Study Of The Effectiveness And Mechanism Of Wind Erosion Control Of Engineering Measures Of Photovoltaic Constructing Land In Northwest Sandstorm Area

Northwest China has the geographical advantage of new clean energy with the development of wind, and solar energy. But the climate characteristics of dry and windy can occur easily erosion in this area, of which the most serious is the wind erosion. Furthermore, in the production of construction, after disturbance of surface and destruction of vegetation, the change of microtopography make the wind speed increase or decline in a sharp, thus occurred undercut or accumulation phenomenon. Study the wind erosion control effectiveness and mechanism of engineering measures of typical photovoltaic power plant project in Mu Us Sand Land can provide the technical reference for the practice research wind erosion in similar projects.In this study, relying on the typical photovoltaic power plant project of Mu Us Sand land in Sandy Area in Northwest to layout straw checkerboard barriers, gravel capping, and red mud covering and their combination. And through long-term field positioning to observe the parameter of wind speed profiles, sand flow structure, wind speed flow field and surface roughness by each measures in the project area, and sand bulk density, porosity and water content. To discussion and analyze the effectiveness and mechanism of wind erosion control measure for each project. The main findings are as follows:(1)Effect of solar panels on the wind velocity flow field characteristicsIn the project external area and middle of solar panels, the winds emerge upward trend with height increases. And between the solar panels of 20 cm ~ 60 cm, the growth rate of winds are greater than the project external area, and the rapid increase of wind speed is not conducive the fixation of sand surface. The space solar panels make the spatial distribution of wind speed flow field change near it, which is significant increasing wind speed of the solar panel outlet of near the surface(The distance solar panel and ground is small), and reducing the wind speed of inlet of far surface(The distance solar panel and ground is big).(2)Wind erosion control benefits of engineering measures.The sand flow structure of each engineering measures in project external area show that red mud covering is the most obvious measures to reduce air handling capacity, and the best effect is the undercut area + gravel / stacking area+ red mud between the solar panels. The relative transport rate of each project measures,emerge a logarithmic distribution function with the height of the ground(correlation coefficients >0.85). Project area periphery bare sand(control) region is the most serious wind erosion, Straw checkerboard barriers, gravel glands and red mud covering will play a role in sand-fixing. Among them,gravel measures gland is the best;Undercut region between the solar panels all engineering measures play a role in sand-fixing,among them, having the best effect of sand-fixing are gravel gland and undercut area + gravel / stacking zone + red mud;The stacking zone between the solar panel all play a sand-fixing effect, except straw checkerboard barriers measures which is serious wind erosion measures. Among them the best effect of sand-fixing are red mud covering measures and undercut area + gravel / stacking area+ red mud.(3)Wind erosion control mechanism of engineering measuresIn the periphery of the project area and between the solar panels, the wind speed increases with the increasing of height of each engineering measures. Among them,in the peripheral of project area, the wind speed reduce at the height of 60 cm,and gravel capping is the biggest to decrease the wind speed; Between the solar panel, the wind speed reduces near the ground 20 cm ~ 40 cm, and gravel gland and red mud covering have the best effect. The gravel gland and straw checkerboard barriers measures improve the near-surface roughness in the project external area; Straw checkerboard barriers, undercut area + gravel / sand accumulation zone + bare, undercut area + gravel / accumulation zone + red mud, and gravel gland measures all improved surface roughness between the solar panels, which play a good benefits of wind erosion control. Sandy soil bulk density is increased, and porosity is reduced within each engineering measures. The trend of volumetric water content of 0~20cm is consistent with the change of depth,which is that the volumetric water content increases with increasing soil depth.,And with the extension of the measures emplaced,the growth rate of volumetric water content of 0 ~ 12 cm is greater than 12~20cm. Among them, the bulk density and porosity of the gravel capping and red mud mulching measures changes significantly in the peripheral project area,and their volumetric water content of 0 ~ 20 cm layer is highest; The bulk density and porosity of the gravel capping, red mud mulching and undercut area + gravel / accumulation zone + red mud measures changes significantly between the solar panel, and their volumetric water content of 0 ~ 20 cm layer is highest. Therefore, they have played very good benefits of wind erosion control.(4)Cost analysis of engineering measuresOn the whole, in the periphery of project area, the best effect of wind erosion control are gravel gland measures and red mud covered measures; and between the solar panel, the best effect of wind erosion control are the gravel gland measures, red mud covered measures and undercut area + gravel / stacking area + red mud. If we need to choose the comprehensive economic structural measures of the project area, red mud covering measures is with the cost of 11.35 and 12.40 yuan per square meter respectively become the first choice with highest cost-effective in the periphery of project area and between the solar panel.