Stability Analysis And Parameter Optimization Of Large-span Rock Drilling Chamber Under Combined Action Of Dynamic And Static

For a large-scale copper mine,the large-diameter vertical deep-hole stage mining house is used for post-recovery mining,and the ore body mining sequence is upward mining.The mining depth of the first mining section exceeds 800 m,and the maximum principal stress in the horizontal direction has exceeded 30 MPa,which belongs to deep high stress mining.The rock drilling chamber is the main area of the charging operation in the mining process,with a length of 80 m and a span of 30 m,which is the main mechanical structure of the stope.Deep high stress,large span of the stope and strong blasting vibration are all important factors affecting the stability of the rock chamber.The rationality of the structural parameters of the rock drilling chamber is the key to the success of the mining house.In this paper,the engineering geological conditions of the stope mining are obtained through site survey,and a series of research methods such as numerical simulation and on-site monitoring are used to analyze the stability of the rock-sparing chamber of the large-span stope,and the drilling chamber of the first mining stope is calculated.The stress and displacement changes of the main mechanical structures,combined with the on-site monitoring results,comprehensively judge the stability of the large-span rock drilling chamber under dynamic and static combined loads.The main structural parameters of the rock drilling chamber were compared and optimized.Obtained the following research results:(1)The rock mechanics parameters are obtained by site survey and data collection.The rock mechanics parameters are reduced by Hoek-Brown criterion,and the reduced rock mechanics parameters are obtained.For the subsequent numerical simulation analysis of the long-span rock drilling chamber stability.(2)Numerical simulation of the stability of the first-stage large-span(30m)stop rock chamber under dynamic and static interactions shows that the stress on the column is concentrated during the mining process,and the damage domain mainly occurs in the support strip.On the column,the displacement of the top plate increases after the loss of the column support.With the disappearance of the support column of the subsequent rock chamber,the displacement of the roof plate reaches the maximum,but no obvious damage occurs,and the columns on both sides of the rock chamber The stress gradually increases and becomes the main support structure.(3)On-site stability monitoring of the main supporting structures such as the roof,column and support column of the large-span(30m)rock drilling chamber of the first mining stop 201,found that with the large-diameter deep hole blasting process,the column stress The rise is very obvious.The subsequent recovery of the rock chamber and the column disappears,and the roof spans over a large span.However,there is no large displacement in the roof of the stop,and the stress in the column is slightly increased.The first mining is only a single stop mining,and the large-span rock drilling chamber mainly has the phenomenon of cracking and spalling of the supporting column and slight lining of the column.During the mining process,the displacement of the roof is small,and the mining is not long after the end of the mining.It can be filled,causing a small-scale fall in a local area in the middle of the top plate,but the roof is generally stable.The monitoring results are in good agreement with the numerical simulation results,which verifies the reliability of the numerical simulation results.(4)Combining the on-site mining technology,the numerical simulation method is used to compare and analyze the stability of the continuous mining rock chamber with three different structural parameters under dynamic and static combined loads.The results show that the span of the stop is 12m(the width of the column)10m)and the mining process span of 18m(inter-column width 18m)two structural parameters mining process,the displacement of the rock chamber is small,no plastic zone,the two sides of the column does not obviously show stress concentration,and the stope span 30m(Inter-column 12m)During the mining process,the top of the rock chamber and the columns on both sides are damaged to varying degrees.Considering the mining efficiency of the stope and taking into account the two-step mining,the structural parameters of the rock chamber are finally adjusted to a span of 18m(the width of the column is 18m).