Stability Analysis For Crown Pillar Under The Filling Body In Dongtong’ V Orebody

With the development of human society, the shallow mineral resources reduce day by day, so mining deep resources become the trend of the times in various complex conditions. For more recycling resources and protect the earth’s surface, the upper goaf filling become the necessary means to cause the deep ore body mining technical condition complex. Filling mining has its particularity: under backfilling, waste rock filling cause vertical load on the infrastructure, changing the structure of the stress state; Flow of water weakens rock filling body, and decreases the strength of rock mass; Because of filling body on microscopic inevitably contain microcracks, micro defect features, the accumulation of blasting vibration effect obviously, having an adverse effect on the stability of filling body.In this paper, combined with the complex conditions of the Dong Xiang copper mine V ore body and mining the status quo, the filling stage under pillar stability study. This paper main work and conclusions are as follows:(1) Using AHP method to obtain the influence about the stability of the filling stage pillar under several relatively important factors. Unit structural parameters in the target layer weights is higher, the next phase of structural parameters on the filling body stability of pillar is bigger, so it is needed to pay attention to mining design. Stope exposure area, phase pillar thickness of the structural parameters in the criterion layer weights is higher; Rock mass structure, mining depth in the geological conditions of rule layer weights is higher; Blasting vibration, the upper filling height weight is higher in the rule layer engineering conditions.The results of the study think that rock mass structure, mining depth, decided to natural conditions, the stope exposed area, stage pillar thickness, blasting vibration are controlled parameters, mining, which should attach importance to it.(2) Introducing the small deformation thin plate theory formula, use its calculate minimum safety thickness of 5 m on stage pillar, the numerical model is established to a further simulation, on the stage from 5 m to 9 m pillar thickness, and concluding that the 15 m, width of stope is recovery unit is 25 meters long, exposed area of 375 square meter, phase pillar thickness of 7 m meets the requirements.(3) Using ls-dyna module of ANSYS software, and simulates the upper filling body, lower for the sublevel stope, cartridge segmented time delay blasting process. The results show that the pillar stress distribute with different charge blasting energy superposition, leading to spike maximum stress increased accordingly, but still smaller than the tensile strength of ore-bearing rock, smaller than the compressive strength, shear strength, so this will not cause adverse effect on the stability of the ore-bearing rock; The displacement of the explosive blasting effect, increasing with the superposition and the number of blasting on the pillar Z direction maximum displacement; Blasting vibration is on the filling of the maximum effective stress, which is smaller than the compressive strength of filling body, and the upper filling body stability will not be destroyed.