Construction Supervision

Summary

As of August 31, 2003, 157.40m were excavated in the Main Tunnel this month, giving a total length of 3,077.30m (progress 79.78%) from the Tunnel Portal.

Sixty (60) niches (14 emergency & call niches and 46 Firefighting Niches) were completely excavated inside the Main Tunnel.

The Main Tunnel Concrete Lining completed up to the end of this month totaled to 2,365.40m (progress 63.33%)

As of August 31, 2003, 174.35m were excavated in the Evacuation Tunnel this month, giving the total length of Evacuation Tunnel excavation reached to 2,990.80m, (progress 77.54%) from the Tunnel Portal.

Main Tunnel 

• Excavation

In the month of September 2003, the rock encountering in the Main Tunnel was continuing in good condition, although they have some safety rockbolts for slickenside and key block were instructed on site by the Engineer. Geologically, the condition was stable on Class B. On some portion, it was classified as class A this month.

Total lengths of 149.00m were excavated in the Main Tunnel this month, giving a total length of 3,226.30m station 4+869.3 (Progress: 83.65%) from the tunnel portal.

• Niche Excavation:

Sixty three (63) Niches – Fifteen (15) Emergency Call Niches and Fourty-eight (48) Firefighting Niches – in the Main Tunnel were already excavated. Excavation of niches continues according to the designed niche distribution plan.

• Lay-by Left No.1, 2, 3, 4 and Right No.1, 2, 3(connected to EP Outlet), 4

The excavation of Lay-by Left Nos. 1, 2, 3, 4 and Lay-by Right Nos. 1, 2, 3, 4, 5 in the Main Tunnel, which has a total length of thirty-two (32) meters each, were completed during the previous months as per original plan. The Lay-by Left No.5 (Lay-by No.10) were also on-going excavation until end of this month.

• Main Tunnel Rear Works (Concrete Works)

The pouring of Class D concrete for the Foundation Beam of the Lining Concrete continued this month from Station 4+187.5 to 4+406.5 with a total length of 219m 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 done on areas with rock bolts.

Installation of EVA Waterproofing Membrane was also continued following the covering of rock bolts. Until the end of this month, a total length of 2,679.5m (Station 1+664~4+343.5) was completely covered with waterproofing membrane. The Engineer continued to require testing of the welded joint sheets using air pressure test, as per procedure stated on the method statement, before continuation of the installation.

Pouring of Concrete Lining was also carried out as per approved design segment. 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 2,330.00 meters. The Concrete Lining works for Lay-by Left Nos. 1, 2, 3 and Lay-by Right No. 1, 2, 3 in Main Tunnel, totaling six Lay-by completed with a length of 197.90m. The Lay-by Left No.4 (Lay-by No.7) were also on-going casting concrete and Vehicular No.2 (CP No.6) completed assembling steel form until the end of this month.

The Main Tunnel Concrete Lining completed up to the end of this month totaled to 2,527.90m (Progress: 65.54%).

For cross passages, only the concrete lining for the blocks connected to the Main Tunnel are being executed. Concrete lining completed until the end of this month includes the Pedestrian Cross Passage No. 1 (Station 2+000), No. 2 (Station 2+400) and Vehicular Cross Passage No. 1 (Station 2+800), and Pedestrian Cross Passage No. 3 (Station 3+190), No.4 (Station 3+688), totaling a length of 16.90m.

Cable Duct Bank:

This month of September 2003, the pouring of concrete for the cable duct bank with manholes, including two (2) lines of embedded conduit pipe with a diameter of 110mm each, were completion the area of Lay-by No.3 and stand-by to Station 3+525.0 awaiting for some of lining concrete completed. The total length poured reaching to 1,831.60m.

Side Drainage/Catch Basin:

This month, the pouring of side drain and setting of pre-cast catch basins was on-going from station 1+670.45 and reached to station 3+444.55m for side drain, totaling a length of 1,831.60m. The setting/installation of pre-cast catch basins started from no. 2 ~ 76, totaling 75nos. (to station 3+520).

• West Side: (Right Side)

Cable Duct Bank:

The conduit duct bank concreting under the walkway structure has been commence from station 1+691.55 and reached to station 2+808.12 giving a length 1,116.57m.

Side Drainage/Catch Basin:

Casting on-site of side drainage on the west side of the Main Tunnel began at Station 1+670.45 and reached to Station 3+432.95 with a total length of 1,796.46m. The setting/installation of pre-cast catch basins were from no. 2 ~ 71, totaling 70nos. (to station 3+395).

• Walkway Structure:

This month, the pouring of walkway structure was continuing. The base concreting works was on-going from station 1+669.70 and reached to station 2+971.5m, totaling a length of 1,301.80m. The sidewall casting concrete were also starting on the same station and reaching to station 2+481.20 with a total length 811.5m. The casting concrete of hydrant pipe saddle inside the walkway structure were also simultaneously execute with a base concrete starting same station and reaching to station 2+785.0 a totaling 1,115.30m.

• Main Drainage:

The Perforated Concrete Pipe diameter 400mm began at station 1+709.4 and reaching to station 2+483.0 with total length of 773.6meters including setting/connection of pre-cast concrete manhole from no.1~4.

• EP No. 1 Concreting Works:

The pouring of Class D concrete for the Foundation Beam of the Lining Concrete was completed from Inlet to Outlet connection to MT.

Installation of Mole Drain Pipes, together with filter cement aggregate, on both sides of the tunnel were also completed connection on the MT.

Installation of EVA Waterproofing Membrane both connections to the MT was completed.

The casting of Lining Concrete from block no. 1 Inlet (station 0+007.26) connected to MT and completed up to block no. 27 (station 0+144.56) which is connection also to MT Lay-by No.5-2 with a total length of 137.30m (Progress: 100%) this month.

Sewage and Drain Pit:

This Month of September 2003, The Sewage Pit No.1 ~2 was already completed and all pre-cast Drain Pit were completed settings this month.

Concrete Pavement:

The casting of concrete pavement had been commenced from station 0+048.37 up to station 0+100.44 both side with a total length 52.07meters.

Evacuation Tunnel

For the Evacuation Tunnel was also in good rock condition up to the end this month. Some round were installing safety rock bolts due to some slickenside with white clay coated. Geologically, the rock condition encountered for both faces (face nos.2 and 3) this month was stable on Class B. On some portion, it was classified as class A this month.

This month also, the contractor excavated another cutting face (Face No.4) through the Additional Temporary Cross Passage no.3. The excavation face no.3 from last month were connected through to the face no.4. The Contractor excavated the Face No. 3 simultaneous with the excavation of Face No.4 by the same ET group. The excavation for Face No. 4 is on-going executing this month.

The Face No.3 excavation length extended by 49.20m and excavation for Face No. 4 side yielded a length of 108.30m. Total excavation length for this month was 157.50m. The distance from the tunnel portal gives a total length of 3,148.30m station 4+971.30 (Progress: 81.63%). 

The Temporary Transformer Niches No. 1~11 were completely excavated as per approved plan submitted by the Contractor.

The Enlarged Pedestrian Cross Passageway Nos. 1 to 5 and the Vehicular Cross Passageway No. 1, 2 was completed.

Ventilation Adit Tunnel

• Concreting Works:

Cut and Cover Section / Connection Lining Concrete at Portal:

The Concrete Lining for Cut and Cover Section, with Portal Wall, and two (2) blocks of Normal Section of Lining Concrete connected to the Cut and Cover Section were completed with a total length 13.97m from Station 1+738.54 to 1+752.51.

Normal Section Lining Concrete:

Pouring of Class D concrete for the Foundation Beam of the Normal Section including for Enlargement Section of Lining Concrete were continuing with a total length of 824.42m (station 0-135.11~0+686.82) on left side and the right sides a length total 776.51m (station 0-135.11~0+662.91).

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 done on areas with rock bolts.

Installation of EVA Waterproofing Membrane for Normal Section was continuing this month from station 0-135.11 ~ 0+633.5 with a total length of 768.11m including completed installation Supply Section (Enlargement Section). The Exhaust Section was also completed installation this month.

Pouring of Concrete Lining was also carried out as per approved design segment. 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 Normal Section of the Ventilation Adit completed until the end of this month totaled to 502.77meters block no.17 to 71 (0-055.05 ~ 0+447.72). Normal Section Concrete lining was temporary stopped after completed the curve section, to extending a length of sliding form to 12meters for straight section until the end this month.

The Enlargement Section Sliding Form from EP No.1 started assembling and will completed on the first week of next month. 

The Ventilation Adit Concrete Lining completed, including Cut and Cover Section together with its connection to the normal section, up to the end of this month totaled to 516.74m (Progress: 27.38%).

Main Drainage:

The Perforated Concrete Pipe diameter 300mm was continuing section no.1 began at station 0-066.83 to station 0+207.0 and section no.2 from station 0+504 to 0+551.0 with total length of 320.83meters including setting/connection of pre-cast concrete manhole from no.1 at the bottom part of VA intersection of Exhaust Shaft Section.

Center Wall Concrete:

This month, the first lift casting of center wall together with the foundation were commencing from the station 0-055.05 and reaching station 0-001.05 with a length total 45meters.

Grouting Works:

This month of September 2003, the Sections “D” at station 0+790 to station 0+770 primary hole and major water seepages grouting injection from last month commencing were already completed. After chemical treatment injection using Denka ES mixed with Setter D-100 and cement milk, the water seepages on that section were became reduced.

Section “C” at station 0+914.5 to station 0+904.5 were also started drilling hole and grouting injection of major water seepages with other primary holes. This location continuing executed until end of this month.

Major Events and Issue

Monthly Meeting

On September 03, 2003, a Monthly meeting was held at the Employers/Engineer’s Office between the Employer, the Engineer and the Contractor.

Safety Patrol and Meeting

Safety Patrol to both Packages was conducted by the Employer, the Engineer, and the Contractors on the morning of September 04, 2003 and held meeting on safety related issues in the afternoon.

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