京沪高速铁路轨下基础建成10周年回顾

孙 钧

(中国科学院资深院士，同济大学一级荣誉教授)

京沪高速铁路轨下基础建成迄今已有10年了，至6月30日，全线开通运营也已有8周年。京沪高铁自开通以来，每年的客流增长20.4%，迄今已累计运送旅客10.3亿人次，是目前世界上运行速度最高和运输效益最好的高速铁路。这些辉煌成绩的取得，离不开其优质的设备系统和良好的基础设施。

要在京沪之间建成能长期保持高速运行的高铁线路，并不是一件容易的事。沿途除了要跨越长江和黄河之外，还要穿越大量的软黏土和松散沙土地带。这对高速铁路的轨下基础结构来说无疑是巨大的挑战。为此，原铁道部从20世纪末就部署了京沪高铁基础设施重点工程的科技攻关。例如南京长江天险的越江方案，就经历了从上元门隧道到大胜关大桥的变迁。大胜关大桥是目前世界上首座6线铁路大桥，也是世界上跨度最大的高速铁路桥梁。

为了攻克软土地区高速铁路路基的长期沉降这一难题，原铁道部组织了原上海铁道大学(现同济大学)、中铁第四勘察设计院、铁道科学研究院和西南交通大学等单位进行科研攻关，并由同济大学牵头，先后在同济大学沪西校区、同济大学嘉定校区和京沪高速铁路正线的昆山试验段开展了长达8年的大型原位试验；每个试验点均进行了超过1 000万次的模拟列车动荷载加载试验，获得了高速铁路软土路基在长期动荷载作用下产生沉降的第一手资料，为路基结构型式和沉降控制措施的设计起到了关键作用。10年来的实践证明，京沪高速铁路路基研究团队对高铁软土路基的方案设计、沉降预测与控制，以及运营维护等方面的研究成果均处于世界前沿水平。

京沪高速铁路的成功，为我国后续各类重大工程的建设起到了非常好的示范作用：首先，但凡重大工程都必须科研先行，只有经过充分的技术论证，才会获得最佳的技术方案；其次，重大工程的科技攻关不是个体行为，而是需要多方进行合作，尤其需要工程单位、高等院校和专业研究机构等“产学研”单位共同参与；此外，在团队合作的同时，还需要充分发挥各个参研个体的积极性，尤其需要项目负责人去调动各方的积极性。

今天，在由衷地祝贺京沪高速铁路轨下基础建成10周年之际，谨以上述一点文字供业界同行共飨，并作为对以上成果的永志纪念。

Commentary

AReviewofBeijing-ShanghaiHigh-speedRailwayLineatthe10thanniversaryofsub-railfoundationcompletion

SUNJun

(Academician of Chinese Academy of Sciences, First Grade Emeritus Professor of Tongji University)

2019 is the 10th anniversary since the sub-rail foundation completion of Beijing-Shanghai High-speed Railway line, which had been operated for 8 years already until June 30, 2019.Since the opening and operation of Beijing-Shanghai High-speed Railway, the passenger flow has been increasing by 20.4% per year averagely.So far, 1.03 billion passengers transported by Beijing-Shanghai High-speed Railway make the line the fastest and the most profitable high-speed railway all around the world.The brilliant achievements of the this line is based on its excellent equipment system and infrastructures.

It was a tough mission to build a high-speed railway line for long-term operation between Beijing and Shanghai, since the railway line had to cross the Yangtze River and the Yellow River, as well as large amount of regions with widely-distributed soft clay and loose sandy soil.The natural environment condition poses great challenge to the design and construction of the sub-rail foundation structures.Actually, the former Ministry of Railways had deployed key infrastructure projects to tackle the scientific and technical problems in the construction of Beijing-Shanghai High-speed Railway started from the end of 20th century.For example, the Nanking Yangtze River crossing scheme had gone through great transition from Shangyuanmen Tunnel to Dashengguan Bridge, the first cross-river bridge with 6 railway lines that boasts the largest span among all bridges for high-speed railway train in the world.

In order to solve the subgrade long-term settlement of high-speed railway line in soft-clay regions, the former Ministry of Railways established a research team, including Shanghai Tiedao University (currently Tongji University), China Railway Siyuan Survey and Design Group Co., Ltd., China Academy of Railway Science Co., Ltd., Southwest Jiaotong University and more to carry out relevant scientific researches.Tongji University took the lead to conduct an 8-year length large scale field tests (located at Huxi and Jiading campuses of Tongji University as well as the Shanghai-Kunshan test section of the real Beijing-Shanghai high speed railway line)to investigate the long-term settlement of subgrade on soft-clay base under dynamic load.For each site, more than 10 million load cycles were applied to simulate the long-term moving train load.According to the field test results, the first-hand information concerning the characteristics of soft soil subgrade settlement performing under long-term dynamic loading were obtained, which played an important role in the design of subgrade structure form and the settlement-control measures.The ten-year operation practice of Beijing-Shanghai High-speed Railway indicates that the research team walks at the forefront of the world in the field of high-speed railway subgrade built on soft clay, in terms of research results including the structure design, settlement prediction, control, operation and maintenance.

The success of Beijing-Shanghai High-speed Railway plays an exemplary role for the later major projects.Firstly, scientific researches have to be conducted prior to the practice, which emphasizes that the best technical scheme comes from the sufficient technical demonstration.Secondly, tackling scientific and technical problems in processing the major projects needs the corporation among multi-entities, especially through the common participation of industries, universities and colleges, as well as the expertise research institutes.Last but not least, the full engagement of the participators′ initiative is also essential throughout the team work, especially of the team-leaders who should mobilize the initiatives.Today, we sincerely congratulate the ten-year old sub-rail foundation of Beijing-Shanghai High-speed Railway, and in the meantime we share these words with colleges and peers, to memorize the above achievements.