In the South China Sea to build that bridge why is harder than climbing Mount Everest?

"The Hong Kong-Zhuhai-Macao Bridge" project is actually a collection of bridge, island, tunnel in one of the large trans-sea, as the name suggests, it is East of Hong Kong, Zhuhai and Macau to the West, completely, once completed, will work closely together in the three places, the regional development impact incalculable.

Even to say away from Zhuhai to Hong Kong by car, will be reduced from three hours previously to half an hour.

From the engineering point of view, said its engineering, Mount Everest, is a little too much.

　　Challenge the limit

First working day after this year's national day, on October 8, pay attention to the news that morning, the Hong Kong-Zhuhai-Macao Bridge Tunnel roots song segment sinking E33 successfully completed docking.

The docking, unavailable for more than 26 hours, extending from the national day holiday until after the holiday, as evidenced by the difficulty.

Simple outline, cross harbour tunnel part of the Hong Kong-Zhuhai-Macao Bridge is composed of 33 heavy pipes into, including 28 straight immersed tube section and 5 curved sinking pipe, total length of 5664 metres. It is China's first offshore immersed tube tunnels, immersed tube is also the world's longest highway tunnel and the only deep immersed tube tunnel, traffic engineering is known as the "Mount Everest".

E33 immersed is not only the first song segments, or East artificial islands the first immersed tube. Although there are 28 sinking pipe has been successfully installed in more than 40 meters deep under the sea, but those are straight line segments immersed, immersed tube install the curve segment, there is no experience to follow.

Said E33 installation difficulty, this immersed tube position is the island on the East island. Sea Island will split from both ends, so the Islands where currents are complex, there will be many problems such as siltation. Secondly, due to the island location in shallow waters, many large work ship could not play a role in many jobs need to be done manually. Curve of immersed tube must be curved, E33, for example, each pipe section 22.5 meters long, slightly curved, assembled together to the final 180 metres long and 5500 meters the curvature of the curve radius and weighs 80,000 tons, the equivalent of an aircraft carrier. Any deviation in the process, any unequal force, may cause deviation.

　　Secured the promotional

Those immersed in Zhuhai's Guishan island just north of head of cattle on the island making, there used to be an island, now built a bridge sink pipe prefabrication plant the cross harbour tunnel, two production lines working, basically two months can produce standard pipe-sinking.

Inside the factory, there are about 2000 workers in struggle. They work and live on the island, not island. Food and water by ship, every month, the building will also be a Barber haircut on the island for the workers.

Sinking-pipe installation is not easy.

In November 2014, E15 immersed tube ready to install, sweeping survey of ditches, mud was found, divers found later floating sludge density is reduced, the project decided to allow E15. To the scene before the sinking island project director Lin Ming ever asked the divers diving operation, resulting in bad news, sediment also increased.

Is installed or return? If you return, immersed tube pull-back to tens of millions of, resurfaced after the cost of bed siltation also cost millions, there are costs such as escort ship, these are money, are the financial pressures. The view was expressed that, to give it a try, even if the accuracy of almost, acceptable. But Lin Ming knows that if there is a problem, the consequences are serious. "It's a lifeline, must not be risking quality and the safety of the bridge. The installation will be aborted, immersed in unloading! "Final decisions, E15 was eventually towed back to precast plant perfectly.

After the discovery, sand mining has an effect on sediment in water, sand mining boats to stop sand near the Guangdong provincial government requirements to ensure smooth construction. E15 expedition for the second time when the bed there was a large amount of sludge, again only to return because construction workers cleaning the bed of sludge at the bottom, and the siltation on the trench slope, then fall into the tank. Two return, some tears on the spot. But it also created a set of early warning and forecasting system of siltation, also developed a set of high-precision cleaning equipment, provided a guarantee for the immersed tube install. In 2015, the project team created a year installing immersed tube section 10 world records.

West Island

At the time of sinking pipe butt joint, how to ensure the leak is a major test for immersed each sink 10 to 30 metres to stop monitoring all data correctly, proceed to the next sinking 10 to 30 meters, before docking after divers use fine tuning system tune many times, as evidenced by its carefully.

Last December, the tunnel Hong Kong former Director of civil engineering Dr Lau Ching-kwong, Dr LAU is the first United Kingdom master of bridge Chinese bridge, China also won the highest award in the engineering profession--"Mao Yisheng award." He asked Lin Ming do you need a raincoat boots, get "no" for an answer. When Dr Lau Ching-kwong is wearing a pair of boots, but sinking pipe joints without any signs of leakage, even in the tunnel did not even have watermarks. He said to Lin Ming, "immersed tube tunnel is not watertight, and so did your tunnel leak. ”

　　Bold vision

Hong Kong-Zhuhai-Macao Bridge project consists of three elements, an island in the sea of bridge and tunnel construction, the second is Hong Kong, Zhuhai and Macau island ports, three are Hong Kong, Zhuhai and Macau to the matching connector.

Engineering is 55 km in length, including bridges, Islands, crossing the main project is the largest and most difficult of quantities, main part of the project consists of about 29.6 kilometers. Principle as shown

Do not know if you understand no, simply, from the bridge to the island, after entering the tunnel, out of the tunnel from the island and the bridge. You might ask, why is the Hong Kong-Zhuhai-Macao Bridge does not choose a bridge, instead of using such complex structures?

This is the reality on the ground to begin. Full bridge low costs, low difficulty, of course, but there are a Lingdingyang Bridge near Hong Kong waterway, is the world's most important trade routes, at present amounts to 100,000 tons to navigation, forward 300,000 ton tanker can go. This form requires a bridge with multi-span, to build several more than 170 meters of the bridge towers, Hong Kong, Macao, Zhuhai, Shenzhen and other Airport Aviation limits cannot exceed 120 meters high.

In order to safeguard air and sea routes, there will be a current program. And the Hong Kong-Zhuhai-Macao Bridge also broke the country are usually "century practice", develop design standards for 120 years.

To cite an example. Like Hong Kong beads o bridge subject engineering preliminary design stage Pearl River mouth Chinese white dolphin national nature reserve within construction programme special argument report, according to this a report, Hong Kong beads o bridge via Pearl River mouth Chinese white dolphin national nature reserve paragraph of engineering in bridge, and tunnel, and island, and construction method, 4 big aspects are has many adjustment, to protection White Dolphin: as deepwater district non-navigation hole bridge by 70 meters increases to 110 meters, shallow water non-navigation hole bridge by 70 meters increases to 85 meters, to reduced Pier Construction method is called by the sea into the land of factory jobs, greatly shorten the time for operations at sea, as well as equipment and so on. After the smooth implementation of the protection of Chinese white dolphins, the corresponding increase of construction cost of 3.67 billion yuan.

Hong Kong-Zhuhai-Macau Bridge project website, see tunnel engineering contract duration is stated in the introduction to island until March 2016, but obviously time was pushed back, with 4 immersed tube is not installed yet. During downtime reasons, and will not repeat them.

This year the Festival, 4,000 islands and tunnel builders spent that afternoon, ⅰ area organized workers to launch youth soccer, basketball matches; at night, all of our employees and their families to celebrate the festive season. V area builders still carried out the construction, preparing for E33 immersed tube install.

This is the builders had spent at the construction site of the 6th Festival. If Hong Kong Tycoon Gordon Wu proposed linking Hong Kong and Zhuhai Lingdingyang Bridge plan count, time has passed for 33 years.

Now, everything is in order, the completion date in sight. On June 29, the main bridge closure. On September 27, the main bridge linking. The run-through was included in Qingzhou channel bridge, river-sea direct link ship channel bridge, Jiuzhou three navigation channel bridge of cable-stayed bridges and 20 km of navigable bridge.

If starting from Zhuhai, in two-way forward on the six-lane bridge, you will first see the Jiuzhou channel bridge of cable-stayed bridge pylon as the "sail".

After 6 km, you can see the towers as "Dolphin" bridge--River ship channel bridge, will make you think of the Chinese white dolphins.

After about 10 km non-navigable spans of the bridge, to Qingzhou channel bridge. Steel structure of the bridge's two towers for the scissors "Chinese knot" style. After a few kilometers, West Island.

Standing on the island, you can imagine the future.

Appendix chart highlights (as at January this year)

(Editors: Biao Guo UN832)
2016-10-15 21:59:18
Integrated

中国在南方海域建这座桥 为什么比攀登珠穆朗玛峰还难？

　　这一以“港珠澳大桥”名之的工程实际上是集桥、岛、隧于一体的超大型跨海通道，顾名思义，它东连香港，西连珠海、澳门，完全建成之后，三地将紧密连接在一起，其对于地区间的发展影响不可估量。

　　即使单说路程，从珠海到香港的车程，将从此前的三个多小时缩短到半小时。

　　而从工程难度上看，说其为工程界的珠穆朗玛峰，真是一点也不为过。

　　挑战极限

　　今年国庆节后的首个工作日，10月8日，注意到这样一条新闻，当天早上，港珠澳大桥海底隧道首根曲线段沉管E33成功完成对接。

　　这次对接，用时超过26小时，从国庆长假延伸到放假之后，其难度可见一斑。

　　简单概括一下，港珠澳大桥的海底隧道部分是由33节沉管对接而成，含28节直线段沉管和5节曲线段沉管，总长5664米。它是中国第一条外海沉管隧道，也是世界最长的公路沉管隧道和唯一深埋沉管隧道，被誉为交通工程的“珠穆朗玛峰”。

　　E33不仅是第一根曲线段沉管，还是东人工岛的首根沉管。此前虽然有28根沉管已经成功安装在40多米深的海底，但那些都是直线段沉管，这次曲线段沉管的安装，没有经验可循。

　　说到E33安装的难度，先来说这根沉管的位置，是在东人工岛的岛头。海水遇岛，会从两端分流，所以岛头位置的海流很复杂，会有回淤等许多问题。其次由于岛头位置水浅，许多大型作业船舶无法发挥作用，很多工作都需要人工完成。曲线沉管必然会有弧度，就以E33为例，每段管节长22.5米，都有细微的弧度变化，拼装到一起最终有180米长，达到5500米曲线半径的弧度，重达8万吨，相当于一艘航空母舰。这一过程中有任何偏差，有任何的受力不均，都有可能引起偏位。

　　滴水不漏

　　这些沉管在位于珠海桂山岛以北的牛头岛上进行制作，那里曾是一座孤岛，如今建起了大桥海底隧道沉管预制厂，两条生产线不断工作，基本上两个月能生产出两个标准沉管。

　　在厂房里，有大约2000名工人在奋战。他们工作、生活都在岛上，基本不下岛。食物和水通过船舶运输过来，每个月，建设方还会请一位理发师上岛为工人们理发。

　　沉管的安装并不是一帆风顺。

　　2014年11月，E15沉管准备安装，当时扫测发现垄沟出现浮泥，后来潜水员发现浮泥密度正在减小，项目部决定让E15出发。到现场要沉放之前，岛隧工程总指挥林鸣破天荒地要求潜水员再次潜水作业，结果有了坏消息，泥沙又增多了。

　　那么是安装还是返航？如果返航，沉管回拖一次要几千万，基床回淤后重新铺设的费用也以千万元计，还有护航船等费用，这些都是钱，都是财务压力。有人认为，不妨一试，即使精度差一点，也能接受。但林鸣知道，如果出现问题，后果是严重的。“这是一条生命线，绝不能拿大桥质量和沉管安全作赌注。中止安装，沉管回航！”最后的决策做出，E15最后被完好地拖回预制厂。

　　之后发现，采砂船作业对水中泥沙有影响，广东省政府要求附近采砂船停止采砂，确保工程顺利施工。等到E15第二次出征的时候，基床竟然又出现了大量的淤积物，只能再度返航，原因是此前施工人员清理了基床槽底的淤泥，而基槽边坡上也有回淤物，后来落入槽中。两次返航，有人当场落泪。但这也催生出一套回淤预警预测系统，也开发出一套深水高精度清淤设备，为之后沉管的安装提供了保障。2015年，项目组创造了一年安装十节沉管的世界纪录。

西人工岛

　　在沉管对接时，如何确保滴水不漏是一大考验，沉管每下沉10到30米就要停下来进行监测，一切数据正常，才继续进行下一个10到30米的下沉，对接前还要经过潜水员用微调系统多次微调，其小心翼翼可见一斑。

　　去年12月，香港土木工程署前任署长刘正光参观隧道，刘正光是首位获得英国桥梁硕士学位的华人，也曾荣获中国桥梁工程界的最高奖——“茅以升奖”。他问林鸣需不需要穿雨衣雨鞋，得到“不需要”的答案。参观时刘正光还是穿了一双雨鞋，没想到沉管的接头没有一点渗漏痕迹，隧道内甚至连水印也没有。他对林鸣说，“沉管隧道没有不漏水的，没有想到你们的隧道能够滴水不漏。”

　　大胆设想

　　港珠澳大桥工程包括三项内容，一是海中桥隧岛工程，二是香港、珠海和澳门三地的人工岛口岸，三是香港、珠海、澳门三地的配套连接线。

　　工程全长为55公里，其中包括桥、岛、隧的主体工程是工程量最大、技术难度最高的，主体工程包括约29.6公里。原理如下图所示

　　不知道大家看明白没有，简单来说就是，从桥到人工岛，之后进入隧道，出隧道从人工岛再上桥。大家可能会问，为什么港珠澳大桥不选择一桥到底，而是采用这样复杂的结构？

　　这就要从当地的实际情况说起。全部建桥当然费用低、难度也低，但是大桥靠近香港方向有一条伶仃洋航道，是全球最重要的贸易航道，目前达到10万吨级通航等级，远期30万吨油轮可以通行。这就要求桥梁采用多跨形式，要建数个170多米的桥塔，但是香港、澳门、珠海、深圳等机场的航空限高不能超过120米。

　　为了保障海空航线，就有了现在的方案。而且港珠澳大桥还打破了国内通常的“百年惯例”，制定了120年的设计标准。

　　再举一个例子。比如《港珠澳大桥主体工程初步设计阶段珠江口中华白海豚国家级自然保护区内施工方案专项论证报告》，根据这一报告，港珠澳大桥途经珠江口中华白海豚国家级自然保护区段的工程在桥梁、隧道、人工岛、施工方法等4大方面均有诸多调整，以保护白海豚：如深水区非通航孔桥由70米增大到110米，浅水区非通航孔桥由70米增大到85米，从而减少桥墩；施工方法由海上作业变为陆地工厂化作业，大大缩短海上作业的时间、人员以及设备等等。中华白海豚保护工作顺利实施后，相应增加工程造价36.7亿元。

　　在中交港珠澳大桥项目的网站，看到，工程简介中写明岛隧工程合同工期是到2016年3月结束，但明显工期被推后了，目前还有4根沉管没有安装。至于期间各类停工原因，也不再赘述了。

　　今年的中秋节，4000名中交岛隧建设者一起共度，当天下午，Ⅰ工区组织青年职工开展了足球、篮球对抗赛；晚上，全体职工和家属共庆佳节。而Ⅴ工区的建设者仍然开展着各项施工，备战E33沉管安装。

　　这已经是这些建设者在施工现场度过的第6个中秋节了。如果从香港富商胡应湘提出兴建连接香港与珠海的伶仃洋大桥方案来算，时间已经过去了33年。

　　如今，一切都在有序开展，完工之日也已在望。6月29日，主体桥梁合龙。9月27日，主体桥梁正式贯通。这次贯通的是包括青州航道桥、江海直达船航道桥、九洲航道桥的三座通航斜拉桥和20公里通航孔桥。

　　如果从珠海出发，在双向六车道的桥面上前行，你会先看到九洲航道桥斜拉桥，主塔如同“风帆”。

　　过了6公里，能够看到桥塔像“海豚”的桥——江海直达船航道桥，会让你想到中华白海豚。

　　过了10公里左右非通航孔桥，到了青州航道桥。该桥的两塔为剪刀撑钢结构“中国结”造型。之后再行驶几公里，就是西人工岛。

　　站在岛上，可以想象未来。

　　附录大事记图表（截至今年1月）

(责任编辑：郭彪 UN832)
2016-10-15 21:59:18
综合