The phantom "Under River"

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The phantom "Under River"


What is

A Phantom River That Surfaces
deep Below the Ground of the city

Torrential rain that rises every year.
Rainwater with nowhere to hide in a concrete jungle.
The rainwater flows into a huge underground tunnel deep beneath the city.

Suddenly, we witness the phantom "Under River".

Underground shopping malls, underground railways, underground roads...
The underground in the urban has developed in the same complex way as the city itself.

The reclamation of the underground is due to the engineers of Daiho Corporation Co., Ltd.

10 meters a day.
A huge shield tunneling machine bores into the complicated underground of Tokyo, to further excavate its underground tunnel.

The phantom "Under River" that deep spans under the city.
It is the secret that protects the city.


The "Under River" That Protects People's Lives
from the Incessant
Urban Floods

Metropolitan cities created with well-developed transportation networks and populated with millions of people are suspect to some particular disasters. One such concern in recent years specific to urban infrastructure is "Urban Flood Damage".

If there is heavy localized rain, the rainwater immediately flows into sewers and small- to mid-sized rivers. If the wastewater treatment fails to trap it, the rainwater then overflows from the sewers and the rivers. In a city coverd with asphalt and concrete, the rainwater has no choice but to overflow the surface of the ground, impairing urban functions and flooding underground spaces. This is what has been termed "Urban Flood Damage".

The impact of recurring torrential rains in recent years has been causing sewage treatment in urban areas to often exceed their capacity.

Aside from the local torrential rains that continue to rise each year, underground spaces such as the malls and subways continue to expand and populations continue to concentrate, making damage control of the urban floods all the more urgent. There is an increased need for underground water retention facilities to buttress their support for the urban population.

"Under River" supports people's lives.


Precipitation in Tokyo today


Data based on JMA 'Precipitation in Tokyo over the past 24 hours in Japan (AMeDAS)'.
( https://www.jma.go.jp/bosai/amedas/)

Average number of occurances from the past five years of at least 50mm of precipitation per hour
Numbers based on nationwide AMeEDAS readings collected at 1,300 locations.

Processed based on the Japan Meteorological Agency "Annual national (AMEDAS [Automated Meteorological Data Acquisition System]) number
of occurrences per hour of precipitation exceeding 50 mm"( https://www.data.jma.go.jp/cpdinfo/extreme/extreme_p.html )


Daiho Corporation's Technology for Excavating
Complex Underground Circumstances.

An underground water retention facility where "Under River" flows.
The facility is made by the 'pneumatic caisson method' and 'shield tunneling method', both of which are leading methods of Daiho Corporation.

The Pneumatic Caisson Method is one that enables the construction of caisson underground structures, which are widely used for pumping stations, bridge foundations, shielding shafts, and underground structures.

The shield tunneling method uses the tubular 'shield tunneling machine' to drill underground, while suppressing the soil to prevent collapse . It involves carving the soil with a bladed tip while slowly digging to form the outer wall of the underground tunnel.

In order to deal with the complex water and sewage systems, subways, road tunnels and other urban underground spaces, a variety of technologies have been developed, including our independently developed 'mud pressure shield method' and 'mud pressure propulsion method'.

At Daiho Corporation, we are creating underground spaces that consider the environment and its safety by combining construction methods using precise calculations.

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The phantom "Under River"

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