苏虞张市域(郊)铁路高架区间标准桥梁初步研究

Preliminary Study on Standard Bridges for Viaduct Section of Suzhou-Changshu-Zhangjiagang Suburban Railway

市域(郊)铁路桥梁占比大,但行业内尚无统一的桥梁建设标准。项目前期研究冗繁,差异大,标准化、科学化水平有待提高。本文以苏虞张线(苏州—常熟—张家港)为例,从结构体系、梁跨选择、下部结构设计等方面,对标准跨度桥梁进行初步研究。结果表明:能适应梁场整孔预制、架桥机架设工法的标准跨度简支梁,是市域(郊)铁路桥梁选择的方向;双线大箱梁为市域(郊)铁路优选梁型;35 m为市域(郊)铁路标准桥梁的最优跨径;35 m梁设计可采用薄腹板、大型号钢束,结构尺寸较优。桥墩纵向尺寸可以优化,高度10 m及以下的桥墩,纵向尺寸可减小至1.2 m,全桥动力性能满足规范要求。打入桩最经济,但受限条件多;预钻根植桩和后压浆桩受压浆质量难以检测或判断影响,可以少量试验应用;常规钻孔灌注桩仍是市域(郊)铁路桥梁主要采用的桩基形式。

The proportion of suburban railway bridges is large,but there is no unified bridge construction standard in the industry.The preliminary research of the project is cumbersome,and the project differences are large.The standardization and scientific level need to be improved.Taking Suzhou-Changshu-Zhangjiagang line of the urban railway as an example to conduct preliminary research on standard span bridges from the aspects of structural system,bridge span comparison and selection,design of substructure and other aspects.The results indicate that the simply supported beam of standard span which can adapt to the entire precast in beam yard and the construction method of erect by erection bridge machine is the chosen direction of the suburban railway.The double-line box girder is the optimal beam type for suburban railway.35 m is the optimal span of the suburban railway standard bridge.The 35 m beam can be designed with thin web and large-size prestressed tendon,the structural measurement is better.The longitudinal dimension of piers can be optimized.For piers with a height of 10 m or less,the longitudinal dimension can be reduced to 1.2 m,which the dynamic characteristic of the whole bridge can meet the code requirement.Driving piles is the most economical,but with many limitations.It is difficult to detect or judge the influence of the pre-bored and root enlarged precast pile and post-grouting of cast-in-place pile which both affected by compression pulp quality,so it can be used in a small number of tests.The conventional bored pile should still be the main pile foundation form for suburban railway bridges.