Surface Deformation Analysis And Forecast Study Of The Underground Mining Mine Based On GPS Monitoring

In underground mining metal mines, because the various geological factors has played a different role in the surface deformation caused by underground mining, the analysis of surface deformation becomes very complicated. The mine ground plan, the surface land-levying, the resident moves, constructs building's use and so on to rely on the rock layer migration rule analysis caused by underground working, while the accuracy of the analysis influences the mine economic efficiency and people's life and property safety directly. So it is necessary to analyze and study surface deformation law caused by underground mining. Taking a typical underground mining in metal mines - Chengchao Iron Western underground mining as the engineering background, the regulations of Mine surface deformation caused by underground mining are studied adopting several methods, including engineering geological analysis, GPS comprehensive in-situ cubic monitoring, as well as theoretical and numerical analysis. This major contents and research results are as follows:1. Use GPS as a new means to monitor the surface deformation caused by underground mining and carried out experiments to study the feasibility of the GPS, prove that even in the complex topography can the accuracy of monitoring obtained by GPS meets the projected surface deformation analysis requirements.2. Investigation analysed the engineering geology and hydro-geological conditions, ore deposit and mining situation in the West Chengchao Iron. Through combining of the geological background, course of collapsing of the earth's surface and monitoring the materials actually, analyse the collapse mechanism of the surface deformation, think that the main factors for surface subsidence and rock deformation are rock structure character, tectonic stress and self-weight stress, groundwater and underground mining, etc. Underground mining is the main reason for rock deformation. The size, shape and location of goaf decide condition of the surface subsidence. Only a certain size gob formed by underground mining, the surface subsidence could occur.3. The surface movement process is rock mass deformation process which is a continuous process of change, showing surface movement characteristics of the funnel-type shape. The growth rate of ground movement and inbreak line in different directions are different, have relationships with mining space size, shape, location. Surface inbreak line has a very close relationship with the begetting and expansion of surface cracks, therefore timely to understand the expansion condition of surface inbreak line contributes greatly to the safety of surface structure building.4. Discrete element method for the prediction of surface deformation tends to be conservative, while the finite element method forecast is then slanting small, but these two methods are insignificant difference. Two kinds of forecasting methods should be combined in practice, and determination of the expansion of the surface deformation should based on the real situation.5. Parameters of surface subsidence prediction method relies on analysis of deformation mechanism, will be divided into mining surface deformation effects and the impact of pre-deformation of two parts, other rock structure character, hydrogeological conditions, tectonic stress such as the impact of the same point comes down to several parameters related to highly exploiting a little influence, through the same height of early mining development of surface deformation monitoring results of the deformation parameters backcalculation, in order to predict the development of surface deformation. This method is simple and swift while calculating,considering the impact of various aspects of surface deformation and timely modification of the parameters to improve the prediction accuracy, can predict in the short-term application, and obtain good results.