Experimental study on mechanical properties of anchor plate and combination components under impact load

In rockburst roadway, the impact load will cause the interaction force between the components of bolt support system and surrounding rock to increase sharply, and the supporting plate is prone to deformation and failure under high force. In view of the above problems, the mechanical properties of three kinds of arched supporting plates and their combined components commonly used in coal mines were tested by using a microcomputer-controlled electro-hydraulic servo testing machine and a self-developed drop hammer impact testing device. The static load-displacement curve, impact time-history curve, displacement time-history curve and deformation and failure characteristics of the samples were obtained, and the impact resistance of anchor supporting plates and combined components was analyzed. The results show that under the static load, the bearing capacity of the supporting plate is 228-243 kN, and the maximum deformation is 14.10 mm. The deformation characteristics are as follows: the arch height is reduced, the four corners are tilted, and the connecting parts are transferred to the center of the circle. Under dynamic load, the deformation of the supporting plates all experienced three stages: arch height reduction, four corners lifting and flattening. When the impact energy was 500-3 000 J, the impact time-history curve showed a sharp rising stage, a shock stage and a rapid decline stage, while when the impact energy was 3 500-5 000 J, the impact time-history curve showed a sharp rising stage, a shock steady load stage, a shock rising stage and a rapid decline stage. With the increase of impact energy, the peak values of impact force of the samples are gradually increased. Compared with its static load, the peak value of dynamic load of the supporting plate sample is obviously larger than its static load. The displacement time-history curve of the samples can be divided into two stages: elastic-plastic deformation and springback deformation. In the elastic-plastic deformation stage, the deformation is linearly related to the acting time, and the average acting time of the maximum deformation of the positive, negative supporting plates and combined components accounts for 68.66%, 69.25% and 66.66% respectively. In the springback stage, the average elastic deformation of the three samples is 1.71, 1.84 and 3.23mm respectively. In the whole impact process, the impact energy average conversion rates of the three samples are 96.82%, 97.33% and 93.78%. Generally speaking, the positive and negative impact mechanical properties and deformation characteristics of the supporting plate are consistent. Compared to single supporting plate, the combined components can achieve the functions of energy absorption, prolonging the overall impact time, shortening the impact time and improving the bearing characteristics of the supporting plate. The research results provide some reference for the selection of supporting plate and combined components for the bolt support of rock burst roadway.