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پژوهش های جغرافیای طبیعی، جلد ۴۵، شماره ۳، صفحات ۱۰۷-۱۲۴
عنوان فارسی بررسی عوامل مؤثر در افت فشار داده های هیدرولیکی جلگۀ گیلان
چکیده فارسی مقاله در جلگۀ گیلان منفی‎شدن افت فشار، به‎ویژه در زمان برداشت زیاد، یکی از مسائل هیدرولیکی منطقه است. تحلیل نتایج آزمایش پمپاژ، در مواردی ضرایب افت فشار در شبکۀ جدار یا در آبخوان را نشان می‌دهد. برای بررسی علل، اطلاعات ششصد حلقه چاه عمیق مورد بررسی قرار گرفته است. تحلیل نتایج پمپاژ که به‎روش افت پله‌ای پمپاژ شده بودند، شاخصی برای طبقه‎بندی در سه گروه کلی تعیین شد. در گروه اول، ضرایب افت فشار در شبکۀ جدار و در آبخوان هر دو مثبت بوده و در گروه دوم، ضریب افت فشار در شبکۀ جدار مثبت ولی در آبخوان منفی و درنهایت در گروه سوم، ضریب افت فشار در شبکۀ جدار منفی ولی در آبخوان مثبت بوده است. بررسی مشخصۀ چاه‌های متعلق به هر گروه و شرایط جغرافیایی و ژئومورفولوژیکی آنها نشان می‌دهد که چاه‌های متعلق به گروه اول، در آبخوان‌های با نفوذپذیری مناسب، پتانسیل خوب و با کیفیت مطلوب حفر شده‌اند. در حالی‎که چاه‌های گروه دوم، در آبخوان‌های با نفوذپذیری کم، پتانسیل ضعیف یا در آبخوان‌های گروه اول اما باکیفیت نامطلوب حفر شده‌اند و سرانجام چاه‌های گروه سوم، در آبخوان‌های با نفوذپذیری مناسب و با کیفیت مطلوب حفر شده‌اند.
کلیدواژه‌های فارسی مقاله
عنوان انگلیسی Investigation about the Effective factors on Pressure Drop in Hydraulic Data in Guilan Plain
چکیده انگلیسی مقاله Extended AbstractIntroductionGroundwater is one of the essential resources for supplying requirements of drinking water,agriculture and industry. This resulted in establishment of civilization in plains and lands whereare far from rivers of freshwater.Regarding low amount annual rainfall in Iran and loss of water as a result of evaporation,volume of water production is about 128 billion cubic meters. From this volume about 83billion cubic meters form surface water resources and 45 billion cubic meters join thegroundwater by penetration. In recent decades, the growth of population and the need for waterresources have led to an increase in exploitation to these essential sources hidden in the heart ofthe earth.Study area of this research is located in southern coast of Caspian Sea in Guilan Province.The research problem is that in some wells the coefficient of pressure drop shows negativefigures whereas in some other wells these figures are positive. It is not clear that what is theeffect of these changes on exploitation of water resources of the aquifer and how much thiseffect is and in what field it may be. This research tries to recognize the factors that affect thisphenomenon besides recognizing the effective reason in negative coefficient of pressure drop inaquifer and lining of wells and determining scientific results and its applied effects. MethodologyIn this research, field method and using step back test has been applied to find the reason of thenegativeness of pressure coefficient in available wells in the plain. Thus, through providingnecessary conditions, digging operation and pumping of more than 600 deep wells have beensupervised and controlled. More than 300 regions were directly controlled. Geographicalfeatures in some of sample wells in the region were taken and the selected points were specifiedon the map by using ArcGIS. Statistics and information related to geographical andgeomorphologic conditions and geology of location of the wells and testing scope of pumpingin the selected wells were collected and was analyzed in the form of graphs by SPSS program.Then, the results were analyzed and all wells were classified in separate groups and those withsimilar situation in the view of pressure drop coefficient were assigned in the same groups.Finally, the selected wells have been classified in three different groups.In the next step, the features of wells in each level such as geographical andgeomorphological conditions, geology of constituting sediment layers in location of the wells,texture of surface water and layers in location of them, technical and expert characteristics ofthe company, the quality of digging and supervising system were all evaluated and compared.Common aspects of well was distinguished in each group. Then, after recognition and regardingthe common aspects of the wells belonging to each group it had been concentrated on the wellswhich had negative coefficient of pressure drop.. Being sure about the result, besides repeatingconsiderations on the ground, they have been controlled and evaluated and in some cases thetest has been performed again.Results and DiscussionDoing pumping test for determination of hydraulic features of groundwater aquifer and well isone of the usual methods. In this case, the pumping test has been done in two different methods:one is pumping by fixed rate (shuttle test) for determining aquifer coefficient and pumping byvarying rate (step pumping) for determining well's coefficients. Therefore, the well's coefficientspecification has been possible just by using the result of pumping with varying rate (steppumping). So, in this research by paying attention to the importance of the coefficients, the dataof step pumping is used for determining features and situations of well and aquifer. Beforestarting test first the water level in the wells has been measured. Then, by doing the operationsof digging and tubing of a well, washing and exiting of the fine-grained materials remained in ithas been done by pure water and pumping method. After providing suitable condition for waterarrival from aquifer layers into the well, water pumping operations has been continued withdifferent engine turn until the water level became fixed. During this period water level wasmeasured based on a predetermined timetable. The process of water level changes and itsconstancy was distinguished and from the results (result related to the first step of the test) thecoefficient related to aquifer has been computed. After being sure about the constancy of thewater level (reaching the water level to the dynamic level), well's rate and in another wordengine's turn has been increased and the act of measuring water depth from the surface up to theconstancy of water level in well has been continued as before. This plan has been implemented at least in four steps with 4 different rates as 4 engine's turns. In the next step, the result of steppumping was analyzed and after finishing field operations and recording figures it wasabstracted in related table.After designing the mentioned table, the coefficient of pressure drop in aquifer (B) has beenobtained by using the curve of especial drop to the rate that the mentioned crossing point of thecurve connect with the widths axis with drawing the related curve. From obtaining pressuredrop in aquifer, the pressure drop in lining network of well (C) was obtained by using y2-y1 (x2-x1) that is, in fact, the slope of especial drop curve to the rate. Finally, after calculating B and C,the table of brief result of pumping is provided.ConclusionConsiderations show that available problems in taking groundwater in Guilan Plain is related tothe nature of the region in terms of sediment texture and hydrologic characteristics of the plain,humanistic factor, the performance of feeding, unsuitable quality of digging and alsoexploitation methods. The groundwater feeding is through different sources such as rivers andnetworks of irrigation channels, floodgate and pools of growing fish that are extensively in theplains, and also free aquifers situated on semi-confined aquifer that have hydraulic balancestate. These sources were useful and can have positive function at increasing the age ofeconomic exploitation of a well. However, due to unfamiliarity of most experts with thementioned phenomenon and varying performance of this phenomenon in different seasons, thewells affected by the mentioned elements will be faced with damages and sometimes it is sosevere that may destroy the well.Considering the effective factors on the pressure drop of hydraulic data in Guilan's Plain bypumping method indicates that the step back method is better for determining hydrauliccoefficient of well. It is suggested that to use this pumping method instead of step pressure.Because for determining the features and real situation of wells and aquifers especially in plainsand coast region, implementing step pumping through step drop is suitable. The data gainedfrom pumping which has been done on more than 600 wells were tested by step drop andapproved these results. The lack of observing technical principles for digging leads to theincrease of pressure drop in well's lining network and causes a speed at the entrance of water tothe wells. Therefore, this will change the physical conditions of water. This may lead totransformation of sodium bicarbonate soluble in water to insoluble carbonate which bysedimentation on the well's lining and general pack of the back of lining's tube and tracks oflining network (shell investing) will increase pressure drop of lining network. Moreover, itdecreases discharge of the wells and intensifies shell investing action which leads to a decreasein economic life time of exploitation.
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نویسندگان مقاله محمدرضا افشاری آزاد | mohammad reza afshari azad
استادیار گروه جغرافیا، دانشگاه آزاد اسلامی، واحد رشت
سازمان اصلی تایید شده: دانشگاه آزاد اسلامی رشت (Islamic azad university of rasht)

محمد پورهشیار | پورهشیار
دانشجوی کارشناسی ارشد جغرافیا، ژئومورفولوژی در برنامه ریزی محیطی، دانشگاه آزاد اسلامی، واحد رشت
سازمان اصلی تایید شده: دانشگاه آزاد اسلامی رشت (Islamic azad university of rasht)

نشانی اینترنتی http://jphgr.ut.ac.ir/article_35838_33db7dade69ccd8e87f942cfee41f8f5.pdf
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