Geomorphic Evolution And Landform Reshaping Of Large Surface Coal Mine In Loess Area

This paper take loess landform as object of study, check and testify the cause of formation and evolution of the loess landform, and based on GIS and hydrological features and methods, it study the tectonic movement, denudation and erosion and human activity in the loess area; analyze the characteristics of channels in Pinshuo open-cast mine, and through the formula of erosion evolution, analyze the dynamic characteristics of the original landform and the reshaped landform; analyze the difference between the traditional landform reshaping and Geomorphic reclamation, taking Pinshuo open-cast mine as an example, discuss Geomorphic reclamation in the loess area, and get the following results:(1) The landform in loess area is based on the tectonic movement of 6 block masses, and through changing the climate, neotectonic movement influence the landform. There are 10 typical sample areas, including Longxi, Yulin, Huining, Pinlu etc. The drainage area threshold is set to 9km2, and all the samples have developed Tableland, Liang, and Mao, and the gradients in Pinlu, Yulin and Huining are about 10°,channel density in Pinlu and Shenmu are about 0.3km/km2.(2) The landform in study area has lost the self-similarity after landform reshaping; the decrease of channel density leads the decrease of catchment ability of the landform; the gap increase between the positive and negative landform, slope of channel increase, and enlarge the erosion.(3) The formula come from the theory of dissipative structure and data of typical hilly topography is suitable for Pinshuo area, and find the landform after reshaping approach the early stage of development in loess area, and the reshaped landform is reasonable as long as the self-organized capability recover.(4) The erosion in loess area has been greater than the historical periods, and completely imitating the original landform and without regard to the problems of loose soil, sedimentation and stress imbalance, the reshaped landform would be great erosive; however, taking all the attention to convenient engineering and increasing cultivated land, the present reshaped landform do not match the surrounding landscape, and the landslide and collapse easily happen.