中老鐵路：“一帶一路”上的黃金線路

文：谷峰

“瀾滄號”行駛在中老鐵路班納漢湄公河橋上The Lancang Bullet Train runs on the Ban Ladhan Mekong River Bridge

2021 年12 月3 日，瀾滄號動車組從老撾首都萬象站緩緩駛出，復興號動車組駛出中國云南昆明站，意味著“中老鐵路”正式通車。這條北起中國云南昆明，南至老撾首都萬象，全長1035 公里的鐵路，是第一條采用中國標準、中老合作建設運營，并與中國鐵路網直接連通的境外鐵路。

打造黃金線路，造福兩國民眾。中老鐵路開通運營四個月，累計發送旅客225.4 萬人次，發送貨物131 萬噸，呈現客貨運輸兩旺態勢。復興號、瀾滄號列車運行安全、綠色、便捷、舒適，縮短了城市間的時空距離，受到鐵路沿線民眾青睞，成為出行首選。中老鐵路架起發展快速路，為沿線民眾開動幸福快車。

回顧建設歷程，從前期研究到勘察設計，再到配合施工，中鐵二院全線勘察設計中始終堅持技術支撐、創新驅動，創下多項世界第一，樹立起電氣化鐵路工程建設新標桿。

遍地荊棘 勇往直前

在許多人眼中，老撾氣候宜人、民風淳樸、風景優美，是旅行者的天堂。但在二院人眼中，密布的山林、頻繁的雨季、落后的交通無疑會給鐵路建設帶來不小的困難。雖然在前往老撾之前，二院的技術人員做足了準備，但萬萬沒有想到，實際情況遠比想象的更加復雜。

老撾基礎設施建設相對落后，在鐵路建設領域影響尤為突出，鐵路前期勘察設計最為依賴的地質、水文等基礎資料嚴重缺乏。受自然和經濟等諸多因素限制，老撾尚未開展基礎地質普查工作，收集到的地質資料非常有限，加之交通不便，密林難以穿行，無人區難以進入等，導致地勘工作難度極大。

針對困局，勘察過程中充分采用非接觸手段進行大面積地質判釋工作，同時擴大工程地質調繪范圍，開展1：50000地質區測，采取鉆探、物探、原位測試、取樣試驗等綜合手段完成了多份地質專題報告。功夫不負有心人，經過大量采樣分析，二院人最終完善了沿線基礎地質資料，厘清地層層序，明確各地層巖性組合及其分布范圍，新建地質構造格架，確定了沿線斷裂帶的活動性及地震動參數。此外，還通過開展小流域暴雨洪峰計算方法專題研究，解決了流量和水位確定的難題。

為了安全、順利完成勘探任務，中鐵二院在勘測過程中，對所有現場工作人員進行了安全和衛生培訓，針對野外可能遇到的危險，也提前做了預防保護措施，雇傭當地具備相應處置經驗的村民一起到現場協助工作，并配置安全帽、工作服，攜帶防護裝備和急救藥品，力爭將安全隱患降至最低。

設計引領 亮點頻現

設計之初，中鐵二院根據國家有關部委要求，制定了將中老鐵路打造為綠色景觀長廊示范性工程的目標。中老鐵路是全球第一條全線開展系統性綠化景觀設計的跨境鐵路，也是亞洲首條融合了生態環保、景觀美化、人文風情的長大干線鐵路工程。該線依托鐵路交通構建了“一帶一路”國際鐵路景觀文化長廊，是區域互聯互通的典范工程。遵循“人工引導自然”理念，減少人為管養，讓自然的力量發揮其應有的效力。采用“海綿城市”理念，全面運用于站前廣場、生產生活區設計中，實現對自然降雨的收集利用及安全排放。

在玉磨鐵路的西雙版納國家級自然保護區，為保護珍稀動物亞洲象，中鐵二院開展了全隧方案、全橋方案、從兩側繞避保護區以及局部架橋4 個主要方案比選，由于地質原因線路難以繞避亞洲象分布區，在鐵路穿越自然保護區約14 公里的范圍內，采取延長隧道減少地表出露、調整隧道斜井位置、“以橋代路”等優化工程形式，避開亞洲象主要棲息活動區域，將工程對亞洲象遷移通道的影響降到最低。

同時，針對亞洲象的活動習性，中鐵二院經過反復科學試驗，創新研發了鋼繩格柵防護柵欄，針對大象可能誤入的鐵路區域，在保護區附近隧道進出口和路橋連接處設置了防護柵欄，并優化施工組織，不在自然保護區內設置臨時工程，要求在施工期間加強管理等，進一步減少工程建設及運營對亞洲象的影響，切實在生態敏感區內形成了“線路方案比選、工程設計優化、防護措施到位、管理要求嚴格”的全過程、閉合式鐵路環保措施體系。

針對中老鐵路沿線日照強烈、雨旱交替、雨季暴雨頻發的環境特征，設計人員優選了植物種類及配置模式，優化路基邊坡綠色防護工程，力求達到四季常綠、三季有花、一段一景的景觀效果。

此外中鐵二院技術人員還結合沿線地區不同的人文地理風情與建筑風貌對全線站房及生產生活用房進行造型及裝飾設計，展示沿線地域文化特色。

云南玉溪地區結合當地彝族與哈尼族民居的典型特征，提取屋檐形式、斗拱特點、裝飾紋理形成建筑的特色風貌。

普洱地區借鑒當地茶文化并結合傣族、哈尼族民居的典型特征，借鑒茶色的肌理與色彩，通過藍灰色屋頂及檐口的細節裝飾，形成地域風格與現代精神相結合的建筑氣質。

西雙版納地區參考傣族民居的特點，利用紅色屋頂與暖灰色墻身結合，在欄桿與空調機位等局部位置點綴傣族地區的紋理裝飾。

中老鐵路玉磨段元江特大橋Yuanjiang Super-large Bridge in Yuxi-Mohan Section of China-Laos Railway

科技創新 攻堅克難

2020 年7 月1 日，由中鐵二院勘察設計的元江特大橋連續鋼桁梁成功合龍。元江特大橋位于云南省元江縣，橫跨紅河深切V 型峽谷，橋高238 米，大橋249 米的主跨創國內鐵路鋼桁梁之最，3 號橋墩高度達154 米，位居同類橋梁世界第一。橋兩岸山體陡峻，區域斷層發育，巖體破碎承載力低。在設計階段，中鐵二院進行了大量地質勘探工作，對多種橋式方案進行詳細的論證比選，最終因地制宜地選定了超高橋墩大跨度連續鋼桁梁橋，降低了造價和養護工作量，并避免了修建纜索體系橋梁。

為設計好這座世界級大橋，中鐵二院同步開展了“抗震及減振”和“風-車-橋耦合動力分析”等多項科技攻關。為確保大橋超高橋墩的剛度及抗震性能，創新性地采用多重鋼橫聯的鋼-砼組合橋墩，既滿足大橋的各項性能要求，節約混凝土圬工量，提高抗震性能，又保證了超高橋墩的美觀和輕盈。

2020 年9 月13 日，由中鐵二院設計的中老昆萬鐵路跨境隧道——友誼隧道順利貫通。隧道全長9595.407 米，連通中國云南省西雙版納傣族自治州磨憨鎮和老撾瑯南塔省磨丁經濟特區。其中，中國境內7170.407 米，老撾境內2425 米，為設計時速160 公里的單線隧道。

隧道建設過程中，遭遇了世界級難題。由于隧道穿越第三系地層含鹽巖，而鹽巖分布范圍及含量具有不規律性，在隧道兩端施工靠近國境線時，鹽巖含量急劇增加，開挖后檢測發現的含鹽量平均約30%，局部高達80%以上，高含鹽段落長達1.7 公里，呈雞窩狀或透鏡狀分布，交通隧道工程穿越如此高含量鹽巖地層，在國內外均屬首例。

針對友誼隧道鹽巖強溶解、強腐蝕、膨脹等特性，中鐵二院設計團隊對高含鹽巖地層中的隧道修建難題進行理論分析和模擬試驗，逐步完善處理方案，同時采取“注漿堵水、全包防水、強化材料防腐、圓形加強結構”的原則進行處理，并根據現場超前地質預測預報情況，科學施策，動態設計，優化支護參數，填補了在該地層下修建隧道的技術空白，確保了友誼隧道按期保質貫通。此外，由于鹽巖具有強腐蝕性，隧道開挖所產生的棄渣可能對環境造成污染，中鐵二院為保護生態環境，在以友誼隧道為中心半徑20 公里的范圍內，比選了20 余處渣場的選址和設計，最終成功解決棄渣難題。

中老鐵路是實現合作共贏的典范。在“一帶一路”倡議下，中老鐵路的開通運營為兩國人民帶來了福音、傳遞了希望，建立起互幫互助、合作共贏的良好雙邊關系，讓共贏的理念落到實處，增進了民生福祉。

On December 3, 2021, the Lancang bullet train departed from Vientiane Station in the capital of Laos,while the Fuxing bullet train departed from Kunming Station in China’s Yunnan Province, meaning that the China-Laos Railway was officially opened to traffic.This railway runs from Kunming in China’s Yunnan Province in the north to Vientiane, Laos’ capital, in the south,covering a total length of 1,035km. It is the first overseas railway jointly constructed and operated by China and Laos based on Chinese standards, and directly connected with China’s internal railway network.

The golden line is built to benefit the people of both countries. In the four months since its operation, the Railway has transported 2.254 million passengers and 1.31 million tons of goods, showing a thriving transportation trend in both passengers and goods. Owing to the safe, green, convenient and conformable operation, as well as time and spacesaving transportation, the Fuxing and Lancang bullet trains are favored by the people along the line, becoming their first choice for traveling. The China-Laos Railway has set up an expressway for the development of both sides and started an express train bringing happiness to the people along the line.

Looking back on the construction process, China Railway Eryuan Engineering Group Co., Ltd., has always pursued technology support and innovation-driven development in the whole process from preliminary research to survey and design, and to cooperation construction, and created many worldtop records, setting a new benchmark for electrified railway construction.

When the going gets tough, the tough get going

For many people, Laos is a paradise for travelers with a pleasant climate,simple customs, charming scenery,and lower cost of living. However,for the staff of China Railway Eryuan Engineering Group, the dense forests,frequent rainy seasons, and backward traffic there undoubtedly mean great difficulties in the railway construction. Technicians were well prepared for the coming difficulties before leaving for Laos, but they never expected that the actual situation was far more complicated than they thought.

The infrastructure construction in Laos is relatively backward, especially in railway construction. There is a serious lack of basic information such as geological and hydrological data, which was significant for the preliminary survey and design of the railway. Restricted by physical and economic geography, Laos has not yet carried out a basic geological survey. Geological exploration is extremely difficult due to poor geological research, limited geological data collected, and bad traffic conditions. It is extremely hard to travel through dense forests and enter depopulated areas.

In view of these difficulties, non-contact means were used in the geological interpretation on a large scale during the investigation. Meanwhile, the technicians expanded the scope of engineering geological survey and mapping, and carried out a geological area survey at a scale of 1:50,000.They took multiple measures to carry out the investigation such as drilling, geophysical exploration, in-situ test and sampling test, and completed a number of special geological reports. As a saying goes, nothing is impossible for a willing heart. After a large number of sampling analyses, the staff of China Railway Eryuan Engineering Group finally improved the basic geological data along the line. They clarified the stratigraphic sequence, defined the lithologic assemblage and distribution range of each layer, built a new geological structure framework, and determined the activity and ground motion parameters of the fault zone along the line. In addition,they addressed the difficulties in determining discharge and water level by carrying out special research on the calculation method of rainstorm peaks in the small watersheds.

In order to complete the investigation task, China Railway Eryuan Engineering Group has carried out safety and health training for all personnel participating in the fieldwork during the investigation. Preventive and protective measures have been taken in advance in case of underlying dangers in the field. In addition, the Group has employed local villagers with corresponding disposal experience to assist in the fieldwork,and provided workers with safety helmets and work clothes,portable protective devices, and first aid medicines to minimize potential safety hazards.

World-leading design with various highlights

At the beginning of the design, China Railway Eryuan Engineering Group set the goal of building the China-Laos Railway into a demonstration project of a green landscape corridor as required by relevant ministries and commissions of China. The China-Laos Railway is the world’s first crossborder one to carry out a systematic greening landscape design for the whole line, and also the first grand trunk railway project in Asia featuring ecological environmental protection, landscape design, and cultural customs. Relying on railway transportation, the line has built a cultural corridor of the international railway landscape on the Belt and Road,serving as a model project of regional interconnection. In the pursuit of “following the laws of nature and reducing human intervention”, China Railway Eryuan Engineering Group strives to enable nature to play its due role in the development.The concept of “sponge city” is fully applied in the design of station squares and production and living areas to realize the collection, utilization and safe discharge of natural rainfall.

In the Xishuangbanna National Nature Reserve of Yuxi-Mohan section, China Railway Eryuan Engineering Group made four alternative schemes, namely holing tunnels in the whole reserve area, building bridges in the whole reserve area,bypassing the reserve area from both sides, and building bridges in part of the reserve area to protect the rare Asian elephants.Due to geological reasons, it is difficult to bypass the distribution area of Asian elephants along the line. Within about 14km of the experimental area of Xishuangbanna National Nature Reserve that the railway passes through, optimized engineering forms, such as extending the tunnel to reduce surface exposure,adjusting the location of the inclined shafts of the tunnel, and replacing roads with bridges, have been adopted to avoid the main habitats of Asian elephants and minimize the impact of the project on the migration passway of Asian elephants.

Meanwhile, according to the habits of Asian elephants,China Railway Eryuan Engineering Group innovated steel grille protective fences through repeated scientific experiments. For areas that the elephants may stray into, protective fences have been set up at the entrance and exit of tunnels and the junction of roads and bridges near the reserve area to avoid accidents. The Group has also optimized its construction organization, such as setting up no temporary work in the reserve area and strengthening management during the construction period, to further reduce the impact of the project construction and operation on Asian elephants. In this way, a closed railway environmental protection system has been formed in the ecologically sensitive areas, which includes the whole process of “scheme selection, engineering design optimization, implementation of protective measures, and strict management requirements”.

Based on the environmental conditions of strong sunshine,alternating rain and drought, and frequent rainstorms during the rainy season along the China-Laos Railway, the designers have selected the suitable plant species and improved the allocation mode to optimize the green protection project of roadbed slopes,striving to achieve the landscape effect of evergreen in four seasons, flowering in three seasons, and one section and one scene.

In addition, the technicians have also made modeling and decoration designs for station buildings and production and living facilities in combination with different cultural customs,and geographical and architectural features of the areas along the line, to show the regional cultural characteristics along the line.

In Yuxi, the typical characteristics of local dwellings of Yi and Hani ethnic groups, such as eave patterns, bracket structures, and decorative textures,have been adopted to form unique architectural characteristics.

In Pu’er, the typical characteristics of dwellings of Dai and Hani ethnic groups have been adopted in combination with the local tea culture. Inspired by the color and texture of tea leaves, the buildings along the line are designed with blue-grey roofs and decorated with special eave patterns, forming a unique architectural style integrating regional characteristics and modern spirit.

In Xishuangbanna, the features of the dwellings of the Dai ethnic group are adopted. Buildings are designed with red roofs and gray walls with a beige undertone, and the texture decoration with characteristics of the Dai ethnic group is applied in railings and air conditioning positions.

Overcoming difficulties through scientific and technological innovation

On July 1, 2020, the continuous steel-truss girders of Yuanjiang Railway Bridge designed by China Railway Eryuan Engineering Group were successfully closed. Yuanjiang Railway Bridge, located in Yuanjiang County, Yunnan Province, crosses the deep V-shaped valley of the Honghe River. With a height of 238m and a width of 249m, its steel truss beams surpass those of the domestic railway bridges, and its No.3 bridge pier is 154m high, ranking first in the world among similar bridges. On both sides of the bridge, there are steep mountains, with developing regional faults and a low bearing capacity of rock crushing. In the design stage, China Railway Eryuan Engineering Group conducted a large number of geological explorations, and compared various bridge designing schemes. Finally, the continuous steel truss beam arch bridge with ultrahigh pier and long span was selected according to local geographical conditions, which can effectively reduce the construction cost and maintenance workload, and avoid the construction of cable system bridges.

綠色邊坡Green roadbed slope

To improve the design of this world-class bridge, China Railway Eryuan Engineering Group has tackled numerous hard-nut problems in science and technology such as seismic performance and vibration reduction, as well as wind-trainbridge coupling dynamic analysis. For the rigidity and seismic performance of the bridge with ultrahigh pier and long span,the technicians innovatively adopted the steel-concrete composite piers with the multi-steel lateral combination to meet the performance requirements of the bridge, which can save the masonry quantity of concrete and improve the seismic performance of the bridge while keeping the beauty and lightness of the ultrahigh piers.

On September 13, 2020, the Friendship Tunnel of the China-Laos Railway, designed by China Railway Eryuan Engineering Group, was successfully completed. The tunnel, with a total length of 9,595.407m, connects Mohan Town of Xishuangbanna Dai Autonomous Prefecture in China’s Yunnan Province and Boten Special Economic Zone in Luang Namtha Province of Laos. It stretches 7,170.407m in China and 2,425m in Laos, and is a single-track tunnel with a design speed of 160 km/h.

During the construction of the tunnel, the technicians encountered a world-class problem. The tertiary strata that the tunnel passes through contain salt rocks, which are irregular in distribution range and content, and the content of salt rocks increased dramatically near the border on both ends of the tunnel. After excavation, it is found that the average content of salt rocks reached about 30% and locally up to 80%, and the section with high content of salt rocks is as long as 1.7km,which is distributed in nest-like or lentoid shapes. It is the first case for a traffic tunnel to pass through the strata with such high content of salt rocks at home and abroad.

Since the salt rocks of the tunnel feature high dissolution, strong corrosion,and huge dilatability, the design team of China Railway Eryuan Engineering Group has conducted theoretical analyses and simulation tests on the hard-nut problems in constructing the tunnel in the strata with high content of salt rocks, and gradually improved the design scheme. Meanwhile,they have taken multiple measures to address these problems, such as blocking water through grouting, adopting fullpackage waterproofing technology,enhancing the anti-corrosion performance of the materials, and building round-shaped frames to strengthen the structure. Based on the advanced geological forecast, the technicians have filled the technical gap of constructing a tunnel in such strata through scientific measures, dynamic design, and optimized support parameters to ensure the Friendship Tunnel will be completed on schedule. In addition, due to the strong corrosion of salt rocks, the slags generated by tunnel excavation may cause pollution to the surrounding environment. To protect the local ecological environment, China Railway Eryuan Engineering Group compared design schemes for over 20 slag disposal pits within a radius of 20km from the Friendship Tunnel, and finally solved the problem of slag disposal.