Experimental Research On Interface Damage Mechanics Model Of Composite Slab Of CRTS Ⅲ Ballastless Track

In this thesis,the static and fatigue mechanical properties of CRTS III slab ballastless track track slab-self-compacting concrete interface and the mechanical properties of portal steel-self-compacting concrete interface are studied.The interface of CRTS III slab ballastless track composite slab is tested and studied.The specific test contents include track slab-self-compacting concrete splitting tensile static and fatigue test and portal steel-self-compacting concrete drawing static and fatigue test.The main research work of this paper is as follows:(1)Theoretical analysis of the cohesion model is carried out,and the basic parameters of the bilinear cohesion model of the concrete interface are determined;a variety of concrete fatigue damage mechanics models based on damage mechanics are analyzed,and the damage variables of track slab-self-compacting concrete are defined,and selected.Fatigue damage mechanics model of track slab-self-compacting concrete;analysis of the bond-slip constitutive relation of steel-concrete,to lay a theoretical foundation for determining the bond-slip constitutive relation of portal steel-self-compacting concrete.(2)The splitting tensile test of the track slab-self-compacting concrete composite specimen was carried out through the resistance strain gauge and dynamic signal acquisition system,and the interface strain and stress relationship of the track slab-self-compacting concrete composite specimen under static force and the specimen interface strain development law and fatigue life of the composite specimen under fatigue load were obtained.(3)The static and fatigue tests were carried out on the portal steelself-compacting concrete pull-out specimen,and the bond-slip relationship between the portal steel and the self-compacting concrete interface of CRTS III slab ballastless track and the fatigue life of the pull-out specimen were obtained.(4)Based on the split tensile static and fatigue tests of the track slab and the self-compacting concrete,the basic parameters of the bilinear cohesion model were calculated,and the parameters of the fatigue damage mechanical model of the track slab-self-compacting concrete interface were fitted.The fatigue S-N curve of the track slab-self-compacting concrete interface was fitted;a four-stage constitutive model of the bondslip interface of the portal steel-self-compacting concrete was established,and the fatigue S-N curve of the portal steel-self-compacting concrete interface was fitted.52 figures,18 tables,118 references in this thesis...