Yong-dong highway that has an important role to connect between the west end and the east resort areas of South Korea was demolished at 205.4km from the west end due to an unexpected heavy rain whose intensity is 62.4mm/h on July 15th, 2006. Foundations of concrete retaining walls contact on Walljeong stream that has a steep bed slope and small water volume except a rainy season were scoured, and the concrete retaining walls were overturned. The water came into the embankment, and the westbound lanes of the highway were destroyed. The highway was blocked to traffic just before a big holiday season, and Korea Expressway Corporation (KEC), an agency of South Korea government, changed the flow line away from the embankment to protect it from scour, and dropped a lot of huge rocks whose diameters are over 1m to recover the demolished embankment. KEC finished the recovery works only for two days and reopen the highway. To prevent the highway from the pavement deformation and the future scour, grouting under pavement and rock-socketed concrete retaining wall with earth anchors without a foot were made for four months after the rapid recover
