Research On Near-Natural Landform Reshaping Simulation Of Inner Dump Of The Open-pit Coal Mine In Grassland Areas

Near-natural landforms reshaping in mining abandoned areas is one of the major issues in the study of land reclamation and ecological reconstruction of mining areas.As the geological foundation of soil and vegetation reconstruction,the stability of landforms reshaped plays an important role in land reclamation.Based on the relevant principles of fluvial geomorphology,the GeoFluv model was used to reshape the appearance of the entire life cycle of Shengli No.1 open-pit coal mine in grassland after learning natural geomorphology features.The landscape evolution model was applied to simulate the changes of geomorphic features under different scenarios.The main conclusions are as follows:(1)Based on the landform characteristics,the process of landform development was divided into three stages: infancy,mature and old age.Taking the parameters representing the overall stability of the geomorphology as the starting point,the stability of the natural reference landform area was quantitatively analyzed by calculating the fractal dimension of the river network and the landform information entropy.The results show that the fractal dimension of river basin and hypsometric integral values of the landform in the natural reference are 1.77 and 0.41,respectively.Both of them indicate that the landform in the natural reference area is at the end of the mature period of development and develops towards the old age.It is in a relatively stable state as a whole and has the reference value.On this basis,according to the needs of the model,normal distribution and mean method are the main mathematical statistical methods to extract the river basin,topography and meteorological parameters of the reference area.(2)Coal mining would lead to the decrease of backfilling surface elevation,and the subsidence of the surface in the whole life cycle was taken as the restrictive condition for landform reshaping.The effects of landform reshaped in different ways were analyzed.The results show that the reconstructed landform is 30.3 m lower than the original surface due to coal mining;the change of parameters has a greater impact on regional soil erosion,and when the parameters are statistical values,the soil erosion is the smallest and the degree of landform stability is the highest,which also proves the reliability of parameter extraction;the landform reshaped in traditional way is in the early stage of the mature period of development,the overall stability is weaker,and the effect of landform integration is poor.However,the landform reshaped in near-natural is in the end of the mature period of development,reaching a relatively stable state,which is superior to the landform reshaped in traditional way in the diversity of landform and environment.(3)Based on the CLiDE landscape evolution model.100 years landscape evolution of natural landform,near-natural reshaped landform and traditional reshaped landform were simulated.The results show that the effect of soil erosion control in the landform reshaped by near-natural way is better than that of the landform reshaped by traditional way.The effect is more notable without considering the landform of the upper and lower junction areas.There is a certain similarity between the gully and the river network evolution process of near-natural landform and that of the natural landform.The river network of the landform reshaped in traditional way has not developed to the stable stage,and the overall stability is weaker,which is consistent with the statistical results of soil erosion and deposition,it is shown that the long-term stability of in near-natural way is higher than that of the landform reshaped in traditional way.