The Numerical Simulation Of The Impact Of Water On The Stress State Of The Porous CA Mortar

In the service process of high-speed rail, the CRTS Ⅰ and Ⅱ type slab track for CA mortar packing layer are observed the degradation and destruction phenomenon of gaps, erosion, crack and fragmentation, and the dynamic water pressure of pore are regarded as the primary cause.The paper is based on the porous characteristics, mechanical characteristics indicators, the porous material model and numerical simulation analysis software to the porosity and pore waters mechanical response in the CA mortar, undering the affect of static and dynamic load and dynamic load-water coupling. Through numerical simulation, it can be obtained that the degradation and destruction mechanism of CA mortar. Mainly the following conclusions:(1) Under setting up different characteristics of porous model by ANSYS finite element software., the simulation analysis of static mechanical responsed in the CA mortar pore can be got, analysis results show that:in the porous model, porous materials will appear the higher stress area and larger vertical displacement, under the condition of hole number unchanged and pore size increasing or pore size unchanged and hole number increasing. The stress and deformation in porous materials will be greater under the greater in the porosity. In the double hole model, the crack produced by the tension and compression varys for the changement of the double holes relative space position. The porosity, pore size and pore distribution are the key factor to influence the response of static mechanics of the CA mortar.(2) Using ANSYS Workbench software, simulating analysis the fluid-solid coupling effect of the CA mortar in the dynamic loads when pore free water does not escape. The result shows that, Under the same load, comparing with the single hole model saturated and unsaturated, it can be concluded that the saturated pore wall has low stress distribution, and the corresponding strain and displacement is high. If the strain exceeds the limit strain of CA mortar, it will cause cracking and pore wall expansion. The external water infiltrated the hole and make it saturated, and the dynamic loading make the strain of the pore wall high and initiating cracking and pore wall expansion again. Repeatedly, under the dynamic load-water coupling repetitive loading, the pore of CA mortar suffered expansion, connectivity, and eventually leading to cracking and chipping damage. Therefore, the research on degradation and invalidation mechanism of cement emulsified asphalt mortar in slab trackbased can be revealed based on analysis methods.(3) Using FLUENT fluid analyetical software to simulate and analyse CA mortar’s reaction when it’s under dynamic load and water quickly penetrate it causing hydraulic fracture.It’s considered that the water in the gaps of slab track and mortar layer quickly penetrate into CA mortar causing a high water percolation pressure.The high speed and stressful current acting like a chock on the surface holes of CA mortar leads to hydraulic fracture.It proves that the initial velocity of flow,porosity and aperture are the main factors which affect hydraulic fracture. The higher the initial velocity of flow,the lower the porosity and the smaller the aperture,the bigger the damage.That’s the main reason responsible for the degradation of mortar filling layer of slab ballastless track.86charts,28tables,86references.