Stability Analysis And Dynamic Response Of Tailing Pond Under Mining Disturbance

This paper discusses the building tailing pond in the coal mining subsidence area in Sijiaying Iron Mine as the engineering background, carried out the dam stability analysis both in static and dynamic conditions of underground mining disturbance. And a fluid-solid-coupling analysis under the seismic load is also carried out to discuss the seismic liquefaction mechanism and catastrophic instability risk. The main research work and the results obtained are as follows.Firstly, the Midas GTS NX software system is used to build the whole tailings pond in complex three-dimensional geological model, including stratums, new and old irregular mining empty areas and coal and the future mining planning areas. Then using the Visual Studio software to develop an interface to convert the model into a format using buy FLAC3D system. Thereby establishing a numerical model of large scale of the tailing pond for stability analysis.Secondly, an intelligent equivalent rock mass parameter identification model is established to get the dam foundation rock mechanics parameters and initial rock stress by applying the genetic programming and genetic algorithm method. Providing reliable parameters for the next static, dynamic and fluid-solid-coupling numerical simulations.Thirdly, using the equivalent rock mechanic parameters, carried out the static stability analysis of the dam foundation under the mining process disturbance in two conditions of building the dam or not. The results show that the influence of mining disturbance on the foundation settlement is significant. With the exploitation of the coal, the south surface collapse pit is significantly expanded to the west, and the dam intensified the settlement of the foundation due to gravity. In 2015, the north and south collapse area are connected to form a new pit. After 2018, the maximum settlement is expected to reach to 4.85 meters. The west dam is the most dangerous place which has instability risk.Fourthly, the impact of earthquake on the stability of the foundation is analyzed after the end of mining in 2018. From the outcomes of foundation settlement and crest acceleration, the influence of earthquake is not significant without the consideration of the seepage.Finally, the fluid-soil-coupling analysis was carried out by using Finn model in FLAC3D software. Using the effective stress theory to judge the condition of liquefaction. According to the Excess Pore Pressure Ratio (EPPR) to evaluate soil liquefaction. The simulation result gets the variation law of the initial dam by the dynamic load in fluid-soil-coupling condition. And from the stress, displacement, acceleration, pore pressure, EPPR and many other indicators, the vibration liquefaction and safety evaluation is analyzed, which providing scientific basis for safe operation of tailings dam constructed in mining subsidence area.