Ecological reconstruction technology of rock slope in open pit based on rock mass quality evaluation and division

Ecological restoration and reconstruction of rock slope in open pit is an important part of green mine con- struction. Research on the ecological reconstruction technology of rock slope in open pit plays an important role in pro- moting green mine construction in China. Nevertheless,the extremely harsh geological conditions of rock slope restrict the smooth development of ecological restoration. In this paper,the authors investigated the eastern slope of Yanshan Iron Mine. Based on the detailed analysis of stratum distribution,lithology,structural plane occurrence and weathering degree of the slope,the DTM model of eastern slope was constructed using three-dimensional laser scanning technolo- gy. Comparing and analyzing the results of three-dimensional laser scanning with the geological plane map,the eastern slope was divided into three regions:north,middle and south. According to rock mechanic test results,combined the spatial geometric information of structural planes in different regions,the BQ classification method was used to evaluate the rock mass quality in above regions. The results show that the rock mass quality grades in the north,middle and south regions are grade IV,III and II,respectively. Taking the highway in the mining area as the dividing line between the upper and lower half of the same region,the rock mass quality in the lower half is better than that in the upper half. Different ecological reconstruction plans,according to the grading results of the slope,were adopted to correspond- ing regions. More specifically,the technology of soil spraying and thick base material spraying were adopted in the up- per and lower half of the northern region,respectively;artificial soil spraying technology based on iron tailings was adopted in the upper and lower half of middle region;and the technological scheme of ecological reconstruction of rock slope combining blasted bird’ s nest,planting hole and high water conservation green spraying was adopted in upper and lower half of southern region. The ecological reconstruction technology of forest land and grassland was adopted in the early stage,while the ecological reconstruction technology combining forest land with traditional Chinese medicine planting land was adopted after soil ripening on the platform. Based on the relationship between the final boundary of slope and the relative position of Xinhe River,the drip irrigation system for slope ecological reconstruction was de- signed to satisfy the need of ecological reconstruction,meanwhile,sewer drainage was used to reduce the influence of groundwater on slope stability. The research results provide a new idea for the selection of ecological reconstruction technology scheme of rock slope in open pits.