京滬高速鐵路軌下基礎建成10周年回顧

孫 鈞

(中國科學院資深院士，同濟大學一級榮譽教授)

京滬高速鐵路軌下基礎建成迄今已有10年了，至6月30日，全線開通運營也已有8周年。京滬高鐵自開通以來，每年的客流增長20.4%，迄今已累計運送旅客10.3億人次，是目前世界上運行速度最高和運輸效益最好的高速鐵路。這些輝煌成績的取得，離不開其優質的設備系統和良好的基礎設施。

要在京滬之間建成能長期保持高速運行的高鐵線路，并不是一件容易的事。沿途除了要跨越長江和黃河之外，還要穿越大量的軟黏土和松散沙土地帶。這對高速鐵路的軌下基礎結構來說無疑是巨大的挑戰。為此，原鐵道部從20世紀末就部署了京滬高鐵基礎設施重點工程的科技攻關。例如南京長江天險的越江方案，就經歷了從上元門隧道到大勝關大橋的變遷。大勝關大橋是目前世界上首座6線鐵路大橋，也是世界上跨度最大的高速鐵路橋梁。

為了攻克軟土地區高速鐵路路基的長期沉降這一難題，原鐵道部組織了原上海鐵道大學(現同濟大學)、中鐵第四勘察設計院、鐵道科學研究院和西南交通大學等單位進行科研攻關，并由同濟大學牽頭，先后在同濟大學滬西校區、同濟大學嘉定校區和京滬高速鐵路正線的昆山試驗段開展了長達8年的大型原位試驗；每個試驗點均進行了超過1 000萬次的模擬列車動荷載加載試驗，獲得了高速鐵路軟土路基在長期動荷載作用下產生沉降的第一手資料，為路基結構型式和沉降控制措施的設計起到了關鍵作用。10年來的實踐證明，京滬高速鐵路路基研究團隊對高鐵軟土路基的方案設計、沉降預測與控制，以及運營維護等方面的研究成果均處于世界前沿水平。

京滬高速鐵路的成功，為我國后續各類重大工程的建設起到了非常好的示范作用：首先，但凡重大工程都必須科研先行，只有經過充分的技術論證，才會獲得最佳的技術方案；其次，重大工程的科技攻關不是個體行為，而是需要多方進行合作，尤其需要工程單位、高等院校和專業研究機構等“產學研”單位共同參與；此外，在團隊合作的同時，還需要充分發揮各個參研個體的積極性，尤其需要項目負責人去調動各方的積極性。

今天，在由衷地祝賀京滬高速鐵路軌下基礎建成10周年之際，謹以上述一點文字供業界同行共饗，并作為對以上成果的永志紀念。

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.