Upward shield tunneling from deep underground stormwater storage pipes in the central areas
The Waterworks & Sewerage Bureau of the city of Nagoya is proceeding with flood control projects throughout the city, in consideration of damages the city suffered from the unprecedented volume of rainfall in September 2000.
To proceed with these flood control projects smoothly, it was necessary to minimize the influence of the construction on underground facilities such as railroads and lifelines, terrestrial traffic systems, and normal activities of citizens, especially in the central area of the city.
To construct the chambers that lead stormwater to the stormwater storage pipe located 30m below the surface in the central area of the city, we used the upward shield tunneling method (Figure. 1), which tunneled the chambers upward from the underground facilities to the surface. This method enabled us to perform the construction with minimal influence
on the surrounding environment.
This paper describes the outline of the construction.
Nagoya City, located near the center of Japan, is the nation’s fourth most populated city with 2.2 million residents.
In September 2000, Nagoya experienced an unprecedented volume of rainfall, with a maximum hourly rainfall of 97.0mm and total rainfall of 566.5 mm, eventually floodingabout 40% of the city’s total area. For this reason flood control projects are currently underway across the city. However, one problem with flood control projects in Nagoya is that few rivers in the city are large enough to safely discharge stormwater exceeding 50 mm/h. Large stormwater
storage pipes are therefore essential to prevent floods in the city.