Integrated Earth Stabilization Solution Reduces Soil Erosion

Neoloy®Geocells enabled the Nuclear Research Center to prevent erosion and stabilize unstable slopes with a green solution.

Challenge

The Nuclear Research Center sits on a mountaintop of pine woods at Da Lat in Vietnam’s southern highlands, a popular resort and tourist destination. A new wing was constructed on the east slope of the site. However, the original steep gradient (covered with trees) was disturbed, unstable and required stabilization. The slope was 2 to 6 meters high at a gradient of 34 degrees, requiring earth stabilization and soil erosion control.

The Center wanted a solution that would not only stabilize the slopes and prevent erosion, but just as important, would also provide a green, attractive and ecological landscape around the facility, to integrate within the area’s natural beauty and forest cover.

Conventional Solution

A conventional engineering solution would have been a concrete reinforced retaining wall. This would have been an expensive, time consuming task involving large earthworks and form-works. It also would not have been a green solution. Segmented retaining wall solutions were considered as well but shipping, mechanical handling and logistics increased their cost.

Neoloy Geocell Cellular Confinement System

Neoloy Geocells were able to provide an integrated earth stabilization solution. This included a reinforced retaining wall to stabilize the slope at the base, and then slope protection for the middle two thirds of the hillside for a very cost-effective solution.

The retaining wall at the base of the wall consisted of 4 cells deep, 660-200 high geocells. These were laid out in offset rows varying in height from 2-4m according to the contour. There was no need to excavate a deep foundation. The two outer geocell fascia rows were filled with crushed stone infill, while the other two rows were backfilled with local soil and compacted.

445-120 high Neoloy Geocells were used for the slope protection. The system was anchored on a 1.5m crest shoulder on top of a woven geotextile, and laid down the long slope with anchors distributed at a density of 1 sqm to stabilize the downslope forces. The infill was gravel with a 28-degree angle of internal friction for effective erosion control. The gravel infill was intended to protect the slope from runoff.

  • Easy logistics and fast installation – cut construction time in half
  • Reliable long-term reliability for retention wall
  • Excellent method for restoration of vegetation due to root-soil interlock
  • Green surface cover for aesthetic landscape
  • Excellent drainage critical for this climate and rainfall
  • Earthquake resistant solution due to system flexibility
  • Considerable cost savings