Abstract:

With the construction of exploration and mining engineering and mining preparation engineering，the industrial orebody is gradually exposed.Compared with the exploration report，the shape of the orebody has changed greatly：（1）The thickness of the orebody becomes thinner and the grade is improved；（2）The stability of the orebody is poor，especially the soft and weak fault gouge exists in the hanging wall of most sections of the orebody.Based on the deterioration of ore occurrence conditions，if the open stope method recommended by the original preliminary design continues to be used，it will lead to low recovery rate，high dilution rate，poor safety and high safety production pressure.In order to adapt to the changed orebody occurrence conditions and solve the above-mentioned safety and economic problems existing in the preliminary design recommended open stope method，the open stope method is changed into a filling method with better safety，higher recovery rate and more environment-friendly.At the same time，reasonable stope structure parameters can effectively control the displacement of rock mass，improve the stress distribution of surrounding rock，and improve the stability of stope.In order to determine the optimal structural parameters of the stope in Gaoerqi lead zinc mine，five stope structure models were established according to the mine geological conditions and orebody occurrence state. The numerical simulation was carried out by the finite element software ANSYS.Comprehensive consideration of the tensile stress， compressive stress and displacement changes of the roof，inter-column，and filling body column，the safety factor is introduced to compare and analyze the simulation schemes.The results show that：Tensile stress occurs stress concentration at the boundary of the model；Compressive stress concentration occurs near the two ends of the stope；Displacement increases gradually with the increase of goaf span；The final optimized stope structure parameter is 75.0 m×6.0 m×1.8 m according to the factors of safety，economy and technology.However，due to the fact that the filling station has not been built，the goaf of one-step stoping can not be filled in time，the exposure time of roof is long，and the risk of roof collapse increases.It is proposed to adopt the one-step 3.5 m-wide strip tight mining method.Due to the increase of stope width in one step，the requirements for the strength of filling body have changed.The stope structure parameters to be adopted in the transition stage of the mine are：Room 75.0 m×3.5 m×1.8 m，pillar 75.0 m × 6.0 m×1.8 m.In order to determine the matching strength of filling body，the numerical simulation was carried out again，and the optimal strength range of filling body was determined to be 1.2~1.4 MPa.The practice in the transition stage of the mine shows that the scheme provides safe operation conditions and achieves good economic benefits，which has reference significance for similar mines.

Key words: stope structure parameters, numerical simulation, filling body strength, ANSYS simulation, stress distribution, displacement change