Research For Stability Analysis And Safety Forewarning Of Cavity Based On Laser 3D Detection

Safety accidents occurred constantly in China metal mines, and the mine production is severely endangered by cavity heavy accidents caused by underground pressure. Especially in some open-pit, large amount of cavities left by conventional underground mining or various unconventional exploitation exit under open-pit limit due to historical reasons, severely threatened the safety of personnel and equipment above. Furthermore, cavities under ground building such as highway are also the great hidden trouble. Thereby, accurate 3D detection is vital for cavity evaluation and disposal; the way to investigate the stress distribution and stability status of those underground cavities based on detected result is the necessary means to guarantee ground personnel and equipment safety; at the same time, real-time and accurate cavity monitoring on the basis of detection and stability analysis for accident prevention is also essential for mine safe production. In the view of this, the main researches in this paper are as follows:a) Laser 3D detection was carried out for the cavities under open-pit limit by using advanced laser detection system which can present cavity 3D model and detailed information.b) The stability of cavity under open-pit limit was analyzed based on the laser detected data. 3D model detected by laser system was imported into SURPAC to construct cavity block model, the transformation mode between SURPAC and FLAC^3D was studied, and the cavity 3D block model was imported into FLAC^3D through composed corresponding program. By this way, the assumed model used by prevenient numerical analysis can be substituted by detected true 3D model to investigate more accurate ground stress distribution and stability status of cavity under open-pit limit.c) The law of rock acoustic emission under dynamic loading was obtained based on experimental study of rock acoustic emission under dynamic loading; the characteristics of rock acoustic emission under dynamic loading were summarized comparing with the ones under static loading. These may provide theoretical support to reasonably interpret rock acoustic emission data inspected under dynamic loading such as blasting and impact etc., and also may propose instructive suggestions for acoustic emission monitoring of cavity under open-pit limit where frequent blasting and large working machines exist.d) The implement scheme of monitoring system which taking acoustic emission monitoring as the primary means assisting by other monitoring methods in the open-pit with cavities under open-pit limit was studied on the basis of cavity 3D accurate detection, stability analysis and acoustic emission experiments of rock under dynamic loading. Scientific and reasonable analysis was carried out for on-site monitoring data to ensure mine safe production.