Windproof efficiency with new biodegradable PLA sand barrier and traditional straw sand barrier

To understand the windproof benefit of new biodegradable PLA sand barrier, we studied respectively the windproof efficiency, roughness of ground surface and wind speed profile characteristics of 1 m×1 m, 2 m×2 m, 3 m×3 m PLA sand barriers by measuring the wind speeds in different heights in PLA sand barrier sample plots. At the same time we took the traditional half hidden straw sand barrier sample plots and shifting dunes as contrast, and studied the difference of windproof efficiency between PLA and straw sand barrier. The results showed that wind speed efficiency could be reduced by PLA sand barrier more significantly than straw sand barrier with the biggest difference 10.3%, the windproof efficiency with 1 m×1 m was better than other two for both PLA and straw sand barriers. Increasing the surface roughness ranked in PLA sand barrier straw sand barrier shifting dune. With the increasing of sand barrier size, the surface roughness showed the decreasing trend. Under the same terrain condition, the average surface roughness in PLA sand barrier sample plots was 1.4 times of that in straw sand barrier. The differences of surface roughness in PLA sand barrier and straw sand barrier on the bottom of upwind slope, mesoslope, slope top and leeward slope were not obvious with its average surface roughness 0.7 cm. The wind speed profile for both 1 m×1 m PLA sand barrier and straw sand barrier appeared as “S” type, while sand barriers of other sizes were as similar as shifting dunes with wind speed profile of exponential distribution. Comparing three sizes sand barriers by both two different materials, the effect of decreasing wind speed became less with the size increase, and the “S” characteristic of wind speed profile was less and less obvious until close to exponential distribution.