Evaluation And Prevention Of Rockburst In Corner Coal Face With Critical And Bearing Pillar

With the coal mining in China moving to the depth,the probability of rockburst events is also increasing,and rockburst has become one of the main dynamic disasters.The unreasonable section coal pillar size is the focus and difficulty in the current research,and engineering practice also shows that due to mining restrictions and other reasons,the critical bearing coal pillars left in the coal mining face have a high impact risk,it is difficult to prevent and control.This paper takes the corner coal working face with critical bearing coal pillars as the background,and carries out impact risk assessment and anti-rockburst design.The relevant geological and mining technology factors are analyzed,and the key influencing factors are the buried depth,the physical and mechanical properties of coal and rock,and the critical bearing coal pillar.By using theoretical analysis,numerical simulation to explore the stress distribution law of the coal pillar,it is believed that the 25 m coal pillar will be in a plastic state after mining and then become unstable,the headentry is located at the position with large bearing pressure.Based on the comprehensive index method and possibility index method,the working face is assessed to have medium impact risk,and there is a possibility of impact,the risk areas are also divided.In order to ensure safe mining,measures have been designed for the connection of the open-off cut and headentry,the closure of the old roadway.At the same time,the anti-rockburst ability of the headentry and track support has been evaluated,and believed that it can meet the demand for prevention of rockburst.Before the mining of the working face,the pre-pressure relief measures of large-diameter drilling combined with blasting to break the bottom are taken for the high-stress roadside and bottom coal area.The drilling cuttings method,microseismic monitoring,and online stress monitoring be adopted to monitor the impact risk data of the working face during the mining period.The pressure relief measures and personnel management be strictly implemented according to the warning indicators.The monitoring data shows that effect is good,which ensures the production safety,it has guiding significance for the prevention and control of rockburst under the similar conditions.There are 36 figures,24 tables and 91 references in this paper.