Gobi Blocks 

 Filter Cloth 

 SECTION 



Gobi Block 

 Perspective 



V 



Holly Beach, La. 



Prototype Installation : 

 Holly Beach, Louisiana. 

 Revetment 3 miles long, 1 on 3 slope, with buried toe. 



Forecast design waves 3.3 feet. 



Revetment was subjected to five storms in first year and sustained 

 minor damage (DeMent, 1969; Cox, 1971). 



Wave Tank Tests : 



1 on 3.5 slope Gobi block revetment was tested at prototype scale in 

 CERC large wave tank. 



Revetment used straight-sided blocks placed directly on filter cloth. 



Zero-damage wave height about 2 feet. (McCartney and Ahrens, 1975). 



Design Factors : 



Zero-damage wave height: 3 feet (estimate based on Holly Beach 

 revetment) . 



Wave runup: 0.8 to 1 compared to smooth slopes (wave tank tests). 



Wave reflection: Moderate (estimated). 



Remarks : 



Gobi blocks came with straight or beveled sides. 



Straight-sided blocks weigh 14 pounds and are placed directly on 

 filter cloth. 



Bevel-sided blocks weigh 12 pounds and can be glued to filter cloth 

 in factory and placed as a mat. 



Grass can grow through block openings which will further increase 

 stability to wave attack. 



Backfilling blocks with sand or gravel also increase revetment 

 stability. 



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