Study on Eccentric Bearing Capacity of Prestressed Expansion Pillars with Different Heights
When using the room-and-pillar and open-pit mining method to mine metal ore,it is often necessary to leave o-riginal rock pillars in the stope to ensure safe operation during the mining period.In order to solve the above problems,a pres-tressed expansion pillar was developed to replace the original rock pillar for support.Based on the support technology of pres-tressed expansion pillars,this paper studies the bearing capacity of prestressed expansion pillars with different heights and ec-centric loading.Based on the indoor tensile test of material mechanics,the material mechanical parameters of the expansion pil-lars are determined.The numerical analysis model of the expansion pillars are constructed by using ABAQUS numerical simula-tion software,and the static buckling analysis are carried out to obtain the failure mode and bearing laws of the strut under the conditions of different heights and eccentricities.The results show that under axial compression,the failure area of the expan-sion pillar is in the middle of the pillar,and its bearing strength decreases with the increase of the height.Under eccentric load-ing,the failure area of the expansion pillar shifts upward with the increase of eccentricity,and its bearing strength decreases.The prestressed expansion pillars are applied to the stoping of original rock pillar on site of a mine,and their bearing perform-ance are monitored.The bearing law is consistent with the numerical simulation.The above study results indicated that the ex-pansion pillars can effectively maintain the stope stability and improve the ore recovery rate.
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