Concrete Wabi Sabi Mountainsides

Concrete Wabi Sabi: Mountainsides

Any look at the aesthetics, or economics, of concrete in Japan would have to look at concreted mountainsides.

There is no doubting that Japanese mountainsides are, by and large, steep. That comes partially from Japan's "newness" geologically speaking, and that steepness causes problems that can be remedies by concrete.

But whether the truly staggering amounts of concreted mountainsides in Japan are truly necessary.... thats another thing.

Like many of the roads, bridges, tunnels, and tetrapods, their function is more to provide profits for concrete and construction companies. And jobs of course.

How Japanese tunnels are built

Our new tunnel will shorten our drive down the river to Gotsu by a little more than 200 meters. Being straight the tunnel will also be more fuel efficient to drive. A rough calculation says that with present traffic density the fuel savings will have paid for the tunnel in only a few million years. Incidentally, that is my village to the left of the tunnel.

This is the machine that actually drills its way through the mountain. I was expecting to see a huge machine almost as big as the tunnel.... watched too many movies I guess! These smaller drill splay out at any angle.

The next stage is to put up steel arches and then a series of steel beams are driven into the mountain radiating out from the tunnel. Then the tunnel is coated in a thin layer of concrete.

The purpose of the steel beams is to stop the tunnel collapsing under the weight of the mountain, represented here in this demonstration by steel nuts.

Next a thick, waterproof, plastic membrane covers the inside of the tunnel followed by a frame of reinforcing rebar,

The final stage involves this huge machine on rails which is a movable form. Its used to pour the final inner walls of the tunnel.

Japanese Tunnels

There are a lot of tunnels in Japan. Not surprising really considering how mountainous it is. The Japanese have become the worlds experts on tunnel construction and have built the longest transport tunnel in the world, the 54k train tunnel connecting Honshu with Hokkaido.

In the 1930's there was a plan to connect Tokyo with the rest of the empire with a high-speed train line that would pass under the sea from Japan to Korea. Incidentally, this is the origin of the Bullet Train.

The little train tunnel above is on our local train line and was dug by hand.

This pedestrian tunnel with hi-tech light show connects Tenmangu Shrine with the National Museum in Dazaifu, Fukuoka.

This somewhat older hand-dug tunnel connects the village of Kimach in Izumo with the sandstone quarry on the other side of the hill.

This long straight pedestrian tunnel goes under the sea and connects Kyushu with Honshu.

What japan also has is thousands and thousands of kilometres of road tunnels. Many of these continue to be built on little used roads and simply "straighten" existing roads that follow rivers.

Which brings me to the subject of tomorrows post.....