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Artificial Ground Freezing in Clayey Soils

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Artificial Ground Freezing in Clayey Soils ARTIFICIAL GROUND FREEZING IN CLAYEY SOILS LABORATORY AND FIELD STUDIES OF DEFORMATIONS DURING THAWING AT THE BOTHNIA LINE TEDDY JOHANSSON Doctoral Thesis Division of Soil and Rock Mechanics Department of Civil and Architectural Engineering Royal Institute of Technology Stockholm, Sweden 2009 TRITA-JOB PHD 1014 ISSN 1650-9501 www.kth.se To my wife, Johanna and my children with all my love The Häggvik tunnel in the spring of 2005 (Stockholm) Don't be too optimistic; the light in the tunnel could be a train (anonymous) Contents CONTENTS Acknowledgements iii Summary v Sammanfattning vii Notation ix Description xvii 1 Introduction 1 1.1 Background ................................................................................................................... 1 1.2 Objectives ..................................................................................................................... 4 1.3 Scope and Structure ..................................................................................................... 4 1.4 Extent and Limitations ............................................................................................... 5 2 Literature study 7 2.1 Introduction .................................................................................................................. 7 2.2 Artificial Frozen Ground ............................................................................................ 8 2.3 Soil Water and Soil Ice .............................................................................................. 23 2.4 Soil Energy Transfer .................................................................................................. 26 2.5 Naturally Frozen Ground and Artificially Frozen Ground, Differences and Similarities ................................................................................................................... 28 2.6 Soil Phase Relations ................................................................................................... 36 2.7 Freezing Process ........................................................................................................ 45 2.8 Thaw Deformation .................................................................................................... 61 2.9 Case Studies ................................................................................................................ 76 2.10 Conclusion .................................................................................................................. 93 3 Ground freezing at the Bothnia Line 95 3.1 Introduction ................................................................................................................ 95 3.2 Geology ....................................................................................................................... 98 3.3 Freeze Technique and Design ................................................................................. 98 i Artificial ground freezing in clayey soils 4 Laboratory study of Bothnia soil 101 4.1 Introduction .............................................................................................................. 101 4.2 Material ...................................................................................................................... 101 4.3 Basic Characteristic of Soil ...................................................................................... 102 4.4 Deformation Characteristic .................................................................................... 104 4.5 Grain Size Distribution ........................................................................................... 106 4.6 Soil Freeze-Thaw Laboratory Tests ....................................................................... 107 4.7 Results ........................................................................................................................ 111 4.8 Conclusion ................................................................................................................. 131 5 Field study and prognoses at the Bothnia Line 133 5.1 Introduction .............................................................................................................. 133 5.2 Site Conditions and Materials ................................................................................. 134 5.3 Temperature Distribution ....................................................................................... 135 5.4 Load Build-up on the Tunnel Roof During the Thawing .................................. 139 5.5 Pore Pressure Build-up During the Thawing ....................................................... 142 5.6 Vertical Deformations; Frost Heave and Thaw Settlement ............................... 146 5.7 Results ........................................................................................................................ 148 5.8 Conclusion ................................................................................................................. 165 6 Analyses and discussions 167 6.1 Introduction .............................................................................................................. 167 6.2 Alterations of Soil Parameters Due to Thawing of Virgin Bothnia Soil .......... 167 6.3 Temperature Development at the Bothnia Line’s Frozen Construction ......... 170 6.4 Ground Heaving at the Bothnia Line’s Frozen Construction ........................... 170 6.5 Naturally Frozen Ground and Artificially Frozen Ground and the Subsequent Thawing ..................................................................................................................... 172 6.6 Thaw Settlement ....................................................................................................... 174 6.7 Tunnel Roof Load .................................................................................................... 182 6.8 Case Studies ............................................................................................................... 182 6.9 Conclusion ................................................................................................................. 183 7 General conclusions 185 8 Suggestions for further research 189 References 191 A Appendix, laboratory tests I B Appendix, field study XXXV C Appendix, JOBFEM analyses XLV D Appendix, CRS-tests XLIX ii Acknowledgements ACKNOWLEDGEMENTS The present research work has been carried out between the winter of 2003 and the spring of 2009 at the Royal Institute of Technology (KTH), division of Soil-and Rock Mechanics. My warmest thanks go to my supervisor’s Professor Staffan Hintze and Professor Håkan Stille, both at the Royal Institute of Technology, as well as to Professor Sven Knutsson at Luleå University of Technology (LTU) for their valuable assistance and viewpoints during the course of work of this thesis. The author participated at the project Södra Länken 04 (SL04) in Stockholm during the stabilization of a future tunnel constructed with help of temporary soil freezing during the winter of 2000 to the spring of 2001. Large problems with deformations of the ground surface arose in conjunction with the thawing of the frozen construction. The research has been initiated by these phenomena and shaped with assistance of, among others, the research director at Skanska, Professor Kyösti Tuutti and the former director of research at Skanska Sweden, Professor Björn Täljsten. A warm thank you to Kyösti Tuutti and Björn Täljsten. A reference committee consisting of people with diverse experience and knowledge in soil- and rock stabilization and freezing has followed the research. This group has worked as a discussion partner and has mainly assisted in competent reviewing of suggested test proposals. The reference committee has consisted of: Ph. D. Anne-Lise Berggren, Geofrost AS, Oslo M. Sc. Lars Bjerin, the Swedish National Road Administration, Region Stockholm Professor Lars-Olof Dahlström, NCC/Luleå University of Technology (LTU) Ph. D. Anders Fredriksson, Golder Associates AB, Stockholm Ph. D. Matti Kivelö, Kivelö Geoteknik AB, Karlskoga Professor Sven Knutsson, Luleå University of Technology (LTU) M. Sc. Gunnar Lejon, Botniabanan AB/the National Rail Administration (Banverket), Stockholm. I wish to express my sincere appreciation to the help given by all the members of the reference committee. Ph.D. Anders Fredriksson has during the course of the work also contributed with assistance in above all numerical calculations. Many thanks to Anders Fredriksson. iii Artificial ground freezing in clayey soils The instrumentation during the field studies has been accomplished with assistance of research engineer Per Delin and Elis Svensson at KTH, division of Soil-and Rock Mechanics. The co-ordination of the instrumentation and the registration of data has been carried out by M. Sc. Gunnar Lejon, at the Bothnia Line. The information from the instrumentation has been registered and compiled by personnel from the Bothnia Line, above all Eero Niemi. Warm thanks to all these contributors. Many thanks to project manager Vesa Vaaranta, Lemminkäinen Construction, whose encouraging assistance and positive attitude have supported the work of this thesis. He has provided registered data for my use, thus allowing unique and important fieldwork to be performed. Research engineer Per Delin has assisted with valuable knowledge and experience in the laboratory at Soil- and Rock Mechanics, KTH. Thank you Per. Assistant professor Sven-Erik Rehnman
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