Deformation Mechanism of Dump with Different Construction Methods in Complex Geological Area of Open Pit Mine
The stability of dump site in complex geological area of open-pit coal mine is related to the normal progress of mining and dumping,and reasonable dumping methods can improve the stability.In Anjialing Open-pit Mine,the inclination of basement suddenly increases and the pit wall deflects.By constructing the 3D numerical model to compare and analyze the de-formation differences of dumps built by two dumping methods:dumping direction paralleled to and crosswise to basement incli-nation respectively,the lateral waste is supported with pit wall,the corresponding failure mechanism was revealed.The result showed that the waste site slides along the bedrock and demonstrated by shear stress,deformation affected by inclination angle is dominated by subsidence,it has the characteristics of continuous arc with steps as unit.The displacement of dump with incli-nation paralleled to that of bedrock is larger than that of dump with of inclination crosswise to that of bedrock,the latter is lar-ger in size.The deformation direction of dumpsite with inclination identical with that of bedrock is parallel to the dip of base-ment,and the displacement is negatively correlated with the distance between grid and pit wall.The displacement along Y-di-rection is distributed in two conical zones under the influence of the base morphology.The deformation direction of dump with dip crosswise to that of bedrock and supported by the pit wall is divided into three parts,and that of zones near foundation and pit wall is deflected and vertically points to the slope surface under the action of gravity and lateral constraints respectively.Un-der the control of basement morphology and pit wall constraints,the shape of deformation boundary is similar to the spindle shape,located in the middle of the slope.The method of dumping direction crosswise to basement inclination suppresses the dump deformation and weakens the stress concentration on the base surface,the zones near pit wall is prone to shear failure due to the dual effects of the squeezing of the upper waste and the shape of pit wall.The research results can provide reference for the construction of similar geological conditions such as dumping sites and landfills.
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