孫 鈞

(中國(guó)科學(xué)院資深院士，同濟(jì)大學(xué)一級(jí)榮譽(yù)教授)

京滬高速鐵路軌下基礎(chǔ)建成迄今已有10年了，至6月30日，全線開(kāi)通運(yùn)營(yíng)也已有8周年。京滬高鐵自開(kāi)通以來(lái)，每年的客流增長(zhǎng)20.4%，迄今已累計(jì)運(yùn)送旅客10.3億人次，是目前世界上運(yùn)行速度最高和運(yùn)輸效益最好的高速鐵路。這些輝煌成績(jī)的取得，離不開(kāi)其優(yōu)質(zhì)的設(shè)備系統(tǒng)和良好的基礎(chǔ)設(shè)施。

要在京滬之間建成能長(zhǎng)期保持高速運(yùn)行的高鐵線路，并不是一件容易的事。沿途除了要跨越長(zhǎng)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(duì)高速鐵路的軌下基礎(chǔ)結(jié)構(gòu)來(lái)說(shuō)無(wú)疑是巨大的挑戰(zhàn)。為此，原鐵道部從20世紀(jì)末就部署了京滬高鐵基礎(chǔ)設(shè)施重點(diǎn)工程的科技攻關(guān)。例如南京長(zhǎng)江天險(xiǎn)的越江方案，就經(jīng)歷了從上元門隧道到大勝關(guān)大橋的變遷。大勝關(guān)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(qū)高速鐵路路基的長(zhǎng)期沉降這一難題，原鐵道部組織了原上海鐵道大學(xué)(現(xiàn)同濟(jì)大學(xué))、中鐵第四勘察設(shè)計(jì)院、鐵道科學(xué)研究院和西南交通大學(xué)等單位進(jìn)行科研攻關(guān)，并由同濟(jì)大學(xué)牽頭，先后在同濟(jì)大學(xué)滬西校區(qū)、同濟(jì)大學(xué)嘉定校區(qū)和京滬高速鐵路正線的昆山試驗(yàn)段開(kāi)展了長(zhǎng)達(dá)8年的大型原位試驗(yàn)；每個(gè)試驗(yàn)點(diǎn)均進(jìn)行了超過(guò)1 000萬(wàn)次的模擬列車動(dòng)荷載加載試驗(yàn)，獲得了高速鐵路軟土路基在長(zhǎng)期動(dòng)荷載作用下產(chǎn)生沉降的第一手資料，為路基結(jié)構(gòu)型式和沉降控制措施的設(shè)計(jì)起到了關(guān)鍵作用。10年來(lái)的實(shí)踐證明，京滬高速鐵路路基研究團(tuán)隊(duì)對(duì)高鐵軟土路基的方案設(shè)計(jì)、沉降預(yù)測(cè)與控制，以及運(yùn)營(yíng)維護(hù)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(guó)后續(xù)各類重大工程的建設(shè)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(jīng)過(guò)充分的技術(shù)論證，才會(huì)獲得最佳的技術(shù)方案；其次，重大工程的科技攻關(guān)不是個(gè)體行為，而是需要多方進(jìn)行合作，尤其需要工程單位、高等院校和專業(yè)研究機(jī)構(gòu)等“產(chǎn)學(xué)研”單位共同參與；此外，在團(tuán)隊(duì)合作的同時(shí)，還需要充分發(fā)揮各個(gè)參研個(gè)體的積極性，尤其需要項(xiàng)目負(fù)責(zé)人去調(diào)動(dòng)各方的積極性。

今天，在由衷地祝賀京滬高速鐵路軌下基礎(chǔ)建成10周年之際，謹(jǐn)以上述一點(diǎn)文字供業(yè)界同行共饗，并作為對(duì)以上成果的永志紀(jì)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.