Study On The Mechanism Of Surface And Strata Movement Caused By Underground Mining In The Western Part Of Jin Shandian Iron Mine

The surface deformation and strata movement caused by underground mining in metal mines are important problems in the study of mine disasters.With the depletion of shallow orebody resources in metal mines,deep underground mining is the main way to obtain metal orebody resources in the future,but with the continuous increase of underground orebody mining depth,The situation of engineering geology and ground pressure control in mining area will become more complex,and the deformation problems such as sxirface collapse and strata movement will be more obvious,and the problems such as a*Ound deformation and destruction of surface structures will be more obvious and serious.Therefore,it is necessary to analyze and study the surface and strata movement caused by underground mining in metal mines.Based on the research background of Zhang Fushan West District of Jinshandian Iron Mine of WISCO Resources Group,this paper aims at the present situation of surface and rock strata movement caused by underground metal mining.By using the methods of field investigation,GPS and digital level comprehensive surface monitoring and limit equilibrium theory analysis,the movement mechanism of surface and rock strata in the western region is mainly studied.The main research contents and results of this paper are as follows:(1)In this paper,the comprehensive geological data of Zhang Fushan West District of Jinshandian Iron Mine are collected,sorted out and studied,and the occurrence and expansion process of surface deformation are analyzed.At the same time,the characteristics of surface deformation in metal mines are summarized.(2)From the investigation of the surface cracks,it is concluded that the extension direction of the cracks in the plane is basically consistent with the trend of the mining area,roughly east-west direction,distributed around both sides of the open pit,showing a number of tensioned fracture zones.Most of the cracks have both horizontal tension and vertical dislocation.(3)Through the monitoring of surface deformation,it can be concluded that the displacement change of GPS measuring point E01-E07 on the 1#measuring line passing through Huang Maowan village shows a trend of slow fluctuation and increase,among which the deformation of measuring point E01 is larger;The deformation of GPS site E08?E14 on the 2#measuring line passing through the village of Ao Beizhuang is mainly concentrated in the area north of the surface fracture between E09 and E10,and the area south of the fracture is in a stable state,including the deformation of the surface of the village where Ao Beizhuang village is located has no increasing trend.The deformation of the GPS measuring point E15?E21 on the 3#measuring line passing through the Xie Mating village is mainly concentrated in the area north of E15,and the E16?E21 area of the measuring point is in a stable state.(4)In this paper,the mechanism and failure process of surface and strata movement in the western region are studied comprehensively,combined with the shape of orebody,monitoring investigation and engineering practice,it is determined that the mechanism of strata movement is the gradual caving of surrounding rock in the upper wall.The progressive caving failure process is mainly divided into four stages:the initial mining stage of open-pit mine,the formation stage of surrounding rock cliff,and the continuous deformation stage of failure surface and tensile fracture.(5)The main influencing factors of surface and strata movement and failure in western region are analyzed comprehensively,it is summarized that the main influencing factors are underground mining,orebody occurrence(scale,shape),rock lithology,geological structure and rock mass structure,in-situ stress field and so on.Among them,the mining of underground metal orebodies is the most direct cause of surface and rock movement.(6)The stability of the surrounding rock in the upper wall of the western region is analyzed by using the limit equilibrium method.It is assumed that when the mining elevation of-115m is in the initial failure state,the failure angle of the upper wall rock mass reaches 69.7 degrees and the caving angle reaches 75 degrees.Figure[68]tabic[16]reference[84].