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16:30-16:50 Lake Mead Intake No. 3 – The TBM Tunneling Experience R. Schuerch and P. Perazzelli, ETH Zurich; J. Nickerson and C. Cimiotti, JV Salini-Impregilo S.p.A and S.A. Healy Co and G. Anagnostou, ETH Zurich This paper presents experiences gained from the construction of the Lake Mead Intake No. 3 project. The 4.7 km long tunnel was excavated with a hybrid TBM (able to operate in both closed and open mode). The tunnel crossed metamorphic and sedimentary rocks under a hydrostatic pressure of about 14 bar. During the excavation of the tunnel the TBM encountered difﬁcult ground conditions caused by a combination of high water pressure, poor ground quality and locally low depth of cover. The adverse conditions required the TBM to be
16:50-17:10 Study of TBM Performance Prediction Using Rock Mass Classiﬁcation A. Salimi and C. Moormann, University of Stuttgart and J. Rostami, Pennsylvania State University Rock mass classiﬁcation systems are often applied in many empirical design practices in rock engineering, some contrasting with the original intent and applications of these classiﬁcation systems, for example, estimation of TBM performance in various ground conditions. While accurate estimation of machine performance is signiﬁcantly impacted by rock mass properties, parameters used in many of the existing classiﬁcations are more related to ground support design and not rock mass boreablity. The results of many investigations on this issue have shown a weak correlation between TBM rate of penetration and rock mass classiﬁcation. This limitation can be overcome by ﬁne tuning the rock mass classiﬁcation input parameters to represent inﬂuence of rock mass properties on TBM performance as has been the objective of RME or QTBM. This paper will offer an overview of the impact of rock mass on TBM performance and introduces an empirical equation for predicting performance of rock TBMs based on rock mass classiﬁcation. The results of the preliminary analysis of a new model has revealed that the use of the proposed system can offer a reasonable accuracy for estimation of TBM performance in various rock masses.
17:10-17:30 MDC’s Hartford, Connecticut South Tunnel Project: Integrating Site Investigation Technology, Geology and Geotechnical Engineering for Effective Ground Characterization R. Dill, L. Martin and W. Song, AECOM and A. Perham, The Metropolitan District Commission AECOM completed a subsurface exploration program for an 18-foot diameter, approximately 4-mile long rock tunnel project in Hartford, CT. The tunnel crosses the regional geologic trend through the middle of a sedimentary basin, passing through four separate rock formations, including two volcanic ﬂows. Faulting is prevalent, with at least 15 faults encountered during the site investigation. Severe artesian ﬂows were also experienced in several of the borings, requiring highly specialized drilling equipment. Sixty-two borings and associated testing were performed to characterize the structural geology, hydrogeology, rock properties and ground conditions. A phased program was carefully planned and implemented with participation of geotechnical and geologic specialists, with thoughtful evaluation along the way to react to the ground conditions encountered, and make appropriate reﬁnements. This paper will discuss the subsurface program details; the integrated efforts used to effectively characterize the ground; and will summarize the ﬁnal characterization presented in the GBR.
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.) Assessment of Rock Cutting Efﬁciency by TBM Disc Cutter Using SPH/FE Modelling H. Jeong and S. Jeon, Seoul National University Various numerical methods have been tried to estimate the cutting forces of a TBM disc cutter. In this study, SPH/FEM coupled method was newly employed to improve the traditional FEM analysis. The disc cutter and rock were modeled by Lagrange and SPH codes, respectively. The numerical cutting test was carried out for representative Korean rocks with different cutting conditions. The results show that the cutting forces obtained from numerical simulation had a good agreement with those from LCM tests, and that applying SPH method to rock cutting model has advantages and improvement compared to traditional FEM method. Erosion criterion and erosion limit were not required to simulate the rock fragmentation process, and the cutting forces from the numerical simulation was more stable and accurate.
The results indicate that the numerical simulation can be successfully used to estimate cutting performance of a TBM.
Performance Prediction of TBMs Using a New Generation of Portable Linear Rock Cutting Machine PLCM C. Balci and R. Comakli, Istanbul Technical University;
C. Polat, Geotata Turkey and D. Tumac, H. Copur and N. Bilgin, Istanbul Technical University Application of mechanical excavators for rock excavation in both civil construction and mining engineering ﬁelds has increased signiﬁcantly in recent years. Prediction of the excavation performance of any mechanical excavators – tunnel boring machines, roadheaders, impact hammers, continuous miners and shearers for any geological formation is one of the main concerns in determining the economics of a mechanized mining and/or tunneling operation. A new portable linear rock cutting (PLCM) device was developed in the Mining Engineering Department of Istanbul Technical University and supported by The Scientiﬁc and Technological Research Council of Turkey (TUBITAK-112M859). The PLCM is used for cutting small core or block rock samples by a real-life mini disc cutter. The results from the PLCM are compared with the results obtained from the full scale rock cutting tests and theoretical model. It is found that there is reliable correlation between test results obtained from both cutting tests and theoretical model.
Riyadh Metro Design and Construction – Design and Construction on the Fast Track H. Schwarz, Egis / RMTC and A. Almousa and F. Al Ariﬁ, Arriyadh Development Authority The Riyadh Metro Project forms part of a complete new public transport system integrated in the urban planning and development of the fast growing capital city of the Kingdom of Saudi Arabia. The Design & Build project consists of 176 km of a new metro network with 57 km of double track single tunnel infrastructures, spread over six metro lines. During the design phase, geological, hydrogeological, geotechnical and geophysical site investigations WTC2016 | SAN FRANCISCO CALIFORNIA, USA WEDNESDAY 27 APRIL were undertaken to chart the, previously uncharted, underground construction space. Different TBM solutions were selected for implementation taking due consideration of the ground conditions of each metro line. The results obtained from deep excavations for underground stations and analysis of the TBM tunneling data will be used as key input for future tunneling projects in the Riyadh and the Kingdom of Saudi Arabia. The present paper details the design conditions and presents the solutions for large diameter tunnels in karstic limestone.
Numerical Evaluation and Optimization of Grout Backﬁll Strategy for a Subsurface Gas Tunnel D. Kandra, D. Abi –Zadeh and C. Brown, Arup Grout backﬁll strategy for a particular subsurface concrete tunnel (~4.9km long, 3.5m in diameter, carrying 20” gas pipeline) was based on achieving 1:100 slope of the ﬁll in order to progressively ﬁll the tunnel, in a series of 350m section. Grout rheology, particularly its non-Newtonian and thixotropic behavior, determines the ﬁnal ﬁll slope for given backﬁll strategy. The objective of this study was to simulate the two -phase grout mix backﬁll process using Computational Fluid Dynamics (CFD) and determine the slope of the ﬁll to validate and optimize the backﬁll strategy. Three dimensional CFD study showed that for a 500m long tunnel section with a single injection point of grout, given its rheology, it will likely keep ﬂowing without ﬁlling the 500m section height wise.
Design optimization for ﬁlling was carried out using two dimensional studies to make the backﬁll process “slope independent” by incorporating a 2.5m high bulkhead at ~1,000m.
Special Support Systems used for the Execution of a Hydrotechnical Gallery Excavated in Difﬁcult Geological Conditions A. Stematiu, S.C. Metroul S.A.; C. Popescu and R. Sarghiuta, Technical University Of Civil Engineering Of Bucharest The tunnel sector is excavated into a rock mass heavily affected by tectonics, deﬁned as a regional fault. The rock around the tunnel support undertakes the non-elastic deformation and gradually detaches from the rest of the non affected rock mass, moving inside of the excavated area and tending to ﬁll up the whole space. The initial solution of using stiff support consisting in double steel ribs I12 with circular shape in the upper part and straight vertical pillars in the lower part has proved to be inadequate. Based on the calculations of the subsidence phenomena and a mathematical model, the proposed alternative support was provided by special circular steel ribs – SG-23 – that allows a limited rib deformation in order to mobilize the contact between the rock contour and the inner face of the rib - not only for the deformed rib but also for the neighboring ribs.
22 – 28 APRIL | MOSCONE CENTER | WTC2016 Posters (Continued) The Next Generation of TBMs and Conveyor Systems for Mining Applications D. Oﬁara and G. Watson, The Robbins Company TBMs have been used in mining in decades past, but their use has been limited and sporadic, due to both perceived and actual application difﬁculties. With new technology and mounting success stories, this is changing. For both coal and metals mining, deep ore bodies require long access tunnels, and an efﬁcient and economical method of reaching those deposits. Today, mining engineers are considering TBMs as part of the overall mine development plan. Planned TBM mine drifts are not only longer, but have more complicated trajectories. Mine development TBMs will have to cope with varying geology, potential for high water inﬂows, steep gradients, and high temperatures. TBM systems are being planned to cope with such difﬁculties. TBM systems will be considered and increasingly deployed for mine development, even if commodity prices remain low. TBMs can satisfy the need for increased productivity, better life of mine infrastructure, and safety. Effective conveyor systems are essential to support TBM operation in many mining applications. Many mine development tunnels are slopes, driven down at the steepest practical gradient to reach the deep ore body. Conveyors are often the only safe and effective way to haul the TBM muck form such tunnels. This paper will review the historical use of TBMs in mining, and will discuss the 2015 status of TBMs and conveyor systems in mining, and the special requirements and adaptable features needed in order to make efﬁcient TBMs a reality in mines worldwide.
Impact of Cutter Ring Design on TBM Performance in Exceptionally Hard Rock – Case Study of TBM Tunneling in Hard Rock Formation in Uma Oya Project, Sri Lanka A. Rahbar, Headrace Tunnel; J. Rostami, The Pennsylvania State University and J. Paulzen Herrenknecht AG Uma Oya Multipurpose Development Project is located in South West Sri Lanka. This project, among many components, involves a 14 km headrace tunnel in very hard and abrasive igneous rocks. The tunnel is under construction by a 4.4 m diameter double shield TBM. The headrace tunnel has already reached 5km milestone and has passed through some reaches of tunnel in very strong intact rocks with no joints. Low penetration at high thrust load has caused frequent stoppages for cutter change leading to low utilization and advance rates due to low cutter life. The original machine was dressed with 27, each 432 mm (17 inch) diameter, 19 mm (3/4 inch) tipped disc cutters. However, various cutter diameters of 432-457 mm (17-18 inch) and cutter tip widths 13 to 19 mm (0.5-0.75 in), have been tried to see if cutter life and penetration rates could be increased. This paper will review the history of the project, the geology of the site, along with TBM performance and cutter life. It will focus on frequency of different cutter failures encountered in various ground conditions. Also, results of using variation of cutter diameter and tip width to cope with the hard rock conditions and their results in increasing machine productivity will be discussed. This allows for better understanding of parameters controlling disc wear/life and leads to better cutter management for more efﬁcient operation of hard rock TBMs in similar conditions.
Future Projects Chair: B. Campbell, JF Shea, USA ITA Co-chair: A. Cornaro, ITACUS Vice Chair, Switzerland 14:00-14:20 The Shortcut – A Subsea Rail Tunnel between Sweden and Germany R. Sturk Skanska Sverige AB, Major Projects and K. O Halvorsen, Deutsche Bahn International GmbH and Coinco e.V.
Northern Europe sees an increasing demand on efﬁcient transport corridors to meet the growth of transportation between Scandinavia and central-Eastern Europe. Sustainable solutions will be required. To that aim, Coinco South outlines the idea of building a ﬁxed rail link between Sweden and Germany to enhance the trafﬁc between these regions and to make it greener. The idea of building a 100 km long bored railway tunnel under the Baltic Sea leads to an extraordinary concept for civil engineering. Early studies on geology conclude that the tunnel is technically feasible, however, it is as important to answer if it makes sense from a socioeconomically point of view. Extensive research studies have started in order to investigate such issues.
Our business needs visionary people and projects to move forward, this paper describes a future challenge for the tunnelling industry that may realize sooner than we think.