefficients of unsaturated soil that were in acceptable correlation with famous models were determined. The constant parameters of some of the equations for estimation of the permeability of unsaturated soil were then estimated. The results finally show a high accuracy of the proposed model for a determination of the constant parameters.

کلیدواژه‌ها [English]

  • Residual Water Content
  • soil water characteristic curve
  • correlation coefficient
  • RETC
  • RMSE

مراجع

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