With the train speed and axle load increasing, excessive stresses are produced and transmitted to the ballast layer, inducing rapid ballast degradation. To solve this issue, the under sleeper pads (USPs) have been widely applied between sleepers and ballast particles as the elastic layer. In this research, laboratory tests using half-sleeper track were carried out to study the ballast bed performance with or without the USPs under static and cyclic loading. Results show that applying the USPs reduces the track stiffness and can decrease the settlement. However, installing the USPs increases the ballast bed acceleration and the sleeper vertical acceleration. The contact areas of sleeper-ballast with USPs are over 5 times as those without USPs. The USPs assist reducing ballast degradation mainly by avoiding the ballast particle breakage at the sleeper-ballast interface and can increase the stress distribution at the longitudinal direction.

随着列车速度和车轴负荷的增加，产生了过多的应力并将其传递到压载层，从而导致压载物迅速降解。为了解决这个问题，在枕木和道ball颗粒之间作为弹性层已广泛应用了枕木下垫（USP）。在这项研究中，使用半卧铺轨道进行了实验室测试，以研究在有或没有USP的情况下在静态和循环载荷下的压载床性能。结果表明，应用USP会降低轨道刚度并会减少沉降。但是，安装USP会增加道ast床的加速度和轨枕的垂直加速度。具有USP的卧铺压载物的接触面积是没有USP的卧铺压载物接触面积的5倍以上。