Experimental Research On Wind Erosion Characteristics Of Loose Pisha-sandstone In Ordos

In the Pisha-sandstone area of the Ordos Plateau,the vegetation is scarce,the ecological environment is fragile and the desertification caused by soil erosion is very serious.And the climate in the area changes significantly with the seasons,At the turn of winter and spring,The temperature difference between day and night is large,and the temperature is lowered at night,so that the water in the soil freezes,the temperature rises during the day,and the water rises.Topsoil moisture content changes greatly,In addition,the winds in the Pisha-sandstone area are relatively strong during this period.Causing severe wind erosion in the area,Therefore,the study of wind erosion characteristics of loose Pisha-sandstone in the sandstone area can provide a basis for soil wind erosion in this area.This paper takes the loose Pisha-sandstone of the Zhungeerqi in ordos as the research object.Performing a simulation test in a wind tunnel,Analysis of different levels of sediment collected by different water cuts and different wind speeds,Study on the variation law of water content and wind speed on sediment concentration at different heights,Revealing the wind erosion in the sandstone area of the sandstorm season,Provide a basis for soil erosioncontrol in this area.The results indicate that:1.The special particle size composition and grading characteristics of the Pisha-sandstone in the clean air state,Even if the water content is very low,when the wind speed is below 15m/s,there is very little sediment concentration only below 60mm from the ground..Large wind erosion can occur only when the wind speed is greater than 15m/s.According to local meteorological data,wind erosion is not the main form of Pisha-sandstone erosion.2.Under net wind,when the water content is less than 5.56%,the water content is smaller,and the sediment concentration increases with the wind speed.The sharper the change,when the water content is greater than 5.56%,the sediment concentration increases with the wind speed.Slow down.It indicates that there is a limit water content of Pisha-sandstone resistance to wind erosion near the moisture content of 5.56%.When the water content is lower than this,the wind erosion is obviously enhanced with the increase of water content.Above this water content,the water content still has an inhibitory effect,but the effect is no longer significantly enhanced.3.Under the wind of sand,with the increase of water content,the sediment concentration under the sand wind gradually decreases with the increase of height.When the water content reaches 8.03%,the sediment concentration is almost unchanged with height above 20mm,especially in 20?40mm.The low amount of sand collected at the site indicates that the sand particles in the wind have a height impact on the surface particle hopping under this water content of only 20 mm,and the particles causing the migration of the topsoil particles are extremely small.Sand wind is also difficult to cause wind erosion on the Pisha-sandstone.It can be seen that when the water content reaches 8.03%,the wind erosion of the sandstone in the sandstone can be effectively suppressed.4.The water content can effectively reduce the wind erosion of the sandstone in the Pisha-sandstone,but the wind speed is higher,and the effect of reducing the water content is not obvious.The wind speed not only increases the amount of sand in the belt,but also increases the number of leaching of the sandstone particles ignited by the ground.It shows that the wind erosion under the wind of the sand is the main form of local Pisha-sandstone erosion.