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Technical Committee 208 /
Comité technique 208
base of the box structure was also fixed to the ground by a
series of mini piles of 16m in length.
Figure 7 shows the rebuilt road section after completion of the
remedial works.
Figure 6. Box-type structure design for road section at Mileage 39Km.
Figure 7. Completion of box-type structure at Mileage 39Km.
2.3
2005 Typhoons Talim & Longwang
The new road section appeared to be in good shape for the next
1-1/2 years until mid of 2005 when the precipitation started to
reach another historic peak.
Figure 8. Failure of box-structure road section due to Typhoon Talim.
In late August of 2005, a severe Typhoon Talim slammed
Taiwan. By considering a series of heavy rainfalls in the
previous two months, the accumulated precipitation of the year
at the site had exceeded 4000mm. As a result, the box-type
structure finally gave up and the entire road section of about
100m in length fell into the valley (Figure 8).
Ground Anchor
Ground Anchor
Mini‐Pile
Unit: cm
Post-failure investigation had revealed that the loss of entire
road section was due to the downslope movement of the uphill
slope mass which pushed the box-type structure, tore down the
ground anchor tendons, and sheared off the mini piles.
Emergency action was implemented right after the failure by
constructing a temporary road to the uphill side and installing I-
beams for the downhill support (Figure 9) in order to maintain
the local traffic (DGH 2005).
Figure 9. Emergency repair of the road section due to Typhoon Talim.
In late September, 2005, the emergency measure failed again
one month after the attack of Typhoon Longwang. The tem-
porary road lost 5m of its road width. Site reconnaissance
showed significant tension cracks at the crest of uphill slope.
District V of DGH had to launch another remedial measure to
mitigate potential impacts on the road section in the future. The
plan had considered mostly the upslope protections that
included filling of tension cracks, rechanneling surface drainage,
installing subsurface horizontal drains, and surface vegetation,
etc. Figure 10 shows the completion of upslope remedial works
after Typhoon Longwang.
Figure 10. Completion of upslope remedial works at Mileage 39Km.
