Study on anti-impact mechanism of pre-stressed anchorage in deep roadway

Aiming at the phenomenon that the anchorage pre-tightening force of surrounding rock is easy to lose under frequent dynamic load impact, taking the return airway of 1303 working face of Lilou coal mine as the engineering background, the relevant research is carried out by combining theoretical analysis with numerical simulation. The evolution trend of anchorage pre-tightening force under dynamic load impact is analyzed, and the influence law of dynamic load parameters on anchorage effect is studied. Based on the analysis of anchorage mechanics and numerical simulation under dynamic load, the reasonable pre-tightening force of anchorage support in return airway of 1303 working face is determined to be 70 kN. The influence of dynamic load amplitude and dynamic load frequency on the anchoring effect is obtained by further simulation. Among them, the larger the dynamic load amplitude, the greater the damage to the anchorage body, and the smaller the dynamic load frequency, the greater the damage to the anchorage surrounding rock. The damage of the surrounding rock is greater under high amplitude and low frequency dynamic load impact than under low amplitude and high frequency dynamic load impact. Through field application, the effectiveness of reasonable pre-tightening force under dynamic load impact to improve the control effect of roadway surrounding rock is verified. The research results can provide reference for mine surrounding rock control under similar conditions.