Basically I have seen another parking lot getting swallowed by a sudden sinkhole and i was wondering how stuff like that even happens?
Is there no way to check if there is a hole under the surface even if it is several 100 meters deep?
In: Earth Science
The hole wasn’t there when they built the building. Something caused the hole, and it happened after the building was built. For example, you can get sinkholes around water pipes if the pipe springs a leak. The water washes the soil away from the pipe, causing a sinkhole.
If a hole is near the surface, you could do a test that is similar to sonar to find it, but this rarely happens because they cannot penetrate very far down.
Another option is to bring a geotechnical company out and drill a bunch of test Boeing’s to see what the Stone is like (which happens anyways with most major construction) but even these will miss things because the Boeing’s are spaced out by dozens of meters, leaving plenty of space for stuff to hide.
In generals sinkholes are only predicable by region. ie if you build in an area that has bedrock that is known to commonly get sinkholes (or just smaller holes in general which can wreck foundations even if the surface doesn’t cave in, the building can start to sink). You have a better chance of encounter a sinkhole.
These areas typically have bedrocks with stones like limestone, that can dissolve from rain/acidic rain over decades.
That’s the real problem with sink holes, even if you did do major testing a verified that there were no sinkholes or issues with the bedrock you’re building on. In 10-20 years there could be a sinkhole forming without anyone knowing, and 25-50 years, which is a common life span of a building/road/parking lot, you can have a sinkhole many feet across that is bout to collapse.
The bedrock can just slowly dissolve out from underneath you.
Edit: source, I work for a Foundation Engineering company that deals with sinkhole affected areas in the Northeast USA.
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