Japanese Land Ministry has been undertaking experiments to identify low-cost construction methods of burying utility lines underground in order to improve urban landscape and disaster-resilience of Japanese cities that have more electric poles on streets than overseas major cities do. The ministry is seeking methods burying electric wires directly underground and in small culverts, which is considered to cost less than the conventional method using common utility ducts laid down deeper.

The existing standards of the Ministry of Economy allow wires buried 1.2meter or deeper. Construction cost reduction accompanying with easing of the restrictions is expected to speed up the process of undergrounding electric poles.

The civil engineering cost to develop conventional shared tunnel is estimated at 35 billion yen per a kilometer, the Land Ministry says. Burying lines 60cm deep from the ground, which is common in such cities as London and Paris, costs only 8 billion yen. (2014/12/4)