| Rockburst is one of the major disasters in coal mines.Most of the rockburst occurs in roadways.Strengthening support is an effective measure to prevent and control rockburst in roadways.Taking the horizontal roadway with circular section as the research object,the research on rockburst prevention and control by bolt support is carried out,and the following research results are obtained.1)Based on Mohr-Coulomb yield criterion and considering the strain softening properties of surrounding rock,the stress,strain and displacement distribution of surrounding rock of circular section roadway are obtained under different supporting conditions,such as no support,bolt support and composite support.Based on the theory of disturbance response instability of rockburst,the critical condition of rockburst in roadway is obtained,and its influencing factors are analyzed.2)The occurrence conditions of rockburst in roadway are characterized by two parameters,namely the critical plastic zone radius and critical load.In engineering practice,the possibility of roadway rockburst can be judged by comparing the actual plastic zone and the stress value of coal and rock mass with the critical value.The influencing factors of critical plastic zone radius include roadway geometric parameters,surrounding rock mechanical parameters and surface support parameters.The influencing factors of critical load include : roadway geometric parameters,surrounding rock mechanical parameters,bolt support parameters and surface support parameters.3)Bolt is indispensable in the composite support system,which can improve the impact resistance of roadway surrounding rock and effectively reduce the risk of roadway impact.Increasing the length and number of bolts can significantly improve the anti-impact effect.By shortening the support lag time and increasing the initial support force,the critical load can be increased,and the better the antiscour support effect.The more complex the geological structure,the greater the tectonic stress influence coefficient,and the smaller the critical mining depth. |
