中老铁路：“一带一路”上的黄金线路

文：谷峰

“澜沧号”行驶在中老铁路班纳汉湄公河桥上The Lancang Bullet Train runs on the Ban Ladhan Mekong River Bridge

2021 年12 月3 日，澜沧号动车组从老挝首都万象站缓缓驶出，复兴号动车组驶出中国云南昆明站，意味着“中老铁路”正式通车。这条北起中国云南昆明，南至老挝首都万象，全长1035 公里的铁路，是第一条采用中国标准、中老合作建设运营，并与中国铁路网直接连通的境外铁路。

打造黄金线路，造福两国民众。中老铁路开通运营四个月，累计发送旅客225.4 万人次，发送货物131 万吨，呈现客货运输两旺态势。复兴号、澜沧号列车运行安全、绿色、便捷、舒适，缩短了城市间的时空距离，受到铁路沿线民众青睐，成为出行首选。中老铁路架起发展快速路，为沿线民众开动幸福快车。

回顾建设历程，从前期研究到勘察设计，再到配合施工，中铁二院全线勘察设计中始终坚持技术支撑、创新驱动，创下多项世界第一，树立起电气化铁路工程建设新标杆。

遍地荆棘 勇往直前

在许多人眼中，老挝气候宜人、民风淳朴、风景优美，是旅行者的天堂。但在二院人眼中，密布的山林、频繁的雨季、落后的交通无疑会给铁路建设带来不小的困难。虽然在前往老挝之前，二院的技术人员做足了准备，但万万没有想到，实际情况远比想象的更加复杂。

老挝基础设施建设相对落后，在铁路建设领域影响尤为突出，铁路前期勘察设计最为依赖的地质、水文等基础资料严重缺乏。受自然和经济等诸多因素限制，老挝尚未开展基础地质普查工作，收集到的地质资料非常有限，加之交通不便，密林难以穿行，无人区难以进入等，导致地勘工作难度极大。

针对困局，勘察过程中充分采用非接触手段进行大面积地质判释工作，同时扩大工程地质调绘范围，开展1：50000地质区测，采取钻探、物探、原位测试、取样试验等综合手段完成了多份地质专题报告。功夫不负有心人，经过大量采样分析，二院人最终完善了沿线基础地质资料，厘清地层层序，明确各地层岩性组合及其分布范围，新建地质构造格架，确定了沿线断裂带的活动性及地震动参数。此外，还通过开展小流域暴雨洪峰计算方法专题研究，解决了流量和水位确定的难题。

为了安全、顺利完成勘探任务，中铁二院在勘测过程中，对所有现场工作人员进行了安全和卫生培训，针对野外可能遇到的危险，也提前做了预防保护措施，雇佣当地具备相应处置经验的村民一起到现场协助工作，并配置安全帽、工作服，携带防护装备和急救药品，力争将安全隐患降至最低。

设计引领 亮点频现

设计之初，中铁二院根据国家有关部委要求，制定了将中老铁路打造为绿色景观长廊示范性工程的目标。中老铁路是全球第一条全线开展系统性绿化景观设计的跨境铁路，也是亚洲首条融合了生态环保、景观美化、人文风情的长大干线铁路工程。该线依托铁路交通构建了“一带一路”国际铁路景观文化长廊，是区域互联互通的典范工程。遵循“人工引导自然”理念，减少人为管养，让自然的力量发挥其应有的效力。采用“海绵城市”理念，全面运用于站前广场、生产生活区设计中，实现对自然降雨的收集利用及安全排放。

在玉磨铁路的西双版纳国家级自然保护区，为保护珍稀动物亚洲象，中铁二院开展了全隧方案、全桥方案、从两侧绕避保护区以及局部架桥4 个主要方案比选，由于地质原因线路难以绕避亚洲象分布区，在铁路穿越自然保护区约14 公里的范围内，采取延长隧道减少地表出露、调整隧道斜井位置、“以桥代路”等优化工程形式，避开亚洲象主要栖息活动区域，将工程对亚洲象迁移通道的影响降到最低。

同时，针对亚洲象的活动习性，中铁二院经过反复科学试验，创新研发了钢绳格栅防护栅栏，针对大象可能误入的铁路区域，在保护区附近隧道进出口和路桥连接处设置了防护栅栏，并优化施工组织，不在自然保护区内设置临时工程，要求在施工期间加强管理等，进一步减少工程建设及运营对亚洲象的影响，切实在生态敏感区内形成了“线路方案比选、工程设计优化、防护措施到位、管理要求严格”的全过程、闭合式铁路环保措施体系。

针对中老铁路沿线日照强烈、雨旱交替、雨季暴雨频发的环境特征，设计人员优选了植物种类及配置模式，优化路基边坡绿色防护工程，力求达到四季常绿、三季有花、一段一景的景观效果。

此外中铁二院技术人员还结合沿线地区不同的人文地理风情与建筑风貌对全线站房及生产生活用房进行造型及装饰设计，展示沿线地域文化特色。

云南玉溪地区结合当地彝族与哈尼族民居的典型特征，提取屋檐形式、斗拱特点、装饰纹理形成建筑的特色风貌。

普洱地区借鉴当地茶文化并结合傣族、哈尼族民居的典型特征，借鉴茶色的肌理与色彩，通过蓝灰色屋顶及檐口的细节装饰，形成地域风格与现代精神相结合的建筑气质。

西双版纳地区参考傣族民居的特点，利用红色屋顶与暖灰色墙身结合，在栏杆与空调机位等局部位置点缀傣族地区的纹理装饰。

中老铁路玉磨段元江特大桥Yuanjiang Super-large Bridge in Yuxi-Mohan Section of China-Laos Railway

科技创新 攻坚克难

2020 年7 月1 日，由中铁二院勘察设计的元江特大桥连续钢桁梁成功合龙。元江特大桥位于云南省元江县，横跨红河深切V 型峡谷，桥高238 米，大桥249 米的主跨创国内铁路钢桁梁之最，3 号桥墩高度达154 米，位居同类桥梁世界第一。桥两岸山体陡峻，区域断层发育，岩体破碎承载力低。在设计阶段，中铁二院进行了大量地质勘探工作，对多种桥式方案进行详细的论证比选，最终因地制宜地选定了超高桥墩大跨度连续钢桁梁桥，降低了造价和养护工作量，并避免了修建缆索体系桥梁。

为设计好这座世界级大桥，中铁二院同步开展了“抗震及减振”和“风-车-桥耦合动力分析”等多项科技攻关。为确保大桥超高桥墩的刚度及抗震性能，创新性地采用多重钢横联的钢-砼组合桥墩，既满足大桥的各项性能要求，节约混凝土圬工量，提高抗震性能，又保证了超高桥墩的美观和轻盈。

2020 年9 月13 日，由中铁二院设计的中老昆万铁路跨境隧道——友谊隧道顺利贯通。隧道全长9595.407 米，连通中国云南省西双版纳傣族自治州磨憨镇和老挝琅南塔省磨丁经济特区。其中，中国境内7170.407 米，老挝境内2425 米，为设计时速160 公里的单线隧道。

隧道建设过程中，遭遇了世界级难题。由于隧道穿越第三系地层含盐岩，而盐岩分布范围及含量具有不规律性，在隧道两端施工靠近国境线时，盐岩含量急剧增加，开挖后检测发现的含盐量平均约30%，局部高达80%以上，高含盐段落长达1.7 公里，呈鸡窝状或透镜状分布，交通隧道工程穿越如此高含量盐岩地层，在国内外均属首例。

针对友谊隧道盐岩强溶解、强腐蚀、膨胀等特性，中铁二院设计团队对高含盐岩地层中的隧道修建难题进行理论分析和模拟试验，逐步完善处理方案，同时采取“注浆堵水、全包防水、强化材料防腐、圆形加强结构”的原则进行处理，并根据现场超前地质预测预报情况，科学施策，动态设计，优化支护参数，填补了在该地层下修建隧道的技术空白，确保了友谊隧道按期保质贯通。此外，由于盐岩具有强腐蚀性，隧道开挖所产生的弃渣可能对环境造成污染，中铁二院为保护生态环境，在以友谊隧道为中心半径20 公里的范围内，比选了20 余处渣场的选址和设计，最终成功解决弃渣难题。

中老铁路是实现合作共赢的典范。在“一带一路”倡议下，中老铁路的开通运营为两国人民带来了福音、传递了希望，建立起互帮互助、合作共赢的良好双边关系，让共赢的理念落到实处，增进了民生福祉。

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.

绿色边坡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.