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Progress Report > Package IA - North Tunnel Section
Summary As of September 25, 2002, total length of Main Tunnel excavation has reached to the Sta. 3+291.3 or 1,638.3 meters (including Four (4) Laybys) from the Tunnel Portal. Thirty-two (32) niches (8 Emergency & Cal Niche and 24 Firefighting niches) were completely excavated inside the main tunnel. Concrete work of Foundation Beam and concrete lining works at the main tunnel were carried out. As of September 25, 2002, concrete lining construction has reached to 878.5 meters. As of September 25, 2002, total length of Evacuation Tunnel Excavation has reached to Sta. 3+239.6 or 1,586.6 meters from the Tunnel Potal. Four (4) Cross Passageways were completely excavated across the Evacuation and Main Tunnel. As of September 25, 2002, total length of Ventilation Adit Excavation has reached to Sta. 0+381.1 or 1,368.4 meters from the Tunnel Portal. Main Tunnel
In the month of
September, fracture zones with water flowing at around 100 liters/min
were encountered on crown part for almost two rounds, from station
3+583.5 to 3+590.3. Due to this, the Engineer gave instruction to
install pattern rock bolts and increase the shotcrete thickness to 10cm.
This geological condition of having joint plane on cutting face and
slickenside was observed since August. Geologically, the condition was
stable on Class B. A total length of 131.50m (station 3+186.3 ~ 3+317.8) was excavated in the Main Tunnel this month, giving a total length of 1,681.80m (Progress: 43.60%) from the tunnel portal.
Thirty (33) Niches – Eight (8) Emergency Call Niches and Twenty-Five (25) Firefighting Niches – in the Main Tunnel were already excavated. Excavation of niches continues according to the designed niche distribution plan.
TThe Layby Left No. 1, 2 and Layby Right No. 1 in the Main Tunnel, which has a total length of thirty-two (32) meters each, were completed as per original plan. The excavation of the Layby Right No. 2 on its original location was also completed, although the location of the Electrostatic Precipitator No.1, which was originally connected to Layby Right No. 2, will be transferred.
The pouring of
Class D concrete for the Foundation Beams of the Lining Concrete
continued this month. The placing of concrete continued from Station
2+583.5 to 2+784.5 on both sides with a total length of 201m on each
side. Installation of
Mole Drain Pipes, together with filter cement aggregate, on both sides
of the tunnel continued simultaneous with the foundation beams. Cutting of Rock
bolt heads and installation of geo-textile covers were continued on
areas with random/safety rock bolts. Installation of
EVA Waterproofing Membrane also continued following the covering of
random rock bolts. The completed laying/installation of membrane reached
to station 2+682.5, totaling a length of 1,018.5m. The Engineer
continued to require testing of the welded joint sheets using air
pressure test, as per procedure stated on method statement, before
continuation of the installation. Pouring of
Concrete Lining also continued as per design segment approved. The
Engineer carefully checked, during the joint survey with the contractor,
the setting of the form for both bulkhead sides and the thickness as per
design requirements. The Concrete
Lining for Standard Section of the Main Tunnel completed until the end
of this month totaled to 840 meters. The Lining Concrete were poured
using Shutter No. 1 from Segment No. 2 to No. 27 (Sta. 1+665 to Sta.
1+977), Segment No. 30 to No. 58 (Sta. 2+027.5 to Sta. 2+375.5) and from
Segment No. 61 to No. 75 (Sta.2+427.5 to Sta.2+607.5). Shutter No.2 was
first used on pouring concrete for Segment No. 28 and No. 29 (Sta.1+977
to 1+984.5 and Sta. 2+015.5 to 2+027.5), which connects the standard
section of the Main Tunnel to Layby Left No. 1. The completed Concrete
Lining includes fifteen (15) Fire Fighting Niches and three (3) Fire
Fighting with Emergency Call Niches. The Concrete
Lining of Layby Left No. 1 in Main Tunnel, totaling a length of 31m on
station 1+984.5 ~ 2+015.5m, including one (1) Fire Fighting with
Emergency Call Niche, was also completed. The Main Tunnel
Concrete Lining completed up to this month totaled to 890.5m (Progress:
23.09%). For the Pedestrian Cross Passage No.1, only the concrete lining for the block connected to the Main Tunnel, which has a length of 4.1m, was completed. Evacuation Tunnel For the Evacuation Tunnel, the rock encountered was in good condition. Generally, the classification of rock was steady on class B and some portion was classified as class A. The excavated tunnel length for the month of September 2002 was 119.50m (station 3+144.8 ~ 3+264.5), giving a total length of 1,621.30m (Progress: 42.04%) from the tunnel portal. This month the excavation of Evacuation Tunnel was shorter due to the excavation of Pedestrian Cross Passage No. 3. This time, the Contractor simultaneously excavated the Cross Passage and Evacuation Tunnel to avoid more delay and to increase the progress, unlike the previous excavation of Cross Passages wherein they totally stopped the excavation of the Evacuation Tunnel. The Temporary Transformer Niches No. 1~7 were completely excavated as per approved plan submitted by the Contractor. This month, the excavation of temporary niche No.8 was also completed. The Enlarged Pedestrian Cross Passageway Nos. 1
and 2 was completed. The Pedestrian Cross Passage No. 3 was also
completed this month, having the same good rock condition as the
Evacuation Tunnel. The Vehicular Cross Passage No.1 was completely excavated from Evacuation Tunnel and Main Tunnel side with a total length of 19.4m. Ventilation Adit Since the beginning of September 2002, fracture zones appeared with water seepage from station 0+471.3 up to station 0+454.3 (03~07 September 2002) and from 0+384.41 up to station 0+364.0 (25~28 September 2002). Therefore, the Engineer issued an instruction to change the supporting system from type I to type II. The Engineer also instructed the contractor to carry out one-hole exploratory drilling on the cutting face at station 0+467.60m to investigate the rock and water condition ahead. The results of exploratory drilling, which was done in the presence of the Consultant’s Geotechnical Engineer, were: from 0~2m - medium to hard (Class C1 ~ B), 2~4 soft (Class C1), 4~8 - medium hard and no water was encountered along the eight (8) meters length drilled hole. The type II supporting system was changed again to type I at end of this month. Generally, the rock encountered was classified as class C1 to B this month. The excavated length for the month of September
was 114.30m (station 0+474.8 ~ 0+360.5), totaling to 1,392.01m
(Progress: 79.43%) from the tunnel portal. Problems Encountered – Main, Evacuation and Ventilation Tunnel This month, the main cause of the delay in the progress of the tunnel excavation may still be attributable to the frequent breakdown of Heavy Equipment, which occurred on almost every shift. Ventilation Adit - Access Road Paving of the second layer of 5cm-thick Asphalt to complete the 10cm-thick from submerged area to the connection of the access road with the National Highway No. 1 was done on 1st and 4th of September 2002. Major Events and Issue Safety Patrol and Meeting:
Organization of Hazama - Cienco6 Labor Union:
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Progress To Date
