Study Of The Law Of Soil Erosion And Its Prediction Methods For The Railway Construction In The Red-Earth Region Of South China

The construction of Chinese railway has stepped into a rapid developing era and promoted national economy greatly. However, at the same time, it destroyed the ecological environment. The original surface soil with strong anti-erosion property was eroded by those railway projects. As a result, the coverage of vegetation was decreased and the slow natural erosion turned into the fast man-made erosion. So I investigated the project of Yong-Tai-Wen railway in the southern red-earth region and analyzed the law of soil and water erosion during the railway construction in that area.Firstly, on the basis of the previous research and experience, I applied the theoretical analysis and the scene monitor to build a runoff plot by choosing a segment in the slope of Yong-Tai-Wen railway. Then, the water erosion experimental analysis was done by monitoring the process of runoff, the soil properties, the silt content of runoff and the amount of natural rainfall. The characters of the water erosion and the influence of each monitoring factor on the slope were analyzed. At last, we built the standard for the erosive rainfall on the embankment slope of the railway in the South China red-earth region.As setting up simple monitoring area in spoil ground to measure the gully erosion amount, the soil erosion was calculated. More, the rainfall erosion forces and their best combination of the railway in the red-earth region of southern China were established.The slope erosion of the Yong-Tai-Wen railway mainly presented as vertical zonations. The erosion type changed from splash erosion to surface erosion, then to the rill erosion. Near the top of the slope the main erosion was the splash erosion and it was not obvious. On the top of the slope the primary erosion were the surface erosion and the rill erosion. On the foot of the slope, it would be dominant by the rill erosion when the concentrated runoff reached certain degree. Erosion gully changed from minor grooves to a major one with several branches. Its section appeared in U-shape. Moreover, upper and lower part of the gully differed greatly. It was a critical stage in the evolvement of the erosion gully. When the erosion gully reached the balanced cross section period, it would not be eroded to the depth but enlarged to either side. It appeared reticular formation on the surface.The rationalization proposal was submitted according to the deficiency of the forecast method by analyzing of the monitoring data and some previous forecast methods.