نوع مقاله : پژوهشی
نویسندگان
1 گروه مهندسی رودخانه و حفاظت سواحل، پژوهشکده حفاظت خاک و آبخیزداری کشور، تهران
2 مدیرکل مهندسی سواحل و بنادر، سازمان بنادر و دریانوردی ایران
3 اداره کل مهندسی سواحل و بنادر، سازمان بنادری و دریانوردی
4 دانش آموخته عمران- سواحل، بنادر و سازه‌های دریایی، دانشگاه تبریز
5 اداره مهندسی سواحل و بنادر، سازمان بنادر و دریانوردی ایران
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Introduction and goal:
Coastal areas in the lowland of coastal watersheds are the location of a significant part of the watershed inhabitants, the place of establishing a service and production chain between the domestic and foreign parts of the country, and significant sea-oriented activities. On the other hand, the coastal zone is affected by the inherent lithology of rock units and coastal landforms and the hydrodynamic conditions of waves, which are affected by erosion and deformation. Therefore, sea-oriented activities develop behind coastal protection structures, especially breakwaters. The research aim was to achieve a stable state of the rubble mound coastal protection structure under the impact of the northern Persian Gulf wave conditions.
Materials amd methods:
The coastal structures are introduced by their structural characteristics, construction materials, and arrangement. To achieve the research objectives, a representative profile near the top of the designed breakwater of the Genaveh port was selected to investigate the stability of the structure under the Northern Persian Gulf wave patterns in the hydraulic laboratory of the Soil Conservation and Watershed Management Institute. One of the essential stages of this research was determining the dimensions of the armor layer of the protective structure/breakwater of Genaveh. One of the significant factors in determining the appropriate parts for the initial armor is their weight. The effective parameters in the design of the protective structure and rabble mound breakwater are divided into three categories including wave-related parameters (environmental), hydraulic parameters, and structural parameters. The damage to the armor layer is estimated by counting the number of displaced rock blocks or measuring the eroded surface of the armor layer in the profile. The calculation method is based on armor pieces moving individually from their original position, and are displaced by a certain minimum amount shown by the ha value. The limit levels that are achieved in each wave impact are called uplift Ru and downlift Rd. These levels are defined relative to the static surface and are among the important design parameters. To test the stability of the selected profile, the JONSWAP irregular wave spectrum, 50-year return period, significant wave height of 2.7 m, period of 6 seconds, and 1.2 times wave height to consider supercritical conditions, were used. The physical model of this research was set up in a two-dimensional wave generator flume with a length of 33 m a width of 5.5 m and a water intake capacity of up to 1.5 m depth with a scale of 1:20 compared to the dimensions of the prototype of the main structure. The aforementioned waves were projected onto the selected profile (P6) for 90 minutes under four conditions: high water (high tide plus wind and wave surge), low water (tide), one-year return period, and 1.2 times the high water, and the changes resulting from the impact of breaking waves were examined by taking photos of the profile before and after using photogrammetry.
Results and discussion:
The laboratory model for investigating the stability of the coastal protection structure designed for the wave conditions of the northern Persian Gulf shows an acceptable design of height and profile of the structure. In other words, the design presented for the implementation of the protective structure in the Genaveh region is reliable from both functional and structural perspectives. On the other hand, this design, especially the armor layer of the protective structure, will modify the slope profile and partial settlement in the filter layer in supercritical conditions. In high water tests, an average of 88% of the recorded runup is at or below the design runup of the structure, and the displacement of the armor layer parts was recorded only in 1/2 high water conditions and limited conditions. Also, the settlement of the filter layer occurs gradually after 1300 waves with a 100-year return period, which will require redesigning the structure with a higher height and heavier rock dimensions.
Conclusion and suggestion:
Based on the resultant data, we concluded that the physical model of the Genaveh coastal protection structure was able to successfully measure the interaction of different wave conditions on the profile, especially the armor layer of the rabble mound breakwater, and provide predictions and stable conditions for implementation and cost reduction of the stockholder agency (Ports and Maritime Organization, PMO). The setting of applied research on the transfer of knowledge and technology for further optimization of the design of protective structures for future construction projects was stated. The present study suggests that PMO should consider precautions to prohibit users from passing along the breakwater for wave conditions in which supercritical waves coincide with the highest astronomical tide level, colliding with the Genaveh protective structure.
کلیدواژه‌ها [English]
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