Airport Coastal Protection, Kinmen, Taiwan

Kinmen Airport, with its south connecting Liaoluo Bay, is the main airport in Kinmen County (a group of the offshore islands on the west side of Taiwan). Its runways, runway shoulders, and stopways are close to the coastline. The construction of a coastal airport requires to do shore protection project adjacent to the sea to averting endangering the safety of takeoff and landing airplanes.

Due to the extreme weather and flood period, the construction area is frequently attacked by waves or heavy rains from typhoons which cause soil erosion in stopway alongside the runway. Part of the revetment or slope was damaged by the seawater erosion, and which forms trenches and gaps; thereby, considering the safety of the airport, it is urgent to repair.

The original design of the riprap revetment is adjacent to the sea; however, its structure is broken and lost protection because of the long-term scrubbing of the toe of the embankment by wave attack. In the project, the designer proposed to place ACETube^® in front of the new riprap revetment to resist wave impact and reduce erosion.

This case is shown in the drawing of the section. First, ACETube^® and geotextile laying process is carried out. After completion, a riprap revetment is constructed in the direction of the airport runway. The retaining wall, built at the top of the revetment near the stopway, makes the protection function of the revetment stronger.

The main function of ACETube^® is to resist the impact of waves on the toe of the bank slope and to avoid the coastal recession from affecting the safety of the airside. The design of the geotextile tube’s size and fabric specifications, in this case, considers the durability and limit of bearing capacity which was designed by mechanical analysis. The revetment built with four ACETube^® is 1868 m long; the size is customized for 31.5 m, 26.5 m, 21.5 m, and 16.5 m according to the needs—length, overlap, and the shape following the coastal line. These biaxial geotextile tubes are made of PP woven fabric with tensile strength (200-II) and 13 m in circumference.

Two years after the completion, the aerial photography shows that ACETube^® effectively avoided the damage of the toe of the revetment. The area near the shoreline behind ACETube^® is formed as dunes which are beneficial for beach nourishment, sand fixation, and sand storage. And this case proves that ACETube^® can achieve both coastal wave energy dissipation and avert coastal erosion. Because ACETube^® is made of durable material, subsequent maintenance operations and costs for revetment can reduce. More importantly, the geotextile tube can fill the in-situ sand, so the transportation fee and engineering carbon emissions are reduced as well. The solution of coastal construction method for the project, undoubtedly, is the best way to prepare for the coming of ETS (Emissions Trading System).