<p><a href="https://www.wired.com/2016/11/fukuoka-japan-sinkhole/" rel="nofollow noreferrer">How Japan Filled That Ginormous Sinkhole In Just One Week</a>:<br />
The Fukuoka sinkhole measuring 8,700 square feet (808 square meter), 65 foot (20 m) deep: <em>they poured a mixture of soil, water, and cement into the hole—they use more than 7,100 cubic meters of the stuff in all</em>. <a href="https://www.youtube.com/watch?v=sKtUtesU_KY" rel="nofollow noreferrer">YouTube timelapse</a>.</p>

<p><a href="http://www.slate.com/articles/news_and_politics/explainer/2010/06/how_to_fix_a_giant_sinkhole.html" rel="nofollow noreferrer">How To Fix a Giant Sinkhole</a> about the two in Guatemala:<br /> The first from 2007 one they filled with a soil cement made from cement, limestone, and water known locally as lodocreto ("mudcrete").</p>

<blockquote>
  <p>It's not clear whether cement is the best option, however. A 6,500-cubic-foot wad of concrete may serve to concentrate water runoff in other areas, leading to more sinkholes. Many engineers prefer the graded-filter technique, in which the hole is filled with a layer of boulders, then a layer of smaller rocks, and, finally, a layer of gravel. This fills the hole, more or less, while permitting water to drain through the area.</p>
</blockquote>

<p>Whether this was actually done with the 2010 one I could not find (yet). Even the <a href="https://en.wikipedia.org/wiki/2010_Guatemala_City_sinkhole#Filling_in_the_sinkhole" rel="nofollow noreferrer">Wikipedia entry on the 2010 sinkhole</a> (which you are also refering to) says <em>This section needs to be updated</em>.</p>

<p>It seems to be closed now, look at <a href="https://youtu.be/hvam_sEuaSU?t=1m41s" rel="nofollow noreferrer">this video fragment</a> compared with the <a href="http://enriquemontalar.com/glosarios-y-sinkholes-en-guatemala/" rel="nofollow noreferrer">bottom picture here</a>.</p>

<p>Note that 7000-8000 m<sup>3</sup> sounds like a lot, but that is only 400-500 truck loads.</p>

<hr>

<p>BTW (I know, that is not answering the question, but it was too nice to not add):<br />Instead of filling them up you can also <a href="http://www.amusingplanet.com/2017/10/a-garden-in-sinkhole.html" rel="nofollow noreferrer">make a garden in them</a>:</p>

<p><a href="https://i.sstatic.net/0J3cH.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/0J3cH.jpg" alt="enter image description here"></a><br />
<sup>Photo credit: <a href="https://www.flickr.com/photos/knitspirit/6962178785/" rel="nofollow noreferrer">KnitSpirit/Flickr</a></sup></p>

CC BY-SA 3.0
2017-09-27T19:09:44.187Z
Thank you Jan, it indeed seems that the **graded-filter technique** would provide a better water drainage, avoiding further collapses. I found that even in a simple [post placement for supporting a tree-house](https://youtu.be/vmnhQTn0Ntk?t=1m53s) gravel is similarly used. I guess the water will flow around a plug-like cement mixture, potentially causing collapses in the surrounding areas.
Armfoot
CC BY-SA 3.0
2017-10-12T04:01:34.350Z
@Armfoot water drainage isn't a stability issue at the scale of a post, aside from maybe protecting the wood from rotting. The gravel provides a little drainage at the very bottom of the post, but is mostly a shortcut for compacting and leveling the bottom of the hole; if you watch that video for just [30 more seconds](https://youtu.be/vmnhQTn0Ntk?t=143), it shows them pull out a bag of cement and fill the rest of the hole with it, encasing the post in concrete.
brichins
CC BY-SA 3.0
2017-10-12T09:39:31.610Z
@brichins thanks for the explanation! It makes sense to use cement/concrete to stabilize the post, it fills up the empty spaces between the gravel too! In the sinkhole case it may not be the best alternative though.
Armfoot
CC BY-SA 3.0
2017-09-26T15:03:57.060Z
2017-10-04T19:56:03.353Z
2017-10-04T19:56:03.353Z
Jan Doggen
<p>There are a few impressive photographs of giant sinkholes that appeared in cities, such as this one:</p>

<p><a href="https://i.sstatic.net/QGRkK.jpg" rel="noreferrer"><img src="https://i.sstatic.net/QGRkK.jpg" alt="Guatemalan sinkhole"></a></p>

<p>However, followup information (e.g. <a href="https://en.wikipedia.org/wiki/2010_Guatemala_City_sinkhole#Filling_in_the_sinkhole" rel="noreferrer">Guatemalan sinkhole</a>) or photographs on how these kind of sinkholes are filled up is hard to find. What approaches may be taken to "repair" or filling up these?</p>

<p>If dumping more earth or materials into them is ineffective due to underground-water, how can they be covered up properly without causing another collapse?</p>

CC BY-SA 3.0
2017-09-26T17:28:37.757Z
The earth has a lot of dirt (citation needed) ;)
bendl
CC BY-SA 3.0
2017-09-26T21:28:52.433Z
When I saw that picture, I thought "that must be photoshopped", but it appears real. Articles [here](https://www.csmonitor.com/World/Americas/2010/0601/Guatemala-City-sinkhole-so-big-so-round-it-doesn-t-seem-real) and [here](http://news.nationalgeographic.com/news/2010/06/100603-science-guatemala-sinkhole-2010-humans-caused/). The second article in particular has some more detailed information/speculation about its formation.
marcelm
<rocks><geomorphology><underground-water>
How are giant sinkholes filled up?
Armfoot
# How are giant sinkholes filled up?

(Asked by: username_0 on 2017-09-26)

There are a few impressive photographs of giant sinkholes that appeared in cities, such as this one:

[![Guatemalan sinkhole](https://i.sstatic.net/QGRkK.jpg)](https://i.sstatic.net/QGRkK.jpg)

However, followup information (e.g. [Guatemalan sinkhole](https://en.wikipedia.org/wiki/2010_Guatemala_City_sinkhole#Filling_in_the_sinkhole)) or photographs on how these kind of sinkholes are filled up is hard to find. What approaches may be taken to "repair" or filling up these?

If dumping more earth or materials into them is ineffective due to underground-water, how can they be covered up properly without causing another collapse?

**Tags:** rocks, geomorphology, underground-water

> **Comments:**
> **username_1**: The earth has a lot of dirt (citation needed) ;)  
> **username_2**: When I saw that picture, I thought "that must be photoshopped", but it appears real. Articles [here](https://www.csmonitor.com/World/Americas/2010/0601/Guatemala-City-sinkhole-so-big-so-round-it-doesn-t-seem-real) and [here](http://news.nationalgeographic.com/news/2010/06/100603-science-guatemala-sinkhole-2010-humans-caused/). The second article in particular has some more detailed information/speculation about its formation.  

---

## 1 answers

### Answer by username_3 on 2017-09-26. Score: 14 | Accepted answer

[How Japan Filled That Ginormous Sinkhole In Just One Week](https://www.wired.com/2016/11/fukuoka-japan-sinkhole/):  
The Fukuoka sinkhole measuring 8,700 square feet (808 square meter), 65 foot (20 m) deep: *they poured a mixture of soil, water, and cement into the hole—they use more than 7,100 cubic meters of the stuff in all*. [YouTube timelapse](https://www.youtube.com/watch?v=sKtUtesU_KY).

[How To Fix a Giant Sinkhole](http://www.slate.com/articles/news_and_politics/explainer/2010/06/how_to_fix_a_giant_sinkhole.html) about the two in Guatemala:  
 The first from 2007 one they filled with a soil cement made from cement, limestone, and water known locally as lodocreto ("mudcrete").

> It's not clear whether cement is the best option, however. A 6,500-cubic-foot wad of concrete may serve to concentrate water runoff in other areas, leading to more sinkholes. Many engineers prefer the graded-filter technique, in which the hole is filled with a layer of boulders, then a layer of smaller rocks, and, finally, a layer of gravel. This fills the hole, more or less, while permitting water to drain through the area.

Whether this was actually done with the 2010 one I could not find (yet). Even the [Wikipedia entry on the 2010 sinkhole](https://en.wikipedia.org/wiki/2010_Guatemala_City_sinkhole#Filling_in_the_sinkhole) (which you are also refering to) says *This section needs to be updated*.

It seems to be closed now, look at [this video fragment](https://youtu.be/hvam_sEuaSU?t=1m41s) compared with the [bottom picture here](http://enriquemontalar.com/glosarios-y-sinkholes-en-guatemala/).

Note that 7000-8000 m3 sounds like a lot, but that is only 400-500 truck loads.

---

BTW (I know, that is not answering the question, but it was too nice to not add):  
Instead of filling them up you can also [make a garden in them](http://www.amusingplanet.com/2017/10/a-garden-in-sinkhole.html):

[![enter image description here](https://i.sstatic.net/0J3cH.jpg)](https://i.sstatic.net/0J3cH.jpg)  
Photo credit: [KnitSpirit/Flickr](https://www.flickr.com/photos/knitspirit/6962178785/)

> **Comments:**
> **username_0**: Thank you Jan, it indeed seems that the **graded-filter technique** would provide a better water drainage, avoiding further collapses. I found that even in a simple [post placement for supporting a tree-house](https://youtu.be/vmnhQTn0Ntk?t=1m53s) gravel is similarly used. I guess the water will flow around a plug-like cement mixture, potentially causing collapses in the surrounding areas.  
> **username_4**: @username_0 water drainage isn't a stability issue at the scale of a post, aside from maybe protecting the wood from rotting. The gravel provides a little drainage at the very bottom of the post, but is mostly a shortcut for compacting and leveling the bottom of the hole; if you watch that video for just [30 more seconds](https://youtu.be/vmnhQTn0Ntk?t=143), it shows them pull out a bag of cement and fill the rest of the hole with it, encasing the post in concrete.  
> **username_0**: @username_4 thanks for the explanation! It makes sense to use cement/concrete to stabilize the post, it fills up the empty spaces between the gravel too! In the sinkhole case it may not be the best alternative though.  

---

