Chapter II: Section 39: 17. Joining Tunnel Struts by Halving 48

18. Round Timber Post and Cap Bearing 48

19. Ceiling Strutting for Tunnel Roofs 49

20. Ceiling Strutting with Side Post Supports 49

21. Sill, Side Post and Cap Cross Frame Strutting 49

22. Reinforced Cross Frame Strutting for Treacherous Materials 49

23. Longitudinal Poling-Board System of Roof Strutting 50

24. Transverse Poling-Board System of Roof Strutting 50

25. Shaft with Single Transverse Strutting 52

26. Rectangular Frame Strutting for Shafts 53

27. Reinforced Rectangular Frame Strutting for Shafts in
Treacherous Materials 53

28. Strutting of Timber Posts and Railway Rail Caps 56

29. Strutting Made Entirely of Railway Rails 56

30. Rziha’s Combined Strutting and Centering of Cast Iron 57

31. Cast-Iron Segment of Rziha’s Strutting and Centering 57

32. Cast-Iron Segmental Strutting for Shafts 58

33. Platform Car for Tunnel Work 59

34. Iron Dump-Car for Tunnel Work 60

35. Wooden Dump-Car for Tunnel Work 60

36. Box-Car for Tunnel Work 61

37. Elevator Car for Tunnel Shafts 65

38. Ground Mold for Constructing Tunnel Invert Masonry 67

39. Combined Ground Mold and Leading Frame for Invert and Side
Wall Masonry 67

40. Leading Frame for Constructing Side Wall Masonry 68

41. Plank Center for Constructing the Roof Arch 69

42. Trussed Center for Constructing the Roof Arch 70

43 and 44. A Typical Form of Timber Lining for Tunnels 73

45. Diagram Showing Forms adopted for Side-Wall Foundations 76

46 and 47. Transverse Sections of Tunnels Showing Methods for
Increasing the Thickness of the Lining at Different Points 79

48. Refuge Niche in St. Gothard Tunnel 81

49. East Portal of Hoosac Tunnel 82

50, 51 and 52. Arrangement of Drill Holes in the Heading of
Turchino Tunnel 91

53 and 54. Arrangement of Drill Holes in the Heading of the Fort
George Tunnel 91

55. Diagram Showing Sequence of Excavations in Drift Method of
Tunneling Rock 102

56. Sketches Showing Sequence of Work in Excavating and Lining
the Simplon Tunnel 111

57. General Details of the Brandt Rotary Drills Employed at the
Simplon Tunnel 112

58. Sequence of Excavation in the Murray Hill Tunnel 124

59. Traveling Platform for the Excavation of the Upper Side of
the Murray Hill Tunnel 125

60. Timbering Used in the Murray Hill Tunnel 126

61. Diagram Showing Sequence of Excavation in Heading Method of
Tunneling Rock 132

62. Method of Strutting Roof, St. Gothard Tunnel 135

63. Sketch Showing Arrangement of Tracks, St. Gothard Tunnel 135

64. Arrangement of Drill Holes in the Fort George Tunnel 137

65. Longitudinal Section of the Heading and Bench Excavation at
the Fort George Tunnel 137

66. Diagram Showing the Arrangement of Drill Holes in the
Heading and Bench of the Gallitsin Tunnel 140

67. Diagram Showing Modification of the Heading and Bench Method 140

68 and 68A. Diagrams Showing Sequence of Excavation in the
Belgian Method 145

69. Sketch Showing Radial Roof Strutting, Belgian Method 147

70. Sketch Showing Roof Arch Center, Belgian Method 147

71. Sketch Showing Method of Underpinning Roof Arch with the
Side Wall Masonry 149

72. Longitudinal Section Showing Construction by the Belgian
Method 149

73. Diagram Showing Sequence of Excavation in Modified Belgian
Method 152

74. Sketch Showing Failure of Roof Arch by Opening at Crown 153

75. Sketch Showing Methods of Repairing Roof Arch Failures 154

76. Diagrams Showing Sequence of Excavation in German Method of
Tunneling 155

77. Diagram Showing Sequence of Excavation in Water Bearing
Material, German Method 156

78. Sketch Showing Work of Excavating and Timbering Drifts and
Headings 157

79. Sketch Showing Method of Roof Strutting 157

80. Sketch Showing Roof Arch Centers and Arch Construction 158

81. Sketch Showing Method of Excavating and Strutting Baltimore
Belt Line Tunnel 162

82. Roof Arch Construction with Timber Centers, Baltimore Belt
Line Tunnel 163

83. Roof Arch Construction with Iron Centers, Baltimore Belt
Line Tunnel 164

84. Diagram Showing Sequence of Excavation in English Method of
Tunneling 167

85. Sketches Showing Construction of Strutting, English Method 168

86 and 87. Sketches of Typical Timber Roof-Arch Centers, English
Method 169

88. Sequence of Excavation in the American Method 172

89. Strutting the Heading in the American Method 172

90. Temporary Timbering of the Roof in the American Method 173

91. Showing Crown Bars Supported by Segmental Arches 173

92. Transversal and Longitudinal Section of a Tunnel Excavated
and Strutted According to the American Method 174

93 and 94. Diagrams Showing Sequence of Excavation in Austrian
Method of Tunneling 177

95, 96 and 97. Sketches Showing Construction of Strutting,
Austrian Method 178

98. Sketch Showing Manner of Constructing the Lining Masonry,
Austrian Method 179

99. Diagram Showing Sequence of Excavation in Italian Method of
Tunneling 183

100. Sketch Showing Strutting for Lower Part of Section 183

101 and 101A. Sketches Showing Construction of Centers, Italian
Method 184

102. Sketch Showing Invert and Foundation Masonry, Italian Method. 185

103. Sketch Showing Longitudinal Section of a Tunnel under
Construction, Italian Method 186

104. Sketch Showing Sequence of Excavation, Stazza Tunnel 186

105. Sketch Showing Method of Strutting First Drift, Stazza
Tunnel 187

106 and 107. Sketches Showing Temporary Strutting Arch
Construction, Stazza Tunnel 187

108. Sketch Showing Preliminary Drainage Galleries, Quicksand
Method 190

109. Sketch Showing Construction of Roof Strutting, Quicksand
Method 190

110. Sketch Showing Construction of Masonry Lining, Quicksand
Method 191

111. Sketch Showing Pilot Method of Tunneling 193

112. Diagram Showing Sequence of Construction in Open-Cut Tunnels 197

113. Sketch Showing Method of Timbering Open-Cut Tunnels, Double
Parallel Trench Method 198

114. Side-Wall Foundation Construction Open-Cut Tunnels 198

115. Wide-Arch Section, Boston Subway 204

116. Double-Barrel Section, Boston Subway 205

117. Four-Track Rectangular Section, Boston Subway 206

118. Section Showing Slice Method of Construction, Boston Subway 206

119. Double-Track Section, New York Rapid Transit Railway 212

120. Park Avenue Deep Tunnel Construction, New York Rapid Transit
Railway 214

121. Harlem River Tunnel, New York Rapid Transit Railway 215

122. Sketch Showing Underground Stream, Milwaukee Water-Works
Tunnel 229

123. Sketch Showing Methods of Lining, Milwaukee Water-Works
Tunnel 232

124. Longitudinal Section of Brunel’s Shield, First Thames Tunnel 241

125. First Shield Invented by Barlow 242

126. Second Shield Invented by Barlow 243

127. Shield Suggested by Greathead for the Proposed North and
South Woolwich Subway 245

128. Beach’s Shield Used on Broadway Pneumatic Railway Tunnel 245

129. Shield for City and South London Railway 246

130. Shield for St. Clair River Tunnel 247

131. Shield for Blackwall Tunnel 248

132. Elliptical Shield for Clichy Sewer Tunnel, Paris 249

133. Semi-Elliptical Shield for Clichy Sewer Tunnel 250

134. Roof Shield for Boston Subway 251

135. Transversal and Longitudinal Section of Prelini’s Shield 252

136. Elevation and Section of Hydraulic Jack, East River Gas
Tunnel 260

137. Cast-Iron Lining, St. Clair River Tunnel 262

138. General Elevations and Sections of Shields 270

139. Plan and Elevation of First Bulkhead Wall in South Tube,
Manhattan 273

140. Typical Cross-Sections of One Tube of Pennsylvania Railroad
Tunnel under the Hudson River 278

141. Sections of Cofferdam, Van Buren St. Tunnel, Chicago 283

142. Showing Working Platforms and Piles Sunk in Dredged Channel 286

143. Showing Sheeting-Piles for the Sides of the Caisson and
Trussed Beam for the Roof 287

144. Showing the Caisson with the Working-Chamber 287

145. Showing the Tunnel Constructed within the Caisson 289

146. Showing Sides of the Caisson and Supports for the Roof 290

147. Showing the Roof of the Caisson Formed by the Upper Half of
the Tunnel 291

148. Showing the Tunnel Completed by Building the Lower Half
within the Caisson 292

149. Transversal Section of the Caissons for the Tunnel under the
Seine River 294

150. Showing the Joining of the Caissons at the Pont Mirabeau
Tunnel under the Seine River 295

151. Cross-Sections and Plans of the Detroit River Tunnel 298

152. Tunneling through Caved Material by Heading 306

153. Tunneling through Caved Material by Drifts 307

154 and 155. Filling in Roof Cavity Formed by Falling Material 307

156. Timbering to Prevent Landslides at Portal 308

157. Shortening Tunnel Crushed by Landslide at Portal 308

158. Extending Tunnel through Landslide at Portal 309

159 and 160. Relining Timber-Lined Tunnel 316

161. Relining Timber-Lined Tunnel, Great Northern Ry 317

162. Relining Timber-Lined Tunnel, Great Northern Ry 318

163. Relining Timber-Lined Tunnel, Great Northern Ry 319

164. Construction of Centering Mullan Tunnel 320

165. Centering Mullan Tunnel 321

166. Relining Timber-Lined Tunnel, Norfolk & Western Ry 322

167. Relining Timber-Lined Tunnel, Norfolk & Western Ry 323