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Soft Ground TBMs – Urban Challenges Chair: K. Rotunno, Northeast Ohio Regional Sewer District, USA Co-chair: C. Lawrence, Mott MacDonald, USA 14:00-14:20 The First EPB TBM Tunneling Application in New York City and its Completion Through Superstorm Sandy A. Cho, C. Moon and R. Flanagan, WSP/Parsons Brinckerhoff and B. Larsen, New York City Economic Development Corporation The U.S. Army Corps of Engineers (USACE)/Port Authority of New York & New Jersey (PANYNJ), as part of their New York and New Jersey Harbor Deepening Project, will dredge this shipping channel to a depth of 16.5 m below mean low water (MLW). By deepening the channel, the new generation of larger, “post-panamax” container ships can be accommodated in local marine terminals, helping to retain the nearly 300,000 jobs and $12 billion in annual wages the PANYNJ provides to the region. The existing siphons are situated at a depth that could be compromised by the dredging in the channel (nycedc.com). The purpose of this project is to build a new 1.83 m diameter water main inside a 3.66m diameter tunnel replacing the two existing siphons in order to provide the necessary backup water supply to Staten Island across the Anchorage Channel within the Upper New York Bay from Brooklyn. The proposed tunnel is approx. 2.9 km long and at a depth of at least 26 m below MLW.
14:20-14:40 The Second Metro Line in Warsaw – Lessons Learned M. Mitew-Czajewska and A. Siemin˙ska - Lewandowska, Warsaw University of Technology The construction of 6.3 km long central part of 2nd metro line in Warsaw was completed in September 2014 (7 stations – out of which three 25m deep stations, built using cut and cover method;
two single-track tunnels constructed using four EPB TBMs as well as a short NATM section with soil freezing below the existing road tunnel). Central section of the 2nd metro line was opened to public after veriﬁcation and testing in March 2015. Design and build tender for the extension of this line in east (three stations) and west direction (three stations) was announced with total length of running tunnels 22 – 28 APRIL | MOSCONE CENTER | WTC2016 – approx. 5 km. Detailed description of a very complex geotechnical context, different construction methods, problems encountered and solved during construction and ﬁnally lessons learned on this interesting project are presented in the paper.
14:40-15:00 Port Mann Main Water Supply Tunnel – Ground Freezing the TBM face under the Fraser River J. A. Sopko, Moretrench and B. Khorshidi and B. McInnes, McNally Construction Inc The Port Mann Main Water Supply Tunnel involves a 1km long tunnel beneath the Fraser River from Surrey to Coquitlam, BC. At depths of up to 60 m below ground, the earth pressure reached 6 bar, the highest tunnel pressure in North America to date. The tunnel is constructed using an EPB TBM and gasketed precast concrete segmental liner. The tunnel and two shafts were constructed in a variety of soil conditions ranging from soft to stiff clays and silts, to compact to very dense sands and gravels. After approximately 800m of mining, a very dense and highly variable soil group consisting of cobbles and boulders halted the TBM.
Several options were considered to stabilize the TBM face so an intervention could be conducted. Although de-watering was considered, there was risk of settlement to the Port Mann bridge piers, which was within 500m of the tunnel. Hyperbarics was also considered, however, the cost, schedule and uncertainty of the work that need to be done, made it a risky option. Ground freezing by Liquid Nitrogen was chosen as the best solution, which would provide a frozen block around the face of the TBM. A temporary platform on the river was designed and constructed to enable drilling and installation of the freezing pipes and temperature monitoring equipment. The operation required close coordination among the tunnelling, marine and freezing sectors.
Following the intervention, the TBM successfully broke through the reception shaft, and the remaining project was completed.
This paper describes the design, construction and operational approaches used for the freezing and serves as a basis for future projects requiring expedited ground freezing.
15:00-15:20 Soft Ground Tunneling Under a Major Provincial Highway in Ontario- Sheppard East LRT, Toronto H. Mahdavi and V. Nasri, AECOM and K. Akbarpour, CH2M The Sheppard East Light Rail Transit (SELRT) project consists of about 13 km of new LRT line which will be constructed along Sheppard Avenue East in Toronto. Included in the alignment is an underground portion crossing under a major provincial Highway. Ministry of Transportation of Ontario (MTO) has guidelines for tunneling under its highways specifying deformation criteria.
An impact analysis was conducted, using three-dimensional (3D) ﬁnite element (FE) modelling, to predict the settlement and angular distortion at Highway 404 ground surface resulting from the construction of the twin tunnels. The results were then compared to deformation criteria deﬁned in MTO’s guidelines and similar
15:20-15:40 From Building Information Modeling to Real Time Simulation in Mechanized Tunneling an Integrated Approach Applied to the Wehrhahn-line Düsseldorf A. Alsahly, V. E. Gall, A. Marwan, J. Ninic G. Meschke, ˙, A. Vonthron and M. König, Ruhr-University Bochum In current tunneling practice, ﬁnite element simulations have become an integral element of the planning and design process. These models are most often manually generated using 2D CAD drawings, which is a laborious and time consuming process. In this paper, we propose a BIM based approach, in which the 3D FE-model is automatically generated through a set of compatible geometries of individual components, i.e. the geology, alignment, lining and the TBM. The BIM model also includes all relevant model parameters of the tunneling project that can then be incorporated into subsequent analysis to be performed during the tunnel drive. The setup and the execution of the FE-analysis are performed automatically utilizing all required data from BIM. The applicability and efﬁciency of the proposed strategies is demonstrated by means of project data from the Wehrhahn-Line metro project in Düsseldorf, Germany. Both the design as well as the construction stage is considered.
15:40-16:10 Break 16:10-16:30 TBM Operation Challenges at DTL3 C931 Project in Singapore E. Farrokh, D. Young Kim, B. Kyung Sim and J. Won Lee, Hyundai Engineering and Construction The contract C931 of the downtown line 3 (DTL3) mass rapid transit system of Singapore includes half a kilometer twin tunnels running between Mattar and Macpherson stations. An EPB TBM of 6.6 m diameter was used to excavate both of these tunnels.
The tunnels pass predominantly through a very stiff silty/clayey ﬁne to coarse sand from the Old Alluvium Formation. In this paper, TBM selection procedure, TBM performance evaluation, and some of the tunneling operation challenges with the TBM in the Old Alluvium Formation are discussed. In this regard, soil conditioning trial tests were performed to resolve the clogging issue and low TBM performance. Thorough TBM operational data analysis was performed to detect high soil abrasivity, backﬁll grout leakage, and foam nozzle clogging. The results of some of the applied modiﬁcations are also discussed to show their effects on the TBM performance improvement. Finally, some of the challenging TBM design speciﬁcations are also discussed.
22 – 28 APRIL | MOSCONE CENTER | WTC2016 16:30-16:50 Inﬂuence of EPB-TBM Heading Conﬁnement Pressure on Surface Settlements: Comparison Between 3D FE Numerical Predictions and in Situ Measurements J.P. Janin, TERRASOL ; P. Renier, EDF and A. Bergère and H.
Le Bissonnais, TERRASOL The most important impact on the environment of a tunnel excavation is the creation of surface settlements, which can generate serious problems in existing civil structures. Nowadays, the mechanized tunneling allows minimizing the settlements, applying a conﬁnement pressure which counterbalances the ground de-conﬁnement. It is thus essential to determine the correct amount of conﬁnement pressure. In this paper, the authors present a 3D numerical study simulating the EPB-TBM excavation of a water tunnel, in the Flanders clays (north of France). Firstly, a simpliﬁed 3D simulation, based on the concept of instantaneous longitudinal settlement curve, was performed to predict the surface settlements for different values of heading conﬁnement pressures. Secondly, the same pressures were tested by the EPB-TBM in a monitoring zone. The comparison between the prediction settlements and the measurements was very satisfactory and allowed validation of the numerical approach and the choice of the optimal conﬁnement pressure value for a sensitive area of the project.
16:50-17:10 Experiences Gained in Heterogeneous Ground Conditions at the Twin Tube EPB Shield Tunnels in Sao Paulo Metro Line 5 M. Comulada and U. Maidl, Maidl Tunnelconsultants;
M Peixoto Silva and G. Aguiar, Consórcio Linha 5 - Lilás and A. Ferreira, Metro Sao Paulo Metro Line 5 Lot 3 in Sao Paulo is being constructed by Consórcio Linha 5 Lilás. This lot extends for 4,940 m as twin EPB shield tunnels under a dense and busy urban area, with an excavation diameter of 6.9 m. The tunnels run predominantly in the tertiary soils of Sao Paulo where extensive experience exists from previous EPB shield tunnel projects. However, new experience is being gained in Sao Paulo in shield tunnelling through Saprolito, the weathered product of the underlying Gneiss crystalline basement, and through the resulting residual soils. Furthermore, experiences in difﬁcult mixed face soil conditions with overconsolidated clay at the face in combination with loose sands at the crown under the groundwater table will be presented. Additionally, the design, operational and controlling approach followed for the shield drive at particular critical cross-sections where the shields were driven close or under buildings.
WTC2016 | SAN FRANCISCO CALIFORNIA, USA WEDNESDAY 27 APRIL 17:10-17:30 Impact of Tunneling on Pile Structures Above the Tunnel Experimental Study on a 1g Reduced Scale Model of TBM J. Bel, D. Branque and H. Wong, Université de Lyon and G.
Viggiani and N. Losacco, University of Rome ‘Tor Vergata’ Within the framework of the European project NeTTUN, the Laboratory of Civil Engineering and Building Sciences of ENTPE in Lyon (France) is in charge of a large experimental campaign to investigate the impact of tunneling on neighbouring piled structures. For this study, an original reduced-scale (around 1:10) physical model of EPBS is used. This "1g" laboratory model is able to reproduce the main features of the excavation method.
For this new experimental program, the miniature EPBS advances inside a large tank ﬁlled with a model soil (dry sand), in which instrumented piles were pre-installed. In this paper, the authors describe brieﬂy the original 3D device and present results concerning the impact of tunneling on a single pile located above the tunnel. Different tunneling face pressure are studied in connection with the practice. Machine parameters, pile solicitations and stress-strain behavior of the soil mass monitored under real time conditions are discussed.
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.) EPB Bypass and Hanging of 2.6 m Dia.
Sewer Under Live Flow Conditions J. A. Schreiner and M. Geary, Mott MacDonald and S. J. Marino, The Regional Municipality of York The Southeast Collector (SeC) is a new 15 km long 3.0 m internal diameter wastewater tunnel designed by Mott MacDonald (HMM) that twins the existing 2.6 m diameter York-Durham Sewage System (YDSS) tunnel. Both sewage tunnels are located north of the City of Toronto in Ontario, Canada. The SeC provides much needed conveyance capacity for the rapidly growing York Region population, supporting development until 2036 and increasing sewage system security (Mott MacDonald and Aecom 2011). Construction of the SeC will also permit ﬂows of the twinned section of the YDSS to be bypassed in order to clean, inspect and carry out any essential maintenance within the YDSS tunnel. Although owned and operated by York Region, the SeC spans two regional municipalities beginning upstream from the intersection of Ninth Line and Rouge Bank Drive in the City of Markham in York Region to the downstream Finch Avenue and Valley Farm Road intersection in the City of Pickering in Durham Region. See Figure 1 for the SeC and YDSS alignment. The project includes 19 shafts and chambers with depths ranging from 8 to 48 m in addition to seven facilities supporting the operation and maintenance of the sewer. The construction contract was awarded to Strabag Inc in July 2011 for $291M CAD. Construction Management services were provided by a joint venture team of Mott MacDonald and AECOM.
An Empirical Relationship for Predicting the Surface Settlement due to the EPB-TBM Excavation – Case Study: Mashad Metro Line 2 B. Eslami and A. Golshani, Tarbiat Modares University (TMU) Surface settlement adjacent sensitive structures have been a challenging issue in the tunnel engineering. In this study, ﬁrst 3D simulation of TBM has been performed with FLAC3D code, After the results were compared with real data monitoring. Sensitivity analysis for all parameters effecting on the surface settlement was carried out, such as tail void grouting pressure (Pt), face pressure (Pf), diameter of the tunnel (D), overburden (q), shield thickness (t) and length of shield (L). Results have shown the face pressure, tail void grouting and tunnel diameter have considerable effect on the maximum ground displacement. In this paper, the monitoring data of metro Mashad were used to verify the numerical simulation. We selected the data monitoring for about 47 sections between A2 to D2 stations and has performed a multiple regression analysis. Based on this analysis, ﬁnally we obtained an empirical relationship that coefﬁcient of regression relationship conﬁrmed sensitivity analysis.
WTC2016 | SAN FRANCISCO CALIFORNIA, USA WEDNESDAY 27 APRIL Evaluation of 3D FE Predictions of Ground Movements Caused by EPB Tunneling in Stiff Clay V. Founta and A. J. Whittle, Massachusetts Institute of Technology This paper describes the development of a 3D ﬁnite element model for predicting ground movements caused by construction of 7.1 m diameter twin bored tunnels for the Crossrail project in London using Earth Pressure Balance (EPB) machines. The model uses the commercial FE code, Plaxis 3D, to represent the face pressure, conical shield, grouting process and activation of precast segmental concrete lining systems through a set of boundary conditions that advance through the soil mass along a prescribed trajectory. The analyses focus on performance of the EPB tunneling machines in greenﬁeld conditions beneath Hyde Park, where the tunneling occurs within deep layers of relatively uniform London Clay. The numerical analyses compare results computed using the Mohr-Coulomb soil model with input parameters calibrated from laboratory element tests. The predictions are evaluated using surface and sub-surface ground movements from a well-instrumented section. The model predicts well the sub-surface vertical movements but tends to overestimate the measured lateral displacements towards the tunnel.
Comparison between Calculated and Actual Face Pressures in EPB TBMs – Case Studies in Seattle, WA E. Alavi, G. Frank and B. Hagan, JayDee Contractors, Inc; C.
LaVassar, McMillen Jacobs Associates; L. Mori, Colorado School of Mines, D. Dugan, North Star and R. Capka, Sound Transit Tunnel face instability is one of the most common issues in EPB tunneling. The evaluation of an ideal face support pressure is a critical element in the design and construction phases of EPB tunneling. In this study, measured tunnel face pressure in three EPB tunneling projects (University Link U230 and U220 projects and the Northgate Link Extension N125 Project) in Seattle, WA is compared with the calculated analytical methods. This comparison shows that the analytical methods generally overestimate the required tunnel face support. The best practice for managing the face pressure in EPB tunneling operation is discussed based on the experience gained through these projects. Furthermore, the algorithm that is developed for identifying ground loss in these projects is addressed.
22 – 28 APRIL | MOSCONE CENTER | WTC2016 Treating Peat-Soil Over São Paulo Metro Line 5 Enabling 10.6M EPB Shield Advance Under Drainage Gallery Foundations A. Koshima, J. Ricardo Lopes, A. Moraes Filho and M. Gomes, Novatecna Consolidações e Construções S.A and A. Coelho Jr, Cetenco Engenharia S.A.
Very low strength alluvial peat soil was found under two old drainage galleries with just 4.3m cover above a twin tunnel due to be excavated by a 10.6m diameter EPB Shield for São Paulo Metro’s Line 5. Alignment was required to strengthen soil and drive the TBM through safely without damaging the galleries. The design included six levels of self-drilling forepoling with lengths up to 15m, using 100 mm-diameter SCH160 metal tubing and injection bulbs with estimated 0.20m diameter. Two 6m-diameter circular shafts were excavated along the shield-tunnel axis, one each side of the galleries, and forepoling fanned out under gallery foundations. Given the peculiar soil and conﬁned working space, more data were needed for correct drilling geometry.
Ground mass treatment was successfully designed and executed and galleries were ﬁtted with instruments to enable the shield’s advance.
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