中文摘要：

研究目的：弹性支承块式无砟轨道由于其良好的减振降噪效果，在隧道和城市轨道交通中得到广泛应用。隧道内为方便排水，一般在线路中心线的仰拱处设排水沟。因施工误差等因素，客货共线隧道内的弹性支承块式无砟轨道的水沟中线与线路中线可能存在较大的偏移，特定条件下偏移会导致盖板破坏及道床板底部分脱空，影响行车安全。本文通过分析水沟偏移对钢轨位移及盖板应力等静力特性的影响，以及道床板脱空对车体加速度、轮重减载率及轨道结构动态响应等动力特性的影响，提出脱空控制指标，为隧道内弹性支承块式无砟轨道道床板底脱空的养护维修提供理论依据。研究结论：（1）水沟偏移对弹性支承块式轨道结构静力特性的影响有限，当支承块悬空25cm时，盖板最大应力仅为0．25MPa；（2）道床板板端脱空长度未超过0．55m时，脱空对车体加速度、轮轨力以及轮重减载率基本无影响；（3）道床板板端脱空长度超过0．55m时，车体加速度、轮轨力以及轮重减载率显著增大，可能会危及行车舒适性和安全性，建议盖板偏移致板底脱空长度控制在0．55m以内；（4）该研究成果可为隧道内弹性支承块式无砟轨道养护维修提供理论参考。

英文摘要：

Research purposes： Owing to its good noise and vibration reduction effect, low vibration track （LVT） is widely used in tunnel and subways. In general, in order to facilitate tunnel drainage, a drainage ditch is located in inverted arch of track center line. Due to construction error and other factors, there might be a big misalignment between track center line and central line of drainage ditch. Under certain conditions, misalignment of drainage ditch will cause damage of cover plate as well as contact loss underneath slab, and then influence driving safety. The control index of contact loss underneath slab is put forward by analyzing the influence of misalignment of drainage ditch on the static mechanical performance of track, for instance, rail displacement and cover plate stress, as well as influence of contact loss underneath slab on the dynamic response of vehicle acceleration, rate of wheel load reduction and so on, which can provide theoretical reference for maintenance of contact loss underneath slab of LVT in tunnel. Research conclusions： （ 1 ） Misalignment of drainage ditch has limited influence on the static mechanical performance of track. When misalignment between supporting block and drainage ditch reaches to 25 cm, the maximum stress of cover plate is 0.25 MPa. （2） When length of contact loss underneath slab less than 0.55 m, contact loss underneath slab has negligible influence on vehicle acceleration, wheel - rail force and rate of wheel load reduction. （3） When the length of contact loss underneath slab exceeds 0.55 m, vehicle acceleration, wheel - rail force and rate of wheel load reduction increased significantly, which can affect the driving comfort and safety ; it is recommended that the length of contact loss underneath slab due to misalignment of drainage ditch should be kept below 0.55 m. （4）The research achievements can provide theoretical reference for maintenance of LVT in tunnel.