Dynamic response characteristics analysis of four column chock shield support under impact load

The hydraulic support equipment is usually used to support the roof in underground mining. During this process, the support bears frequent impact load, which greatly weakens its dynamic stability. To study the dynamic response characteristics of the support, when it bears the impact load at the top beam and shield beam, the numerical model of the support is established using ADAMS and the equivalent variable stiffness damping system was used to replace the column system. An active static load is applied vertically above the top beam to simulate the roof gravity force, and the impact load is applied downward perpendicular to the top beam and shield beam. Based on the above model, the dynamic response of the key parts of the support, when different impact loads are applied to the top beam and shield beam, and the influence of offset loading on the stability of the support are analyzed. Then, when considering asymmetric bracing conditions, the dynamic characteristics of hydraulic support under impact load are discussed by setting different initial support forces. The results show that when under a single impact load, the load variation coefficient of the front column reaches 1.41, which is the most sensitive to the impact load at the front end of the top beam. When the top beam and shield beam bear the impact load at the same time, the support hinge joint response more violently to the impact load acting on the top beam end and the upper area of the shield beam, and the maximum load change coefficient is 0.64, which greatly affects the overall stability of the hydraulic support. When the support bears to lateral torque, the weakening effect of offset load acting on different positions on the bearing performance of the support is the same, and the magnitude of offset load is positively correlated with the weakening effect. When considering the different initial load ratios (ILR) of the column, it is found that the hinge joint of top beam and shield beam is the most sensitive to the change of ILR, and the insufficient initial support of the front column has the greatest weakening effect on the bearing performance of the support. The research results can help to optimize the structure of the support shield support and improve the bearing reliability of the hydraulic support.