full Annual Report 2003(5.9

Image of “Total Construction
System of Shield Tunnels for
Traffic Infrastructure”
Image showing how Shiodome
Media Tower’s hybrid airconditioning
system works
Air flow
Fire prevention system for underground
space — fire compartment
using water screen system
Total Construction System of Shield Tunnels for Traffic Infrastructure
Growth in urban renewal and the passage of special legislation on public use of space deep underground
have seen the increasing use of underground space for infrastructure, and plans that
include the use of space deep underground for arterial roads in cities have made the cut and cover
method difficult. It is in this context that Kajima has developed new technology that has made it
possible to construct special sections of road tunnels (emergency parking bays, ramp tunnels) deep
underground, and by integrating this with previously developed large-diameter shield tunnel technology,
has developed a “Total Construction System of Shield Tunnels for Traffic Infrastructure.”
This new technology comprises three methods: the “shield tunneling method of partly widening
cross-sectional area,” the “shield tunneling method of reducing cross-sectional area” and the
“shield tunneling method of applying recoverable and reusable machines.”
Large-Scale Hybrid Air-Conditioning System with Natural Ventilation for Offices
The heightened level of interest in environmentally-friendly buildings has resulted in stronger demand
for natural ventilation. As well as developing specific design tools for the cost-efficient design of buildings
using natural ventilation, Kajima has compiled a list of items for examination at the planning
stage, including airflow simulation, assessment of the thermal environment, and a ventilation control
strategy, which have led to the realization of large-scale hybrid air-conditioning systems with natural
ventilation for offices. In the case of some buildings, we have commissioned natural ventilation
systems and double-skin facades, and have confirmed their favorable performance.
Fire Prevention System for Underground Space — Water Screen System
As illustrated by the public use of space deep underground, the role of underground space in urban
renewal is being re-evaluated. In doing so, however, fire safety requires serious attention.
Experiments using scaled models have been repeated numerous times for railroad and vehicle tunnels,
underground streets, and underground parking lots, resulting in the development of highly
accurate simulation technology for simulating fire behavior in such spaces. Furthermore, knowledge
gained through these activities has been used to develop and construct a fire prevention system in
which compartments use water screens, a completely new concept. As well as localizing the size of
the area affected by a fire and providing a safe evacuation environment, the system also inhibits
rapid combustion, thus minimizing structural damage.
Development of a Quantitative Assessment System for the Environmental Functions of
Greenspaces — “m-EASE (microscale Environmental Assessment System on Ecology)”
Kajima has developed a quantitative assessment system for the environmental functions of greenspaces
called “m-EASE,” a green CAD system through which a quantitative assessment of the following
six environmental functions of greenspaces can be made: fixation of atmospheric CO2;
atmospheric purification; mitigation of heat island effects; preservation of biological diversities;
improvement of scenery; and fire prevention. Use of this system has made it possible to promptly
and effortlessly formulate proposals for optimum greenspace plans corresponding to customers’
needs at the planning and design stages. The system also enables constructive “quantitative
assessment of the environmental functions that greenspaces already possess” and “prediction of
future changes of the functions of greenspaces.”
Environmental Jet Method
The environmental jet method is a ground contamination cleaning technique that is able to partially
clean contaminated ground (soil and ground water) using intersecting jet flows of water. This
method has the following advantages: (1) it is possible to partially clean at only the depths required;
(2) it can be applied to various kinds of contaminated substances; (3) it can even be applied to contaminated
layers difficult to penetrate with water (clay, etc); and (4) it can be applied in small places
and even inside buildings.
Kajima offers the following three options, depending on the contamination circumstances and
budget for the cleaning work.
1) The Jet Replace method for substituting contaminated soil with non-harmful materials.
2) The Jet Blend method for cleaning ground water by mixing cleaning materials in contaminated
water layers.
3) The Jet Rinse method for cleaning contaminated soil.
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