1604年水上之城的不沉秘密：泥、水、木交织的奇迹
Mud, water and wood: The system that kept a 1604-year-old city afloat
译文简介
本文揭示了威尼斯这座拥有1604年历史的水上奇迹之城得以屹立不倒的核心秘密：一套由泥浆、水与木材巧妙结合的古老人工地基系统。与现代建筑依赖钢筋混凝土不同，威尼斯建立在数百万根深入淤泥的短木桩之上，这些木桩并非触及基岩，而是利用土壤摩擦力和静水压力原理，像“倒置的森林”般支撑起宏伟的宫殿与钟楼。文章详细介绍了这一工程的精妙之处
正文翻译
Most modern structures are built to last 50 years or so, but ingenious ancient engineering has kept this watery city afloat for more than 1,600 years – using only wood.
大多数现代结构的建筑寿命约为50年，但凭借精妙的古代工程学，这座水城仅依靠木材，就已屹立不倒超过1600年。
As any local knows, Venice is an upside-down forest. The city, which turned 1604 years old on March 25, is built on the foundations of millions of short wooden piles, pounded in the ground with their tip facing downwards.
正如当地人所深知的，威尼斯是一座“倒置的森林”。这座城市在3月25日迎来了1604岁生日，它建立在数百万根短木桩的地基之上，这些木桩尖端向下打入地底。
These trees – larch, oak, alder, pine, spruce and elm of a length ranging between 3.5m (11.5ft) to less than 1m (3ft) – have been holding up stone palazzos and tall belltowers for centuries, in a true marvel of engineering leveraging the forces of physics and nature.
这些树木包括落叶松、橡木、桤木、松木、云杉和榆木，长度从不足1米（3英尺）到3.5米（11.5英尺）不等。几个世纪以来，它们一直支撑着石制的宫殿和高耸的钟楼，利用物理规律和自然力量创造了真正的工程奇迹。
In most modern structures, reinforced concrete and steel do the work that this inverted forest has been doing for centuries. But despite their strength, few foundations today could last as long as Venice's.
在大多数现代建筑中，钢筋混凝土和钢材承担了这片“倒置森林”数百年来所做的工作。然而，尽管这些现代材料强度很高，如今却鲜有地基能像威尼斯地基那样持久。
"Concrete or steel piles are designed [with a guarantee to last] 50 years today," says Alexander Puzrin, professor of geomechanics and geosystems engineering at the ETH university in Zurich, Switzerland. "Of course, they might last longer, but when we build houses and industrial structures, the standard is 50 years of life."
瑞士苏黎世联邦理工学院（ETH）地球力学与地学系统工程教授亚历山大·普兹林（Alexander Puzrin）表示：“如今混凝土或钢桩的设计寿命（质保期）通常为50年。当然，它们的实际寿命可能更长，但当我们建造房屋和工业结构时，50年是标准寿命。”
The Venetian piles technique is fascinating for its geometry, its centuries-old resilience, and for its sheer scale. No-one is exactly sure how many millions of piles there are under the city, but there are 14,000 tightly packed wooden poles in the foundations of the Rialto bridge alone, and 10,000 oak trees under the San Marco Basilica, which was built in 832AD.
威尼斯木桩技术因其几何结构、跨越数百年的韧性以及宏大的规模而令人着迷。虽然没有人能确定城市下方究竟有多少百万根木桩，但仅里阿尔托桥（Rialto bridge）的地基中就有1.4万根紧密排列的木桩，而建于公元832年的圣马可大教堂下方则有1万棵橡树。
"I was born and raised in Venice," says Caterina Francesca Izzo, environmental chemistry and cultural heritage professor at the University of Venice. "Growing up, like everyone else, I knew that underneath the Venetian buildings, there are the trees of Cadore [the mountain region next to Venice].
“我在威尼斯出生并长大，”威尼斯大学环境化学与文化遗产教授卡特里娜·弗朗西斯卡·伊佐（Caterina Francesca Izzo）说道，“和大家一样，我从小就知道威尼斯建筑下方埋着卡多雷地区（威尼斯附近的山区）的树木。
But I didn't know how these piles were placed, how they were counted and knocked down, nor the fact that the battipali (literally the 'pile hitters') had a very important profession. They even had their own songs. It is fascinating from a technical and technological point of view."
但我当时并不知道这些木桩是如何放置、计数和打入地下的，也不了解‘打桩人’（battipali）曾是一门非常重要的职业。他们甚至有自己的歌曲。从技术和科技的角度来看，这非常吸引人。”
The battipali would hammer down the piles by hand, and they would sing an ancient song to keep the rhythm – a haunting and repetitive melody with lyrics that praise Venice, its republican glory, its Catholic faith, and declare death to the enemy of the time, the Turks. On a more lighthearted note, a Venetian expression still in use today, na testa da bater pai (literally 'a head that is good to pound down the piles') is a colourful way of saying that someone is dull or slow-witted.
“打桩人”会通过手工将桩木锤入地下，并唱着古老的歌谣来保持节奏——那是一种萦绕心头、循环往复的旋律，歌词歌颂威尼斯的共和荣光、天主教信仰，并对当时的敌人土耳其人发出最后通牒。有趣的是，威尼斯至今仍在使用的一句俚语“na testa da bater pai”（直译为“一颗适合打桩的脑袋”类似中文榆木疙瘩），是一种生动形象的说法，形容某人头脑迟钝或愚笨。
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Only once, early on in his career, Puzrin has been asked to provide a guarantee of 500 years for a construction a Baháʼí temple in Israel.
在普兹林的职业生涯早期，他仅有一次被要求为以色列的一座巴哈伊灵曦堂建筑提供500年的质保。
"I was kind of shocked because this was unusual," he recalls. "I was really scared, and they wanted me to sign. I called my boss in Tel Aviv, a very experienced, old engineer and I said, 'What are we going to do? They want 500 years.' He answered, '500 years? [pause]. Sign.' None of us is going to be there."
“我当时有点震惊，因为这太不寻常了，”他回忆道，“我很害怕，而他们想让我签字。我给在特拉维夫的老板——一位非常有经验的老工程师打了电话，我说：‘我们该怎么办？他们想要500年的保证。’他回答说：‘500年？（停顿）。签吧。到那时候我们都不在了。’”
The people who drove the piles into the silt were known as battipali, or pile hitters, and used a song to help them keep the rhythm as they worked
那些将木桩打入淤泥的人被称为“打桩工”（battipali），他们在工作时会通过唱歌来帮助保持节奏。
The piles were stuck as deep as possible, until they couldn't be pounded down any further, starting at the outer edge of the structure and moving towards the centre of the foundations, usually driving nine piles per square metre in a spiral shape. The heads were then sawn to obtain a regular surface, which would lay below sea-level.
木桩被尽可能深地打入，直到无法再向下推进为止。打桩从建筑结构的外缘开始，向地基中心移动，通常以螺旋状每平方米打入九根木桩。随后，桩头会被锯平以获得一个规整的平面，该平面位于海平面以下。
Transverse wooden structures – either zatteroni (boards) or madieri (beams) – were placed on top. In the case of the bell towers, these beams or boards were up to 50cm (20in) thick. For other buildings, the dimensions were 20cm (8in) or even less.
横向的木结构——无论是“zatteroni”（大木板）还是“madieri”（方木梁）——会被放置在顶端。在建造钟楼的情况下，这些梁或板的厚度可达50厘米（20英寸）；对于其他建筑，尺寸则为20厘米（8英寸）甚至更薄。
Oak provided the most resilient wood, but it was also the most precious. (Later on, oak would only be used to build ships – it was too valuable to stick in the mud.) On top of this wooden foundation, workers would place the stone of the building.
橡木提供了最强的韧性，但也是最珍贵的材料。（后来，橡木只被用于造船——因为它太宝贵了，不舍得埋进泥里。）在这些木质地基之上，工人们会放置建筑所需的石材。
The Republic of Venice soon began protecting its forests to provide sufficient wood for construction, as well as for ships. "Venice invented sylviculture," explains Nicola Macchioni, research director at the institute for bioeconomy at Italy's National Council for Research, referring to the practice of cultivating trees.
威尼斯共和国很快就开始保护其森林，以提供充足的建筑和造船用材。“威尼斯发明了林业学（sylviculture），”意大利国家研究委员会生物经济研究所的研究主任尼古拉·马基奥尼（Nicola Macchioni）解释道，他指的是育林实践。
"The first official sylviculture document in Italy is indeed from the Magnificent Community of the Fiemme Valley [to the north-west of Venice], dating from 1111AD. It details rules to exploit the woods without depleting them."
“意大利第一份官方林业文件确实出自费梅山谷（Fiemme Valley，位于威尼斯西北部）的‘杰出社区’，日期可追溯至公元1111年。它详细规定了在不枯竭资源的情况下开发木材的规则。”
According to Macchioni, these conservation practices must have been in use years before they were written down. "That explains why the Fiemme Valley is still covered by a lush fir forest today." Countries such as England, however, were facing wood shortages by the middle of the 16th Century already, he adds.
根据马基奥尼的说法，这些保护措施在成文之前必然已经实施多年。“这解释了为什么今天的费梅山谷依然覆盖着繁茂的冷杉林。”他补充道，相比之下，像英国这样的国家到16世纪中叶就已经面临木材短缺的问题。
The wooden piles beneath Venice are slowly degrading as anaerobic bacteria attack the cell walls of the wood fibres
威尼斯地下的木桩正在缓慢降解，因为厌氧细菌正在侵蚀木材纤维的细胞壁。
Venice is not the only city relying on wooden piles for foundations – but there are key differences that make it unique. Amsterdam is another city partially built on wooden piles – here and in many other northern European cities, they go all the way down until they reach the bedrock, and they work like long columns, or like the legs of a table.
威尼斯并不是唯一依赖木桩作为地基的城市，但其独特的关键差异使其与众不同。阿姆斯特丹是另一个部分建立在木桩上的城市——在这里以及许多其他北欧城市，木桩一直延伸到接触岩层，它们像长柱子或桌腿一样发挥作用。
"Which is fine if the rock is close to the surface," says Thomas Leslie, professor of architecture at the University of Illinois. But in many regions, the bedrock is well beyond the reach of a pile. On the shore of Lake Michigan in the US, where Leslie is based, the bedrock could be 100ft (30m) below the surface.
“如果岩层靠近地表，这样做没问题，”伊利诺伊大学建筑学教授托马斯·莱斯利（Thomas Leslie）说。但在许多地区，基岩远在木桩触及范围之外。在莱斯利所在的美国密歇根湖畔，基岩可能位于地表以下100英尺（30米）处。
"Finding trees that big is difficult, right? There were stories of Chicago in the 1880s where they tried to drive one tree trunk on top of another, which, as you can imagine ended up not working. Finally, they realised that you could rely on the friction of the soil."
“找到那么大的树很难，对吧？19世纪80年代的芝加哥曾流传过一些故事，说人们试图将一根树干打在另一根上面，你可以想象，这最终行不通。最后，他们意识到可以依靠土壤的摩擦力。”
The principle is based on the idea of reinforcing the soil, by sticking in as many piles as possible, raising substantial friction between piles and soil. "What's clever about that," says Leslie, "is that you're sort of using the physics…
这一原理基于加固土壤的想法，即通过尽可能多地打入木桩，在木桩与土壤之间产生巨大的摩擦力。“其精妙之处在于，”莱斯利说，“你正在利用物理学……
The beauty of it is that you're using the fluid nature of the soil to provide resistance to hold the buildings up." The technical term for this is hydrostatic pressure, which essentially means that the soil "grips" the piles if many are inserted densely in one spot, Leslie says.
它的美妙之处在于，你利用土壤的流体性质来提供阻力，从而支撑起建筑。”莱斯利表示，这在技术术语上被称为“静水压力”，本质上意味着如果在一个地方密集插入多根木桩，土壤就会“抓紧”它们。
Indeed, the Venetian piles work this way – they are too short to reach bedrock, and instead keep the buildings up thanks to friction. But the history of this way of building goes back further still.
事实上，威尼斯的木桩正是以此方式运作的——它们太短，无法触及基岩，而是依靠摩擦力支撑建筑。但这种建筑方式的历史还可以追溯到更久远以前。
The technique was mentioned by 1st-Century Roman engineer and architect Vitruvius; Romans would use submerged piles to build bridges, which again are close to water. Water gates in China were built with friction piles too.
1世纪的罗马工程师和建筑师维特鲁威（Vitruvius）曾提到过这种技术；罗马人会使用水下木桩来建造桥梁，这同样靠近水。中国的闸门也是利用摩擦桩建造的。
The Aztecs used them in Mexico City, until the Spanish came, tore down the ancient city and built their Catholic cathedral on top, Puzrin notes. "The Aztecs knew how to build in their environment much better than the Spanish later, who have now huge problems with this metropolitan cathedral [where the floor is sinking unevenly]."
普兹林指出，阿兹特克人在墨西哥城也使用过这种技术，直到西班牙人到来，拆毁了古城并在其上建造了天主大教堂。“阿兹特克人比后来的西班牙人更懂得如何在他们的环境中建筑，而现在的西班牙人在处理这座由于地面沉降不均而受损的大教堂时面临着巨大的问题。”
Puzrin holds a graduate class at ETH that investigates famous geotechnical failures. "And this is one of these failures. This Mexico City cathedral, and Mexico City in general, is an open-air museum of everything that can go wrong with your foundations."
普兹林在苏黎世联邦理工学院开设了一个研究生班，专门研究著名的岩土工程失败案例。“这就是其中一个案例。这座墨西哥城大教堂，以及整个墨西哥城，简直是一个关于地基可能出现的所有问题的露天博物馆。”
The wood, soil and water all combine to provide Venice's foundations with remarkable strength
木材、土壤和水共同作用，赋予威尼斯地基非凡的强度
After more than a millennium and a half in the water, Venice's foundations have proved remarkably resilient. They are not, however, immune to damage.
在水中浸泡了超过一个半世纪后，威尼斯的地基展现出了惊人的韧性。然而，它们并非无坚不摧。
Ten years ago, a team from the universities of Padova and Venice (departments ranging from forestry to engineering and cultural heritage) investigated the condition of the city's foundations, starting from the belltower of the Frari Church, built in 1440 on alder piles.
十年前，一个来自帕多瓦大学和威尼斯大学的团队（成员涵盖林业、工程和文化遗产等系部）对城市地基状况展开了调查。他们从弗拉里教堂（Frari Church）的钟楼入手，这座钟楼建于1440年，支撑在桤木桩之上。
The Frari belltower has been sinking 1mm (0.04in) a year since its construction, for a total of 60cm (about 24in). Compared with churches and buildings, belltowers have more weight distributed on a smaller surface and therefore sink deeper and faster, "like a stiletto heel", says Macchioni, who was part of the team investigating the city’s foundations.
自建成以来，弗拉里钟楼每年下沉1毫米（0.04英寸），累计下沉了60厘米（约24英寸）。曾参与该地基调查团队的马基奥尼表示，与教堂和普通建筑相比，钟楼的重量分布在更小的表面积上，因此下沉得更深、更快，“就像细高跟鞋一样”。
Caterina Francesca Izzo was working on the field, core drilling, collecting and analyzing wood samples from underneath churches, belltowers and from the side of the canals, which were being emptied out and cleaned up at the time. She said that they had to be careful while they were working on the bottom of the dry canal, to avoid the wastewater sporadically gushing from the side pipes.
卡特里娜·弗朗西斯卡·伊佐当时正在现场工作，负责钻取岩芯、收集并分析来自教堂、钟楼下方以及运河侧边的木材样本——当时这些运河正被排干进行清理。她说，在干涸的运河底部工作时必须非常小心，以避开侧面管道偶尔喷出的废水。
The team found that throughout the structures they investigated, the wood was damaged (bad news), but the system of water, mud and wood was keeping it all together (good news).
团队发现，在他们调查的所有结构中，木材确实受损了（坏消息），但水、泥土和木材组成的系统将一切维系在了一起（好消息）。
They debunked the common belief that the wood underneath the city doesn't rot because it's in an oxygen-free, or anaerobic, condition – bacteria do attack wood, even in absence of oxygen. But bacteria action is much slower than the action of fungi and insects, which operate in the presence of oxygen.
他们揭开了一个普遍的误区，即认为城市下方的木材因处于无氧（厌氧）环境而不会腐烂——实际上，即便在缺氧状态下，细菌也会攻击木材。但细菌的作用速度远慢于在有氧环境下运作的真菌和昆虫。
Furthermore, water fills up the cells that are emptied out by bacteria, allowing wooden piles to maintain their shape. So even if the wooden piles are damaged, the whole system of wood, water and mud is held together under intense pressure, and is kept resilient for centuries.
此外，水分会填满被细菌掏空的细胞，使木桩得以保持形状。因此，即使木桩受损，木材、水和泥土构成的整个系统在巨大的压力下仍能紧密结合，并保持数百年的韧性。
"Is there anything to worry about? Yes and no, but we should still consider continuing this type of research," says Izzo. Since the sampling 10 years ago, they hadn't collected new ones, mainly because of the logistics involved.
“有什么需要担心的吗？既有也无，但我们仍应考虑继续此类研究，”伊佐说。自十年前那次取样后，他们由于物流等实际困难，尚未收集新的样本。
It's not known for how many more hundreds of years the foundations will last, says Macchioni. However, [it will last] as long as the environment remains the same.
马基奥尼表示，目前尚不清楚这些地基还能维持多少个百年。然而，只要环境保持不变，它就能[继续存在]。
The foundation system works because it is made of wood, soil and water." The soil creates an oxygen-free environment, the water both contributes to that and maintains the shape of the cells, and the wood provides friction. Without one of these three elements, the system collapses.
地基系统之所以奏效，是因为它由木材、土壤和水共同组成。”土壤创造了无氧环境，水既有助于维持这一环境，又保持了细胞的形状，而木材则提供了摩擦力。一旦失去这三个要素中的任何一个，系统就会崩溃。
In the 19th and 20th centuries, wood was completely replaced by cement in foundation construction. In recent years, though, a new trend of building with wood has gained increased interest, including the rise of wooden skyscrapers.
在19和20世纪，木材在地基建设中被水泥完全取代。然而近年来，用木材建造建筑的新趋势引发了越来越多的关注，包括木结构摩天大楼的兴起。
"It's kind of the cool material right now, and for really good reasons," comments Leslie. Wood is a carbon sink, it's biodegradable and thanks to its ductility, it's considered among the most earthquake-resistant materials.
“木材是目前非常‘酷’的材料，而且理由非常充分，”莱斯利评论道。木材是碳汇，具有生物可降解性，且由于其延展性，被认为是最抗震的材料之一。
"We can't of course build entire cities on wood nowadays because we are too many on the planet," adds Macchioni, but it's undeniable that without artificial materials and without motors, ancient builders just had to be more ingenious.
“当然，我们现在无法在木材上建造整座城市，因为地球上的人口太多了，”马基奥尼补充道。但不可否认的是，在没有人工材料和电动机的时代，古代建筑师必须更加聪明。
Venice is not the only city with wooden foundations, but it is "the only one [where the friction technique was used] en masse that is still surviving today and is so insanely beautiful", adds Puzrin. "
普兹林补充说，威尼斯并不是唯一拥有木质地基的城市，但它是“唯一大规模使用[摩擦桩技术]且至今幸存、美丽得令人疯狂的城市”。
There were people out there who didn't study soil mechanics and geotechnical engineering, and yet they produced something we can only dream about producing, which lasted so long. They were amazing, intuitive engineers who did exactly the right thing, taking advantage of all these special conditions."
“在那个时代，人们虽然没有学习过土壤力学和岩土工程，但他们却创造了我们只能梦寐以求、如此长寿的作品。他们是令人惊叹的、直觉敏锐的工程师，利用所有这些特殊条件，做出了完全正确的决策。”
* The illustrations in this story are for artistic purposes only and are not a true representation of the timber pile foundations under Venice, which are tightly packed and do not have branches.
注：本文中的插图仅用于艺术目的，并非威尼斯木桩地基的真实写照；真实的地基由紧密排列、无分枝的木桩构成。