| For advance using underground mining, and implementation of large-scale open-pit miningin the late. In the period of underground mining a hidden gob appeared. This security problem forthe open-pit mining work brought serious challenges. When design of various types of plan inopen-pit mining platform, the safety of opencast mining must take into account. Use open pitmines concealed mined-out area exploitation as the theme, with an open pit mine as the researchobject, use FLAC3D software to work out numerical simulation and stability analysis. Throughstudy the strength characteristics of rock mass, understand the original rock stress state and stressredistribution. focuses on the security thickness of open pit mining platform, as well as therelationship between the related factors; According to the strength theory of rock, failure criterion,the rock mass and mined area ware analysised of in different reserved height mining platform,and with the relationship of horizontal span. The mechanical of three relationship between roofheight of open-pit mining platform, security thickness and mined area span. The results obtainedare as follows:(1) By calculating the opencast mining platform damage range, it is largely influenced bythe two factors, distribution span mined area, the thickness of the working platform for opencastmining. For different sizes of empty areas, designed different simulation programs, in theprograms, changing the span with different levels and the different roof heights, thecomputational analysis found that for different values of these two factors, the extent of damagepit mining operations platform also produced a lot of difference;(2) Through the study of rock failure criterion, the Mohr theory and Mohr criterion appliedto the program, provides the feasibility of numerical simulation analysis; Mohr strength theoryassumes that the destruction of the material that is mainly determined by its major principal stressand minor principal stress, namely σ1and σ3, regardless of the intermediate principal stress. Sothat you can study the stress state in the plane stress state conditions, Moore represented by σ1and σ3-Coulomb failure criterion. For the next major principal stress is tensile stress of thesituation, but also improve the Mohr-the missing part of the guidelines, the destruction ofvarious circumstances have made the corresponding damage calculation method;(3) The destruction of the state of different conditions, gives a fitting the curve of damagerange from opencast working platform; through research under different design conditions, theextent of damage occurring pit mining platforms there are significant differences in value, but allthe curves on the trends have one thing in common: not a great span of time in the range of empty areas, as the extent of damage to the roof span occurring dramatic increase growth approximatesa straight line; after a period of rapid growth, the growth curve begins to become slow destruction,but they are still on the rise, with all curves of this specific destruction of features;(4) Based on the study on the failure curve, the safety thickness of opencast workingplatform was calculated out. The requirements for different security to mining unit presents asafety factor to choose from, as there is a similar mine production signed by meaning. |
