风沙区超大工作面开采土地损伤的演变与自修复特征.

In order to find out the evolution laws of land ecological environment due to Super-large Coalface Mining (SCM)，a monitoring system of land ecological environment had been established at some typical workface in Shendong Coal Mine，the self-healing or natural healing abilities of land surface deformation，cracks and soil quality in the area had been investigated. The result shows that:① for an equivalent mining unit，the total amount of the surface movement and transformation of SCM was similar to traditional mining methods. However，the influenced time by mining was reduced around 50%，and the relative uniform subsidence region achieved 78% of the total subsidence area at once，its topography recovery as pre-mining showed a distinct ability of self-healing;② the ground cracks had obvious subarea feature with strong self-healing capacities. The dynamic cracks developed at uniform subsidence area without obvious heads in mining direction，which would close soon during the mining process. Its development cycle function was established with mining and geology. Marginal fissures occurred at mining boundary with ‘O’ shape，the angle of crack was nearly vertical. The width of crack trip was smaller than that in traditional mining，with the value range from 40-50 m;③ the changes of soil physical properties were consistent with the characteristic of surface deformation and ground cracks development. Within one year subsidence，the soil physical properties of uniform subsidence area tended to reach pre-mining levels，and most coal mining influence disappeared. By contrast，the heterogeneous subsidence needed manual control due to marginal cracks. The research results could provide a new principle for the ecology restoration at the coal mining subsidence area in the region. [ABSTRACT FROM AUTHOR]