Investigation of Dynamic Behaviour of Four-Leg Hydraulic Support under Double-Impact Load

Abstract

Hydraulic support is the key support equipment for underground coal mining. The frequent impact load during the mining process easily causes damage to the hinge joints and reduces the stability of the hydraulic support. To improve the stability of the hydraulic support, a rigid-flexible coupling numerical model of the support has been developed. The validity of the model is verified through the static loading test. Next, the impact loading test of the hydraulic support is carried out. The force response characteristics of the hinge joints and the vibration response characteristics of the leg system are discussed when both the canopy and goaf shield bear impact load. The results indicate that when only the canopy bears the impact load, the hinge joint of the front leg is the most sensitive (up to 139.4 %). When the impact load acts both on the canopy and goaf shield, the dynamic response of each hinge joint of the hydraulic support (except the rear leg) reaches the peak value. With the backward movement of the impact load on the goaf shield, the hinge joint force presents different pressure-relief characteristics.