We are driving 8 meter (26 foot) concrete pilings into the ground to support our new child home. It would be a bit cheaper if we could just dig down a ways and pour some footings, as has often been done in the past in this area. I had been wondering about the necessity of this until I went out and watched them drive some of the pilings. I include a U Tube movie of the driving of one of these pilings. It is pretty typical. I don’t yet know how to edit these things so it is nearly ten minutes long, the time it takes to drive this piling.
Basically, they drive the piling until it goes all the way in, or until it won’t go any further. Either way works fine. We are building one house now, but driving pilings for the two next door houses as well. This avoids having to later drive pilings right next to a completed house, which could cause it to crack.
What you see in this movie is how easily the piling goes in for the first few meters. It really sinks in fast until it hits deeper more dense soil. Apparently that is due to the nature of the soil in the old rice fields, and also that we have placed 1.3 meters of fill on top of that. That is why, where we have built the road, we first dug out a half meter of dirt before filling that half meter plus the other 1.3 with a different kind of dirt we haul in. Every 20 cm layer of road fill was compacted, so the road areas are different.
In the above picture you see Ho, one of our fathers, walking toward the pilings for the first three houses.
By the way, the area around here is very flat, no hills. If you want dirt for fill, you must dig a hole, which becomes a lake. Fortunately, the government wants a reservoir ten kilometers north of here. We are digging it out for them, and get the dirt for free. It’s a good deal for both of us.