板式轨道充填层自密实混凝土的动态力学特性
Dynamic mechanical properties of filling layer self-compacting concrete applied in slab track system

为掌握高速铁路CRTSIII型板式无砟轨道充填层自密实混凝土(SCC)在高速列车等动载作用下的力学特性，采用Ф75 mm分离式霍普金森压杆(SHPB)试验方法，研究充填层SCC在10~100 s-1条件下的动态力学性能，并基于应变等价性假说和统计损伤理论建立充填层SCC动态本构模型。研究结果表明：随着应变率增加，SCC的破碎程度增大；SCC的峰值强度、峰值应变和比能量吸收均随应变率的增大而增大，表现出明显的应变率敏感性，且其应变率敏感性大于普通混凝土；建立的动态本构模型可用来描述SCC在相应应变率下的应力应变关系。
In order to better understand the mechanical properties of self-compacting concrete (SCC) applied in CRTS III type slab ballastless track filling layer under dynamic load such as high speed train, dynamic mechanical properties of filling layer SCC under 10~100 s-1 were studied using split Hopkinson pressure bar (SHPB) method, and the corresponding dynamic constitutive model was established based on strain equivalence hypothesis and statistical damage theory. Results show that the larger the strain rate is, the higher damage level SCC specimens present; The peak strength, peak strain and specific energy absorption of SCC specimens increase with growing strain rate, showing prominent strain-rate sensitivity; Moreover, the level of strain-rate sensitivity for SCC is larger than that for normal concrete. The established dynamic constitutive model can be used to describe the dynamic stress-strain relationship of SCC under investigated strain rates