بررسي آبشكن بر الگوي جريان و تثبيت ساحل در رودخانه كارون با استفاده از نرم ‌افزار CCHE2D

Investigation of breakwater on flow pattern and shoreline stabilization in Karoun river Using software (CCHE2D)

ﭼﮑﯿﺪه از ﺟﻤﻠﻪ روشﻫﺎي ﻣﺘﺪاول ﮐﻨﺘﺮل ﻓﺮﺳـﺎﯾﺶ ﮐﻨﺎري رودﺧﺎﻧﻪﻫﺎ ، اﺳـﺘﻔﺎده از آﺑﺸـﮑﻦﻫﺎي ﻧﻔﻮذﻧﺎﭘﺬﯾﺮ ﻣﯽﺑﺎﺷـﺪ ﮐﻪ در ﺻـﻮرت ﻃﺮاﺣﯽ و اﺟﺮاي ﺻـﺤﯿﺢ ، ﻋﻼوه ﺑﺮ ﮐﻨﺘﺮل ﻓﺮﺳـﺎﯾﺶ ﮐﻨﺎري، ﻣﻨﺠﺮ ﺑﻪ ﺑﺎزﯾﺎﺑﯽ و اﺣﯿﺎي اراﺿـ ﯽ ﺑﺎ ارزش ﺣﺎﺷـ ﯿﻪ رودﺧﺎﻧﻪﻫﺎ ﻣﯽﺷـﻮد. آﺑﺸـﮑﻦﻫﺎ ﻋﻼوه ﺑﺮ ﮐﻨﺘﺮل ﻓﺮﺳـﺎﯾﺶ ﮐﻨﺎري ، ﻣﻨﺠﺮ ﺑﻪ ﺑﺎزﯾﺎﺑﯽ و اﺣﯿﺎي اراﺿـﯽ ﺑﺎ ارزش ﺣﺎﺷـﯿﻪ رودﺧﺎﻧﻪ ﻣﯽﮔﺮدﻧﺪ و در ﺻـﻮرت ﻋﺪم اﺟﺮاي ﺻـﺤﯿﺢ و ﻃﺮاﺣﯽ ﻏﻠﻂ ﻣﻤﮑﻦ اﺳـﺖ ﺑﺎﻋﺚ ﺗﺸـﺪﯾﺪ ﻓﺮﺳـﺎﯾﺶ و ﻧﺎﺑﻮدي ﺧﺎكﻫﺎي زراﻋﯽ ﺷـﻮﻧﺪ. ﺷـﺎﯾﺪ ﺑﺘﻮان ﮔﻔﺖ ﻣﻬﻢﺗﺮﯾﻦ ﻗﺴـﻤﺖ ﻃﺮاﺣﯽ آﺑﺸـﮑﻦﻫﺎ، ﺟﺎﻧﻤﺎﯾﯽ آﻧﻬﺎ ﻣﯽﺑﺎﺷـﺪ. ﺑﺮاي ﺗﻌﯿﯿﻦ ﻃﻮل آﺑﺸـﮑﻦﻫﺎ و ﻫﻤﭽﻨﯿﻦ ﻓﺎﺻـﻠﻪي آﻧﻬﺎ ﺗﺌﻮري ﺧﺎﺻـﯽ وﺟﻮد ﻧﺪارد. در اﯾﻦ ﺗﺤﻘﯿﻖ ﺑﻪ ﺷـﺒﯿﻪﺳـﺎزي اﻟﮕﻮي ﺟﺮﯾﺎن ﺣﻮل آﺑﺸﮑﻦﻫﺎي ﺳﺎده در رودﺧﺎﻧﻪ ﮐﺎرون ﺣﺪ ﻓﺎﺻﻞ اﻫﻮاز ﺗﺎ ﺧﺮﻣﺸﻬﺮ در ﻣﺤﺪوده 5 ﮐ ﯿﻠﻮﻣﺘﺮي ﺟﻨﻮب اﻫﻮاز ﭘﺮداﺧﺘﻪ ﺷﺪ. ﻧﺼﺐ آﺑﺸﮑﻦ در ﻗﻮس ﺑﯿﺮوﻧﯽ ـﺑﻪ ﻋﻠـﺖ ـﭘﺎﯾﯿﻦ آوردن ﺳــﺮﻋـﺖ، ﺑـﺎﻋـﺚ ﺟﻠﻮﮔ ﯿﺮي از ﻓﺮﺳــﺎﯾﺶ و در ﻧﺘﯿﺠـﻪ ﺗﺜﺒﯿـ ﺖ ﺳــﺎﺣـﻞ ﻣﯽﺷــﻮد. ـﺑﺎ اﻓﺰاﯾﺶ دﺑﯽ از 100 ـﺗﺎ 2000 مترمكعب بر ثانيه سرعت جريان از0/17 متر بر ثانيه به 2/1 متر بر ثانيه رسيد و با نصب آبشكن سرعت جريان از 0/11 متر بر ثانيه به 0/57 ﻣﺘﺮ ﺑﺮ ﺛﺎﻧﯿﻪ رﺳـ ﯿﺪ. ﻫﻤﭽﻨﯿﻦ ﺗﻨﺶ ﺑﺮﺷـ ﯽ از 0/08 ﻧﯿﻮﺗﻦ ﺑﺮ ﻣﺘﺮ ﻣﺮﺑﻊ ﺑﻪ 9/36 ﻧﯿﻮﺗﻦ ﺑﺮ ﻣﺘﺮ ﻣﺮﺑﻊ رﺳـ ﯿﺪه و ﺑﺎ ﻧﺼـﺐ آﺑﺸـﮑﻦ ﺗﻨﺶ ﺑﺮﺷـ ﯽ از 0/03ﻧﯿﻮﺗﻦ ﺑﺮ ﻣﺘﺮ ﻣﺮﺑﻊ ﺑﻪ 0/72 ﻧﯿﻮﺗﻦ ﺑﺮ ﻣﺘﺮ ﻣﺮﺑﻊ رﺳـ ﯿﺪ. ﻧﺘﺎﯾﺞ ﮐﺎﻫﺶ ﺳـﺮﻋﺖ ﺟﺮﯾﺎن و ﺗﻨﺶ ﺑﺮﺷـ ﯽ ﺑﺎ ﻧﺼـﺐ آﺑﺸـﮑﻦ ﺑﯿﺎﻧﮕﺮ اﻧﺪازه ﻣﺤﺪوده ﺗﺎﺛﯿﺮ آﺑﺸﮑﻦ ﺑﺮ ﺟﻠﻮﮔ ﯿﺮي از ﻓﺮﺳﺎﯾﺶ ﺳﺎﺣﻞ ﻗﻮس ﺑﯿﺮوﻧﯽ ﻣﯽﺑﺎﺷﺪ.

One of the common methods of controlling river erosion is the use of impermeable culverts. In case of correct design and implementation, in addition to lateral erosion control, it leads to recovery and restoration Lands along rivers. If not implemented correctly and incorrectly designed, it may intensify erosion and destruction of arable soils. Perhaps the most important part of drop design is their location. There is no specific theory for determining the length of drops as well as their distance. In this study flow pattern was simulated around simple drops in the Karoun River between Ahvaz and Khorramshahr within 5 km south of Ahvaz. Installing the breaker in the outer arch due to slowing down Prevents erosion and thus stabilizes the beach. With the increase of discharge from 100 to 2000 cubic meters per second, the flow velocity has increased from 0.17 meters per second to 2.1 meters per second and with the installation of the drop, the flow rate has increased from 0.11 m / s to 0.57 m / s. Also, the shear stress increased from 0.08 N / m2 to 9.36 N / m2 and with the installation of the shear stress breaker, it increased from 0.03 N / m2 to 0.72 N / m2. The results of reducing the flow velocity and shear stress by installing a drop indicate the size of the impact area of the breaker on preventing erosion of the outer arch banks