Research on mining damage characteristics of roadway support structure in high stress area

There are fissures in the surrounding rock of the roadway in the high stress area, and the support structure is more likely to develop instability and damage due to mining. At present, there are few researches on the damage evolution characteristics of the roadway support structure during mining. In the context of the geological characteristics of the 3316 working face in Shuangliu Coal Mine, the dynamic evolution characteristics of the support structure of the 3316 extraction roadway under the influence of mining are studied using the methods of mine dynamic load measurement, in-situ detection and numerical simulation. The results show that: ① Mining has significant influence on the dynamic load of the roadway support structure in the high stress area, and the mining influence enhancement factor reaches 2.1-5.8, resulting in some anchors (cables) reaching the yield limit or even breaking. Therefore, there are risks of instability and damage of the roadway surrounding rock. ②The increase of mining stress causes the expansion of secondary fissures inside the surrounding rock, which are concentrated in the range of 0-2.44 m. The coefficient of fissure expansion of the surrounding rock affected by mining is 1.92-2.54. The cohesion of the surrounding rock is reduced, which accelerates the damage of support structure and leads to the increase of roadway deformation. ③The influence of mining on the damage of the support structure has significant time-dependent characteristics. The force of the support structure at the working face over 10-70 m from the measurement point is most influenced by mining, and the force of the two sides of the support structure is asymmetric. By optimizing the key support parameters such as anchor strength, anchor cable diameter and inter-row spacing, the support strength can be effectively improved. The deformation value of the roadway roof is 146 mm, which is 71.7% less than the deformation before optimization, and the stability control of the roadway surrounding rock is obtained.