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V. Potts, Donaldson Associates Ltd and A. St. John and S. Sismondi, BAM Ferrovial Kier Joint Venture An inherent aspect of any tunnelling project is ground risk: how it is identiﬁed, quantiﬁed and managed throughout the various stages of a project. Early identiﬁcation of these risks, such as adverse ground conditions or potential obstructions is crucial; however speciﬁc identiﬁcation of all risk s will inevitably be limited by the extent of the desk study, ground investigation and accuracy of as -built information available, particularly in a densely populated urban environment such as London with a long and varied history of development. It is therefore crucial to have suitable plans and procedures in place for dealing with potential ground risk scenarios if they occur during construction work to ensure the safety of the workforce and to protect nearby critical assets. A number of experiences of potential ground risk were encountered during the Sprayed Concrete Lining (SCL) works on Crossrail contract C300/410 which was constructed by a joint venture of BAM Ferrovial Kier (BFK). The C300/410 works, undertaken in the heart of London, comprised of over 2.5km of SCL tunnels for Bond Street and Tottenham Court Road Stations and the Fisher Street crossover, as well as two 6.2km TBM tunnel drives between Royal Oak and Farringdon.
WTC2016 | SAN FRANCISCO CALIFORNIA, USA MONDAY 25 APRIL Back Analysis of High Tunnel Convergences in Clayey Marls E. Misano, J. Coubray and F. Espinoza Carmona, Systra and E. Chiriotti Ganntas Tunnel is part of the modernization project of the railway between Alger and Oran, in Algeria. In order to double and rectify the existing line between El Affroun and Khémis Miliana, the alignment foresees the excavation of a 7 km-long, twin tunnel. The excavation works started in June 2011 with the contractor CCECC, under the supervision of SYSTRA. Excavation is driven in conventional method by hydraulic hammer on 8 different fronts at the same time, since the excavation was started also from a junction window towards the middle of the tunnel. The minimum longitudinal distance to be respected between two contiguous tunnel faces has been set to 30 m. The tunnel cross-section is a 70 m² oval shaped proﬁle, the temporary support consists of shotcrete, bolts and steel ribs. A 30 to 50 cm thick, cast in situ concrete ﬁnal lining is provided as well. When the tunnel reached a fault zone in soft clayey marls, extreme squeezing occurred, works were stopped, and re-proﬁling operations were needed along more than 100 m tunnel length. At present, works proceed slowly at this excavation face since high convergences are still registered and the end of works is not expected before December 2016.
The World Tunnel Congress The Including NAT2016 World Tunnel Congress Including NAT2016 22 – 28 APRIL | MOSCONE CENTER | WTC2016 TUESDAY 26 APRIL MORNING ITA WTC 2016 Open Session 8:30-12:30 Moscone Center, North Building, Hall E 134/135
INDUSTRY ADVANCESThis year’s ITA Open Session will focus on advances that the industry is achieving across a broad cross-section of topics that affect our business. Topical areas will include conventional and mechanized tunneling, controlled blasting, ﬁber-reinforced precast concrete segments, the measurement and interpretation of in-situ stresses for application to high stress environments and pressurized conveyances, the challenges that we face in developing underground space in urban settings, and the management of construction risk through improved contracting practices.
At the core of the ITA are 13 Working Groups that operate with
the following objectives:
• promote understanding of the techniques of underground works (planning, design, construction, operation, use and maintenance) through knowledge sharing;
• inﬂuence decision-makers by providing information on the beneﬁts of underground works and on the needs for further research;
• produce reports that contain speciﬁc recommendations for how Member Nations can implement safe and economic construction methods; and
• promote the exchange of knowledge and lessons learned so that all Member Nations can beneﬁt from a global knowledge base
ITA Open Session
INDUSTRY ADVANCESSession 1 – Completed Working Group Reports Session Chair: Tarcisio Celestino
Session 1 will focus on recently completed technical reports prepared by the following Working Groups:
• WG 2 Research: Twenty Years of FRC Tunnel Segments Practice: Lessons Learned and Proposed Design Principles
• WG 11 Immersed and Floating Tunnels:
Owners Guide to Immersed Tunnels
• WG 14/19 Mechanized and Conventional Tunnelling:
Recommendations on the Development of Underground Projects with Respect to The Tunnelling Methods
• ITAtech: Guidance for Precast Fibre Reinforced Concrete Segments – Volume 1: Design Aspects
• ITAtech: Vibration Control in Urban Drill & Blast Tunnelling Presentations will be made by the Working Group Animateurs and ITAtech Committee Chairs for each of the completed publications.
Session 2 – Current and Future Topics Session Co-chairs: Priscilla Nelson and Randall Essex This session will address ongoing research efforts, where active Working Group members and other industry representatives will engage the audience in discussions by means of panelist presentations and audience commentary and feedback. Audience members will be encouraged to comment on: what has been presented;
whether they agree or disagree with speciﬁc ideas and approaches;
what their personal experience would suggest; and what issues they believe should be addressed in future Working Group activities.
Topics to be addressed will include:
• Risk Management – Current Practices
• Fibre Reinforcement of Precast Concrete Segments
• In-situ Measurements for High Stress Conditions and Pressurized Conveyances
• A review of past contracting practices and why they have not worked to the satisfaction of the stakeholders
• Improved contracting practices from around the world, including Switzerland, South Africa, France, USA, Asia, and Middle East
• ITA’s collaboration with FIDIC to develop new FIDIC contract clauses that better address subsurface risk
• Political and commercial challenges of developing underground space in urban areas, and lessons learned from past and ongoing projects
Participating Working Groups will include:
• WG 2 Research
• WG 3 Contractual Practices
• WG 20 Urban Problems and Underground Solutions 22 – 28 APRIL | MOSCONE CENTER | WTC2016
ITA OPEN SESSION
INDUSTRY ADVANCESSession 2 – Ongoing WG Research Topics Session Co-chairs: Priscilla Nelson and Randall Essex 9:45 WG 2 Research Chungsik Yoo, Animateur
• Risk Management – Current Practices
• Fiber Reinforcement of Precast Concrete Segments
• In-situ Stress Measurements for High Stress Conditions and Pressurized Conveyances
11:00 WG 3 Contractual Practices Arnold Dix, Animateur
• Application of Improved Practices to Global Forms of Contract
• Results of Worldwide Questionnaire on contracting practices
• ITA/FIDIC joint efforts to enhance FIDIC management of subsurface risk
Itacus “Think Deep” Open Session Towards a New Urban Paradigm 14:00-17:30 Room 120 The ‘Think Deep’ Open Session 2016 organised by ITACUS will show you where we stand in our quest towards an urban underground future. By looking at the past, present and future but also by challenging common perceptions we will ask ourselves what the new urban paradigm could be. This year in October, 30,000 people will gather in Quito, Peru, for the Habitat III conference that hopes to agree to a new urban agenda. Last year in Paris, the world agreed on measures to take to face the challenge of climate change during COP21. If one thing has become clear it is that cities are key to change and that change requires the public sector, the private sector and non-governmental organisations to work together. The new urban paradigm is not only needed, an urban underground future needs to be part of it. The ‘Think Deep’ Open Session will entertain you, provide you with provoking thoughts, challenge what you have always thought and engage you to become part of a movement that aims at creating an urban underground future for our cities. 25 Years after the Tokyo Declaration on Underground Space, time has come to renew our pledge and to afﬁrm our commitment. A commitment to contribute to the new urban agenda, and to the future of cities that will be resilient, sustainable, inclusive and liveable; cities that we all need.
14:00 Opening of Session by Antonia Cornaro and Han Admiraal 14:15 Session I: A New Urban Paradigm;
Past, Present, Future In this session we will hear from Prof. Dr. Ray Sterling and Dr.
Nobuharu Isago on project past, present and future. We will look at the future of underground space with representatives of ACUUS and we will interact with you, the audience.
15:45 Session II: A New Urban Paradigm;
Challenging Common Perceptions Part of the new urban paradigm could be to break down our common perceptions and open up to new ideas. Yvette Körber will introduce us to the concept of urban underground freight, while Nicolas Ziv will question whether we should only be transporting people below the surface in our MRT systems. Petr Salak will introduce the new ITACUS-ISOCARP Young Professionals Think Deep Programme. Again we want to interact with you as audience on the new urban paradigm.
17:15 Summary and Close of Session
Tunnel Interactions with Ground and Structures Chair: M. Fowler, WSP/Parsons Brinckerhoff, USA ITA Co-chair: E. Grov, ITA WG 12 Animateur, Norway 14:00-14:20 Evaluation and Construction Impact of a Deep Excavation for the 73-story Wilshire Grand Tower on the Existing Metro Red Line Tunnels in Downtown Los Angeles J. Yao and M. R. Crow, Los Angeles County Metropolitan Transportation Authority; Y. Sun, J. T. Waggoner, and R. Geraili Mikola, McMillen Jacobs Associates and M. B. Hudson, Amec Foster Wheeler The Wilshire Grand redevelopment project in downtown Los Angeles includes construction of a new 73-story tower. Construction required excavation up to 93 feet deep (28 m). The south side of the excavation, up to 57 feet deep (17 m), required placement of shoring within about 6 to 10 feet (1.8 to 3.0 m) horizontally away from a 400-foot-long (122 m) section of one of the existing Los Angeles Metro Red Line twin subway tunnels. These tunnels were constructed using a 22-foot-diameter (6.7 m) digger shield, and were initially supported with expanded, precast concrete segments, with ﬁnal cast-in-place reinforced concrete lining. The temporary shoring system for the deep excavation consisted of soldier piles generally spaced at 8 feet (2.4 m) on center with multiple levels of tieback anchors extending above the subway tunnels. The lowest level of bracing consisted of rakers supporting walers attached to the soldier beams because installation of tieback anchors at that level would conﬂict with the tunnels. Numerical analyses were performed to predict tunnel movement caused by the excavation and its effects on the train operations. This paper describes the numerical modeling, tunnel and geotechnical instrumentation and monitoring program, and comparison of the computed and observed tunnel responses to the deep excavation and tower construction.
With increasing urban redevelopment in major cities, the project is a valuable case history for excavation adjacent to existing tunnels.
WTC2016 | SAN FRANCISCO CALIFORNIA, USA TUESDAY 26 APRIL 14:20-14:40 Effects of Tunnel Excavation on Historical Buildings by a Fully Coupled Soil-structure Interaction 3D Analysis – A Case Study from Copenhagen “Cityringen” Metro Line A. Damiani, L. Alﬁeri and S. Cavagnet, Lombardi Ingegneria Srl and S. Notarianni and G. Fantauzzi, Copenhagen Metro Team The new tunnels of the Copenhagen “Cityringen” will be excavated, at Kongens Nytorv square, crossing over the existing M1 and M2 metro lines. After the crossing, the tunnels will underpass the historical building of the Magasin du Nord and adjacent masonry buildings, with a minimum tunnel cover of about 4.5 m. The tunnels have an internal diameter of 4.9m and are being excavated through earth pressure balanced Tunnel Boring Machines in mixed face.
The Magasin du Nord estate is characterized by a very complex structure, with different blocks built in different times. An assessment of the condition of the building and its sensitivity to tunnelling-induced ground movements has been conducted through a fully coupled soil-structure interaction analysis; based on the results of this analysis, mitigation measures have been designed.
14:40-15:00 Construction of an Underpass Crossing in Proximity of a Railway Track S. Honda, T. Takahashi, and H. ITOI, Tokyo Construction Ofﬁce;
M. SHIMIZU, East Japan Railway Company and H. Izumi, M.
Kurisu and T. Nagao, Tekken Corporation Grade separation of roads and railway tracks is an effective method for solving trafﬁc-related issues in cities. However, in urban areas where the existing trafﬁc infrastructure is already overcrowded, construction of new roads often faces problems especially in the proximity of existing structures.