1.Geotechnical Challenges and Solutions at the Port of Miami Tunnel Project R. Storry , Geotechnical Director Bouygues Civil Works12th Australian Tunnelling Conference, Melbourne, 2013

2. CONTENT of PRESENTATION Project Introduction and ScopeGeological Challenge of the ProjectGround Investigation PreformedConstruction Challenges; Shafts Tunnelling Spoil Conditioning Hyperbaric works Cross Passages 3. BACKGROUND The Port of Miami is Miamis second largest economic generator. The Project will provide direct access to the Port of Miami cruise and cargo ports from the Interstate Highway System Increasing the cargo capacity (currently 6.8 million tons of cargo) Eliminating cargo truck traffic in Downtown Miami (currently about 7000 movements daily)Public-Private Partnership (PPP) Project Design-Build-Finance-Operate-Maintain 55-Month Design & Construction Schedule 30-Year Operation/Maintenance PeriodTotal Construction Cost US $710 Million Geotechnical Contingency/Risk Sharing Program- $180 Million 4. PROJECT LOCATIONAtlantic Ocean Watson IslandBiscayne BayCity of Miami Miami Beach Dodge IslandProject Site 5. PROJECT SCOPE Roadway ImprovementsBridge WideningMacArthur Causeway Bored Tunnels Biscayne Bay Government Cut ChannelTunnel PortalPort of Miami Dodge Is.Tunnel PortalPOM Roadway Improvements 6. SUMMARY OF TUNNEL BORES AND CHALLENGES2 tunnels each 1.27 km longTunnel bore 12.87m (11.3m ID)8 piece rings using 1.7m long, 615mm thick universal segments5% maximum grade and a tight horizontal curve Rmin= 305mLow ground cover : from existing grade to 1.5 Tunnel Dia. ( less than 1 Dia. in Channel)Tunnel Separation: 1/3 to 1 Dia. (edge to edge)Cross passages required every 240m (5 number) Image courtesy of BCWF/Jacobs 7. PROJECT SCHEDULE Project Start:October 2009Notice to Proceed (Construction):May 2010TBM Erection:August-November 2011TBM Launch from Watson:November 11, 2011TBM Arrival Dodge (Breakout):July 31, 2012TBM Turn around:Three monthsTBM Launch from Dodge:October 29, 2012Final TBM Break out:May 2013Project Substantial Completion:May 2014 8. GEOLOGICAL CHALLENGE Project site consists of man-made islands at sea-level and carbonate sedimentary sequence (10,000 to 2 Million years old). Heterogeneous profile of relatively thin variably cemented sedimentaryrock layers, loose sediments and intermediate geo-materials which vary both laterally and vertically. Geologic Units : Miami Limestone Formation (S3), Fort ThompsonFormation (S5), Anastasia Formation (S6), Key Largo Formation (S7) & Tamiami Formation (S8). 9. GEOLOGICAL CHALLENGE Biscayne Aquifer: Highly Permeable and interconnected to Atlantic Ocean Tunnelling challenges First time large diameters tunnelling attempted in Floridahighly permeable, up to k=10-2m/sec and void content up to 60%, (imposes restriction of type of TBM),unstable ground, low ground cover, high hydrostatic pressures; andvarying mixed-faced conditionsSound technical solutions required 10. GEOLOGICAL CHALLENGE LAYER S7 27m to 36m bgl. SPT N = significant zones 30m depth;Conventional techniques SPT, rotary coring, shallow CPT, geophysical surveysUnconventional techniques Deep CPTs , 150 to 300 mm Sonic CoresSpecific Techniques Large Diameter Shafts (2.1m), Downhole Video, Hydrophysical Investigation 12. COMPLEMENTARY GROUND INVESTIGATIONS Complementary Ground Investigation (CGI); Performing the works within cruise ship channel was a great challenge to overcome - GI work was carried out on a 24hr / day basis when no cruise ships were in port (1 to 3 days per week). Biscayne Bay is an aquatic preserve strictly managed no spillage or leakage 13. SPT and ROTARY CORING Complementary Ground Investigation (CGI)Layer S5Layer S6Layers S1 - S4 Layer S8 14. COMPACTION GROUTING TRIAL (CA REQUIREMENT) Purpose: Treat zones of loose sand foreseen by tender interpretation Define parameters for full scale grouting to improve bearing capacity in loose sand areas in Layer 7 where intersected by TBMResults: Conclusion: The Layer 7 was not able to be densified by compaction grouting despite having significant zone of SPT N