| تعداد نشریات | 282 |
| تعداد نشریات سازمان | 80 |
| تعداد شماره‌ها | 3,262 |
| تعداد مقالات | 36,058 |
| تعداد مشاهده مقاله | 55,187,793 |
| تعداد دریافت فایل اصل مقاله | 94,186,284 |
مطالعۀ آزمایشگاهی عملکرد انواع سیستم‌های زهکشی در بدنۀ سد خاکی همگن واقع بر بستر آبرفتی | ||
| تحقیقات مهندسی سازه های آبیاری و زهکشی | ||
| دوره 26، شماره 100، مهر 1404، صفحه 127-105 اصل مقاله (1.29 M) | ||
| نوع مقاله: مقاله پژوهشی | ||
| شناسه دیجیتال (DOI): 10.22092/idser.2026.371869.1635 | ||
| نویسندگان | ||
| عاطفه عرب1؛ حجت احمدی* 2؛ نور علی حقدوست2؛ بهرام نورانی3 | ||
| 1دانشجوی دکتری، دانشگاه ارومیه ،ایران | ||
| 2گروه علوم ومهندسی آب، دانشگاه ارومیه، ایران | ||
| 3دانش آموخته دکترای مهندسی آب-سازه های آبی ،دانشگاه تبریز، ایران | ||
| چکیده | ||
| یکی از مهم‌ترین عوامل تخریب و شکست سدهای خاکی، پدیدۀ نشت و پیامدهای جانبی ناشی از آن است. کنترل نشت نقش اساسی در افزایش ایمنی و پایداری سدهای خاکی دارد. هدف از این پژوهش، مقایسۀ آزمایشگاهی عملکرد انواع سیستم‌های زهکشی در کنترل نشت و کاهش فشار آب منفذی در بدنۀ سد خاکی همگن ساخته‌شده روی بستر آبرفتی است. در این مطالعه، یک مدل فیزیکی از سد خاکی به ارتفاع 25 سانتی‌متر واقع بر بستر آبرفتی همگن به ضخامت 25 سانتی‌متر ساخته شد. به منظور بررسی کمی تأثیر زهکش‌ها بر میزان نشت و رفتار هیدرولیکی سد، سه نوع سیستم زهکشی شامل زهکش افقی، زهکش پنجه و زهکش دودکشی ساده بررسی و نتایج آن ها با حالت بدون زهکش مقایسه شد. پارامترهای اصلی شامل دبی نشت، مسیر جریان و فشار آب منفذی در زیر بدنه اندازه‌گیری و تجزیه و تحلیل گردید. نتایج آزمایش‌ها نشان داد که در داده‌های حاصل از پیزومترهای به کار رفته در بدنۀ سد خاکی مورد مطالعه، زهکش دودکشی عملکرد بسیار بهتری نسبت به زهکش پنجه از خود نشان می دهد. این در شرایطی هست که به طور متوسط مقدار فشار آب منفذی در پی را به حدود 25 درصد نسبت به دیگر حالات کاهش داد. در این میان، زهکش افقی و زهکش پنجه نتایج مشابهی را در خصوص کاهش فشار آب منفذی از خود نشان دادند. بررسی سرعت نشت و حرکت آب در داخل بدنۀ سد برای دو حالت زهکش افقی و پنجه با حالت بدون زهکش نیز مقایسه شد و نتایج این بررسی نشان داد که در زهکش پنجه سرعت حرکت آب به میزان جزئی حدود 2 درصد بیشتر از زهکش افقی است و نسبت به حالت بدون زهکش سرعت جریان 10 درصد بیشتر است. با این حال، طول مسیر نشت به میزان 26 درصد کوتاه تر شده است. نتایج این پژوهش در انتخاب سیستم مناسب زهکش برای سدهای خاکی همگن موثر و مفید خواهد بود. | ||
| کلیدواژه‌ها | ||
| سد خاکی همگن؛ زهکش دودکشی؛ زهکش افقی؛ زهکش پنجه؛ میزان نشت | ||
| عنوان مقاله [English] | ||
| Experimental Investigation on the Performance of Different Drainage Systems in a Homogeneous Earth Dam Over an Alluvial Foundation | ||
| نویسندگان [English] | ||
| Atefeh Arab1؛ Hojjat Ahmadi2؛ NourAli Haghdoust2؛ Bahram Nourani3 | ||
| 1Phd Candidate, Department of Water Engineering, Urmia University, Iran | ||
| 2Department of Water Engineering, Urmia University, Iran. | ||
| 3Department of Water Engineering, University of Tabriz, Iran | ||
| چکیده [English] | ||
| Extended Abstract Introduction Earth dams are the most common type of dams due to their cost-effectiveness, and they make up the majority of the world's dams. Water seepage is one of the most important issues in the design and safety of earth dams, as it can lead to increased pore water pressure, reduced shear strength, the occurrence of piping phenomena, and ultimately dam failure. Statistics show that approximately 35% of dam failures are directly or indirectly related to seepage. This risk is particularly exacerbated in dams built on permeable alluvial foundations. To control seepage, various measures are employed, including drainage systems in the dam body and foundation. Blanket drains, toe drain, and chimney drain, whose main roles are to collect leaked water, reduce pore water pressure, and lower the water table. Although the use of chimney drains has become more common in recent years, new studies show that horizontal drains, especially their length, can have a significant impact on reducing pore water pressure and improving dam stability, while parameters such as drain thickness, height, and angle play a lesser role. Seepage in earth dams is examined using numerical and experimental methods. Numerical methods are fast and cost-effective, but laboratory studies are of high importance as a basis for validating numerical results and for a detailed examination of the dam's actual behavior. Given that the impact of different drainage geometries with the same length has not been fully investigated to date, this study designs a laboratory model of a homogeneous earth dam to examine the effect of various drainage types with equal lengths and different geometries on seepage discharge and flow patterns in an earth dam located on an alluvial bed. Methodology In this study, a homogeneous earth dam was constructed using glass bead material, which contains glass particles with sizes ranging from 0.7 to 3.5 millimeters. The dam model was designed in a drainage box with dimensions of 150 cm length, 10 cm width, and 60 cm height, and included 5 piezometers to monitor changes in pore water pressure under the dam structure. The purpose of this experiment was to investigate the effect of the downstream drain's geometric shape on seepage from the dam. To observe the water seepage, artificial sunset yellow dye and potassium permanganate were used to visualize the flow lines. An air tank was also placed above the laboratory box to keep the water level in the dam constant. The hydraulic conductivity of the material was estimated to be 0.128 cm/s using the constant head permeability test. The height of the constructed dam was 25 cm above the level of the permeable layer, which, considering the location of the overflow weirs, resulted in a reservoir water level of approximately 22 cm. The crest width was 10 centimeters, and the upstream and downstream body slopes were equal to the dam width at the foundation, which was 130 centimeters. Figure 1 illustrate the details of the constructed dam. To study the effects of different drain system and their geometry, three different drain system involving blanket, toe and chimney drain were studied and compared with the basic state of an earth dam with no drain system. The length of all implemented drains was almost identical equal to 21 cm. The dimensions of the drains were presented in table1. The coarse gravel was used to create the employed drains. To avoid any mixing of the fine glass beads within the coarse materials of drains, a fine mesh fabric was placed around the drain system. The thickness of the gravels in the drains was 3 cm. Results and Discussion The summery of the achieved results were presented in figure 2 in terms of pore pressure in the base of the dam. In this figure each curve belongs to the specific drain. As seen, the toe and blanket drains have similar effect in removing of pore water pressure, while the chimney drain is very effective, comparing to other drain. Additionally, the seepage line was investigated in the toe and blanket types to evaluate the seepage velocity and their lengths. The results are shown in figure 3. As seen in this figure, the seepage path through the earth dam from the identical inlet point has different outlet point. The length of the seepage path in toe drain and blanket drain significantly is shorter than that in no-drain. Among toe drain, blanket drain, and chimney drain , the toe drain has the shortest seepage path. Conclusions The objective of this study is to evaluate the performance of various drainage systems in controlling seepage and mitigating pore water pressure within a homogeneous earthen dam constructed on an alluvial foundation under laboratory conditions. To quantitatively assess the influence of drainage systems on the seepage rate and the dam's hydraulic behavior, three drain configurations: horizontal or blanket drains, toe drains, and chimney drains, were investigated. Their performance was subsequently compared to a control scenario with no drainage system. The findings of this investigation demonstrate that chimney drains are superior comparing to other drain types in reducing pore water pressure; however, they concurrently lead to a higher rate of seepage. When drain length is held constant, horizontal drains are preferable to toe drains. Nevertheless, the implementation of toe drains can enhance the structural stability of the dam body due to the incorporation of a substantial volume of coarse-grained material. This particular aspect, however, warrants further investigation to enable a quantitative comparison of its outcomes with those of other drainage configurations. Based on a value analysis conducted by considering three parameters—pore water pressure reduction, seepage discharge, and the volume of material utilized as a cost factor—the chimney drain yields the highest value, whereas the toe drain yields the lowest. It is noteworthy that the differential in value between the chimney drain and the toe drain is marginal. | ||
| کلیدواژه‌ها [English] | ||
| Blanket Drain, Chimney Drain, Permeable base, Seepage Rate, Toe Drain | ||
| مراجع | ||
|
Ahmadi, H., Abtahi, T. & Aghazadeh, N. (2017b). Effect of hydraulic functions in transient seepage analysis through the earth dam and its foundation (Case study: Derik Earth Dam). Iranian Water Researches Journal, 11(4), pp.1–11. Ahmadi, H. & Rezaei, H. & Zeinalzadeh, K. (2017a). An experimental study of the influence of hydraulic conductivity function on modeling seepage through earth dam cores. Iranian Journal of Soil and Water Research, 45(3), pp.299–307. (in Persian) Ahmadi, H., Salimi, H. & Hemmati, M. (2018). Analysis of seepage through earth dams by using finite difference numerical method and extended pressure technique. Journal of Research in Irrigation and Drainage Engineering Structures, 19(72), pp.1–14. (in Persian) Ahmadi, H. & Vahid, R. (2014). Investigation on the effects of hydraulic conductivity function in unconfined seepage analysis (Case study: Hassanlu Earth Dam). Iranian Journal of Irrigation and Drainage, 8(3), pp.430–442. Al‑Yaqoubi, S., Al‑Maktoumi, A., Obnosov, Y. & Kacimov, A. (2024). Clogging of toe drain drastically affects phreatic seepage in earth dams. Advances in Water Resources, 190, 104737. Amr, R., Refaiy, N. M., Aboul, A., Neveen, Y., Saad, D. A. & Molla, E. (2021). Modeling the effect of downstream drain geometry on seepage through earth dams. Ain Shams Engineering Journal, 12, pp.101–113. Çalamak, M., Bingöl, A. N. & Yanmaz, A. M. (2018). Effect of drainage properties on seepage behavior of earth‑fill dams. Proceedings of the 12th International Congress on Advances in Civil Engineering. Istanbul, Turkey. Djehiche, A., Amieur, R. & Gafsi, M. (2012). Seepage through earth dams with chimney drain on pervious foundation. Advanced Materials Research, 452, pp.538–542. Elnashar, W., Abd‑Elhamid, H. F., Zeleňáková, M. & Elyamany, A. (2023). Value engineering approach to evaluate the agricultural drainage water management strategies. Water, 15(4), 831. Garg, S. K. (2013). Irrigation engineering and hydraulic structures (23rd rev. ed.). New Delhi, India: Khanna Publishers. Hassan, W. H. & Zwain, H. M. (2024). The influence of drain pipe location and diameter on seepage through an earth dam. Ain Shams Engineering Journal, 15, 102475. Javani, A., Yusefzadeh‑Fard, M. & Moradi, G. (2015). A study on the effect of implementing waterproof membrane on reduction of water seepage from earthen dams (Case study: Shahid Madani Earth Dam, Tabriz, Iran). Cumhuriyet Üniversitesi Fen Edebiyat Fakültesi Fen Bilimleri Dergisi, 36(3), pp.2693–2717. Kashef, A. A. I. (1965). Seepage through earth dams. Journal of Geophysical Research, 70(24), pp.6121–6128. Kouhpeyma, A., Kilanehei, F., Hassanlourad, M. & Ziaie‑Moayed, R. (2022). Numerical and experimental modelling of seepage in homogeneous earth dam with combined drain. ISH Journal of Hydraulic Engineering, 28(3), pp.292–302. Liu, K., Vardon, P. J. & Hicks, M. A. (2019). Probabilistic analysis of seepage for internal stability of earth embankments. Environmental Geotechnics, 6(5), pp.294–306. Mahmoud, A., Badakhshan, M. & Seifi, A. (2016). The effect of horizontal drain length on seepage discharge, uplift force and hydraulic gradient in homogeneous earth dams by numerical simulation. Specialized Scientific Quarterly of Construction Engineering and Management, 1(3), pp.45–55. (in Persian). Malekpour, A., Farsadizadeh, D., Hosseinzadeh Dalir, A. & Sadrekarimi, J. (2012). Effect of horizontal drain size on the stability of an embankment dam in steady and transient seepage conditions. Turkish Journal of Engineering and Environmental Sciences, 36, pp.139–152. Mohebat Zadeh, A., Meshkal, M. & Hedayat, N. (2011). Seepage analysis in earth dams with clay core using SEEP/W software (Case study: Karkheh Earth Dam). Proceedings of the 6th National Congress of Civil Engineering. Semnan University, Iran. (in Persian) Mohammed, Y. F., Salama, N. Y. & Al‑Labban, F. A. S. (2014). Seepage analysis of a zoned earth dam by finite elements. International Journal of Engineering Research and Applications, 5(8), pp.128–139. Mahmoud, M. M. & Shen, Z. Z. (2024). Seepage behaviour through earth dams with zones of different filling materials. Water SA, 50(1), pp.106–120. https://doi.org/10.17159/wsa/2024.v50.i1.4055 Nasrollahi, M. (2011). Investigation of different combinations of trench depth and clay blanket for reducing seepage in earth dams (Case study: Satarkhan Dam) (M.Sc. Thesis), Faculty of Agriculture, University of Tabriz, Tabriz, Iran. (in Persian) Omofunmi, O. E., Kolo, J. G., Oladipo, A. S., Diabana, P. D. & Ojo, A. S. (2017). A review on effects and control of seepage through earth‑fill dam. Current Journal of Applied Science and Technology, 22(5), pp.1–11. Rahimi, H. (2015). Earth dams. Tehran, Iran: University of Tehran Press. (in Persian) Shirazi, M. G., Rashid, A. S. B. A. & Ganiyu, A. A. (2023). Analysis of seepage control system improvement in an earthen dam. Dams and Reservoirs, 33(1), pp.27–33. Zhang, L. M., Xu, Y. & Jia, J. S. (2009). Analysis of earth dam failures: A database approach. Georisk, 3(3), pp.184–189. https://doi.org/10.1080/17499510902831759 Zhang, X. S., Wang, C. Y., Wong, H., Jiang, T. & Dong, J. Y. (2022). Modeling dam deformation in the early stage of internal seepage erosion: Application to the Teton Dam, Idaho, before the 1976 incident. Journal of Hydrology, 605, 127378. https://doi.org/10.1016/j.jhydrol.2021.127378 Zheng, H., Shi, Z., Shen, D., Peng, M., Hanley, K. J., Ma, C. & Zhang, L. (2021). Recent advances in stability and failure mechanisms of landslide dams. Frontiers in Earth Science, 9, 65993 | ||
|
آمار تعداد مشاهده مقاله: 260 تعداد دریافت فایل اصل مقاله: 159 |
||