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Soil Conditioning in Doha Metro Project – Qatar A. Picchio, MAPEI DOHA L.L.C. and D. Negro Enrico and B. Alessandro, MAPEI S.p.A The Doha Metro Project is one of the most relevant tunneling ongoing project. The whole project comprehends about 100 km of tunnels with 21 EPB TBMs working contemporarily. Due to the variability of the geological formations, the soil conditioning is a relevant aspect of this project because the parameters should be frequently adjusted to achieve the best performances of the TBMs. The study of the soil conditioning has been carried out accurately to obtain the best results on site. The study of WTC2016 | SAN FRANCISCO CALIFORNIA, USA WEDNESDAY 27 APRIL the geotechnical data, the choice of the most suitable foaming agents and polymers and the laboratory study of the soil conditioning has been a fundamental part of the job. The application of the soil conditioning products on site with the analysis of the TBM data have conﬁrmed the preliminary study results with some correlation between the features of the ground and the soil conditioning parameters to be used.
An Experimental Apparatus to Estimate the Shear Strength of Conditioned Soil for EPB D. Martinelli, R. Winderholler and D.Peila, DIATI - Politecnico di Torino This paper presents a technical description of an experimental procedure developed for the geotechnical characterization of granular soils conditioned for EPB tunneling using a modiﬁed direct shear box. As the main concerning parameters of the conditioned soil mass were their undrained properties, in order to preserve its pseudo-ﬂuid characteristics, a watertight direct shear apparatus was constructed. A comparison between the results obtained under dry, saturated and conditioned conditions is presented.
Using Laboratory Testing for Designing an Optimum Field Grout for the Millwoods Double Barrel Replacement Project C. El Mohtar, University of Texas at Austin; J. J. Brady, ILF Consultants, Inc and R. Sangroya, H. Jaffal, W. Shun Kwan and A. K. Miller, University of Texas at Austin The design of an appropriate pre-grouting program can be the difference between a successful tunnel construction and an expensive on-the-go repair. However, current grout design relies heavily on rules-of-thumb and outdated charts. The geotechnical investigation is rarely targeted towards grouting design and the ﬁnal grouting decisions are made based on ﬁnes content or soil classiﬁcation. The current paper presents an experimental study performed to determine the optimal grout for a tunnel in soft ground below the ground water table (GWT). The testing program consisted of sieve analysis and undrained static triaxial tests on reconstituted sonic samples. Rheological tests were used to compare the different grout mixes and identify best candidates before performing one-dimensional permeation tests.
Pressure and volume measurements during the permeation tests, along with the unconﬁned compression strength results on the permeated soils, helped evaluate the ﬁltration potential for the different grouts and select the optimal grout.
Rehabilitation and Operation & Maintenance Chair: M. Rispin, Normet Americas Inc, USA ITA Co-chair: W. Burger, ITAtech Sub AG Rebuilt Equipment leader, Germany 14:00-14:20 National Tunnel Inspection Program Manual for Tunnel Operations, Maintenance, Inspection, and Evaluation W. Bergeson, Federal Highway Administration In 2012, Congress passed ‘MAP-21’, which required all highway tunnels on US public roads to be inventoried and inspected. As part of this mandate, the Federal Highway Administration concurrently published the National Tunnel Inspection Standards, the Tunnel Operations, Maintenance, Inspection, and Evaluation Manual, and the Speciﬁcations for National Tunnel Inventory on July 14, 2015. This new National Tunnel Inspection Program focus is to improve safety and provide reliable levels of service.
Data collected will be entered into a national tunnel database to assist tunnel owners with the development of data-driven and risk-based evaluation methods as part of their cost-effective asset management program. This paper provides essential background information on the federal program; it discusses key documents such as the NTIS, TOMIE Manual, SNTI, and MBE; and it provides information on the comprehensive and refresher training developed by the FHWA.
14:20-14:40 Optic Fiber Structural Monitoring System for Pavoncelli Bis Hydraulic Tunnel G. Eccher, SWS Engineering S.p.A.; M. Caponero, Enea;
R. D’Angelis, Consortium: Vianini Lavori S.p.A. – Ghella S.p.A. – Giuzio S.r.l and P. Cucino, SWS Engineering S.p.A.
This paper describes the optic ﬁber structural monitoring system implemented for Pavoncelli Bis tunnel. The paper highlights the optic ﬁber sensors customization capabilities, how they smoothly ﬁt precast concrete lining processes and TBM operations, and how a lifelong service monitoring can be achieved. An overview of readings’ evolution during excavation concludes the paper.
22 – 28 APRIL | MOSCONE CENTER | WTC2016 14:40-15:00 Inspection Equipment Study on Subway Tunnel Defects Y. Sun, Y. Xue, H. Huang and F. Wang, Tongji University Increasing attention to subway tunnel maintenance is being paid with the high speed development of urban rail transit system in China. A novel moving tunnel inspection equipment based on machine vision is developed in this paper. High resolution image acquisition system is proposed for tunnel crack and leakage inspection. The main components of this image acquisition system includes high speed CCD cameras, linear lights and high performance computer. To inspect the crack less than 0.3mm with a 3-5km/h speed in subway tunnel, we need to consider resolution and line rate of camera, pixels of cameras, range of inspection and illumination intensity of lights simultaneously. The optimization design is proposed to make the equipment more convenient for tunnel use. Entire tunnel situation can be detected and recorded in a single inspection process. This equipment has already been veriﬁed in Shanghai subway tunnel for defects inspection.
15:00-15:20 Innovative Rehabilitation Approach for Overstressed Existing Linings using an Adaptable Yielding Support System A. G. Nitschke, Shannon & Wilson, Inc; W. Dolsak, DSI Underground Systems, Inc; V. Gall, Gall Zeidler Consultants, LLC;
J. Dase, Rio Tinto Kennecott Copper and I. Ossenbühl, BUM Beton- und Monierbau GmbH Yielding support systems for application in underground construction have a long history, primarily in mining. Typical examples are tunnels subject to loading conditions that lead to overstressing of the newly installed support or existing tunnel structures in active fault zones. Recent applications for tunnel rehabilitation projects unveiled the capabilities and ﬂexibility of combined yielding support systems presented in this paper. Frequently, the main requirements for tunnel rehabilitation applications are a fast, safe, and simple installation along with the need for ﬂexibility with regards to existing tunnel geometries. A combined support system consisting of steel sets with yielding connections and special groutable hoses has proven to be an efﬁcient support measure providing a multitude of advantages compared to conventional rehabilitation approaches. The presented yielding support system provides an immediate and active support, while it allows for controlled yielding upon experiencing loads beyond its support capacity.
15:20-15:40 Hydraulic Assessment and Rehabilitation of a Deep Stormwater Tunnel M. Haggerty and B. Barnes, Barr Engineering Co Around Minneapolis and Saint Paul, Minnesota, the local geology includes the St. Peter Sandstone, which is easily minable and has facilitated construction of interceptor tunnels for storm water and sanitary tunnels since the 1800s. The elevation of the geologic WTC2016 | SAN FRANCISCO CALIFORNIA, USA WEDNESDAY 27 APRIL units allowed gravity-driven ﬂows from the downtown areas all the way to the Mississippi River. Through many years of service, some of these tunnels have experienced degradation and require maintenance. Additionally, increased stormwater surface runoff can result in internal pressurization of the tunnels, accelerating degradation. Because structural failure or collapse of any of these interceptor tunnels would create a signiﬁcant repair challenge, the city of Minneapolis has been inspecting and designating tunnels in its system for periodic review and repair. One of these, the St. Mary’s/Hiawatha tunnel, was rehabilitated using a grouting program. A hydrologic model was also used to improve understanding of pressurization events during some storms, leading to construction of a near-surface pressure dissipation chamber to provide increased hydraulic capacity.
15:40-16:10 Break 16:10-16:30 Life-Cycle Costing – An Economic Approach to Evaluate the Operational Equipment of Tunnels H. Adden and M. Thewes, Ruhr University Bochum;
A. Lehan, Federal Highway Research Institute and J. Schwarz, University Bundeswehr Munich To more rigorously address tunneling risks to above-ground structures, vulnerability evaluation of all structures along a tunnel route is required. This multi-block area along the route can be considered a district. To fully assess each structure within inﬂuenced zone, a district-level model may provide new insights as to risk evaluation. However, populating such a model with the existing geometry poses a major challenge as measured drawings are not readily available. Cost-effective population of such a model could arguably involve remote sensing data. However even for unreinforced masonries, where external, above-ground geometries can be captured, without a prohibitively expensive building-by-building survey many factors would remain unknown.
To consider these uncertainties in an automatic way, a performance assessment framework is proposed. Such a framework allows a more rigorous, initial, risk quantiﬁcation than is currently possible within models generally being used. This paper introduces considerations for application of a district-level, tunnel-risk screening tool.
16:30-16:50 Rehabilitation of Farnworth Tunnels – Modifying Victorian tunnels for the 21st Century E. Murphy and S. Beauchamp, OTB Engineering Ltd and S. Cowell, J Murphy & Sons Ltd Electriﬁcation of the heavily trafﬁcked Manchester to Preston route by Network Rail required the rehabilitation of the Victorian era Farnworth Tunnels to accommodate 21st century high speed trains. Network Rail, J. Murphy and Sons Ltd (JMS) and OTB Engineering Ltd (OTB) collaborated closely to complete these works in close proximity to heritage infrastructure whilst 22 – 28 APRIL | MOSCONE CENTER | WTC2016 maintaining a rail service on the route. This signiﬁcant challenge has been mastered by a combination of detailed investigation, complex modelling, robust design, extensive monitoring, ground treatment, secant piling, sprayed concrete, steel arches and segmental lining techniques. Investigation of the “Down” Tunnel found deformation and cracking of the lining and this was reconstructed during 11 weekend possessions. The “Up” Tunnel was ﬁlled with low strength concrete and a 9m diameter open face shield was used to construct an 8m diameter segmental lined tunnel during a 23 week blockade whilst trafﬁc was maintained in the “Down” Tunnel.
16:50-17:10 The Four Fates of the 140-Year-Old Baltimore and Potomac Tunnel K. R. Ott, WSP/Parsons Brinckerhoff; W. A. Prosser, Jr., Amtrak and P. Rice, WSP/Parsons Brinckerhoff The existing Baltimore and Potomac (B&P) Tunnel accommodates Amtrak and MARC service between Baltimore, MD and Washington, DC and local freight service. The Baltimore and Potomac Tunnel Replacement Project proposes new tunnel construction through Baltimore, MD along the Northeast Corridor that maintains connections to Baltimore Pennsylvania Station.
After the Replacement Project is constructed and operational, the disposition of the existing B&P Tunnel must be determined.
Alternative uses for the existing 140-year-old B&P Tunnel can be considered, such as conversion for non-rail use, rehabilitation, or complete modernization for continued rail trafﬁc.
17:10-17:30 The Light at the End of a 40-Year-Old Tunnel – Retroﬁtting of an Existing Tunnel as Part of the New Second Avenue Subway Project, New York M. Trabold, AECOM; R. Giffen, Arup, and P. Lemus, 3EE Cruz Co Inc Contractors & Engineers As part of the new 2nd Ave Subway Project, an existing tunnel constructed in the 1970’s will be connected to the new subway and used as new running tunnels. The existing tunnel had to be modiﬁed to comply with newer structural and ﬁre life safety codes and to be connected to the new cut and cover station at 96th St. This paper will discuss the complexities of tying an existing tunnel constructed over 40 years ago into the new station and allowing for movements due to the unloading of the existing tunnel and the differential settlement of the two structures during both the construction and permanent condition. Topics that will be discussed include structural analysis, ground improvement techniques, selection of support of excavation walls, working in contaminated soil and instrumentation and monitoring of the structures. It will also cover retroﬁtting the tunnel to comply with updated Fire/Life/Safety requirements.
Alternative Study of Rehabilitation Options for Heroes Tunnel: A New Approach M.R. Jafari, L. Murphy, S.K. Kalluri and D.M. Giel, CDM Smith Built in 1940’s to provide a key roadway arterial between New York and Boston, the Heroes Tunnel is the only highway rock tunnel in the state of Connecticut and is part of the Wilbur Cross Parkway. This 365.0 m long tunnel consists of two barrels, each with two lanes of trafﬁc, and carries over 71,000 vehicles per day. For nearly 70 years, the tunnel has seen millions of vehicles pass through but time has taken its toll and now the tunnel lining, ventilation system and radial section joints are signiﬁcantly deteriorated and in need of rehabilitation. Owned and maintained by the Connecticut Department of Transportation (CTDOT), CTDOT initiated a unique managed approach to mitigate the risk, social impacts and ﬁnancial implications associated with rehabilitation of this tunnel. This new approach consists of performing ﬁeld inspection and conducting a comprehensive study to explore six rehabilitation options, including construction of new tunnels and
enlarging the existing tunnels. The main criteria for this study are: