## 7 Conclusions  
Taking the LVT in the heavy-haul railway tunnel as the research object, based on the two LVT full-scale test models of TLVT and ILVT, the geometric shape retention ability and mechanical properties of the LVT are studied. Based on this, the length and width of the track slab are optimized, and the following conclusions are drawn:  
1. Compared with TLVT, the design of ILVT can reduce the vertical displacement of the rail and support block, better control the amount of track sinking, and improve the driving safety of LVT. At the same time, ILVT also improves the anti-overturning ability of the rail and support block under lateral load, reduces the expansion of the gauge and the lateral spacing of the support block, improves the stability of the track structure, and is more suitable for heavy-haul railways.
2. When conducting experiments and finite element analysis, it can be clearly found that under the action of vertical load, the longitudinal load sharing value of ILVT at the loading point is significantly greater than that of TLVT. It can be seen that the improvement of the short side slope of the support block can indeed increase the efficiency of the structure at the loading point in the load sharing of the wheel load. From another perspective, it reflects that the ILVT has a better load bearing capacity.
3. Combining relevant specifications, it is calculated that TLVT reaches the static management value when the axle load is 31.4t; the ILVT reaches the static management value when the axle load is 35.2t. It can be seen that ILVT has better resistance to gauge changes and can be applied to heavy-haul railway lines with larger axle loads.
4. The unfavorable position of the TLVT track bed is mainly at the surface of the support block corner point, while the unfavorable position of the ILVT track bed occurs at the corner of the support block extending from the surface of the track bed to the bottom of the groove and the short side of the slab end. It can be seen that although the two structures are similar, their force characteristics are significantly different.
5. Research shows that the LVT structure, which is generally considered to be only used for low axle loads, can indeed meet the operation of heavy-haul trains with axle loads of 35t and below. However, considering the possible operation of the 40t axle-loaded heavy-haul train in the future, it is necessary to appropriately lengthen the longitudinal length of the structure, increase the reinforcement and increase the strength of the structural material to ensure its possible future force performance.  
Conceptualization, Z.Z. and G.P.; methodology, W.G.; software, G.P.; validation, Z.Z., G.P. and X.H.; formal analysis, W.W.; investigation, J.H.; resources, S.L.; data curation, A.A.S.; writing--original draft preparation, Z.Z.; writing--review and editing, Y.Y.; visualization,Z.Z.; supervision, Z.Z.; project administration, X.D.; funding acquisition, X.D.; All authors have read and agreed to the published version of the manuscript.  
This research was funded by the Open Fund Project of State Key Laboratory of High-speed Railway Track Technology, grant number [2021K002]; Hunan Provincial Natural Science Foundation Project, grant number [2019J40384]; Scientific Research Test Project of China Railway Corporation, grant number [SY2016C001]; the Fundamental Research Funds for the Central Universities of Central South University, grant number [2019 zzts873].  
Not applicable.