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Progress Report > Package IA - North Tunnel Section
Main Tunnel
In the month of May, the rock encountered in the Main Tunnel was classified as Class C1 to B until the end of the month. In the beginning of May 2002, a small fracture zone appeared from the right side of the tunnel face, which became bigger while moving gradually towards the left until disappearing around middle of this month. The face was also observed as damp to having water dripping. Right after the disappearance of this bad rock condition, fracture zones and some joints surfaced again from the left corner, which is almost parallel to tunnel axis and with small water inflow. On the right sidewall, some slicken side joint with dripping water that caused over break after blasting was also encountered. The fracture zone on left side face of tunnel that was moving towards the right of the tunnel face continued until the end this month. The major strike and dip of fracture zone are N30-80o and 65-80o. The dip direction is to the North. So, based on the rock condition, the rocks were classified as class C1 to B. Because of the rock condition encountered, the Resident Chief and Tunnel Engineer gave instruction to install random pattern/safety rock bolts and to increase the shotcrete thickness from 50 mm to 100 mm. A total length of 159.40m (station 2+603.9 ~ 2+763.3) was excavated in the Main Tunnel this month, giving a total length of 1110.3m (Progress: 28.78%) from the tunnel portal.
Twenty-one (21) Niches - Five (5) Emergency Call Niches and Sixteen (16) Firefighting Niches - in the Main Tunnel were already excavated. Excavation of niches continued according to the design niche distribution plan.
The Layby-Left No.1 and Layby-Right No.1 had been completed since last month.
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+015 to 2+183.5 on both sides with a total length of 168.5m each side. The foundation beams on both sides of the Pedestrian Cross Passage No.1 were completed last month. Installation of Mole Drain Pipes, 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 for type IV to type II, up to Sta. 2+055m, were completed for this month and has been continuing for the pattern and random/safety rock bolts. Installation of EVA Waterproofing Membrane also continued for this month although the progress was slow based on the advance excavation round completed. The Chief Residence Engineer strongly pushes the contractor to avoid delays on the following lining concrete. The completed laying/installation of membrane covered up to station 2+117, totaling a length of 453m. The Engineer continued to require testing of the welded joint sheets using air pressure test, as per procedure stated on method statement, prior to continuation of the installation. Pouring of Lining Concrete 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 Works for the Standard Section of the Main Tunnel started with the first block (L/C No. 2) located from Sta. 1+665 to Sta. 1+677. Twenty-eight blocks (L/C No.28) from station 1+665 ~ 1+977m and station 2+027.5 ~ 2+051.5, totaling to 336 meters, including five (5) Fire Fighting Niche, two (2) Emergency call, and two (2) Notch box out with vertical groove for electric cable for Jet Fan were already completed. The Concrete Lining of Layby Left No.1 in Main Tunnel has also been started and the first segment, one (1) block of 12m length, at station 1+984.5 ~ 1+996.5m was completed. The form setting for the second segment of the Layby and the connecting first block (segment no. 3) of the Pedestrian Cross Passage No.1 has been going-on. The concrete pouring of the second segment and the connecting first block will be done at the same time. The Main Tunnel Lining Concrete completed up to this month totaled to 348m (Progress: 9%). Evacuation Tunnel In the Evacuation Tunnel, the condition of the rock encountered was generally good, although at some times we had experienced water flowing on the excavation face. Geologically, the rock condition was stable on class B. On some portions, it was almost classified as class A this month. The excavated tunnel length for the month of May 2002 was 133.3m (station 2+607.0 ~ 2+740.3), giving a total length of 1087.3m (Progress: 28.19%) from the tunnel portal. The Temporary Transformer Niches No.1~5 were completely excavated as per approved plan submitted by the contractor. The Enlarged Pedestrian Cross Passageway Nos. 1 and 2 has been completed since last month. The ventilation
system made for Evacuation Tunnel through Pedestrian Cross Passage
No. 2 has a good result and improved the ventilation. Wasted air coming
from the Main tunnel was still eliminated out through Pedestrian Cross
Passage No. 2 and then through the Evacuation Tunnel Ventilation Adit For Ventilation Adit Tunnel this month of May, the condition of the rock encountered was generally good compared with last month. From the month of April until 8th of May 2002, bad rock condition continued to be experienced. Some fracture and crashed zone with soft filling and water flowing from excavation face of tunnel were observed. Therefore, the support type III to type II remained until the 8th of this month. Starting from the 9th of this month, the rock condition suddenly changed and became good even though some cutting face have water flowing from drilling hole and the water hardship were continuing from behind the face and from the cutting face. Nevertheless, the Engineer issued an instruction to change the supporting system to type I until the end of this month. Last 29th of this month, after blasting on Station 0+825 to 0+820.5, the Contractor encountered some cave-in at the crown part with soft filling and water flowing. This cave-in had caused overbreak and the Engineer, together with PMU 85 Vice Project Manager, attended the joint site inspection. Geologically, on the average, the rock condition is classified as B. Some cutting face with water inflow from the drilling hole continued until the end of this month. The excavated
length for the month of May is 133.8m (station 0+942.8 ~ 0+809.0),
totaling to 940.51m (Progress: 53.66%) from the tunnel portal. Ventilation Adit - Outside Works The spreading of aggregate base coarse and spraying of primary bitumen coat for the asphalt pavement of the access road to Ventilation was completed on 15th of May 2002. The contractor's schedule for asphalt pavement placing will be in two (2) months. Activities for Coming Month
Main Tunnel excavation will be continued and expected total tunnel length excavation until end of June 2002 is 1,270 meters from the tunnel portal. Evacuation Tunnel excavation will be continued and expected total tunnel length excavation until end of June 2002 is 1,170 meters from the tunnel portal. Excavation of Cross Passage No. 3 is scheduled on the last of June 2002. Construction
of Concrete Lining Works at the Main Tunnel will be continued
and expected constructed length until end of June 2002 is 528
meters. Construction of Concrete Lining at Cross Passage No. 1
is also scheduled during the month of June 2002. Mole Drain construction for Drainage Works inside the Main Tunnel will be continued and expected length of installation will be 1,266 meters until end of June 2002. Construction of Foundation Beam for Concrete Lining Works at the Main Tunnel will be continued and expected constructed length until end June 2002 is 1,316 meters. Installation of Waterproof Membrane will be continued throughout the month of June 2002 and expected length of installation is 600 meters. Ventilation Adit Tunnel excavation will be continued and expected total tunnel length excavation until end of June 2002 is 1,080 meters from the tunnel portal. Access
Road Works at the Ventilation Adit will continued.
Continuous operation of the Waste Water Treatment Plant. Operation & Maintenance of Primary Water Control System. Operation of Primary Control System in Main, Evacuation and Ventilation Adit Tunnels will be continued. Dewatering inside the three tunnels will be continued. Installation and Operation of Ventilation Systems and Lighting System in Main, Evacuation and Ventilation Adit Tunnels will be continued. Maintenance and Operation of all equipments will be continued. Maintenance of Contractor's office & camps will be continued This homepage is presented by the Consultant Team Any further question should be forwarded to Webmaster or Consultant Team |
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Progress To Date
