Ground Response to Tunnel Construction for the Jakarta MRT

Transcription

1 Ground Response to Tunnel Construction for the Jakarta Hendarto Jamie Standing Department of Civil and Environmental Engineering Imperial College London London SW7 2AZ Presented in the 9th International Symposium on Geotechnical Aspects of Underground Construction in Soft Ground, IS - São Paulo.

2 Outline 1. Background 2. Project description 3. Site conditions 4. Tunnel construction 5. Monitoring 6. Summary and conclusions 2

3 1. Background Jakarta Source: Google Earth 3

4 1. Background (cont'd) Transportation and the Grid lock in Jakarta Source: Jakarta 4

5 2. Project description Jakarta Mass Rapid Transit (J-): Bringing Relief to the grid lock in Jakarta Jakarta and its surrounding areas (Abidin, et al., 2011) J- development, 2016 Jakarta q North to south corridor = 25 km (NS 1 = 15 km (under construction), and NS 2 = 10 km) q East to west corridor = 87 km q Twin tunnels along approximately six km. q Six underground stations 5

6 2. Project description (cont'd) Jakarta - NS 1 Project Jakarta Project Contract CP104/105 Excavation TBM Shield - EPB Outside Diameter m m Concrete Lining Segment 250 mm 300 mm CP106B TBM Shield - EPB 6

7 3. Site conditions stratigraphy Geology Stratum Consistency / relative density SPT N-values Upper layer - alluvial AC1 Very soft to firm clay or silt 1-8 AC2 St i f f cl ay or si l t 8-15 AS1a Loose sand < 10 AS1b Medium sand Lower layer - dilluvial DC1 Very stiff clay or silt DC2 Hard clay or silt > 30 DS1 Dense sand > 30 7

8 3. Site conditions stratigraphy (cont d) 8

9 3. Site conditions Atterberg limits 9

10 3. Site conditions observation wells Project Area Observation wells Monitoring ID Maximum (m) Minimum (m) Deviation (m) Transition area OW 1 Trans OW 2 Trans CP104 Observation summary of 17 wells. Senayan station OW 1 SNY OW 2 SNY Transition area. Istora station OW 1 IST OW 2 IST CP105 Bendungan Hilir station OW 1 BDH OW 2 BDH Setiabudi station OW 1 STB OW 2 STB Dukuh Atas station OW OW CP106 Bunderan HI station OW OW OW OW OW Ground water level is fluctuated m within one cycle season (wet/dry seasons = 6months). 10

11 4. Tunnel construction The sequences south north EPB - CP104/105 Four EPB shield machines manufactured by JTSC Two machines for CP 104/105 (south to north) The others for CP 106 (north to south) 11

12 4. Tunnel construction The EPB machines CP104/105 Machines were manufactured by Japan Tunnelling Systems Corporation Source: Jakarta 12

13 4. Tunnel construction Lining and grouting Lining Five precast-concrete segments and one wedge shaped key piece (K) Thickness = 250 mm for CP104/105 and 300 mm for CP106 Grouting Cement paste Accelerator Cement (kg) Bentonite (kg) Stabilizer (kg) Water (kg) Sodium silicate (litre)

14 4. Tunnel construction Face and grout pressure Face pressure from five construction cycleas near Bunderan HI sation and B20 The average face pressure was 170 kpa 14

15 5. Monitoring B20 Thamrin 9, 40 floors & 3 basements North BCA Tower 56 floors & 2 basements Bunderan HI station B20 15

16 5. Monitoring Section B20 (cont d) Thamrin 9 BCA Tower 16

17 5. Monitoring Section B20 (cont d) 7 surface settlement points 2 extensometers (2 anchors in each) 7 Bulk Unit Weight Water Content Plasticity Index Liquidity Index Specif ic Gr avit y Void Ratio SPT Values Tunnel axis D = 6.65m Elevation (m) Elevation (m) Elevation (m) Elevation (m) Elevation (m) Elevation (m) Elevation (m) γ, kn/ m wp,wn,wl, % PI, % LI Gs e SPT 17

18 5. Monitoring Section B20 (cont d) Surface displacements Vertical displacement (mm) Vertical displacement (mm) Point 3 above SB south passed bound B20 -(SB) 17 March tunnel 2016 Point SB tunnel 5 above 12m north beyond bound B20 (NB) tunnel NB passed B20-4 May 2016 NB tunnel 10m beyond B20 SB passed B20 17 March SB tunnel 2016 axis NB passed B20 NB tunnel axis 4 May Jan Feb Mar Mar 0 20-Apr May May 40 Offset Date of from observation the central (in alignment, 2016) x: m 18

19 5. Monitoring Section B20 (cont d) Subsurface displacements 19

20 6. Summary and conslusions Ground characterization along the Jakarta NS1 1 summarized. At transition section, the tunnels pass through very soft soft ground; Most of the tunnels pass through stiff hard ground. EPB shield machines were used for the Jakarta project. The ground tends to have high fluctuation of ground water within one cycle season (wet-dry). Vertical displacements of the road pavement from tunnel construction are small ( < 10 mm) and sometimes upward. To obtain meaningful data with such small displacements, Precise monitoring systems are needed. 20

21 7. Acknowledgment Indonesia Endowment Fund for Education, LPDP Ministry of Finance - Republic of Indonesia; Jakarta Office; Shimizu - Obayashi - Wijaya Kar- ya - Jaya Konstruksi (SOWJ) Joint Venture for CP 104 and CP 105; Sumitomo Mitsui - Hutama Karya (SMCC HK) Joint Venture for CP

22 Thank you very much 22