Stability of Geobags in Riverbank Erosion Protection Structures - Experimental and Numerical Study

充砂土工袋是一种新型的防冲系统，但由于其柔韧性和多孔性，相对于传统的硬质防护系统具有优势。土工袋护岸结构在亚洲已成功实施了15年，但在各种水袋和袋袋界面条件下，单元稳定性仍存在不确定性。其主要原因是现有的设计公式是针对硬质材料而制定的，没有考虑土工袋的柔性特性。阿尔伯塔大学和西北水利顾问公司（NHC）合作的目标是确定影响土工袋稳定性的关键因素，提高我们对土工袋河岸保护系统性能的理解，并开发一个可靠的土工袋尺寸设计公式。拟议的研究项目将包括一个大规模的系统实验室实验与计算建模相结合。考虑到土工袋的灵活性，将建立作用在土工袋表面上的水压力与土工袋稳定性之间的关系。研究结果将用于制定尺寸计算公式，并将纳入指南。改进的知识将提供指导，并促进土工袋护岸结构设计标准的制定。结合过滤性能和稳定性，土工袋是理想的临时工程，可以从河流系统中删除，以及准备工作，是后来纳入permanentworks。这项研究将促进更广泛地应用土工袋，这将大大降低与材料、建筑、洪水破坏和随后的恢复工作有关的成本，并促进加拿大各地可持续的侵蚀控制。

Sand-filled geotextile bags (geobags) are a comparatively new erosion protection system, howeveradvantageous over traditional hard armour system, credited to their flexible and porous nature. Geobagriverbank protection structures have been implemented with success for about 15 years mostly in Asia, butthere are remaining uncertainties about the element stability under various water-bag and bag-bag interfaceconditions. The main reason is that existing design formulae are made for hard material and do not consider theflexible nature of the geobags. The goals of the partnership between the University of Alberta and theNorthwest Hydraulic Consultants (NHC) are to identify the key factors affecting geobag stability, enhance ourunderstanding of the performance of geobag riverbank protection system, and develop a reliable designformula for sizing the geobags. The proposed research project will include a large-scale systematic laboratoryexperiments in conjunction with computational modeling. The relationships between hydraulic forces exertedon the bag surface and bag stability will be established, taking into consideration the flexibility of the geobags.The findings will be used to develop a sizing formulae and will be incorporated into guidelines. The improvedknowledge will provide guidance and facilitate the development of a design standard for geobag riverbankprotection structures. Combining filter properties with stability, geobags are ideal for temporary works that canbe removed from the river system, as well as preparatory works that is incorporated later into the permanentworks. This research will facilitate wider application of geobags which will greatly reduce the cost related tomaterial, construction, flood damage and subsequent restoration work, as well as promote a sustainable erosioncontrol across Canada.