Deformation law and damage conduction mechanism of rock and soil in typical high-cold open-pit mining area in the western regions

The western cold areas and ecologically fragile mining areas along the Belt and Road are the main zones for China's open-pit coal mining. Yet, due to the complicated rock mass damage mechanism from intensive open-pit mining and drastic environmental changes, coupled with the great difficulty in controlling rock-soil deformation and slope stability, these mining areas are suffering from severe damage and degradation of the mining environment. To elucidate the deformation patterns and transmission mechanisms of rock and soil under open-pit mining, three open-pit mining areas in the Junggar Coalfield of Xinjiang were selected, and ten large-scale open-pit coal mines were targeted. Using 41 scenes of Sentinel-1A radar imagery and 13 months of monthly external dumping data from the mines, the study applied the Small Baseline Subset Differential Interferometric Synthetic Aperture Radar (SBAS-InSAR) technique and conducted Pearson correlation analysis with temporal meteorological factors. The research examined the characteristics of rock-soil deformation in mining disturbance zones, analyzed the spatial-temporal deformation patterns and disturbance distances of different deformation zones, explored the correlation between deformation zone distribution and mining-spoil spatial layout as well as external discharge loading, and investigated the transmission mechanism of mining-induced rock-soil deformation. The results indicate that the spatial dis-tribution of rock-soil disturbances caused by open-pit mining in the Zhundong region exhibits significant heterogeneity. Three typical deformation patterns are observed in slope rock-soil masses: settlement and uplift in inner and external spoil dumps; end slopes with either vertical distribution of external spoil dumps or no external spoil dumps; and end slopes with offset parallel distribution of external spoil dumps. The disturbance distance of mining-induced rock-soil deformation demonstrates a clear bounded nature, with settlement and settlement-uplift deformation in the Zhundong region confined within 1705 m and 1392 m, respectively. The subsidence deformation of rock masses under mining disturbances exhibits significant temperature-dependent temporal effects, showing moderate or strong correlations between deformation and temperature during freezing and thawing periods, with subsidence deformation zones manifesting stability and abrupt changes, respectively. Under the constrained deformation effect of three-dimensional support from the working slope and inner dump, the settlement zone exhibits a “saddle-shaped” distribution. The distribution of bulge zones is closely related to external dumps, with bulge deformation volume showing a strong correlation with external discharge loading (correlation coefficient r_xy > 0.82). Based on the influence relationship between unloading rebound deformation and bulge deformation induced by external discharge loading, an asym-metric loading model for external spoil dumps on end slopes under mining-induced unloading conditions was constructed. The stress transmission process of surcharge was revealed, and a modified bearing capacity formula for spoil dump foundations was proposed. The elastic foundation beam effect of local bulge caused by surcharge was clarified, Based on this effect, a slope stability calculation formula considering the additional stresses transferred from the external waste dump is proposed, and the bulge transmission mechanism of the elastic foundation beam on slopes was elucidated, based on substrate hard rock conduction layer. The findings provide theoretical and data support for the precise analysis of mining-induced damage and the development of eco-friendly mining technologies in high-altitude open-pit mining areas in western China.