重载铁路路基基床填料参数选取及优化分析

The Parameter Selection and Optimization Analysis of Filler of Subgrade Roadbed for Heavy Haul Railway

研究目的:重载铁路运输是铁路货运发展的方向,大轴重、长编组发展趋势对铁路路基基床填料的选取提出更高的要求。与国外重载铁路设计技术标准对比,国内现有规范对基床填料性质和压实标准的规定较为固定单一且偏于安全,同时我国填料工程性质随地域变化差异较大,因此应在分析国外重载铁路技术标准的基础上,结合我国地域广阔的特点,对现行规定进行优化。本文基于强度和变形控制准则,在已知基床各结构层尺寸的情况下,检算各结构层所需填料类型及压实标准等设计参数,并以此为基础对填料参数的最终确定提出优化建议。研究结论:(1)针对《重载铁路设计规范》(报批稿)路基基床结构(基床表层+基床底层)设计检算算例,确定填料参数并加以优化,计算结果显示:设计轴重27 t、行车速度100 km/h条件下,基床表层填料最低标准为K30=190 MPa/m,满足规范要求,基床底层填料最低标准为K30=110 MPa/m,对比规范相当于将填料压实标准降低一级,表明基床填料技术标准尚可进一步优化;(2)重载铁路路基基床填料选取时,表层宜优先选择级配碎石以满足路基的承载要求,底层填料在满足结构设计最低标准的基础上,随着填料性能的提升可适当减薄底层厚度或表层级配碎石层厚度,从而取得较好的经济和环境效益;(3)该研究成果对我国重载铁路技术标准的完善以及"走出去"战略的实施具有指导意义。

Research purposes ： Heavy - haul railway transportation is the direction of railway freight development. The trend of large axle load and long marshaling of heavy haul put forward higher requirements to the selection of filler of railway subgrade. Compared with the foreign technical standards of heavy haul railway designing, the regulations about properties and compaction standard of subgrade filler of the existing specifications at home is relatively fixed single and on the safe side, besides, filler properties have large differences packing with regional change, therefore we should analyze the design standard of the foreign heavy haul railway and combine with the characteristics of China＇s vast territory, put forward the improvement and optimization for the existing provisions. Combined with the control conditions of strength and deformation, check types of filling and compaction standard of the corresponding structure layer required design parameters such as filler in the known bedding of each structure layer dimension case, and provide optimization suggestions based on the method for the determination of parameters in the end. Research conclusions ： （ 1 ） According to the subgrade bed structure （ bedding facing and roadbed） of code for designing heavy haul railway, design test cases and the packing parameters were determined and improved. The results showed： under the conditions of 27 t axle load and design vehicle speed of 100 km/h, the minimum compaction standard of filler for the bedding facing is K30 = 190 MPa/m, meeting the requirements of specification; the minimum compaction standard of filler for the roadbed is K30 = 110 MPa/m, equivalent to the compaction standard of lower level compared with specifications. The calculation results showed that the subgrade filling technology standard can be optimized further. （2） The bedding surface layer should make a preferred choice of graded stone to satisfy the bearing requirement of subgrade ; Based on the minimum structures design standards, the thickness of the roadbed or the bedding facing graded stone layer can be appropriately reduced with the roadbed filler performance improved to achieve the effect of cost saving and obtain good economic and environmental benefits. （3） The research result has guiding significance to the improvement of the technical standard of heavy haul railway in china and the implementation of going - abroad strategy.