{"id":4576,"date":"2012-04-08T13:39:35","date_gmt":"2012-04-08T13:39:35","guid":{"rendered":"http:\/\/blogs.agu.org\/landslideblog\/?p=4576"},"modified":"2012-04-08T13:39:36","modified_gmt":"2012-04-08T13:39:36","slug":"images-of-the-three-gorges-dam-ship-lock-wall","status":"publish","type":"post","link":"https:\/\/blogs.agu.org\/landslideblog\/2012\/04\/08\/images-of-the-three-gorges-dam-ship-lock-wall\/","title":{"rendered":"Images of the Three Gorges Dam ship lock wall"},"content":{"rendered":"

I am currently in China visiting the Three Gorges University to discuss research collaboration.\u00a0 The university is located within 45 km of the Three Gorges Dam site, and is responsible for monitoring many of the unstable and potentially unstable slopes on the banks of the reservoir.\u00a0 My hosts have been kind enough to take me to a few of the more notable sites over the last couple of days.\u00a0 The first was the cut slope on the walls of the flight of ship locks at the dam site itself. This is an image of the dam from the downstream:<\/p>\n

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This is the central part of the dam, which provides the spillways.\u00a0 As the flow is low in the spring the spillways are not being used.\u00a0 The dam is a strange structure – not aesthetically pleasing in any way, as many dams are.\u00a0 Indeed, I found it to be surprisingly brutal although, as in the image above, the geometrical shapes in the spillway do create some very strange optical illusions (the image is not altered at all).<\/p>\n

From the true left bank of the upstream side the dam looks like this:<\/p>\n

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The scheme is truly epic in scale and ambition.\u00a0 The model below shows the layout:<\/p>\n

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This is the view from downstream (the cleaner is not a part of the actual scheme, in case you were wondering…).\u00a0 In the view the main dam is on the left side.\u00a0 It consists of three sections – a central section comprising the spillways and on either side sections that contain banks of electricity generators.\u00a0 On the right side of the main dam is a narrow channel leading to the ship lift, which is currently under construction.\u00a0 On the right side of the model is the two flights of five ship locks, cut through the hillside.\u00a0 This channel had to be sliced through the granite, which required the construction of an extremely high cut slope wall.\u00a0 This is the ship lock system as from the viewpoint between the locks and the dam.\u00a0 Note the superstructures of the ships just visible in the upper lock on the left side (this is the downstream direction for the ships).\u00a0 Note that you can only see two out of each of the two flights of five locks:<\/p>\n

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One of the great challenges of building this lock system was the creation of the box-cut that contains it.\u00a0 The total excavation depth is 170 metres, consisting of a lower 68 metre vertical section for the locks themselves (with of course a central island between them that is 57 m wide (note the crane in the above image for scale), and a 102 m benched slope above.\u00a0 The standards required here were very high – the river is an essential communication and freight route to Central China, so the loss of the locks is intolerable.\u00a0 Furthermore, the locks themselves are of course holding back the reservoir, so deformation of for example the lock walls that support the gates must be minimal.<\/p>\n

The walls are strengthened with about 2000 pre-stressed cables up to 60 m long and over 100,000 rockbolts before the slope face was sealed with concrete.\u00a0 The slope is drained with a set of tunnels, from which there is a set of boreholes drilled to provide complete coverage through the rock mass.\u00a0 These slope stabilisation measures can be seen in the image below, which shows a drainage tunnel and the heads of the pre-stressed cables:<\/p>\n

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Also visible in this image is the monitoring system now deployed to ensure the stability of the site.\u00a0 This includes both geodetic measurements using standard field techniques and GPS monitoring, plus measurement of the groundwater conditions.\u00a0 It has been reported from the site that the deformation of the slopes is minimal (generally less than 30mm).<\/p>\n","protected":false},"excerpt":{"rendered":"

Yesterday I visited the site if the Three Gorge Dam. This post shows some images of the impressive cutslope above the ship locks<\/p>\n","protected":false},"author":22,"featured_media":4582,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[602],"tags":[16,616,71,469,615],"class_list":["post-4576","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-photo-gallery","tag-china","tag-cutslope","tag-dam","tag-featured","tag-three-gorges"],"_links":{"self":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/4576","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/users\/22"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/comments?post=4576"}],"version-history":[{"count":0,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/4576\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media\/4582"}],"wp:attachment":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media?parent=4576"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/categories?post=4576"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/tags?post=4576"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}