After 4 Years, Seattle's Giant Tunneling Machine Finally Breaks Through

Source: Wired.com
Author: Jack Stewart
Date: April 5th, 2017

Bertha has broken through. After nearly four years underground, Seattle's beleaguered boring behemoth clawed its way into daylight yesterday, leaving a 1.7-mile tunnel behind it. And now that its job is done, workers can at last move an aging, potentially dangerous stretch of elevated highway below the surface, and build a new public space on Seattle's waterfront in its place.
在西雅图地下工作近四年后,饱受争议的巨型挖掘机 Bertha 在昨天终于重见天日,完成了 1.7 英里隧道的挖掘工作。此后,西雅图海滨一段年久失修、存有安全隐患的高架路将移入这段隧道,这一地段也将被改造成海滨公共空间。

The tunneling machine, named for former Seattle mayor Bertha Knight Landes, boasts a 57-foot diameter and measures 325 feet long. After dropping into a pit in July 2013, it started digging the tunnel that will hold the replacement for the Alaskan Way Viaduct, an elevated highway that was partly demolished after being damaged by a 2001 earthquake.
这台挖掘机以西雅图前市长 Bertha Knight Landes 命名,直径 57 英尺,长达 325 英尺。Bertha 于 2013 年 7 月进入地下,开始挖掘。隧道建成后,将取代在 2001 年地震中部分受损的 Alaskan Way 高架路。

Bertha's job was supposed to take two and a half years, but in December 2013, disaster struck: After just 1,000 feet of work, temperature spikes inside the machine set alarm bells ringing, and Bertha had to stop. The contractor says an 8-inch steel well casing, a bit of pipe, basically, fouled the cutting tools and damaged the blades at the front. (Washington State disagrees on the cause; lawyers are fighting it out.)
Bertha 的工作原本计划需要两年半完成,然而在 2013 年 12 月,灾难降临了:在仅仅推进了 1000 英尺后,机器内部温度急剧升高并触发警报,导致停工。承包商表示,事故原因是一个直径 8 英寸的钢制水井(也就是一些管道)损坏了机器前部的切割片。(州政府对此并不认同,并派出律师以查明原因。)

Eventually engineers determined that seals on the main bearing needed replacing, and the most efficient thing to do was to dig down 120 feet to where Bertha was stuck, pull the cutting head up to the surface, and do repairs on site. That took technicians two years, but they finally sent Bertha on its way again in December 2015. And on Tuesday, it finally gnawed through the concrete wall of a newly constructed, 90 feet deep, 'disassembly pit'.
工程人员最终决定更换机器主轴的密封装置,最优方案则是在 Bertha 被困住的地方掘地 120 英尺,将受损切割片拉上来,进行现场维修。该过程耗时两年,最终成功在 2015 年 12 月重新启动了 Bertha 。在本周二,随着Bertha 抵达一个 90 英尺深的混凝土“拆卸坑”,整个隧道至此贯通。

Bertha broke through a new concrete wall into a disassembly pit. *Copyright: Washington State Dept. of Transportation*

Now, workers will cut 7,982-ton Bertha into about hundreds of 20-ton pieces, so they can crane them out and truck them away. They'll decide if parts can be salvaged for use on other projects, or if they should be recycled. No surprise, that'll take several months. (Dismemberment beats being buried alive: After a 200-ton tunneling machine finished its work under New York City, workers abandoned it instead of hauling it back up.)
重达 7982 吨的 Bertha 在这个深坑内将被拆卸成数百个重约 20 吨的零件,便于吊装和运输。工程人员尚未决定这些零件能否用于其他类似工程,或者将它们回收处理。毫无疑问,这一拆卸过程将会耗时数月。(在纽约市,曾有一台 200 吨重的挖掘机,在完成使命后被弃置地下,未能“重见天日”。)

Engineers will cut the machine into pieces no more than 20 tonnes in weight, so that they can be removed on trucks. *Copyright: Washington State Dept. of Transportation*

This breakthrough is just the start. Now construction crews have to finish a double deck highway inside the 60-foot diameter tube, complete with lighting, ventilation, and fire detection systems. Washington State's Department of Transportation says inspectors will test more than 8,500 components over the next two years, before signing off and letting traffic through.
隧道本体的贯通仅是一个开始。后续工程将在这个直径达 60 英尺的隧道中修建一条双层高速公路,以及照明、通风、防火等配套设施。华盛顿州交通部表示,他们将在今后两年内,对隧道内超过 8500 处关键点进行检测,随后宣布正式通车。

Bertha's journey has been a slow one, even when compared to other boring projects. London carved 23 miles of tunnels under the city for a new Crossrail train in just three years, using eight machines. And serial entrepreneur and traffic hater, Elon Musk says he can find a better way to build tunnels, which he sees as a way to increase road capacity. He is digging a test trench outside the HQ of his company SpaceX in Los Angeles, and while he admits "We have no idea what we're doing," he says he hopes to increase the speed of tunneling by 500 to 1,000 percent. Eventually he'd like to see a network of tunnels up to 30 layers deep under cities, with traffic whizzing in three dimensions, instead of just two on the surface.
相比其他隧道工程, Bertha 可谓行动迟缓。伦敦仅仅耗时三年、使用八台机器,就挖掘了 23 英里的隧道。连环企业家、痛恨堵车的 Elon Musk 也表示,他将发明更优方法来修建隧道,增加道路容量。他还在洛杉矶 SpacesX 总部外面挖了一条沟,进行试验。尽管他承认“我也不知道我们在干嘛”,他仍然希望将掘进速度提升 500~1000% 。他最终的愿望,是在城市之下修建多达 30 层的隧道网络,将交通形式由地表的二维升级为三维。

Musk may want to look at Seattle for a reality check on the difficulties of working underground. The $2 billion Alaskan Way Viaduct replacement in Seattle is now slated to open in early 2019, fully three years behind schedule. But hey, at least there's now light at the end of the tunnel.
或许 Musk 需要来西雅图看看,感受地下施工的种种实际困难。如今,一拖再拖的西雅图 Alaskan Way 高架入地工程计划于 2019 年早期竣工,这比最初计划整整晚了三年。不过也别灰心,现在好歹算是有了盼头。


main bearing 主轴承
serial entrepreneur 连环企业家


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