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A. Lueghamer, AGRU Kunststofftechnik GmbH and G. Recher, Telene SAS In view of a global trend towards urbanization, more and more trunk sewers and combined sewer overﬂow tunnels (CSO) with medium to large diameters and the corresponding link sewers are currently built and under design. Shielded tunnel boring machines using segmental lining as tunnel support represent an efﬁcient solution for construction of new wastewater and supply tunnels.
Especially in the ﬁeld of sewers, the durability of concrete structures both exposed to any groundwater present on its exterior and to aggressive waste water as well as gases on its interior is a key requirement. Despite thorough research on segmental lining and mechanized tunneling machinery, conventional thermoplastic liners show comparatively minimal progress in terms of practical advancements. This is in contrast with the development of the latest segment embedded high density polyethylene (HDPE) system.
Based on experiences achieved, this paper discusses the latest development of an integral protective lining system in respect of material characteristics and its adaptability to both project and customers’ demands. Reviewed performances, as the bondage behavior of the embedded HDPE system at axial stress loads due to acting thrust cylinders during ring build as well as the ability to drain pressurized water behind the embedded membrane, tested at full scale segments, are also presented. The paper is round off by presenting ﬁrst details of sewer projects endeavoring to utilize this cutting-edge solution for an integral concrete protection, which will be commenced beginning of 2016.
15:00-15:20 Monitoring Mechanisms of Tunnel Lining Settlement using Instrumented Bolts and Conventional Survey Method – Assessing Neutral Axis of Longitudinal Flexure M. Wilcock and K. Soga, University of Cambridge and P. Wright, Ch2m This paper discusses how an existing grey cast iron segmental tunnel lining responds to construction of a new SCL tunnel transversely beneath with zero clearance; how the damage assessment for the existing tunnel was conducted for impact of longitudinal movement; how the tunnel is subsequently instrumented to observe both movement and stress manifestation at its longitudinal connections and how the results from the instruments compare with the prediction. An assessment of neutral axis of the tunnel in longitudinal ﬂexure is also explored using interpolated horizontal displacement data from a conventional monitoring system.
WTC2016 | SAN FRANCISCO CALIFORNIA, USA MONDAY 25 APRIL 15:20-15:40 High Performance Ground Prediction Ahead of TBMs – The NeTTUN System “TULIPS” T. Camus, NFM Technologies The current ground prediction situation is of great concern for tunneling contractors, and the subject has been quite widely addressed over recent years, for instance by the French Eupalinos 2000 program, which tested a variety of technological approaches. A number of interesting projects were executed, such as the SOUND and OnSITE projects, part of the German Geotechnologien program: these projects are focused on seismics, while other techniques such as radar are not considered. Little information and even less industrial applications have been released apart from lab simulations and numerical modelling. A number of ﬁeld tests in different conﬁgurations have been carried out for compression waves, but the results were often not reliable or convincing, and therefore little has been reported in open literature.
15:40-16:10 Break 16:10-16:30 The Lee Tunnel Beckton London: An Innovative Use of FRC From Design to Construction Phase B. de Rivaz and J. Greenhalgh, Bekaert Maccaferri Underground Solutions This paper is based on the Lee Tunnel project, which is part of the Thames Water’s Tideway Project. The client Thames Water has employed a Joint Venture of Morgan Sindall/Vinci Grand Projets and Bachy Soletanche to undertake the design and construction of the project under the management of CH2M Hill at a value in excess of £635 million ($990 millions). The 3 main elements of the tunnel project being the permanent lining to the shafts, the precast segmental lining, and the secondary tunnel lining that are all reinforced with 3 different types of Dramix steel wire ﬁbres and each element will be described in this paper. This paper will explain the basic structural design of FRC (ﬁbre reinforced concrete) based on the post cracking residual strength and will describe all the steps of this project, the testing program realized to support innovative design and the main technical learning point.
16:30-16:50 Tunneling Under the Norris Cut Channel – World Firsts to Overcome the Adverse Ground of Miami B. Theron, Bessac and B. Caro Vargas, Nicholson Construction In early 2014, Nicholson Construction was awarded, together with its tunneling sister company Bessac, the Norris Cut Miami Tunnel Project. The 2.5-meters diameter segmental lined tunnel, 1600-meters long, is aimed to replace the existing 54” forcemain connecting the Water Treatment Plant (WTP) on Virginia Key to Fisher Island. To overcome the highly permeable limestone of the Fort Thomson Karstic Formation (one of the most permeable formation in the World), the project team has developed State of 22 – 28 APRIL | MOSCONE CENTER | WTC2016 the Art solutions: The TBM is launched with pipe-jacking technique for the ﬁrst 70-meters and then converted to segment erection mode. It allows substantial schedule savings and drastically reduces the size of the circular launching shaft. The TBM, jointly designed and manufactured by Bessac and Herrenknecht, can convert from slurry to EPB mode within a few minutes. The cutters can be replaced by wet divers thanks to an innovative application in the TBM industry.
16:50-17:10 Unique Characteristics for the Design and Construction of the New Twin Tunnel “Caltanissetta” on Highway 640 in Sicily, Italy. Practical Experience in Using 15.08 m. (50 feet) Diameter E.P.B. Machine G. Luca Menchini, P. Francesco Paglini and P. Francesco Boschi, Cooperativa Muratori & Cementisti C. M. C. di Ravenna Società Cooperativa The double tunnel “Caltanissetta” is part of the ANAS (National Road Agency)’s $1.3 B. Highway 640 Caltanissetta-Agrigento (Sicily-Italy) Rehabilitation Project, consisting in upgrading of 40 miles of highway. The Italian construction company Cooperativa Muratori Cementisti di Ravenna, is the General Contractor for the design and build contract. The “Caltanissetta” tunnel consists of two separate tubes, each with 4 km length and inside diameter of 13.50 m., in order to host 3 trafﬁc lines and an emergency line. The excavation is carried on with a 15m diameter EPB machine, 0.60m thickness precast lining, overburden from 5m to 130m. The ﬁrst tube is com completed, and the second one is going to start, after shifting of the EPB. The paper examines the design and construction aspects related both to Machine and Tunnel, including challenges such as the presence of poor soils, fault zone and hydraulic pressure along the tunnel alignment.
WTC2016 | SAN FRANCISCO CALIFORNIA, USA MONDAY 25 APRIL 17:10-17:30 Istanbul Strait Road Tube Crossing: Challenges, Risks and Mitigation Strategies N. Munfah, HNTB Corp; G. Clark, WSP/Parsons Brinckerhoff; B.
Arioglu, Yapi Merkezi Construction Inc; S. Zlatanic, HNTB Corp and T. Togan, WSP/Parsons Brinckerhoff The 13.2 m diameter double deck Istanbul Strait Road Tube Crossing is one of the most challenging underwater tunnel projects in the world. Subjected to 11 bars of hydrostatic pressure, variable geology, and being in a very active seismic area, the execution of the project required innovative solutions, sophisticated construction techniques, and prudent risk management approach. The 5 km tunnel consists of 3.4 km TBM bored tunnel, 1 km twin NATM tunnels, and cut and cover sections. The project is being delivered in a Build-Operate-Transfer (BOT) contract in a public-private partnership. The technical challenges, coupled with ﬁnancial l and commercial risks required the implementation of sophisticated risk management tactics including the provision of Independent Design Veriﬁcation. Presently, the project is in its advanced stages of construction with a recent successful TBM breakthrough on August 22nd 2015. The paper presents the technical challenges of the project from the design, construction, and risk management aspects and provides the status of the construction. and commercial risks required the implementation of sophisticated risk management tactics including the provision of Independent Design Veriﬁcation. Presently, the project is in its advanced stages of construction with a recent successful TBM breakthrough on August 22nd 2015. The paper presents the technical challenges of the project from the design, construction, and risk management aspects and provides the status of the construction.
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.) Innovative Support of Cross-Passage Openings in Segmented Liner K. Rössler and P. Vitek, Metrostav The Ejpovice tunnels in Czech Republic were built by EPBM in soft Clyashale, and in weathered proﬁle with low soil overburden. The segmented liner at the cross-passage openings required support, which would not interfere with the EPBM clearance envelope during the scheduled pull back of the EPBM through both tunnel tubes.
For that reason support frames or radial bolting could not be used.
Improvement of Precast Concrete Segmental Lining by Post-tensioned Strands B. Khorshidi, McNally Construction Inc The ultimate objectives of the post-tensioned strands are the integration of precast segments into a ring and providing pre-stress in the tunnel circumference. The method involves inserting strand through the preliminary embedded duct in the precast concrete segments and then tensioning the strand by jack and fastening it.
The post-tensioned strand eliminates necessity of bolt connections between the segments and reduce the labor cost and increase speed of lining construction. Pre-stressing of the segmental lining reduces the steel reinforcement or ﬁber volume in precast segments and/or thickness of the precast segments which would result in reducing the manufacturing cost of them. Pre-stressing would reduce cracking and increase water tightness and would provide smooth intrados due to eliminated bolts joints in the tunnel lining.
Pre-stressing would increase resistance to internal pressures as well. Further, this system could work very well structurally in tunnels with squeezing rock or tunnel with high seismic loadings.
Risk Reduction and Performance Improvement through TBM Robotization S. Moubarak, NFM Technologies and T. Camus, NFM Technologies Since the introduction, several decades ago, of the ﬁrst concepts of tunnel boring machines (TBMs), the unremitting increase of mechanized and automated tasks and the reduction of manual tasks carried out by human operators have gone hand in hand with the continuous improvement of these machines. In the present state of TBMs, the replacement of worn cutting tools is a critical, tedious, and dangerous manual operation especially for earth pressure balanced (EPB) and slurry TBMs. Furthermore, hyperbaric interventions increase risk to the operators and require long decompression procedures that increase the idle time of the machine and reduce its efﬁciency. Tunnel boring contractors are therefore increasingly interested in automating these operations to reduce the risks to human workers and improve the TBM’s performance. Moreover, the demand for new, ambitious and challenging tunneling projects (very deep, high pressure boring) is ever increasing, but the supply of suitable TBMs is limited and the risk from working in the hyperbaric environments becomes increasingly unacceptable. Reducing the risk on the operators can be achieved using different strategies. The most common alternative to hyperbaric operations is a proper ground treatment at the excavation face, which is still the current practice for major interventions.
WTC2016 | SAN FRANCISCO CALIFORNIA, USA MONDAY 25 APRIL Use of Two Novel Hybrid-Type “Crossover” TBMs for Hard Rock Conditions with Water Inﬂows M. Isaman, The Robbins Company Mixed ground tunnels come in all kinds. In rock tunnels with possible faults and high pressure water, the challenges are many. With the advent of Crossover TBMs, contractors can minimize machine wear in such conditions while maximizing efﬁciency. The newest generation of Crossover is exempliﬁed by two projects in Albania and Turkey. A 5.56 m Crossover TBM destined for Turkey’s Gerede Water Transmission will be assembled using Onsite First Time Assembly (OFTA) from within an existing tunnel. The unique machine will bore through 30 fault zones requiring the TBM to be sealable to up to 20 bar so pre-consolidation grouting can be done. If boring under pressure is required, the TBM will bore sequentially using the screw conveyor fore and aft gates. Skewing further towards hard rock, a unique 6.2 m diameter Double Shield TBM with Crossover features was designed for Albania’s Moglicë Headrace Tunnel. The machine features closure doors and a sealing system to contain inrushes of water until they can be grouted off. This paper will discuss the unique aspects of the Crossover designs, including their inception as based on past projects in difﬁcult ground, and their utilization at the two current projects.
Great ideas are just below the surface We are designing the City of Atlanta’s top priority infrastructure project – the Raw Water Delivery System. It consists of 5 miles of 10-foot diameter tunnel up to 500 feet deep, two construction sha s, a raw water intake, and three pump stations. Being delivered via a CM@Risk contract, this is one of the largest such tunnels ever built in North America.
Anil Dean is our Deputy Tunneling and Trenchless Technology Practice Leader Design with community in mind stantec.com/water