In this project, geotextiles were employed to reinforce the banks both upstream and downstream of water gates, providing protection against erosion and ensuring the safe operation of the water gates.
Project Overview:
The Xi River embankment commonly features reinforced concrete box bottoms and prefabricated beam-type retaining walls for water gates. This type of watergate offers advantages such as ease of construction, low cost, and structural rationality. However, the riprap protection on the upstream and downstream banks of the gate chamber undergoes severe erosion during operation, necessitating significant manpower and material resources for annual maintenance. More critically, this situation continually jeopardizes the safe operation of the gate structure.
Solution:
To address this issue, we will use geotextiles to provide erosion protection for the upstream and downstream banks of the water gate chamber. The specific construction steps are as follows:
- Fabrication of Geotextiles: Select suitable geotextile materials and cut and splice them according to design requirements to ensure their dimensions and shapes meet specifications.
- Fixing the Geotextiles: Fix one end of the geotextile with expansion screws to the sidewall of the empty box bottom and roll it into a cylindrical shape. Then, transport the fixed geotextile and the floating gate to the gate site.
- Unfolding the Geotextiles: Utilize the two different flow directions before and after the low tide (flow cessation) to unfold and spread the geotextiles on the water surface along the direction of the tide. This step requires divers to operate underwater to ensure the geotextiles are fully unfolded and closely adhere to the water’s surface.
- Securing the Geotextiles: Tension the surrounding nylon ropes and fix the geotextiles with steel pipe piles. This ensures that the geotextiles remain stable under the scouring of water flow without shifting or floating.
- Riprap Protection: Uniformly throw stones onto the surface of the geotextiles to prevent erosion and abrasion from water flow. When throwing stones, it is necessary to control their particle size and thickness to meet design requirements.
- Regular Monitoring and Maintenance: During the project operation period, monitor and maintain the geotextiles to ensure they are intact. Promptly repair or adjust any damages or displacements detected.
Application Effect:
By using geotextiles to provide erosion protection for the upstream and downstream banks of the water gate chamber, the scouring problem has been successfully resolved, eliminating the need for substantial manpower and material resources to be invested annually. At the same time, the safe operation of the gate structure has been ensured, and the service life and stability of the project have been improved. After several years of regular monitoring, no scouring phenomena have been detected, and there has been no need to add additional riprap stones as a result.
