Queries 【A】:
The following figures show the excavation volume of Underground Station which were calculated
by JST approximately, except C1 09 VIDYUT BHAWAN STN and C2 06 MOIN-UL-HAQ STN
As you know the construction cost of underground station is related to volume of excavation in most
subway station projects.
For the Corridor 2, the excavation volume ranges from 95,000 m3 to 111,000 m3(Average is
10,000m3)
In this case that each underground station excavation volume of the Corridor 2 is nearly identical.
However, each underground station excavation volume of the Corridor 1 is quite different.
For example, the excavation volume of Patna Junction STN is almost 2.2 times from average
volume of the Corridor 2 underground station, also the excavation volume of PATNA ZOO STN is
almost 1.3 times and VIKAS BHAWAN STN is 1.2 times.
This means that it is very difficult to use station numbers solely to estimate the cost of the
underground station.
JST proposes that the number of equivalent stations depends on the volume of excavation to be
considered when estimating the costs of the Corridor1 underground stations.
Excavation Volume of
Underground Station of Corridor 1:(Unit m3)
250 000
200 000
150 000
100 000
50 000
Station Body Excavation
Entrance Excavation
C1 10 Patna
C1 09 VIDYUT
BHAWAN
C1 08 VIKAS
BHAWAN
C1 07 Zoo
C1 06 Raja Bazar
C1 05 Rukanpura
0
Excavation Volume of
Underground Station of Corridor 2:(Unit m3)
250 000
200 000
150 000
100 000
50 000
Station Body Excavation
Entrance Excavation
C2 07RAJENDRA
C2 06 MOIN UL HAQ
C2 05 UNIVERSITY
C2 04 PMCH
C2 03 GANDHI
MANDAN
C2 02AKASHUVANI
0
Queries 【B】:
Earthquake resistant countermeasure method
Do you consider earthquake resistant countermeasure for civil structure?
・For bridge;
Could you provide earthquake resistant countermeasure for bridge? such as;
(1) Seismic isolation rubber support with stopper
By superimposing rubber and steel plates in a sandwich-like shape, it has the effect of following
the movement of the girder and reducing the seismic force.
However, earthquake displacement of this system is large than allowable rail track displacement
then it is necessary stopper system.
(2) Girder Connection
A bridge collapse prevention device, it connects the two consecutive girders with the cable
chain and prevents the girder from falling.
(3) Installation of displacement restricting structure:
When the support is damaged, the girder falls onto the beam and prevents a difference in level
from being formed on the road. Increase the area of the beam top surface to prevent the girders
from falling.
(4) Securing the girder length:
Preventing the girder from falling by rigidly connecting the girders,
It connects two girders with the cable chain and prevents the girder from falling.
(5) Displacement restriction device:
When the bearing is damaged, the girder falls onto the beam and prevents it from moving and
making a step on the road.
・For pier;
Could you provide earthquake resistant countermeasure for pier?
・For retaining wall at Ramp section
Could you provide earthquake resistant countermeasure for retaining wall at Ramp section?
・For underground structure
Could you provide earthquake resistant countermeasure for TBM lining (RC-Segment), Cross
passage, U-Type retaining wall at Ramp section, Shaft, Box Culvert and Underground station?
・For embankment at New Depot
Could you provide earthquake resistant countermeasure for embankment at New Depot?
・Seismic design method of TBM lining
Could you provide seismic design method of TBM lining?
Queries【C】:
Countermeasure of rain water flooding under climate change
As you know, there are rainwater flooding accident for subway in the Word due to climate change,
one is “12 dead in Zhengzhou train and thousands evacuated in Henan on 21st July 2021”.
Following table shows outlines the flooding countermeasures used for entrances and exits of
subways in Japan and Thailand. Using these countermeasures for reference, it had planned
to adopt stairs and frame barriers (as used in Bangkok and Singapore) as flooding
countermeasures for Metro Manila Subway stations also. Similarly, for elevators, entrances
and exits, it is planned to adopt raising against inundation and putting in a slope for disabled
persons.
Table1. Inundation Countermeasures for Subways in Japan and Thailand
Countermeasure
Tokyo Metro
Bangkok MRT
At entrances and exits with a risk of inundation, stairs and
frame barriers (35 cm × 2 tiers ＝ 70 cm) have been
installed.
At entrances and exits of stations at low elevation east of
the Sumida River, water sealing doors have also been
installed.
Stairs and frame barriers (1 m) have been installed at
stations with a risk of inundation.
The same countermeasures are utilized in Singapore.
Example
Source: JICA Study Team
Patna Metro has considered the raised floor level for each entrance of underground station.
JST has queries that how to decide this raised height for each entrance of underground station?
JST proposes the flood barrier panels, the proposed design policy is to install the buoyancyoperated self-rising flood barrier panels as the secondary countermeasure.
Entrances, elevators and elevator sheds are required to have countermeasures against flooding
while maintaining both the convenience and the accessibility during normal operation hours.
In principle, it is proposed to adopt a combination of raised entrance floor levels and flood barrier
panels as are used in Japanese subways.
Example of a raised entrance floor level at the subway
entrance
(example of Japanese underground station)
Floor Barrier Panels / Water-stop boards (an example of
Japanese underground station)
Source: JICA Study Team
Figure 2.
Examples of flood countermeasures in Japan
In addition, although there are various types of flood barrier panels, those of aluminum panel
type are proposed because of the advantages that the panels can be produced and installed
up to a maximum panel height of 1.5 m, there shall be no restriction on the installation width,
stepwise installation with multiple layers of panels is possible, panels are light in weight and
all components can be handled and installed by station staff members without difficulty, and
it is less expensive.
Source: JICA Study Team (Quoted from catalog of manufacturer)
Figure 3.
Examples of flood panel
Source: JICA Study Team
Figure4.
Countermeasures for Flooding at Station Entrances
Queries【D】: Countermeasures method against flooding for Ventilation Towers and
Ramp area
Could you provide Countermeasures method against flooding for Ventilation Towers and
Ramp area?
Regarding the ventilation towers, it is proposed that the lower part of the walls up to
approximately 3m above the ground level have no opening, such as openings for installation
of ventilation louvers, in order to avoid any negative impacts of the ventilation wind to the
passers-by, and as a result thereof, no additional countermeasure against flooding is needed.