WWW.DISSERTATION.XLIBX.INFO
FREE ELECTRONIC LIBRARY - Dissertations, online materials
 
<< HOME
CONTACTS



Pages:     | 1 |   ...   | 21 | 22 || 24 | 25 |   ...   | 29 |

«TECHNICAL PROGRAM Download the WTC 2016 App Booth Underground connections What if you could rely on a global network of experts who can bring an ...»

-- [ Page 23 ] --

08:50-09:10 A Model to Predict the Performance of EPB-TBMs in a Complex Geology in Istanbul N. Bilgin, Istanbul Technical University; M. Namli, Medeniyet University and H. Copur, C. Balci, A. Shaterpour Mamaghani, Istanbul Technical University It is expected that more than 10 Billion USD will be spent in Istanbul in coming years on tunnel boring especially with EPB-TBMs. However the geology of Istanbul is very complex. Geologic formations changing from Paleozoic to Cenozoic ages cause tremendous problems due to frequently changed rock formations and andesite and diabase dykes. This paper summarizes a universal model to predict the performance of EPB-TBMs which is created upon the data base collected from several projects. The model is based first on predicting field specific energy and power consumed of TBMs using geo-mechanical properties of the excavated material and TBM diameter. Later net production rate is calculated using field specific energy and power consumed by TBM. A methodology to predict machine utilization factor permits to calculate daily advance rates. The validity of the model is tested using the data obtained from two recent metro tunnel projects.

22 – 28 APRIL | MOSCONE CENTER | WTC2016 09:10-09:30 Pressure Distribution along the TBM Body in EPB Tunneling B. Hagan, E. Alavi, G. Frank and M.A. DiPonio, JayDee Contractors, Inc and L. Mori and M. Mooney, Colorado School of Mines The data from EPB cells located inside the pressurized chamber of EPB TBMs and also the data from the pressure sensors in grout lines are quite important in controlling the EPB operation. However, there have always been questions in regards to pressure distribution along the shield body. Could the pressure distribution data be used to come up with potential locations for ground loss? Does the overcut region, the space between the shield body and the maximum cut diameter, consist of broken material or EPB muck, or does that region consist primarily of void space? During free air interventions, how does pressure distribute along the TBM body?

To address these questions, one of the two EPB TBMs used in the Northgate Link Light Rail project in Seattle, WA is equipped with EPB cells in front and rear body to monitor the pressure distribution along the TBM body in addition to the standard 6 EPB cells located inside the cutterhead chamber and pressure sensors located at the grout lines. This paper discusses the results of this study and weighs on the valuable data that can be collected by using the shield pressure sensors.

09:30-09:50 Analysis of Effect of Waterhead on Stability of Excavation Face of Slurry Balanced Shield Z. Yang, Qingdao University of Technology; Q. Liu, West Coast Railway Transportation Co, Ltd and M. Zhang and X. Guan, Qingdao University of Technology In slurry balanced shield tunneling, how to ensure the safety of construction and to reduce the influence on the environment has arisen wide attention of scholars both at home and abroad. But now it is still in the stage of experience as to the instability mechanism of the slurry shield tunneling excavation and its stability analysis. Based on the large-diameter model tests and FLAC 3D, the effect of the different waterhead (non-water, 0.9m and 1.1m) on stability of excavation face of slurry balanced shield is investigated, and the stability mechanics is proposed. The results show that: waterhead heights play an important role on excavation face instability features of slurry balanced shield in sandy stratum, Regarding the different waterhead heights, the development mode of the excavation face instability features can be divided into non-water mode, lower-waterhead mode and higher-waterhead mode; soil arching is existed in the process of excavation face instability, the settlement of ground lags behind excavation face failure, the soil arching will block or eliminate the effects of ground settlement; excess pore water pressure need to be considered besides earth pressure and hydrostatic pressure when the supporting force is calculated.

WTC2016 | SAN FRANCISCO CALIFORNIA, USA WEDNESDAY 27 APRIL 09:50-10:10 Shield Tunnelling in Pure Sands – Merging the Application Fields of EPB and Slurry Shield Technology U. Maidl and M. Comulada, Maidl Tunnelconsultants and A. Mahfuz Monteiro, C. Henrique Turolla Maia and J. Claudio Di Dio Pierri, Constructora Norberto Odebrecht, Brazil Pure sands are typically the domain of slurry shields due to their high permeability and their granular characteristics. On the other hand, the Earth Pressure Balanced (EPB) shield machine technology has advanced in recent years with improved conditioning agents and shield machines that are equipped with slurry injection facilities and alternative mucking methods. These new EPB machines have steadily increased the range of application of the EPB technology. The contribution discusses the capacities and operational features of hybrid EPB vs. slurry shield technology in pure sands. At the example of the Metro Line 4 in Rio de Janeiro (Brazil), the contribution shows that EPB tunneling in pure sands is possible and it is compared with a state-of-the-art slurry shield project as the KASIG project in Karlsruhe (Germany). Furthermore, the control of the support pressure by means of foam conditioning and slurry injection in conjunction with a close, real-time monitoring of machine parameters is discussed.

10:10-10:40 Break 10:40-11:00 Study of Wear in Conditioned Granular Soil by Using a New Test Device C. Oñate Salazar, D. Martinelli, C. Todaro and D. Peila, DIATI and A. Boscaro, UTT, Mapei SpA The wear phenomenon in TBM machines is not a simple issue, as many parameters are playing an important role on the consumption of the tools during a tunnel excavation. The action of the wear due to the contact with the soil can occur on the excavation tools, on the cutterhead, in the excavating chamber and on the screw conveyor. The test developed at the Laboratory “Tunnelling and Underground Space Center” of the Politecnico di Torino is aimed to reproduce the interaction between the tools and the excavated material, simulating the excavation conditions in terms of soil conditioning and water content. The test, which is not standardized, is studied to evaluate the wear in a global point of view. The present work starts by testing the influence of the use of chemical agents during the conditioning phase on the drop of the wear phenomenon, in terms of metal weight loss.





22 – 28 APRIL | MOSCONE CENTER | WTC2016 11:00-11:20

Earth Pressure Balance TBM Soil Conditioning:

It’s About the Pressure M. Mooney, Y. Wu, L. Mori and R. Bearce, Colorado School of Mines, and M. Cha, Texas A&M University Proper soil conditioning is critical for effective earth pressure balance (EPB) TBM tunneling. The formation soil at the cutterhead must be transformed into a highly compressible, low shear strength and low permeability paste within the excavation chamber to allow optimal EPB performance. This behavior must be maintained for a certain residency time. The vast majority of published studies on conditioned soil behavior have been performed under atmospheric conditions; however, the desired soil behavior must occur under chamber pressures that can reach 5-7 bar.

The influence of pressure on conditioned soil is significant and is dramatically different than behavior under atmospheric pressure. This paper illustrates how pressure influences conditioned soil behavior and how atmospheric test results must be viewed in the context of expected chamber pressures. The influence of pressure on bubble-soil interaction (including with time) is shown through digital image analysis. The compressibility, shear strength, and abrasivity of conditioned soil under pressure is presented and explained in terms of density, soil and air compressibility and porosity.

11:20-11:40 Performance Optimization in Clogging Soils through Process Controlling U. Maidl, M. Comulada and J. Stascheit, Maidl Tunnelconsultants Cohesive soils are notorious for causing clogging of the cutter head and the excavation chamber of tunnel boring machines (TBMs). While clogging leads to a drastic reduction in excavation performance, it further induces higher wear of tools and other parts of the cutter head and may even prevent a controlled support of the tunnel face and, thus, lead to face collapse and excess settlements or sinkholes.

Employing well-balanced soil conditioning techniques, the clogging tendency can be significantly reduced. The monitoring and control of soil conditioning as well as the timely detection of potential clogging tendencies require a close monitoring of all relevant machine parameters and measurements. To this end, a reliable and powerful Process Controlling software that gathers all machine and process-related information is a prerequisite for successful mitigation of clogging-induced problems. The remainder of this contribution is organized as follows: First, a brief introduction to the Process Controlling system PROCON is given. Afterwards, the mechanisms and mitigation techniques of clogging are discussed. Finally, an example is given how Process Controlling has been employed to soil conditioning in a tunneling project with highly clogging soils.

WTC2016 | SAN FRANCISCO CALIFORNIA, USA WEDNESDAY 27 APRIL 11:40-12:00 Transient Face Support in Slurry Shield Tunneling Due to Different Time Scales for Excavation Sequence of Cutting Tools and Penetration Time of Support Fluid M. Thewes, B. Schoesser And Z. Zizka, Ruhr-University Bochum The support pressure of a slurry shield corresponds to the in situ earth and groundwater pressure to ensure the stability of the tunnel face. The support fluid (bentonite suspension) penetrates from the excavation chamber into the pore space and transfers the support pressure to the granular structure of the soil within this zone. At the same time, the cutting tools rotate periodically with the cutting wheel and remove the penetrated soil up to a certain cutting depth at the face. Shortly after the tool passing the penetration process starts again. Both, the support pressure and the soil excavation, act in the same direction at the tunnel face, but they are subject to different cyclic intervals. This relationship between the time needed for the transient penetration process and the interval of the cyclic passage of the cutting tools at a local point at the face is examined and the impact onto the global face stability is discussed.

12:00-12:20 Assessment of EPB Soil Conditioning on Two TBMs by Using Apparent Density L. Mori and M. Mooney, Colorado School of Mines and E. Alavi, G. Frank and M. DiPonio, JayDee Contractors Inc A study was conducted on the N125 project in Seattle to investigate the use of apparent density as an assessment tool for the effectiveness of soil conditioning. The formation of an air bubble as well as the plugging of cutterhead and excavation chamber can be a result of improper soil conditioning. Both air bubble formation at the top of the excavation chamber and developing plugging issues can be identified by analyzing the apparent densities in the excavation chamber. In this study, apparent densities less than unity were observed in the upper portion of both northbound and southbound TBMs, suggesting the presence of an air bubble. Apparent densities greater than the in-situ soil density were observed in the lower portion of the excavation chamber.

Particularly high values of apparent density were coincident with clogging observed at multiple locations along the alignment. The combination of less than unity upper chamber apparent density and very high apparent density in the lower portion of the chamber are related, and indicate the inability of the TBM to effectively condition and mix the soil in the chamber.

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.) Microscopic and Experimental Analysis of the Tribological System of TBM-tools J. Küpferle, A. Röttger, W. Theisen and M. Alber, Ruhr-University Bochum Wear of TBM tools has a major influence on the advance rates of a tunneling progress. Wear-prediction models are based (amongst others) on the abrasivity of the present geology, which is determined with the help of laboratory tests. To evaluate the results from such tests in a reasonable context, in this work the tribological system TBM-tool is considered from the view of materials technology. Therefore, microstructure of different application-oriented materials are presented and discussed in terms of their wear behavior respectively wear-resistance. The significant influence of the tool-materials on the abrasivity of the geology and thus the influence on wear-prediction models has been pointed out. Furthermore, LCPC-, Cerchar- and nano-scratch-experiments have been performed to confirm the aforementioned statements. The material-dependent wear-mechanisms and their correlation in terms of tunneling have shown that it is mandatory to consider the complete tribological system to estimate the wear of TBM tools.

The Interplay of Face Support Pressure and Soil Permeability on Face Stability in EPB Tunneling P. Sitarenios, D. Litsas and M. Kavvadas, National Technical University of Athens The paper discusses the results of 3D finite element analyses to investigate the effect of face support pressure and soil permeability on face stability conditions in EPB tunnelling. Two main types of face behavior are identified: Undrained conditions ahead of the tunnel face, typically occurring in soils with permeability less than about k=5 10-7m/s, are shown to be favourable for face stability;

analyses show that an applied face pressure comparable with the initial hydrostatic pore pressure is sufficient for adequate face stability, even for soils of relatively low strength. Drained or partially conditions, typically occurring in soils with permeability higher than about k=5 10-6m/s, show that face stability is strongly dependent on the effective stress of the muck; the presence of even a small effective stress in the muck is very beneficial for face stability conditions and can be a possible explanation of successful EPB tunnelling through relatively permeable soils.



Pages:     | 1 |   ...   | 21 | 22 || 24 | 25 |   ...   | 29 |


Similar works:

«City and County of Denver 201 West Colfax Ave., Dept. 705 • Denver, Colorado 80202 • 720-913-5000 • FAX 720-913-5247 www.denvergov.org/auditor Dennis J. Gallagher Auditor Prevailing Wage/Certified Payroll Overview What is the basis for Prevailing Wage? It's the Law: Prevailing Wage is covered under Section 20-76 of the Revised Municipal Code of the City and County of Denver. The law declares that any contractor or subcontractor at any tier who performs construction, alteration,...»

«Zoning 11162011 Page 1 of 16 Minutes of the Zoning Board of Appeals Sheffield Lake, Ohio November 16, 2011 The regular meeting of the Zoning Board of Appeals was held Wednesday, November 16, 2011. Chairwoman Jancura called the meeting to order at 7:05 PM.ROLL CALL OF MEMBERS: Present: Jancura, Tatter, McClelland, Kovach Attending: Council Members; Bring, Rosso, Stark, Elliott, Law Director Graves, Building Inspector Nemec, Planning Commission; Chairman Scott Jancura and Member Debbie Belaska,...»

«CONTENTS Page No.1. Introduction 1 2. Meaning of Crime/Violence against Women 1 3. Constitutional and Legal Provisions for Women 2 Constitutional Provision 2 Legal Provisions 3 4. Classification Crime Against Women 4 Crimes under Indian Penal Code 4 Crimes under Special and Local Laws 7 Reported Incidents of Crime 9 Crime Against Women in Cities 13 5. International Initiatives to Curb Gender Violence 14 6. National Initiatives to Curb Gender Violence 15 7. Verma Committee Report 16 8....»

«ASISTA Staff Gail Pendleton, Co-Director. Co-founder of the National Network to End Violence Against Immigrant Women ( NNEVAIW) Winter 2008 Edition Sonia Parras Konrad, A Note from the Co-Directors Co-Director. Founder of the MUNA Legal Clinic, Des Moines, Dear ASISTA Readers: Iowa. This newsletter focuses on the immediate issue of interim relief applications that Maria Jose Fletcher, Staff must be transformed into U visa applications by April 14, however, since then, CIS Attorney....»

«ZAMBIA Misrule of law: Human rights in a state of emergency 1. Introduction In the initial days after an attempted coup on 28 October 1997, front-page editorials appeared in the state-controlled newspapers that advocated the suspension of human rights for anyone connected with the coup. The government-owned Zambia Daily Mail newspaper told its readers in a front-page editorial: “The coup plotters.had no regard for human rights and should not expect sympathy and human rights themselves..The...»

«5/1/2010 11:34:22 AM HALBROOK_11_FINAL_04.14.2010.DOC HELLER, THE SECOND AMENDMENT, AND RECONSTRUCTION: PROTECTING ALL FREEDMEN OR ONLY MILITIAMEN? Stephen P. Halbrook* In District of Columbia v. Heller, Justice Scalia began his analysis of the perceived meaning of the Second Amendment during Reconstruction by writing that “[i]n the aftermath of the Civil War, there was an outpouring of discussion of the Second Amendment in Congress and in public discourse, as people debated whether and how...»

«CITY COUNCIL, CITY OF ROCKFORD JOURNAL OF PROCEEDINGS SEPTEMEBER 2, 2008 COUNCIL CONVENED AT 6:16 P.M.1. The invocation was given by Pastor David Sorrell, First Church of the Nazarene/Police Chaplain and the Pledge of Allegiance was led by Council Page Carla Centeno.2. Roll Call: Mayor Lawrence J. Morrissey Aldermen: Sosnowski, Curran, Mark, Wasco, Bell, Jacobson, Thompson-Kelly, Johnson, Timm, Beach, Holt, Beck, McNeely, Conness -14Absent: -03. Alderman Mark moved to accept the Journal of...»

«March 25, 2015 United States Supreme Court Limits Investor Suits for Misleading Statements of Opinion The United States Supreme Court issued a decision yesterday that resolves a split in the federal courts of appeals regarding when statements of opinion may give rise to liability under the federal securities laws. In Omnicare, Inc. v. Laborers’ District Council Construction Industry Pension Fund, No. 13-435, the Supreme Court addressed the pleading standard for claims alleging a false or...»

«AU ST R A L I A N P OR K LIMIT ED Minimising Odour from Piggeries 2015 MINIMISING ODOUR FROM PIGGERIES 1 PROJECT TITLE: Demonstration of How to Achieve Best Management Practices – Environmental Management PROJECT NUMBER: 2013/031 RESEARCH ORGANISATION: FSA Consulting PRINCIPAL INVESTIGATOR: Ms Robyn Tucker, FSA Consulting, Private Bag 260, Horsham Vic 3401 DISCLAIMER The opinions, advice and information contained in this publication have not been provided at the request of any person but are...»

«1/35 SCA/6223/2011 JUDGMENT IN THE HIGH COURT OF GUJARAT AT AHMEDABAD SPECIAL CIVIL APPLICATION No. 6223 of 2011 With SPECIAL CIVIL APPLICATION No. 12009 of 2011 For Approval and Signature: HONOURABLE THE CHIEF JUSTICE MR.BHASKAR BHATTACHARYA AND HONOURABLE MR.JUSTICE J.B.PARDIWALA ========================================== =============== Whether Reporters of Local Papers may be 1 allowed to see the judgment ? 2 To be referred to the Reporter or not ?` Whether their Lordships wish to see the...»

«OFFICE OF THE STATE CORONER FINDINGS OF INQUEST CITATION: Inquest into the death of Lawrence Edward JEFFREY TITLE OF COURT: Coroner’s Court JURISDICTION: Cairns FILE NO(s): COR 2638/08(8) DELIVERED ON: 19 May 2010 DELIVERED AT: Cairns HEARING DATE(s): 30 April 2010 & 18 May 2010 FINDINGS OF: Mr Michael Barnes, State Coroner CATCHWORDS: CORONERS: death in custody, natural causes REPRESENTATION: Counsel Assisting: Mr Peter Johns Department of Community Safety: Ms Melinda Zerner Table of...»

«Copyright by Hamid Rahim Sheikh The Dissertation Committee for Hamid Rahim Sheikh certifies that this is the approved version of the following dissertation: Image Quality Assessment Using Natural Scene Statistics Committee: Alan C. Bovik, Supervisor Lawrence K. Cormack, Supervisor J. K. Aggarwal Chandrajit Bajaj Gustavo de Veciana Joydeep Ghosh Image Quality Assessment Using Natural Scene Statistics by Hamid Rahim Sheikh, B.Sc., M.S. DISSERTATION Presented to the Faculty of the Graduate School...»





 
<<  HOME   |    CONTACTS
2016 www.dissertation.xlibx.info - Dissertations, online materials

Materials of this site are available for review, all rights belong to their respective owners.
If you do not agree with the fact that your material is placed on this site, please, email us, we will within 1-2 business days delete him.