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22 – 28 APRIL | MOSCONE CENTER | WTC2016 Posters (On display in the exhibit hall during exhibit hours. Authors will be at their poster from 13:00-14:00 for discussion.) The First Adoption of Soil Cement Steel Diaphragm Walls in the Construction of Underground Railway Station Y. Morimoto, K. Nakanishi and M. Karasawa, Japan Railway Construction, Transport and Technology Agency (JRTT) Shin-Yokohama station (tentative name), one of the station of the Sotetsu-Tokyu through line (ST line), is under construction by the OPEN-CUT method. The Underground Soil-Cement Steel Diaphragm Wall is implemented as an earth retaining wall. This earth retaining wall is utilized as a main body of a subway station.
It is the ﬁrst time to utilize this earth retaining wall as the main body. There are two difﬁcult issues for this project. One is that this station is planned under busy major road and there are many underground utilities, for example, an electrical transmission line.
Because of that, construction area is limited. The other is that this station is located in a thick soft clay layer. This layer has a high risk of consolidation settlement because of draining during main excavation. Thus, high water tightness is required for this earth retaining wall. This paper reports design and construction methods for the Underground Soil-Cement Steel Diaphragm wall introduced as a part of the body of the subway station.
Crack Width Reduction in Reinforced Concrete Members Using Barchip Macro-Synthetic Fibers E. S. Bernard, TSE Pty Ltd Conventional steel bar reinforcement is used in many tunnel linings to provide high ﬂexural and tensile load resistance. The resulting Reinforced Concrete (RC) tunnel linings may suffer ﬂexural cracking during service or, in the case of precast concrete segments, during production, handling, or installation. Cracks can lead to corrosion of steel reinforcement, so limits are placed on maximum acceptable crack widths to reduce the likelihood of corrosion during the intended design life (AFTES, 2013; MC2010, 2012). However, the relatively light level of reinforcement used in many applications can result in quite wide in-service crack widths, so either additional steel bar reinforcement is required to limit maximum crack widths, or ﬁbers can be included to control crack widths. Numerous investigations have been undertaken into the efﬁcacy of including steel ﬁbers to reduce crack widths in conventionally reinforced members (Stang and Aarre, 1992;
Abrishami and Mitchell, 1997; Bischoff, 2003; Dupont and Vandevalle, 2003; and Jansson et al, 2010), but steel ﬁbers suffer the problem that they are at least as sensitive to corrosion at cracks as steel bars and therefore have similarly tight limits placed on acceptable crack widths (AFTES, 2013).
WTC2016 | SAN FRANCISCO CALIFORNIA, USA TUESDAY 26 APRIL Tunnel Lining for Drill and Blast Tunnels B. Johansson, Skanska Sverige AB Every tunnel designer has to consider the power of water ingress when designing a new tunnel. Either you choose solutions with simple methods to divert the ingress water or a robust system with the intention that it will give gain on low maintenance costs and a long lifetime. This article describes a new method to divert ingress water in a robust way and more economical than traditional concrete lined tunnels. This system is based on a bolt grid suspending a water tight membrane, which is reinforced and covered with sprayed concrete. The method has been in limited use in Sweden since 2005 and with continuous improvement, still going on, it is now applied for the large project “Förbifart Stockholm”, a 21km long highway project.
Lifetime of Polyethylene Geomembranes for Water Prooﬁng of Tunnels M. Haager and D. Nitsche, AGRU Kunststofftechnik GmbH;
M. Bredács and A. Frank, Polymer Competence Center Leoben (PCCL) GmbH and G. Pinter, Montanuniversitaet Leoben The reliable prediction of service lifetime of tunnel constructions is of essential technical and economic interest. Polymers used for tunnel liners have to fulﬁll the requirement of 100 years lifetime. However, today no reliably proven test method is available which conﬁrms such long lifetimes. The current paper introduces a recently started research project which focuses on lifetime prediction of highly ﬂexible, very low density polyethylene (VLDPE) for tunnel geomembranes. Different PE grades in combination with different antioxidant packages are conditioned at elevated temperatures and immersed in different media. Initial results conﬁrmed signiﬁcant material aging of unstabilized resins already after exposure of up to 34 weeks, at least at the highest exposure temperature of 80 °C. To consider application relevant material properties the material characterization was done by means of tensile tests and dynamic oxidation induction temperature tests.
High pressure liquid chromatography was used for further investigation of antioxidant consumption kinetics.
Design and Construction Aspects of Pneumatically Applied Concrete Final Tunnel Linings Recent Experience at the East Side Access (ESA) Project in New York V. Gall, Gall Zeidler Consultants; A..J. Thompson, Mott MacDonald and A. Valdivia, W. Cao, C. Cicileo, and J. Schabib, WSP/Parsons Brinckerhoff The East Side Access Project involves the construction of geometrically complex underground structures including a large number of caverns and bifurcations. Initially conceived as dual lined structures with either traditional concrete or shotcrete ﬁnal linings (SFL), construction economy, advances in concrete placement technology and scheduling among others led to a wide use of what is referred to as freeform or pneumatically applied concrete (PAC) for the construction of tunnel ﬁnal linings. PAC is a method of applying concrete without using formwork, where a wet mix concrete is pneumatically installed to encase reinforcement to full lining thickness. PAC has been widely adopted at ESA well beyond initial expectations. The paper addresses the 22 – 28 APRIL | MOSCONE CENTER | WTC2016 Posters (Continued) design and construction aspects by the PAC method and contrasts it to traditional SFL lining placement. The experience made provides guidance for future PAC and SFL applications.
Experiences with Spray Applied Waterprooﬁng Membranes – Experiences and Investigations with a EVA Based Membrane in a Tunnel Environment F. Clement, BASF Construction Chemicals and K. Gunnar Holter, NTNU Typically waterprooﬁng of conventionally excavated tunnels has been done by installing pre-fabricated sheet membranes between the primary temporary support lining and the secondary permanent inner lining. The membrane acts as a separation or sliding layer between the linings, which is often desirable. The geotextile installed behind the sheet membrane provides the required drainage and protection of the system. The design of the tunnel lining is strongly inﬂuenced and limited by the use of waterprooﬁng sheet membranes. Since primary and secondary linings are separated from each other, forming a double-shell lining system. In that case the secondary lining must be designed for all permanent loads, although the sprayed concrete primary lining continues resists ground and water loads for a long time after construction. Signiﬁcant progress has been made in sprayed concrete technology over the last two decades, with advanced admixtures, as well as the improved application technology using spraying robots. The development of new admixtures like superplasticizers based on poly-carboxylates, alkali free accelerators and silica fume, enables designers to use permanent sprayed concrete linings (SCL) increasingly for long-term service life.
Instrumentation and Monitoring Chair: A. Marr, Geocomp Corp, USA ITA Co-chair: O. Schneider, ITAtech Sub AG remote Measurement Leader, Switzerland 14:00-14:20 Redeﬁning Settlement Control Industry Standards
with Modern Mechanized EPB Tunnelling:
Eglinton Crosstown LRT Tunnel Case Study A. Solecki and A. Taghavi, Mott MacDonald and I. Hassan, Metrolinx The Eglinton Crosstown Light Rail (LRT) Project is part of an $8.4 billion investment to expand transit in the Toronto, Canada area and is the largest transit project initiated in Province’s history.
Settlement control and impact to over 1400 adjacent structures due to tunnelling was identiﬁed early as a critical project risk.
The ground conditions along the 10km tunnel alignment consist of water bearing soft ground deposits (clays, sands, silts) which required careful analysis and control during design and construction. This paper will describe the process used to analyze settlements along the numerous of adjacent structures and evaluate achieved settlement results to those used during design. The paper will demonstrate that with the appropriate design speciﬁcations, selection of modernized EPB machines, and contractor performance, settlement can be maintained well below typical industry (volume loss) standards, expanding the application and suitability of soft ground tunnelling in sensitive settlement areas.
14:20-14:40 Observed Loading Behavior during Cross Passage Construction – Brisbane Airport Link Project J. Kuyt and M. Mooney, Colorado School of Mines; M. Mangione, Arup and Z. LI, Colorado School of Mines Twin bored tunnels are commonly used for a variety of road and tunnel projects throughout the world. A major component of these twin tunnel projects is the construction of connecting cross passages that provide emergency access between tunnels and space for tunnel service equipment. Cross passages can present signiﬁcant geotechnical risk and technical challenges to a project – support systems must be considered for redistributing loads around the mainline tunnel openings and supporting new loading resulting from excavation activities. Additionally, cross passages pose risks to construction schedule and cost because of their sequencing at the end of construction, so mitigation of schedule overruns can be critical. By observing ﬁeld instrumentation data records from completed projects, a better understanding of the force development in each temporary structure can be achieved with indication of which structures are the most critical to support ground loads. This paper discusses the data obtained during the 22 – 28 APRIL | MOSCONE CENTER | WTC2016 Brisbane Airport Link construction project, a road tunnel located in Brisbane, Australia. Strain gauge instrumentation data from the precast segmental lining and propped opening steel sets is presented with relation to the construction sequence and local geology. Interpretations and conclusions based on the observed trends are proposed, with several key mechanisms affecting the loading and unloading identiﬁed.
14:40-15:00 Evaluation of Settlement Monitoring over 6.75 Miles of Tunneling – Updating Prediction Methods and Designing Better Monitoring Programs L. Salvati, C. LaVassar, and L. Sla, McMillen Jacobs Associates;
J. Theodore, Sound Transit and L. Galisson, SolData Sound Transit’s University Link and Northgate Link projects will add 6.75 miles (10.9 km) of twin-bored tunnel to Seattle’s light rail system, extending the route north from downtown Seattle. The tunnels are being constructed primarily in glacial soils using pressurized-face tunnel boring machines. Cover over the tunnel alignment varied from 13 feet to over 300 feet (4–91 m).
Since the tunnels are located in densely populated urban areas, controlling ground movements and monitoring settlement were essential to success of these projects. Hundreds of geotechnical instruments, including extensometers, surface settlement points, and near-surface settlement points, were used in both projects to monitor settlement. The observed data were compared to settlement predictions made prior to tunneling, and analyses performed to update empirical factors to better estimate settlements. Recommendations for designing efﬁcient and cost-effective settlement monitoring programs are provided based on the review of the monitoring data and analyses.
15:00-15:20 A Case History: Convergence in a Shear Zone at Devil’s Slide J. B. Decker, Kiewit Infrastructure Engineers Co and P. H. Madsen, Kiewit Infrastructure Co During the excavation of the north bound tunnel of the Devil’s Slide Tunnel project, deformation (convergence) was measured after passing through fault Zone B. The tunnel convergence was not symmetrical, but was larger on the left side of the proﬁle. It was determined that a shear zone nearly parallel with the tunnel drive was contributing to the uneven deformation. This paper will discuss how it was determined that the shear zone existed and how multi-point borehole Extensometers (MPBX) were used to verify that a signiﬁcant amount of the deformation was occurring due to movement along the shear zone as the excavation was advanced. In addition, performance of the shotcrete liner in the area of the convergence will be examined. Finally, the paper will consider the means and methods that were utilized to ultimately control and stabilize the deformation.
WTC2016 | SAN FRANCISCO CALIFORNIA, USA TUESDAY 26 APRIL 15:20-15:40
Sarpolite to Hard Rock and Everything in Between:
SEM Tunneling Through Corestone Laden Ground in Hong Kong S. Pollak, H. Lagger and F. Vasilikou, Arup USA, Inc and G. Cachia, Vinci Construction Grands Projets The Shatin to Central Link is a new rail line being constructed to cater for the growing passenger demand between the North-East New Territories and the urban areas of Hong Kong. Contract 1103, which will provide the 4 km of running tunnels between the new Hin Keng and Diamond Hill Stations, was tendered in a design-build framework and awarded to Vinci Construction Grands Projets (VCGP) in October 2012, with Arup as Vinci’s lead designer. One of the most challenging pieces of work on the contract involved the construction of 133m of SEM mined tunnel on the northern end of the project. The Northern Mined Section (NMS) is an undrained, twin track, single bore proﬁle, broken out through the southern pipe pile wall of the Hin Keng Station cut and cover box, Figure 1.
The tunnel has maximum excavated dimensions of 14.5m span x 12m height, with track spacing of 6.175m. The general excavation sequence consisted of 3 stages; a 6m high top heading (73.1m2), followed by bench (27.3m2), and invert (26.7m2).