海底倾斜矿体开采沉陷预测研究

Study on Subsidence Prediction of Inclined Orebody Cut and Fill Mining in Seabed

三山岛金矿新立矿区是我国唯一一座海底金属矿山,其对开采技术的要求较高,海下开采遇到了严重的安全问题,其中海底移动变形对采矿安全造成重大威胁。金属矿开采所引起的覆岩移动和变形是一个复杂的力学问题,掌握采空区覆岩体采动岩体移动规律和实现对覆岩沉陷的有效预测是新立矿区亟待解决的重要课题。通过对新立矿区井下55线各中段石门巷道顶板位移进行监测,得到了充填法开采倾斜金属矿体的覆岩移动和变形特征。在此基础上,提出了倾斜金属矿体充填采矿法引发覆岩内部移动和变形的悬臂梁机制。最后,通过分析顶板位移监测数据和位移曲线特征,提出了倾斜矿体充填法开采覆岩沉陷预测的轮廓函数方法。该方法由几个指数函数组成,采用该方法得到的沉陷预测曲线与实测结果十分接近,预测准确率都在85%以上。该研究结果对海底矿山的安全生产具有重要的指导意义。

Xinli mining area of Sanshandao gold mine is the only undersea metal mines in China,its mining technology demand is higher,and also have serious security problems.At present,at home and abroad,the research on the prediction of rock mass movement and surface subsidence caused by coal mining is relatively mature,and a variety of practical subsidence models and realistic surface subsidence prediction methods are formed.However,most large and medium metal mines are mined using filling methods.The effect of repeated mining not only makes the mines face new deformation and damage of the filling body,and with the continuous expansion of the scale of the filling body,the large-scale deformation and destruction of the filling body further complicates the movement of rock mass.Finally,threatening the safe production of mines.With the popularization of filling mining methods,the law of rock mass movement and surface deformation caused by filling mining has become an urgent problem to be solved.The in-depth study of this problem can provide the basis for rock movement and surface settlement for the safe mining design of submarine mines,and provide a conceptual model for the prediction of rock mass movement and surface settlement caused by mining.So,grasping mining-induced movement rules of overburden above goaf and realizing valid predictions for overburden movement are the problems to be solved for Xinli seabed gold mine.The monitoring of the displacement of rock mass is a direct means to study the movement and deformation of rock mass caused by inclined orebody mining.The movement and deformation characteristics of inclined overburden in mining by filling method are obtained by monitoring the displacement of roof of each level of the 55 lines underground in Xinli mining area.On this basis,the paper firstly proposed a cantilever mechanism to explain movement and deformation in overburden rocks triggered by cut and fill mining method in metal mines with inclined veins.Based on the analysis of the displacement monitoring data of roof,and according to the characteristics of the displacement curve,the profile functions method is proposed to predict the subsidence of inclined overburden in mining by filling method.The method consists of several exponential functions and the subsidence curve obtained by this method is very close to the measured results.And the accuracy of the prediction is all above 85%.Therefore,the research results have important guiding significance for the safe production of submarine mines.