نوع مقاله: مقاله پژوهشی

نویسندگان

1 استاد گروه آبیاری و زهکشی، دانشکده مهندسی علوم آب، دانشگاه شهید چمران اهواز

2 دانش آموخته کارشناسی ارشد، دانشکده مهندسی علوم آب، دانشگاه شهید چمران اهواز.

3 استاد بازنشسته گروه آبیاری و زهکشی، دانشکده مهندسی علوم آب، دانشگاه شهید چمران اهواز.

چکیده

یکی از روش‌های مناسب برای تعیین هدایت هیدرولیکی اشباع خاک در بالای سطح ایستابی، روش پرمامترگلف است. هدف از این پژوهش، واسنجی روش پرمامتر گلف با استفاده از روش پمپاژ به داخل چاهک کم عمق (SWPT) برای یک خاک لوم بود. این تحقیق برای اعماق خاک 30 و 60 سانتی­متری در مزرعه آزمایشی دانشکده مهندسی علوم آب دانشگاه شهید چمران اهواز انجام شد.با انجام  آزمایش گلف با استفاده از تحلیل دو عمقی می‌توان ضرایبی نظیر هدایت هیدرولیکی اشباع (Kfs) و پارامتر مربوط به خصوصیات خاک غیر اشباع  را،  از حل دستگاه معادلات دو مجهولی به­دست آورد. از آن­جا که تعدادی از جواب­های تحلیل دو عمقی گلف به علت ناهمگن بودن دستگاه معادلات توأم، غیرمنطقی می‌باشند، در این تحقیق از تحلیلهای تک عمقی لاپلاس (KL) با فرض صعود مویینگی صفر، تک عمقی ریچاردز با فرض   و تک عمقی رگرسیون پایه‌ای ریچاردز (KR) برای رفع جواب­های غیرمنطقی دستگاه پرمامترگلف استفاده شد. در این تحقیق مشخص گردید که به علت بالا بودن انحراف معیار مقادیر  در آزمایش­های گلف، بهتر است مقدار آن را ثابت در نظر گرفت. در اراضی مورد آزمایش با بافت خاک لومی، هدایت هیدرولیکی با روش پمپاژ به چاهک سطحی 80 درصد بیشتر از هدایت هیدرولیکی با روش گلف به­دست آمد. در صورتی که نتایج به­دست آمده از روش گلف در ضریب 87/4  ضرب شوند، نتایج  روش گلف معادل روش پمپاژ به چاهک سطحی خواهند بود. ضمنا بر پایه نتایج حاصله، روش گلف، مناسبترین روش تعیین هدایت هیدرولیکی اشباع خاک در بافت  لوم می­باشد.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Calibration of the Guelph Permeameter Method Using Shallow Well Pump-in Test (SWPT) for Hydraulic Conductivity Measurement and Derivation of single depth Laplace and Richards Equation for a Loam Soil

نویسندگان [English]

  • Abd Ali Naseri 1
  • Zzeinab Nnaderi 2
  • HeidarAli Kashkooli 3

1 Professor, Irrigation and Drainage Department, Faculty of Water Science and Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran

2 Former Grad. Student, Faculty of Water Sciences and Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran.

3 Retired Professor, Irrigation and Drainage Department, Faculty of Water Science and Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran.

چکیده [English]

Saturated hydraulic conductivity is a vital soil propriety in controlling infiltration and runoff, drainage, extracting pesticides, and herbicides from soil profile and transfer them to ground water. The auger-hole method is the most famous and the most common method to measure the hydraulic conductivity (K) that have been used normally for years. Using this method is possible where the water table is high and in a one-meter range from the soil surface. In the measurement of saturated hydraulic conductivity some problems occur when the water table of the soil is very deep. In arid and semi-arid areas especially in summer, the water table is so low making it impossible to use ideal methods.To determine the hydraulic conductivity rates of soils above the water table, different methods are used. These methods have always been faced with weakness in theoretical bases or practical problems as well as being time consuming and costly. One of these methods is the shallow well pump-in test which is the most adaptable method used for this purpose. However, a new method has been developed to measure the hydraulic conductivity above water table which is called the Guelph Permeameter method. As the Guelph method was introduced by Reynolds and Elricks (1985), great changes have been made in this field, and due to the strong theoretical bases, being less time-consuming and cheaper to perform, Guelph method attracted lots of attention. The aim of this research was to calibrate the Guelph Permeameter for the measurement of saturated hydraulic conductivity using the Shallow Well Pump-in Test (SWPT) method at an experimental farm in Shahid Chamran University of Ahvaz. This research examines the calibration of Guelph Permeameter method by using shallow depth pumping test method for a loam soil in this region.

کلیدواژه‌ها [English]

  • Saturated hydraulic Conductivity
  • Guelph Permeameter
  • Single Depth Analysis

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