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15:00-15:20 Seismic Performance of Wine Caves A. Kositsky and S. Lewis, Condor Earth Technologies, Inc The South Napa Earthquake of 2014 caused ground motion at numerous reinforced concrete-lined (shotcrete-lined) winery tunnels in Napa County and Sonoma County, California. The occurrence of seismic ground motion at these tunnel complexes, known as wine caves, presented an opportunity to reevaluate seismic performance of reinforced concrete and reinforced shotcrete lined tunnels. The authors of this paper updated the most recent comprehensive compilation and evaluation of case studies by Power and others (1998), which correlates peak ground acceleration (PGA) at tunnel sites to damage. For this update, the authors evaluated the seismic performance of 31 wine caves near the South Napa Earthquake epicenter; including some of the 90 wine caves they designed since 1991, some caves designed by others, and additional caves constructed by contractors that they frequently work with. Tunnel designers can use the new data presented in this paper to help evaluate the usefulness of detailed seismic design analyses.
22 – 28 APRIL | MOSCONE CENTER | WTC2016 15:20-15:40 Tunnel Deformation Mode and Loading Magnitude During Large Earthquake A. Kusaka, Public Works Research Institute; K. Kawata, Oriental Consultants Co, Ltd. and N. Isago, Public Works Research Institute Rock tunnels suffered severe damage from recent large earthquakes in Japan, despite the empirical knowledge that tunnels tolerate earthquakes better than surface structures. Seismic design for rock tunnels have therefore become a fascinating subject for many tunnel engineers. However, even basic behavior, including deformation mode and loading magnitude for hard-rock TBM tunnels and conventional ones during earthquake, has not been fully understood due to lack of actual seismic data; while EPB and slurry TBM tunnels take account of seismic design in Japan if needed.
This study conducted a dynamic measurement in an actual road tunnel constructed in rock. The strongest aftershock of “the 2011 off the Paciﬁc coast of Tohoku Earthquake” (Mw = 7.1) occurred during the measurement, providing precious data to examine deformation mode of the tunnel. Considering the acquired data, numerical analysis was also performed to calculate loading magnitude to cause fatal fracture of tunnel lining during earthquake.
15:40-16:10 Break 16:10-16:30 Tunnel Deformations Caused by Compensation Grouting at Crossrail Farringdon Station A. Gakis and T. Schwind, Dr. Sauer & Partners Ltd and B. Grau, Technical University of Graz & Dr. Sauer & Partners Ltd In Crossrail’s Farringdon station, compensation grouting was successfully utilized to mitigate the surface settlements induced by the tunneling works. The main focus of this study was the platform tunnels, which were approximately 300m long each and were enlarged to platform size using sequential excavation method (SEM) from the existing TBM running tunnels, initially supported using sprayed concrete linings. The rear grouting injections were carried out at a typical distance of minimum 5m above the completed, fully strengthened shotcrete lining hence inducing some additional stresses. In tunnel monitoring using surveying targets was performed systematically to ensure that no excessive distortion of the initial shotcrete lining occurred. 3D ﬁnite element analyses were utilized to back calculate the actual “effective” pressure that was imposed on the completed shotcrete rings against the additional measured in-tunnel displacements due to the compensation grouting episodes. Additionally an assessment of the theoretical, “maximum” allowable grouting pressures that would lead to overstressing of the lining is presented.
WTC2016 | SAN FRANCISCO CALIFORNIA, USA TUESDAY 26 APRIL 16:30-16:50 Time-Dependent Deformations of Excavations and Tunnels in the Greater Toronto Area A. Cushing and J. Hurt, Arup and J. Carvalho, Golder Associates The shales of the Greater Toronto Area (GTA) have been known to experience time-dependent deformations (TDD); those initiated by excavation-induced stress relief which progress with time as a function of rock porewater salinity, access to freshwater (or air) of lower salinity, clay and calcite content, and the buildup of swelling pressures within the rock mass. These deformations can induce long-term pressures on shaft walls and tunnel linings, especially if the permanent works are constructed soon after excavation, with very little time delay. This paper presents measurements of time dependent deformation of recent shaft and tunnel projects constructed in the GTA, and draws conclusions regarding the main inﬂuences on the TDD. The key input parameters for the numerical predictive model are critically assessed. Projects which are discussed include the Billy Bishop Airport Pedestrian Tunnel, Hydro One Midtown Tunnel and Hanlan Feedermain (Contract 3).
16:50-17:10 Istanbul Strait Road Tunnel Project – Seismic Joint and Passive Fire Protection in Double Deck TBM Tunnel J. Kim, D. Lee, M. Öztürk and J. Lee, YMSK Joint Venture and T.
Kim and B. Arıog˘ lu, Yapı Merkezi Yapı Merkezi Ins¸aat ve Sanayi A.S¸.
Istanbul Strait Road Tube Crossing Project (Eurasia Tunnel) includes
3.34 km of a bored double-deck tunnel under the Bosphorus Strait, at a maximum depth of 106 m from the sea level, and 1 km of twin NATM tunnels on the Asian side. The region’s variable geology, hydrology and propensity for seismic activity, combined with high water pressure and large -diameter/double-deck tunnel conﬁguration, make the Eurasia Tunnel one of today’s most challenging and complex projects under construction. Due to the site’s proximity to the active North Anatolian Fault, the tunnel is designed to withstand a 7.5 magnitude earthquake. The tunnel penetrate s through both the Trakya bedrock (on both European and Asian sides) and the alluvial sediments at the bottom of the channel. The tunnel is designed to accommodate differential displacements by introducing seismic/ ﬂexible joints at proper locations at the transition zones between rock and soft soils. Tunnel ﬁre is also a signiﬁcant design consideration for undersea tunnel due to that the rubber protecting it in close proximity of the seismic joint should resist a ﬁre for long term safety and durability. This paper mainly focuses on the design for method of tunnel response analysis in transverse and longitudinal direction against seismic demands relating with the seismic joints.
22 – 28 APRIL | MOSCONE CENTER | WTC2016 17:10-17:30 Assessing the Interaction between the Excavation of a Large Cavern and Existing Tunnels in the Alps M. Semeraro, E. Misano, M. Schivre and A. Bochon, Systra The Laboratoire Souterrain de Modane (LSM) is an underground research laboratory located in the Western Alps on the French – Italian border. It is located in the middle of the 13km long Fréjus highway tunnel that links Modane (France) to Bardonecchia (Italy) in correspondence of the highest overburden of 1800m. The LSM current activity is mainly based on the investigations about the dark matter and requires very sensitive instrumentation which shall be protected from cosmic rays. To comply with the new legislation about safety in tunnels, the highway tunnels owners agreed in 2007 the construction of a parallel safety tunnel, at an average distance of 50m from the existing tunnel and the laboratory owner CNRS (Centre National de recherche scientiﬁque) also decided to extend the existing laboratory with the construction of a new 17000 m3 cavern allowing the installation of wider and more powerful instruments that could increase chances of success of research.
Structural Impacts to Tunnels Due to Flooding R. Sandiford and T. Moon, HNTB In 2012, Superstorm Sandy (Sandy) caused extensive ﬂooding in many of the tunnels in New York City. The inundation resulted in two distinct stress changes to the tunnel structures. The ﬁrst stress change was water pressure on the inside face of the tunnel lining. The second condition related to the change in buoyancy of the tunnels. In areas where the tunnels were supported on rock and an adjoining area supported on soft soil, overstress issues arose. Numerical analyses were performed to assess the structural impacts of the tunnel water inundation; especially stress changes due to internal pressure as well as changes resulting from the buoyancy effects. The paper will discuss the assessment process and its results; it will demonstrate that the change in internal pressure were of little consequence, however the change in buoyancy resulted in signiﬁcant increases in bolt stresses.
3-Dimensional Analysis of EPB TBM Operation in Close Proximity to Pile Foundations M. Sepehrmanesh and V. Nasri, AECOM; and M. Partovi, TNO DIANA This paper presents an assessment of the impact of tunneling and its associated risks on pile foundations located in the inﬂuence zone of tunneling operation. Tunneling in proximity of pile foundations introduces deformations in piles and in turn induces additional axial and bending forces. In modern mechanized tunneling, ground convergence is controlled through balancing the earth pressure at the tunnel face as well as applying pressurized bentonite through the shield.
Reducing ground deformation can consequently lower the additional deformations and forces developed in the pile foundation and lessen the associated construction risk. In this paper, comprehensive detailed ﬁnite element modeling was performed to quantify the effect of the different parameters on induced forces in piles. Finite element models took into account the nonlinear behavior of soil and pile-soil interface. The modeling results are of practical importance in risk evaluation of tunneling in vicinity of pile foundations.
Seismic Response of Cylindrical Tunnel with Void behind the Lining based on Three-Dimensional Elastodynamics N. Yasuda, K. Tsukada and T. Asakura, Kyoto University Old tunnels that were constructed using conventional methods in Japan often have voids around the tunnel crown, i.e., there are partial discontinuities between the lining and ground, and almost all tunnels that were severely damaged by the earthquake have those defects. For understanding the effect of a void behind the lining on seismic damage of tunnels and for planning countermeasures against a severe earthquake, three-dimensional elastic solutions for a deep cylindrical tunnel, with a void behind the lining, under the oblique-incidence of shear wave are derived. Numerical results show that a void does not cause the large stress concentration to the lining under oblique-incidence of shear wave. Reinforcements of the lining where large stress concentration has already occurred are necessary 22 – 28 APRIL | MOSCONE CENTER | WTC2016 Posters (Continued) as the countermeasure because it is probable that there are high correlations between large stress concentration in the lining caused by voids before an earthquake and seismic damage of tunnels.
Tunneling in Close Proximity to Structures in Downtown Los Angeles – A Brief Overview of Settlement Effect Evaluations H. Yang, S. Von Stockhausen, K. Huynh, and D. Penrice, Mott MacDonald and T. T. Vu, AECOM The Regional Connector Transit Corridor is a 1.9 mile long light rail transit project in downtown Los Angeles, California. The project includes approximately 4,930 feet of twin bored tunnels together with a mined crossover cavern, 3 deep stations, and other cut-andcover structures. The bored tunnels will be excavated using an earth pressure balance tunnel boring machine through Fernando Formation (extremely weak to weak rock) and alluvium. The tunneling will be performed in close proximity to a large number of existing structures, including the existing Metro Red Line tunnels with as little as 6 feet of separation. Thus, the evaluations of the tunneling effect on these structures and the instrumentation and monitoring program is an essential part of the project design. This paper provides a very brief overview of the considerations and evaluations of the tunneling effects on the existing structures and results of evaluation obtained during the ﬁnal design stage of the project.
Laboratory Test on the Effect of Risk Mitigation Measures Against Earthquake for Existing Rock Tunnel K. Kawata, Oriental Consultants Co, Ltd and N. Isago and A. Kusaka, Public Works Research Institute Strong earthquakes occur frequently in Japan, and some rock tunnels have sustained severe damages on their permanent lining. Many road tunnels, which were constructed by conventional steel arch support and timber lagging method, exist in Japan and they need risk mitigation measures against earthquakes as per our empirical knowledge. Many reinforcing measures for deformed tunnels that may be effective against earthquakes are developed;
however, behaviors during earthquakes are not fully understood.
In this study, static loading tests and numerical analysis, which WTC2016 | SAN FRANCISCO CALIFORNIA, USA TUESDAY 26 APRIL simulate a loading condition during earthquakes, were carried out to clarify the effect of the countermeasures. The Load-bearing capacity is estimated for the tunnel structures facilitated by the installment of an inverted arch; however, a joint between inverted arch and sidewall become structural weakness. Rock bolts and carbon ﬁber sheets have a potential able to mitigate the risks of collapse of the lining by the forces from an earthquake.
Dynamic Interaction between Railway Tunnels at Multi-leveled Tunnel Intersection H. Kim, K. Kim and J. Shin, Konkuk University and H. Moon, Dasan Consultants In urban areas, it is often required to construct additional railway tunnels beneath existing railway tunnels. In this case, dynamic interaction between tunnels at the intersection becomes an important issue, as it ampliﬁes structural behavior causing damage to structures and inconvenience to passengers. In this study, vibration superposition effect at the intersection between existing and newly constructed tunnels is investigated by the numerical method. Dynamic interaction mechanism is ﬁrstly examined using simple sine wave load, and then a typical analysis for actual multi-leveled tunnel intersection is performed. The results show that the dynamic ampliﬁcation due to dynamic interaction of tunnels is 149% at the crown of lower tunnel. This indicates that the vibration superposition effect must be considered when the planning and design of a new tunnel beneath the existing tunnel.