The Ingenieur Vol 57 January-March 2014 The Ingenieur Vol 57 January-March 2014 | 页面 13

Figure 1 – Pahang-Selangor Raw Water Transfer Project

Method) and one section with a length of 0.9km
excavated by the Cut and Cover method.
This tunnel route passes under the Titiwangsa
Main Range located in middle of Malaysia Peninsula
(Figure 2). The maximum overburden of the tunnel
is 1,246m at the state border between Selangor
State and Pahang State. The overburden is more
than 1,000m at TBM-1 and 1565m at TBM-2.
As of November, 2013, all the excavation
works had been completed except for TBM1 and
TBM 2 which is about 1.8km, The final breakthrough
is targeted for the end of February 2014. Figure
3 shows the cross section and the progress of
works of the raw water transfer tunnel. Table 1, in
Appendix 1 shows the features of the raw water
transfer tunnel and related works.
Several types of supports were also used
with respect to the rock types (Table 3 and Table 4
in Appendix 2)
Geological Conditions
Figure 4 shows the geological conditions and
fault zones along the tunnel route. Almost 90%
of the rock formations are granite and the rest
are meta-sedimentary rock. The average uni-axial
compressive strength of the granite varies from
150-200 MPa. It is expected that more than 85% of

the tunnel alignment
consists
of
hard
granite
in
good
condition
(Rock
Classification
A&B
according) based on
the Japan Highway
Public
Corporation
(JHPC) as shown in
Table 2 of Appendix 1.
Figure 2 – Location of
Raw Water Tunnel

Challenges in Tunnel
Construction
Deep tunnel construction involves high risks
and uncertainties due to minimum availability of
geological data and limited equipment capabilities
used in soils investigation. Through experience and
employing the best engineering practices one can
predict the problems which mi