Reinforced Earth Embankment, Taiwan Pavilion Expo Park, Hsinchu, Taiwan

Taiwan Theme Pavilion in "Expo 2010 Shanghai China" was an outstanding creation designed by Taiwanese architects. The emblem featured a flying “sky lanterns” which has a traditional meaning of the purification of minds and praying for blessings to the sky. At the end of Expo 2010, Hsinchu City Government awarded the bidding and relocated the facility to Hsinchu City. It was determined to be combined with other creative culture complex to become a permanent landmark in the area. To facilitate the passages of numerous visitors, Hsinchu City Government required constructing a 250m long and 10m high service road to connect the downtown and the Pavilion Park.

The service road was constructed immediately adjacent to the Long-En Canal, an important waterway for agriculture irrigations. The transmission of water is not allowed to be disconnected or contaminated in anytime. The abundant groundwater also has presented great difficulty for the construction and the stability of road embankment. In addition, because of the features of the Park, this service road must be aesthetic and eco-friendly.

The conventional solution is to build a cast-in-place cantilever retaining wall to support the embankment. However, the installation of foundation required diverting the canal and therefore the water transmission was likely to be disturbed to a great extent. The limited proximity and longer construction schedule finally made such a scheme both impractical and unacceptable. Therefore, the designer suggested using ACEGrid^® geogrid as reinforcing material to build a 2-stage mechanically stabilized earth (MSE) retaining wall to support the embankment. It was constructed with geogrid wrap-around facing in backward slope shape. An approximate inclined ratio of 0.2:1 (H:V) was designed for the MSE wall so that the most possible width of the service road could be maintained. To keep the overall stability of such a steep slope, tie-back plate system was installed at the lower section of the MSE structure to further restrain the ACEGrid^®. In addition, because of the adjacent canal, occurrence of foundation hydraulic destructions was highly likely. Two layers of stone-filled gabions, wrapped around with high strength ACETex^® PP geotextiles, were placed at the base of the MSE wall. The earth structure then was constructed layer by layer with 0.5m increments until reaching the design height.

Most of backfill and foundation stones were from the site. It not only maximized the utility of local resources, but also reduced the cost and pollution due to transportation. With stacked soil-filled sandbags used for slope face protection, a few months after the completion of MSE wall, greenery vegetation complement to the blooming and colorful landscape has made the service road as attractive as it was expected.