<p>Acknowledgement VII</p> <p>Foreword IX</p> <p>List of symbols used XV</p> <p>I. Greek symbols XV</p> <p>II. Latin symbols XV</p> <p><b>1 Basics 1</b></p> <p>1.1 Basics and technical implementation of bentonite lubrication systems 1</p> <p>1.2 Annular gap lubrication in pipe jacking 5</p> <p>1.3 Preliminary remarks about the ground 6</p> <p><b>2 Bentonite and bentonite suspensions 9</b></p> <p>2.1 Composition and structure 9</p> <p>2.2 Hydration behaviour 10</p> <p>2.3 Card house structure and thixotropy 11</p> <p>2.4 Yield point, viscosity and gel strength 12</p> <p>2.5 Stability 17</p> <p>2.6 Usual types of bentonite 19</p> <p><b>3 Additives 21</b></p> <p>3.1 Polymers 21</p> <p>3.2 Types of polymer additives 24</p> <p>3.3 Overview of polymer additives and their functions 27</p> <p><b>4 Correct preparation of bentonite suspensions 29</b></p> <p>4.1 Mixing 29</p> <p>4.2 Mixing equipment 33</p> <p>4.3 Mixing instructions 34</p> <p>4.4 Hydration tank 35</p> <p><b>5 Properties of the suspension and measurement processes 37</b></p> <p>5.1 Viscosity: Marsh funnel 37</p> <p>5.2 Yield point: ball-harp rheometer 40</p> <p>5.3 Viscosity and gel strength: Rotational viscometer 42</p> <p>5.4 Filtrate water and thickness of filter cake: filter press 43</p> <p>5.5 Density 45</p> <p>5.6 Water hardness: test strips 46</p> <p>5.7 pH value 46</p> <p>5.8 Conductivity 46</p> <p>5.9 Temperature 47</p> <p><b>6 Ground and groundwater 49</b></p> <p>6.1 Geology of solid rock 49</p> <p>6.2 Geology of soils 65</p> <p>6.3 Stability and stand-up time 85</p> <p>6.4 Hydrogeology 88</p> <p>6.5 Influence of various rock properties on the use of bentonite 99</p> <p>6.6 Contamination in the ground, groundwater or mixing water 100</p> <p><b>7 Bentonite suspensions for annular gap lubrication 105</b></p> <p>7.1 Size of the annular gap 105</p> <p>7.2 Vertical position of the pipe string in the driven cavity 107</p> <p>7.3 Functions of the lubricant in the annular gap 111</p> <p>7.4 Adaptation of the bentonite suspension to the ground 119</p> <p>7.5 Rheological parameters of the bentonite suspension 124</p> <p>7.6 Suspension quantities 132</p> <p>7.7 Time-dependant loss volumes 147</p> <p>7.8 Lubrication strategies 148</p> <p><b>8 Lubrication technology 155</b></p> <p>8.1 Arrangement and spacing of the lubrication points in the pipe string 155</p> <p>8.2 Number and arrangement of the injection fittings per lubricating point in the pipe cross-section 156</p> <p>8.3 Non-return valves 157</p> <p>8.4 Lubrication circuit 158</p> <p>8.5 Interaction between the support pressure at the face and the annular gap pressure 159</p> <p>8.6 Bentonite supply in the starting area 160</p> <p>8.7 Lubricant pressure, lubricant quantity and pressure losses 161</p> <p><b>9 Reporting 163</b></p> <p>9.1 Which parameters should be documented for bentonite lubrication? 163</p> <p>9.2 Forms 163</p> <p><b>10 Lists of the required injection quantities 167</b></p> <p>10.1 Explanation of the lists 167</p> <p>Literature 197</p>