复合板是CRTS Ⅲ型板式无砟轨道的核心部件，在服役期间组合荷载循环作用下，容易出现层间离缝、门型钢筋松动、自密实混凝土开裂破损等状态。这不但会增加养护维修工作量，还会影响高速列车运行安全。开展服役期间CRTS Ⅲ型板式无砟轨道复合板损伤演变研究以保证其处于良好状态是当前亟待解决的关键性课题。为此，本项目拟采用理论研究、试验研究和现场调研相结合的方法，采用等效细观模型考虑混凝土细观结构空间和力学特性分布的随机性、考虑自密实混凝土徐变影响、考虑钢筋与混凝土相互作用及考虑无砟轨道在复杂荷载下的损伤演变，建立和验证服役期间组合荷载下路基上CRTS Ⅲ型板式无砟轨道复合板多尺度三维有限元损伤演变模型。基于该模型，并结合现场调研和理论分析，研究路基上CRTS Ⅲ型板式无砟轨道复合板在服役期间组合荷载下损伤演变机理和规律。研究成果可进一步完善无砟轨道设计理论，并为行业相关标准的修订提供理论依据。

Compound plate is the key component of CRTS Ⅲ slab track. Bad states, such as gap between slab and self-compacting concrete, looseness between portal reinforcement and surrounding concrete, crack and damage of self-compacting concrete and so on, are easy to appear in compound plate of CRTS Ⅲ slab track under cyclic action of combined loads during service life. These bad states not only increase the maintenance work, but also affect the running safety of high-speed train. Conducting research on damage evolution of compound plate of CRTS Ⅲ slab track during service life to keep it in good status has become a key issue to be solved urgently at present. In this project, using theoretical methods, experimental methods and in-situ investigations together, a multi-scale three-dimensional finite element method damage evolution model of compound plate of CRTS Ⅲ slab track on subgrade under combined loads during service life, which adopts equivalent meso model to consider the random distribution of spatial location and mechanical parameter in meso-structure of concrete, considers the creep of self-compacting concrete, considers the interaction between steel bar and concrete, considers the damage evolution of ballastless track under complex loads, will be established and verified. Based on the model, combined with theoretical analysis and in-situ investigation, evolution mechanisms and laws of compound plate of CRTS Ⅲ slab track on subgrade under combined loads during service life will be studied. The findings from the study can further enrich the design theory of ballastless track and provide theoretical basis for the revision of related standards.