Study On Wind-sand Flow Under Different Underlying Surface Conditions Of Minqin Oasis External

Sand movement and soil erosion as a major dust storm physical processes of the natural environment and human impact of causing serious.n recent years, sand movement caused by the disaster in China has aroused a great deal of concern, and in-depth study of the mechanism of sand movement is now considered a key factor in wind that comprehensive understanding and prevention of disasters, so the scientists in this respect a great deal of research.Based on this, this article studies scholars in the past, based on the specific circumstances of Minqin oasis peripherals different background conditions of the sand surface for observation and study of traffic flow through the observation data revealed quantitative and qualitative analysis of different surface conditions on the sand stream flow, flow structure of sand to study the different surface types Minqin unique movement of the sand flow and the characteristics of the planning for the Minqin oasis desertification, desertification control projects and the implementation of fixing the choice of measures to provide a theoretical basis, and science and technology support.The results show that:1.No cover on the movement of dunes wind speed (V) and near the ground within the 0-50cm sediment transport rate Q (g / cm.min) the mathematical relationship between the power function curve (Q = aV^b); from the general trend, the sand the distribution of flow is at the top of the largest sand dune, sand dunes in central Secondly, the sand dunes at the bottom of the smallest.Surface 0-30cm layer of sediment flow rate (g/min.cm²) and height h (cm) to comply with the negative exponential relationship between the function Q = ae.(bh) (a, b are constants); 0～30cm height of the largest sediment appear in the bottom (0～2cm), accounting for 40% of the total for the peristaltic sediment; transport rate under the same conditions at the top of the largest and central second, bottom of the smallest.2.Nitraria gravelly sand flat wind speed (V) and near the ground within the 0-50cm sediment transport rate Q (g / cm.min) the mathematical relationship between the power function curve (Q = aV^b); near-surface airflow 0～30cm layer of sediment transport rate (g/min.cm²) and height h (cm) to comply with the negative exponential relationship between the function Q = ae^bh (a, b are constants); 0～30cm height of the largest in the bottom sediment (0～2cm), accounting for 21% of the total, the movement of sand to the main saltation; in the same wind conditions, the sediment transport rate is inversely proportional to the size and surface roughness, and is inversely proportional to sand cover.3.Nitraria sandbags on the ground from the whole financial year, about 0～50cm sand flow in terms of total flow: Q_{at the bottom of the leeward slope}> Q_{at the bottom of the windward slope}> Q_{at the top}; Nitraria Nitraria package on the cover of sand the size of the impact of significant flow , the cover Nitraria smaller, the greater the wind flow. Nitraria three parts of sand Height 0～30cm sediment are the largest fixed at the bottom (0～2cm), respectively, 32.53%, 27.98%, 33.45% ,0～8cm of the sediment concentration of 70 total % of; near-surface 0～30cm layer of sediment flow rate (g/min.cm²) and height h (cm) are to comply with the relationship between the power function Q = ah^b (a, b are constants); leeward slope of the sediment transport rate the most, slightly larger than at the bottom of the wind at the top of the slope.4.Nylon mesh, clay and straw sand barrier of wind-sand current distribution of the total flow at the top of the sand dunes followed> the central sand> sand dunes at the bottom;. Nylon mesh barrier sand, clay and straw sand barrier sand barrier, respectively, the maximum sediment concentration in the 14-16cm ,22～24cm and 22～24cm, the total accounted for 17.74%, 17.53% and 19.13%; three sand barrier against wind and sand-fixation efficiency of the Q_clay intermediumnylon.5.Ammodendron lam in the ground, with the increase in porosity, sand flow into the exponential function Q = 412.38e0.7877L (R2 = 0.9127) increase . Different porosity of the sand flow under the condition of the structure are in accordance with the law of diminishing power function Q = ahb (a, b are constants); porosity ammodendron for 47% of the forest better than the porosity of 36% of Haloxylon forest. Three porosity sand flow under conditions of maximum sediment concentration are fixed at the bottom (0～2cm), respectively, 44.47%, 48.78%, 38.60%, and 0～8cm of the sediment concentration in total about 80% ; 30% Nitraria gravelly sand flat> ammodendron Lin> Nitraria package> clay sand barrier> intermedium sand barrier> nylon sand barrier; from the wind flow the seasonal distribution of the total flow, the spring> summer> winter> autumn...