Abstract
The modeling of flood-induced bend scour near embankment toes can provide important information for river engineering, embankment safety warnings, and emergency action management. During the rainy seasons, short-term general scour and bend scour are the most common causes for the failure of reinforced concrete embankments in Taiwan. To gain a deeper understanding of the scouring process near embankment foundations, this study proposed a straightforward and practical method for bend scour simulation. The proposed simulation method is subdivided into three stages: two-dimensional flow simulation, general scour estimation, and bend scour estimation. A new bend scour computation equation is proposed and incorporated into a two-dimensional hydraulic finite-volume model for simulating the evolution of bend scour depth around embankment toes. The proposed method is applied to simulate the temporal evolution of bend scouring near the Shuideliaw Embankment on the Cho-Shui River in Taiwan, where serious failure occurred during the June 2012 monsoon. Field data were gathered using the numbered-brick technique at the Shuideliaw Embankment to demonstrate the accuracy of the proposed method. The results of the bend scour simulations compared reasonably well with field measurements, indicating close agreement in terms of water levels and bend scour depths near the Shuideliaw Embankment. The proposed method was found to quickly estimate the maximum short-term general scour and bend scour depths for further enhancement of the safety of the embankment toe.
Highlights
Embankments are natural or man-made hydraulic structures used to prevent inundation disasters in adjacent flood-prone areas
Following the numerical framework proposed by Hong et al [22], a new composite method based on the combination of flow, general, and bend scour computation equations is proposed to estimate the evolution of scour depth at an embankment toe on a river bend
According to the results described in the previous section, the proposed bend scour computation equation was verified to be suitable for simulating embankment toe scour in this case study
Summary
Embankments are natural or man-made hydraulic structures used to prevent inundation disasters in adjacent flood-prone areas. Few investigators have reported the simulations of embankment toe scour in a river bend, especially for reinforced concrete embankment structures. This paper follows the idea of Hong et al [22] to propose a new modeling methodology for simulating the temporal evolution of scour depth at embankment toes in river bend reaches. Due to the different physical mechanism of bridge and bend scours, a new bend scour computation equation is proposed and integrated with a 2D shallow water flow model based on the finite-volume model [24,25,26], leading to a new and reliable method, which is the main contribution of this paper. This paper investigates flood-induced embankment toe scour by using the field data collected with the numbered-brick method. 12 sets of bend scour data were collected were collected to develop a new bend scour computation equation for rivers in Taiwan.
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