Aiming at the breaking problem of anchor bolt in roadway retaining filling body, No. C0202 Face of Chiyu Mine was taken as the engineering background, the breaking characteristics and mechanism of anchor bolt were analyzed by field investigation, laboratory test, mechanical modeling and theoretical analysis. The research showed that the bolt fracture mainly concentrates on the thread section, which was mainly brittle fracture. The failure process was divided into three stages: crack propagation, rapid propagation and instantaneous fracture. The concentrated load on the tail thread section was 5 ~ 7 times the load on the rod body, which was the main reason for the breakage. The strength factor K of fracture mechanics was introduced to establish the mechanical model. The analysis showed that the critical size depth was jointly affected by the pretightening force and the construction angle of the bolt, which were proportional and inversely proportional. The larger the pre-tightening force, the smaller the installation angle, the larger the critical fracture size, the less easily the rod was broken. Based on the above research, the breaking reasons were analyzed in detail from the aspects of dynamic pressure influence and anchor bolt material, and the corresponding improvement measures were put forward to effectively avoid the breaking of anchor bolt and ensure the success of roadway retaining.
