1
00:00:04,120 --> 00:00:07,200
Speaker 1: Get in touch with technology with tech Stuff from half

2
00:00:07,200 --> 00:00:13,840
Speaker 1: stuff works dot com. He there, and welcome to tech Stuff.

3
00:00:13,880 --> 00:00:17,960
Speaker 1: I'm your host, executive producer, Jonathan Strickland, and I love

4
00:00:18,120 --> 00:00:22,759
Speaker 1: all things tech. And in past episodes of tech Stuff,

5
00:00:22,840 --> 00:00:26,239
Speaker 1: I have covered stuff like the history of subway systems,

6
00:00:26,320 --> 00:00:30,200
Speaker 1: and I've given an overview of the Boring Company that's

7
00:00:30,280 --> 00:00:33,400
Speaker 1: one of Elon Musk's companies and its mission to create

8
00:00:33,479 --> 00:00:36,920
Speaker 1: underground tunnel systems beneath cities to allow for a new

9
00:00:36,960 --> 00:00:40,560
Speaker 1: method of getting around town and also methods for getting

10
00:00:40,640 --> 00:00:44,880
Speaker 1: between towns. So you've got the loop and the hyper

11
00:00:44,920 --> 00:00:48,000
Speaker 1: loop concepts. But today I'm going to talk more about

12
00:00:48,040 --> 00:00:52,559
Speaker 1: the enormous machines used to dig out tunnels as well

13
00:00:52,600 --> 00:00:54,279
Speaker 1: as the smaller ones that are used to dig out

14
00:00:54,320 --> 00:00:58,200
Speaker 1: smaller tunnels, the ones that are used for utility lines,

15
00:00:58,680 --> 00:01:01,720
Speaker 1: or the ones that are really huge to make transportation tunnels.

16
00:01:01,920 --> 00:01:05,360
Speaker 1: Those are gigantic, they're incredibly interesting, and they consist of

17
00:01:05,400 --> 00:01:08,960
Speaker 1: multiple machines joined together to make a comprehensive tunneler. So

18
00:01:09,680 --> 00:01:12,560
Speaker 1: this is a this is a big topic, both figuratively

19
00:01:12,680 --> 00:01:16,840
Speaker 1: and literally. So first, let's talk about the challenges that

20
00:01:16,880 --> 00:01:19,920
Speaker 1: we face if we want to dig a tunnel, specifically

21
00:01:19,920 --> 00:01:22,959
Speaker 1: a tunnel under a populated area like a city. So

22
00:01:23,640 --> 00:01:25,280
Speaker 1: we have to make sure that the method we use

23
00:01:25,319 --> 00:01:28,760
Speaker 1: will not create structural problems for the region above. Right,

24
00:01:28,800 --> 00:01:31,920
Speaker 1: we don't want any collapses. The tunnel can't create any

25
00:01:31,959 --> 00:01:37,600
Speaker 1: welling or sink holes. Uh if it cannot undermine buildings.

26
00:01:38,240 --> 00:01:40,680
Speaker 1: The method we use has to preserve the stability of

27
00:01:40,720 --> 00:01:45,720
Speaker 1: everything else above it, or catastrophe will occur. Obviously, Likewise,

28
00:01:46,120 --> 00:01:49,440
Speaker 1: the method we use needs to protect the tunnel that

29
00:01:49,600 --> 00:01:52,320
Speaker 1: we're digging. We have to create a way to prevent

30
00:01:52,360 --> 00:01:56,480
Speaker 1: the tunnel from collapsing in on itself. Through stone, maybe

31
00:01:56,480 --> 00:02:00,720
Speaker 1: this requires a little bit of work just to force everything,

32
00:02:00,720 --> 00:02:02,920
Speaker 1: but through soft earth you have to come up with

33
00:02:02,960 --> 00:02:05,160
Speaker 1: something else. So there's got to be a mechanism to

34
00:02:05,240 --> 00:02:09,040
Speaker 1: improve the structural stability of a tunnel. The machine we

35
00:02:09,160 --> 00:02:11,519
Speaker 1: build has to be able to cut through lots of

36
00:02:11,560 --> 00:02:17,080
Speaker 1: different kinds of ground, from sandy soft material to rocky surfaces,

37
00:02:17,240 --> 00:02:21,440
Speaker 1: or dry material to wet mud. So the cutting edge

38
00:02:21,440 --> 00:02:24,440
Speaker 1: of the tunnel er has to be capable of handling

39
00:02:24,520 --> 00:02:26,360
Speaker 1: all of that, or you need to be able to

40
00:02:26,360 --> 00:02:29,720
Speaker 1: swap out cutting edges depending upon the kind of ground

41
00:02:29,720 --> 00:02:33,160
Speaker 1: you're going through, and that's easier said than done. Typically

42
00:02:33,639 --> 00:02:37,880
Speaker 1: you just want to keep the same cutting edge on

43
00:02:38,120 --> 00:02:41,280
Speaker 1: your your tunnel, or for the entirety of a dig

44
00:02:41,720 --> 00:02:44,760
Speaker 1: you may have to replace little components on it, but

45
00:02:45,080 --> 00:02:47,960
Speaker 1: that's a lot easier in the grand scheme of things

46
00:02:48,000 --> 00:02:51,800
Speaker 1: than replacing an entire cutting head. We'll get more into

47
00:02:51,840 --> 00:02:53,680
Speaker 1: that in a bit. We also have to have a

48
00:02:53,680 --> 00:02:57,399
Speaker 1: way to remove all the material we're cutting or digging through.

49
00:02:57,400 --> 00:03:01,880
Speaker 1: The excavated material, which is often called muck or spoil.

50
00:03:02,320 --> 00:03:05,160
Speaker 1: All of that stuff has to go somewhere, so whatever

51
00:03:05,200 --> 00:03:08,080
Speaker 1: method we use needs to take that into account so

52
00:03:08,120 --> 00:03:10,880
Speaker 1: that we can manage all that mess as we keep digging.

53
00:03:11,320 --> 00:03:14,519
Speaker 1: The digging mechanism needs a method for transporting the muck

54
00:03:14,760 --> 00:03:19,320
Speaker 1: or spoil out from behind the cutting head and preferably

55
00:03:19,360 --> 00:03:23,919
Speaker 1: out of the tunnel itself. So modern tunneling machines do

56
00:03:23,960 --> 00:03:28,400
Speaker 1: these things in really interesting ways. There are differences between

57
00:03:28,440 --> 00:03:31,919
Speaker 1: the various machines. They generally are doing the same thing,

58
00:03:32,000 --> 00:03:33,960
Speaker 1: but they do it in different ways. Some are almost

59
00:03:34,080 --> 00:03:38,720
Speaker 1: completely automated, others have a balance between human controlled systems

60
00:03:38,760 --> 00:03:42,600
Speaker 1: and automated systems. The Boring Company posted a video that

61
00:03:42,640 --> 00:03:46,640
Speaker 1: showed a machine apparently following the input of someone holding

62
00:03:46,720 --> 00:03:51,760
Speaker 1: an Xbox game controllers. So that was interesting. Now, I

63
00:03:51,800 --> 00:03:55,280
Speaker 1: don't know if that machine was actually following the directions

64
00:03:55,320 --> 00:03:57,880
Speaker 1: of the person with the controller or the whole thing

65
00:03:58,000 --> 00:04:02,560
Speaker 1: was an orchestrated video. It seemed to correspond with the

66
00:04:02,680 --> 00:04:05,600
Speaker 1: person holding the controller, although that could have been a

67
00:04:05,680 --> 00:04:08,920
Speaker 1: very well rehearsed routine and the person with the controller

68
00:04:09,040 --> 00:04:13,240
Speaker 1: is just pushing the controls in different directions and hitting

69
00:04:13,280 --> 00:04:17,440
Speaker 1: different buttons in time with something that has already been programmed.

70
00:04:17,440 --> 00:04:21,640
Speaker 1: That's a possibility. I suppose there's no reason someone couldn't

71
00:04:21,680 --> 00:04:25,160
Speaker 1: make an interface between a game controller and a huge machine.

72
00:04:25,640 --> 00:04:28,120
Speaker 1: But then, considering the precision needed for some of the

73
00:04:28,160 --> 00:04:30,919
Speaker 1: operations we're going to talk about, it does make me

74
00:04:30,960 --> 00:04:33,919
Speaker 1: a little skeptical. I mean, it's possible that the video

75
00:04:33,960 --> 00:04:36,800
Speaker 1: is completely legitimate, but I'm a bit concerned about the

76
00:04:36,800 --> 00:04:39,000
Speaker 1: work the machine would be doing in that case, because

77
00:04:39,600 --> 00:04:42,600
Speaker 1: I play Xbox a lot and precision is not one

78
00:04:42,600 --> 00:04:46,000
Speaker 1: of the words I would use to describe the control system.

79
00:04:46,000 --> 00:04:50,800
Speaker 1: But maybe I'm wrong. It's entirely possible. Now, Ideally, the

80
00:04:50,800 --> 00:04:54,640
Speaker 1: device we create should be able to cut through the ground,

81
00:04:55,200 --> 00:04:57,680
Speaker 1: shore up a tunnel as it does so so that

82
00:04:57,720 --> 00:05:01,680
Speaker 1: the tunnel remains stable, move the spoil or muck from

83
00:05:01,760 --> 00:05:03,720
Speaker 1: the dig so it's out of the way, and do

84
00:05:03,839 --> 00:05:07,599
Speaker 1: so without disrupting anything above the ground. So how the

85
00:05:07,680 --> 00:05:11,600
Speaker 1: heck is that possible? Well, first, the type of tunneling

86
00:05:11,640 --> 00:05:14,400
Speaker 1: machines we use to drill the way for stuff like

87
00:05:14,560 --> 00:05:17,719
Speaker 1: utility lines to subway trains or tunnels come in a

88
00:05:18,000 --> 00:05:23,160
Speaker 1: range of sizes. Some are relatively small, and they're meant

89
00:05:23,160 --> 00:05:26,960
Speaker 1: for digging tunnels that will house cables or utility lines.

90
00:05:27,680 --> 00:05:31,960
Speaker 1: The company Robbins produces small tunneling machines that range from

91
00:05:32,000 --> 00:05:35,719
Speaker 1: two feet or about sixty one centimeters up to six

92
00:05:35,760 --> 00:05:39,160
Speaker 1: ft or one point eight meters in diameter. They make

93
00:05:39,200 --> 00:05:42,560
Speaker 1: bigger ones too, but these are the ones that they consider,

94
00:05:42,760 --> 00:05:46,920
Speaker 1: these small boring machines from two to six feet in diameter,

95
00:05:47,520 --> 00:05:51,640
Speaker 1: and these machines actually rely upon another device. It's called

96
00:05:51,680 --> 00:05:56,279
Speaker 1: an augur boring machine, which provides two things. It provides

97
00:05:56,320 --> 00:05:59,880
Speaker 1: the rotational force that is used to turn the cutting head,

98
00:06:00,200 --> 00:06:03,560
Speaker 1: which is the part of the tunneler that actually makes

99
00:06:03,600 --> 00:06:07,599
Speaker 1: contact with the earth, and it also provides the forward

100
00:06:07,760 --> 00:06:12,200
Speaker 1: thrust to push that cutting head against the earth, so

101
00:06:12,240 --> 00:06:15,320
Speaker 1: that it is continuously making that contact and cutting away.

102
00:06:16,120 --> 00:06:19,680
Speaker 1: The cutting face or the cutting head and the end

103
00:06:19,720 --> 00:06:22,800
Speaker 1: of the augur can interlock with each other sort of

104
00:06:22,839 --> 00:06:26,640
Speaker 1: like a socket wrench, and it's detachable sockets. So you've

105
00:06:26,680 --> 00:06:29,880
Speaker 1: got the end of this auger blade coming in all

106
00:06:29,920 --> 00:06:33,920
Speaker 1: the aug boring machine that connects it its sockets into

107
00:06:34,560 --> 00:06:39,280
Speaker 1: the actual cutting head, and that's where you can transfer

108
00:06:39,360 --> 00:06:42,599
Speaker 1: the rotational force from the auger boring machine to the

109
00:06:42,600 --> 00:06:45,840
Speaker 1: cutting head, which spins like a disc on the other

110
00:06:45,920 --> 00:06:48,599
Speaker 1: end of the scale. So that's the small side. If

111
00:06:48,640 --> 00:06:50,720
Speaker 1: you want to talk big, let's go with the biggest

112
00:06:50,760 --> 00:06:54,080
Speaker 1: there ever was, at least up to now. You've got

113
00:06:54,120 --> 00:06:59,920
Speaker 1: something like Bertha. Bertha was the largest boring machine ever

114
00:07:00,200 --> 00:07:04,360
Speaker 1: made so far. Anyway, the cutting face, that is the

115
00:07:04,760 --> 00:07:09,120
Speaker 1: front of the cutting head, measured fifties seven feet in diameter,

116
00:07:09,480 --> 00:07:15,360
Speaker 1: that's seventeen point four meters. The machines length from the

117
00:07:15,400 --> 00:07:18,160
Speaker 1: face of the cutting head all the way to the

118
00:07:18,160 --> 00:07:21,840
Speaker 1: back of the machine was three hundred twenty six ft

119
00:07:22,000 --> 00:07:26,360
Speaker 1: or nine nine meters. While a small boring machine is

120
00:07:26,360 --> 00:07:29,360
Speaker 1: an extension of an auger and it gets its rotational

121
00:07:29,400 --> 00:07:32,520
Speaker 1: power and its forward thrust from this auger boring machine.

122
00:07:32,760 --> 00:07:37,000
Speaker 1: Bertha was like a giant tunneling facility. It had a

123
00:07:37,080 --> 00:07:40,920
Speaker 1: frame mounted behind the cutting head that housed stuff like

124
00:07:41,040 --> 00:07:44,040
Speaker 1: break rooms and an operator office. So you had people

125
00:07:44,640 --> 00:07:49,560
Speaker 1: walking inside this giant machine that had a shielded part

126
00:07:49,600 --> 00:07:52,080
Speaker 1: in the front where the cutting head was, and then

127
00:07:52,080 --> 00:07:54,960
Speaker 1: the part in the back was. It looked like a big,

128
00:07:55,000 --> 00:07:59,640
Speaker 1: open scaffolded machine with lots of conveyor belts and these

129
00:07:59,680 --> 00:08:02,680
Speaker 1: little rooms for for operator rooms and break rooms that

130
00:08:02,760 --> 00:08:06,680
Speaker 1: kind of stuff. So the cutting head looks like a

131
00:08:06,720 --> 00:08:10,720
Speaker 1: big disc with teeth sticking out of the face of it,

132
00:08:11,360 --> 00:08:16,520
Speaker 1: and then behind that you've got this big cylinder. The shield.

133
00:08:17,400 --> 00:08:20,360
Speaker 1: The shield is what protects the cutting head and the

134
00:08:20,400 --> 00:08:24,120
Speaker 1: immediate part of the tunnel or from behind the cutting

135
00:08:24,160 --> 00:08:29,880
Speaker 1: head and keeps the earth stable behind it, so it's uh,

136
00:08:30,120 --> 00:08:33,880
Speaker 1: it's keeping everything from caving in essentially. Behind that, you've

137
00:08:33,920 --> 00:08:38,880
Speaker 1: got an enormous um crane. More on that in a bit,

138
00:08:39,440 --> 00:08:42,960
Speaker 1: and you also have a screw conveyor. A screw conveyor

139
00:08:43,120 --> 00:08:46,120
Speaker 1: is kind of like an auger. It's got this helical

140
00:08:46,360 --> 00:08:49,560
Speaker 1: screw that's designed to lift spoil or muck up to

141
00:08:49,640 --> 00:08:52,880
Speaker 1: a conveyor belt. The conveyor belt sends all that muck

142
00:08:52,960 --> 00:08:55,680
Speaker 1: back through the back of the machine and eventually completely

143
00:08:55,679 --> 00:08:58,400
Speaker 1: out of the tunnel. All of these elements are mounted

144
00:08:58,440 --> 00:09:00,719
Speaker 1: within this enormous metal for aim that's part of the

145
00:09:00,760 --> 00:09:05,160
Speaker 1: tunneling machine. It's typically held into place by hydraulic legs

146
00:09:05,200 --> 00:09:08,040
Speaker 1: that brace against the sides of the tunnel to keep

147
00:09:08,080 --> 00:09:11,800
Speaker 1: it steady. The frame or maybe wheels as well. It

148
00:09:11,880 --> 00:09:14,560
Speaker 1: could be wheels that are are locked into place. They

149
00:09:14,559 --> 00:09:17,200
Speaker 1: have very powerful breaks and they just locked into place

150
00:09:17,320 --> 00:09:20,080
Speaker 1: on the sides of these tunnels. Bertha was a special

151
00:09:20,120 --> 00:09:23,760
Speaker 1: type of borer called an earth pressure balanced tunneling boring

152
00:09:23,800 --> 00:09:27,200
Speaker 1: machine or EPB. I'll explain more about that and a

153
00:09:27,240 --> 00:09:31,240
Speaker 1: little bit. So let's start with the small boring machines.

154
00:09:32,240 --> 00:09:34,880
Speaker 1: A lot of the principles behind the small boring machines

155
00:09:34,920 --> 00:09:37,720
Speaker 1: apply to the larger ones. That's just they're much bigger scale.

156
00:09:38,120 --> 00:09:41,440
Speaker 1: So the drive for those smaller machines, as I mentioned,

157
00:09:41,520 --> 00:09:44,800
Speaker 1: was an auger boring machine. Now, an auger is a

158
00:09:44,840 --> 00:09:47,360
Speaker 1: tool that's a type of drill. Usually it has a

159
00:09:47,360 --> 00:09:50,080
Speaker 1: helical bit, meaning the bit is in the shape of

160
00:09:50,120 --> 00:09:53,400
Speaker 1: a helix, and the helical bit acts like a screw

161
00:09:53,440 --> 00:09:56,280
Speaker 1: conveyor and It works on the same principle as an

162
00:09:56,280 --> 00:10:01,000
Speaker 1: ancient piece of technology called Archimedes screw. And your typical

163
00:10:01,040 --> 00:10:05,559
Speaker 1: Archimedes screw has a helical bit housed inside a pipe,

164
00:10:06,160 --> 00:10:08,839
Speaker 1: and you don't have a whole lot of space between

165
00:10:08,920 --> 00:10:11,760
Speaker 1: the screw and the pipe, so the screw is very

166
00:10:11,840 --> 00:10:15,040
Speaker 1: snug inside this pipe. You can rotate it, but that's

167
00:10:15,040 --> 00:10:18,760
Speaker 1: all you know. It's it's otherwise almost essentially making contact

168
00:10:18,840 --> 00:10:21,560
Speaker 1: with the sides. It's very important for this. You set

169
00:10:21,559 --> 00:10:24,640
Speaker 1: the screw at a forty five degree angle with the

170
00:10:24,679 --> 00:10:28,440
Speaker 1: lower section immersed in water. So imagine you have a

171
00:10:28,480 --> 00:10:32,240
Speaker 1: low body of water. You insert and Archimedes screw at

172
00:10:32,240 --> 00:10:34,920
Speaker 1: this forty five degree angle into the water, and then

173
00:10:34,960 --> 00:10:38,600
Speaker 1: when you turn the screw, it will lift or pump

174
00:10:38,880 --> 00:10:41,920
Speaker 1: water out of the low end. As the water moves

175
00:10:42,080 --> 00:10:44,880
Speaker 1: up the screw, it acts like a rotating ramp and

176
00:10:44,960 --> 00:10:48,000
Speaker 1: it pushes the water up traps the water lifts it

177
00:10:48,080 --> 00:10:50,520
Speaker 1: up to a higher elevation, so you can actually transfer

178
00:10:50,600 --> 00:10:53,400
Speaker 1: water from a low area to a high area using this.

179
00:10:53,679 --> 00:10:56,760
Speaker 1: You can build one of these yourself with a dowel

180
00:10:56,840 --> 00:10:59,800
Speaker 1: and some plastic tubing and you just wrap the plastic

181
00:10:59,800 --> 00:11:03,800
Speaker 1: two being around the dowel and a spiral, and when

182
00:11:03,840 --> 00:11:06,400
Speaker 1: you put the dowel into water and you keep the

183
00:11:06,440 --> 00:11:08,760
Speaker 1: dowel at like a forty five degree angle, as long

184
00:11:08,760 --> 00:11:12,240
Speaker 1: as you're turning the dowel in the proper direction, it

185
00:11:12,280 --> 00:11:14,880
Speaker 1: will continue to dip into the water, and that water

186
00:11:14,960 --> 00:11:17,840
Speaker 1: will slowly make its way all the way up the

187
00:11:17,880 --> 00:11:21,560
Speaker 1: coil as you rotate the dowel. Augers are used for

188
00:11:21,600 --> 00:11:25,320
Speaker 1: all sorts of things. So wood drill bits typically have

189
00:11:25,520 --> 00:11:29,120
Speaker 1: those helical grooves in them, and this helps convey shavings

190
00:11:29,160 --> 00:11:31,679
Speaker 1: out of the hole that you're drilling and gets that

191
00:11:31,880 --> 00:11:33,960
Speaker 1: those wood shavings out of the way so they don't

192
00:11:34,000 --> 00:11:37,080
Speaker 1: just gum up the space. And you can use an

193
00:11:37,080 --> 00:11:40,760
Speaker 1: auger to drill holes into the earth. The tunneling machines

194
00:11:40,760 --> 00:11:44,440
Speaker 1: i'm talking about used augers for their rotational force and

195
00:11:44,480 --> 00:11:47,880
Speaker 1: their ability to transport spoil out of a tunnel. The

196
00:11:47,920 --> 00:11:51,920
Speaker 1: actual cutting head of these tunneling machines wasn't on the

197
00:11:51,920 --> 00:11:54,800
Speaker 1: augur itself. It was a separate piece and it does

198
00:11:54,840 --> 00:11:59,000
Speaker 1: the actual tunneling part. The auger boring machines sold by

199
00:11:59,000 --> 00:12:03,440
Speaker 1: companies like Robin are large devices that allow for horizontal

200
00:12:03,640 --> 00:12:08,319
Speaker 1: boring and they look like these big metal rectangular construction devices,

201
00:12:09,040 --> 00:12:12,960
Speaker 1: and out of one end parallel to the ground is

202
00:12:13,000 --> 00:12:16,120
Speaker 1: the auger blade. So to use one, first thing you

203
00:12:16,120 --> 00:12:19,400
Speaker 1: would do is you would dig a pit down to

204
00:12:19,679 --> 00:12:23,120
Speaker 1: whatever level you need so that where the tunnel is

205
00:12:23,160 --> 00:12:24,760
Speaker 1: going to be. So you're gonna actually have to dig

206
00:12:24,800 --> 00:12:28,320
Speaker 1: a pretty long and deep rectangular pit and get it

207
00:12:28,320 --> 00:12:31,240
Speaker 1: down to the level where you're gonna dig this tunnel.

208
00:12:31,720 --> 00:12:36,959
Speaker 1: And then you would put down tracks which the auger

209
00:12:37,679 --> 00:12:44,000
Speaker 1: boring machine would sit on, and probably a concrete barrier

210
00:12:44,120 --> 00:12:48,560
Speaker 1: at the back to act as a surface that the

211
00:12:48,600 --> 00:12:51,800
Speaker 1: auger boring machine can thrust off of to start with.

212
00:12:52,720 --> 00:12:57,360
Speaker 1: And that's your basic point of operations for the beginning

213
00:12:57,360 --> 00:13:03,120
Speaker 1: of your tunneling process. The machine will provide the torque

214
00:13:03,400 --> 00:13:06,520
Speaker 1: necessary for everything to work, and torque is a twisting

215
00:13:06,600 --> 00:13:10,320
Speaker 1: force that tends to cause rotation. When you use a screwdriver,

216
00:13:10,760 --> 00:13:15,440
Speaker 1: you are applying torque to a screw. With augur boring machines,

217
00:13:15,800 --> 00:13:19,040
Speaker 1: torque comes from the rotational force created by the motor

218
00:13:19,160 --> 00:13:21,800
Speaker 1: driving the auger And I've talked a lot about motors

219
00:13:21,800 --> 00:13:24,120
Speaker 1: in previous episodes of Tech Stuff, So rather than go

220
00:13:24,240 --> 00:13:28,120
Speaker 1: on through all that again, we'll just say it's a

221
00:13:28,160 --> 00:13:32,120
Speaker 1: motor that creates the rotational force. The international systems of

222
00:13:32,280 --> 00:13:36,280
Speaker 1: unit metric for torque is the Newton meter and Augur

223
00:13:36,360 --> 00:13:40,160
Speaker 1: boring machine on the more modest side, might produce a

224
00:13:40,200 --> 00:13:43,559
Speaker 1: peak torque of about four hundred newton meters or two

225
00:13:44,640 --> 00:13:47,680
Speaker 1: foot pounds of force. I've got a lot more to

226
00:13:47,720 --> 00:13:50,360
Speaker 1: say about these tunneling machines, but first let's take a

227
00:13:50,440 --> 00:14:01,559
Speaker 1: quick break to thank our sponsor the honors. Rotational force

228
00:14:01,760 --> 00:14:05,640
Speaker 1: transfers to the cutting head of this boring machine. These

229
00:14:05,679 --> 00:14:08,920
Speaker 1: components make contact with what's called the cutting face of

230
00:14:08,960 --> 00:14:12,120
Speaker 1: the dig that's the part of the earth or rock

231
00:14:12,320 --> 00:14:15,680
Speaker 1: that the cutting head is actually making contact with. The

232
00:14:15,720 --> 00:14:19,360
Speaker 1: cutting head is the surface that goes against the rocks, boulders,

233
00:14:19,360 --> 00:14:22,800
Speaker 1: and sand. So this cutting surface can have numerous tools

234
00:14:22,840 --> 00:14:26,640
Speaker 1: on it, including cutting disks which are used mostly to

235
00:14:26,760 --> 00:14:32,480
Speaker 1: break up rocks and boulders, scrapers and other projections meant

236
00:14:32,520 --> 00:14:35,760
Speaker 1: to remove material to excavate it, to break it up,

237
00:14:35,920 --> 00:14:39,560
Speaker 1: excavate it and move it back into the back part

238
00:14:39,760 --> 00:14:44,000
Speaker 1: of this tunneling machine. They also typically have gaps in

239
00:14:44,040 --> 00:14:47,800
Speaker 1: the face of the cutting head that allows this spoil

240
00:14:47,880 --> 00:14:51,320
Speaker 1: to pass through the cutting head and move back through

241
00:14:51,600 --> 00:14:56,040
Speaker 1: the chain. Uh the spoil is able to come through

242
00:14:56,080 --> 00:14:58,720
Speaker 1: that way, it encounters the auger blade that acts like

243
00:14:58,760 --> 00:15:02,600
Speaker 1: a conveyor screw, and the auger blade will pull the

244
00:15:02,680 --> 00:15:06,800
Speaker 1: spoil or muck away from the cutting surface. Now, not

245
00:15:06,880 --> 00:15:10,440
Speaker 1: all cutting tools are suitable for all types of ground. Some,

246
00:15:10,600 --> 00:15:12,480
Speaker 1: like the cutting disks, like I said, are really good

247
00:15:12,480 --> 00:15:15,400
Speaker 1: for breaking up larger rocks and boulders into smaller pieces.

248
00:15:15,640 --> 00:15:18,080
Speaker 1: But if you're encountering a lot of mud or water

249
00:15:18,320 --> 00:15:22,200
Speaker 1: in this tunneling job, a different selection might be needed

250
00:15:22,520 --> 00:15:25,080
Speaker 1: in order to dig the tunnel and to convey the

251
00:15:25,120 --> 00:15:29,320
Speaker 1: material to the conveyor screw and maintain the cutting faces stability.

252
00:15:29,520 --> 00:15:32,680
Speaker 1: Wet ground presents challenges in that regard. I'll talk more

253
00:15:32,720 --> 00:15:36,280
Speaker 1: about that in a bit. So the cutting tools tend

254
00:15:36,280 --> 00:15:40,000
Speaker 1: to be made from really really hard materials because you

255
00:15:40,040 --> 00:15:42,960
Speaker 1: want them to last a good long while, preferably for

256
00:15:43,040 --> 00:15:45,960
Speaker 1: the length of the tunneling job. So you might use

257
00:15:46,040 --> 00:15:49,480
Speaker 1: something like tungsten carbide, and it's also sometimes just called

258
00:15:49,520 --> 00:15:52,880
Speaker 1: carbide for short. And this is a pretty cool material.

259
00:15:53,320 --> 00:15:57,360
Speaker 1: So tungsten is more than twice as dense as steel.

260
00:15:57,760 --> 00:16:01,840
Speaker 1: The process for making tungsten carbide involves lots of steps,

261
00:16:01,880 --> 00:16:07,360
Speaker 1: but essentially you're taking ore that contains tungsten, so something

262
00:16:07,400 --> 00:16:10,160
Speaker 1: like wolf from right. Uh. So you take wolf from

263
00:16:10,240 --> 00:16:12,720
Speaker 1: right and you crush it. You maybe you treat it

264
00:16:12,720 --> 00:16:15,400
Speaker 1: with some chemicals, You heat it up, and you end

265
00:16:15,480 --> 00:16:18,760
Speaker 1: up with something like tungsten oxide. Then you treat it

266
00:16:18,840 --> 00:16:21,800
Speaker 1: in a carbonizing process, such as heating it to more

267
00:16:21,840 --> 00:16:26,240
Speaker 1: than twelve degrees celsius. This removes the oxygen from that

268
00:16:26,360 --> 00:16:30,760
Speaker 1: mixture and it binds carbon to the tungsten. Then you

269
00:16:30,800 --> 00:16:34,320
Speaker 1: sort out the grains of tungsten carbide into piles based

270
00:16:34,320 --> 00:16:37,200
Speaker 1: on grain size. You typically would use something like a

271
00:16:37,240 --> 00:16:41,200
Speaker 1: sieve to do this. So you pass through sieves and

272
00:16:41,280 --> 00:16:43,560
Speaker 1: you get the finest grains out, and then you go

273
00:16:43,800 --> 00:16:47,680
Speaker 1: with progressively larger sieves to get the other grains. You

274
00:16:47,760 --> 00:16:51,960
Speaker 1: mix that with some other materials, including cobalt. Cobalt connect

275
00:16:52,000 --> 00:16:54,960
Speaker 1: as a binding agent. You press the mixture into a

276
00:16:55,040 --> 00:16:59,560
Speaker 1: mold high temperature mold for the whatever tool you're building.

277
00:17:00,200 --> 00:17:03,160
Speaker 1: Then you put it into what was called a centering furnace,

278
00:17:03,200 --> 00:17:05,960
Speaker 1: which is hot enough to melt the cobalt, which then

279
00:17:06,000 --> 00:17:09,199
Speaker 1: binds everything together kind of like the force. Then you

280
00:17:09,240 --> 00:17:13,240
Speaker 1: remove the tungsten carbide you and uh then hone it

281
00:17:13,280 --> 00:17:15,800
Speaker 1: down to its final size and its final shape. And

282
00:17:15,800 --> 00:17:18,199
Speaker 1: I've skipped a lot of details here. Anyone who has

283
00:17:18,240 --> 00:17:21,280
Speaker 1: worked with tungsten carbide, who's made the stuff knows that.

284
00:17:21,680 --> 00:17:23,720
Speaker 1: But this is a very high level kind of look

285
00:17:23,760 --> 00:17:25,639
Speaker 1: at the process. And in the end, what you have

286
00:17:25,800 --> 00:17:29,120
Speaker 1: is a tool much stronger than steel that can stand

287
00:17:29,200 --> 00:17:30,679
Speaker 1: up to a lot of wear and tear, which is

288
00:17:30,720 --> 00:17:34,480
Speaker 1: perfect for cutting into stuff like stone and breaking up rocks.

289
00:17:34,720 --> 00:17:37,720
Speaker 1: So the business end of the boring machine is the

290
00:17:37,720 --> 00:17:40,960
Speaker 1: cutting head, and that's typically protected by some shielding that

291
00:17:41,119 --> 00:17:44,920
Speaker 1: that sort of cylinder that's from the point of the

292
00:17:44,960 --> 00:17:49,200
Speaker 1: cutting face and extends back quite a bit. And then

293
00:17:49,520 --> 00:17:54,720
Speaker 1: sometimes you might use a length of pipe right behind that,

294
00:17:54,960 --> 00:17:58,880
Speaker 1: especially if you're using cutting these utility size holes, then

295
00:17:59,000 --> 00:18:03,600
Speaker 1: you would have metal pipe that would be connected to

296
00:18:04,240 --> 00:18:07,639
Speaker 1: the cutting head and surrounding the auger blade. On the

297
00:18:07,760 --> 00:18:12,080
Speaker 1: really big machines, it's typically part of the boring machine itself.

298
00:18:12,119 --> 00:18:16,040
Speaker 1: You don't just have a cutting head that's extending from

299
00:18:16,080 --> 00:18:20,000
Speaker 1: a pipe. It's all part of the same machine. This

300
00:18:20,160 --> 00:18:24,280
Speaker 1: big shield that will extend back several feet. The shielding

301
00:18:24,680 --> 00:18:27,280
Speaker 1: keeps the area near the face stable and it makes

302
00:18:27,320 --> 00:18:29,919
Speaker 1: direct contact with the earth that you're cutting through, So

303
00:18:30,000 --> 00:18:32,320
Speaker 1: it's it's sort of the tip of the tunneling machine.

304
00:18:32,440 --> 00:18:34,920
Speaker 1: So the cutting surface of the toweling machine presses against

305
00:18:34,960 --> 00:18:38,400
Speaker 1: the cutting face and turns it up to start digging horizontally.

306
00:18:38,880 --> 00:18:42,040
Speaker 1: The pressure is generated by these in the small ones

307
00:18:42,080 --> 00:18:46,720
Speaker 1: by the boring machine. It has those tracks I talked

308
00:18:46,720 --> 00:18:50,160
Speaker 1: about that's laid down in the pit and it starts

309
00:18:50,200 --> 00:18:53,320
Speaker 1: to roll forward, and the rolling forward is what puts

310
00:18:53,359 --> 00:18:57,480
Speaker 1: the forward thrust against the the cutting head which makes

311
00:18:57,640 --> 00:19:01,240
Speaker 1: contact with the the earth it starts to cut through

312
00:19:01,440 --> 00:19:04,240
Speaker 1: and tunnel in. This is a very slow process. It

313
00:19:04,359 --> 00:19:07,360
Speaker 1: is not happen quickly at all. So when I say

314
00:19:07,440 --> 00:19:11,000
Speaker 1: roll forward, I really just mean putting forward pressure, forward

315
00:19:11,040 --> 00:19:15,240
Speaker 1: thrust on that cutting head. Uh. The process itself takes

316
00:19:15,359 --> 00:19:20,359
Speaker 1: quite a long time, and the auger is typically wheeled

317
00:19:20,640 --> 00:19:23,439
Speaker 1: and has some sort of bracing technology to hold it

318
00:19:23,480 --> 00:19:27,840
Speaker 1: into place so that it doesn't just push itself backward

319
00:19:28,320 --> 00:19:31,439
Speaker 1: while it's trying to cut through this tunnel. Between the

320
00:19:31,480 --> 00:19:36,840
Speaker 1: auger boring machine and the tunneler that you've you're using,

321
00:19:36,880 --> 00:19:39,480
Speaker 1: you would lay down this metal pipe that contains the

322
00:19:39,520 --> 00:19:43,040
Speaker 1: auger blade and it would attach to either end right,

323
00:19:43,080 --> 00:19:46,120
Speaker 1: So one end of the auger blade attaches to the

324
00:19:46,200 --> 00:19:49,120
Speaker 1: cutting head, the other end of the auger blade attaches

325
00:19:49,160 --> 00:19:52,600
Speaker 1: to the auger boring machine. And then the auger boring

326
00:19:52,640 --> 00:19:55,919
Speaker 1: machine starts to turn, the auger blade turning, the cutting

327
00:19:55,920 --> 00:19:59,840
Speaker 1: head starts to tunnel into the earth. But obviously this

328
00:20:00,000 --> 00:20:03,359
Speaker 1: only allows you to tunnel so far right. Eventually you're

329
00:20:03,400 --> 00:20:06,879
Speaker 1: going to push the auger boring machine up against the

330
00:20:06,960 --> 00:20:10,880
Speaker 1: point where the tunnel opens up. So what happens then?

331
00:20:10,920 --> 00:20:14,040
Speaker 1: How do you go any further? If you're digging a

332
00:20:14,080 --> 00:20:16,280
Speaker 1: short tunnel, obviously it's not a problem. But if it's

333
00:20:16,280 --> 00:20:18,840
Speaker 1: a long tunnel, what do you do? Well, what you

334
00:20:18,880 --> 00:20:21,560
Speaker 1: would do is you would stop the auger boring machine.

335
00:20:21,880 --> 00:20:24,520
Speaker 1: You would you would stop your tunneling process. This is

336
00:20:24,520 --> 00:20:27,879
Speaker 1: the cutting phase. You'd stop the cutting phase, and you

337
00:20:27,880 --> 00:20:31,879
Speaker 1: would detach the auger boring machine from the blade and

338
00:20:31,920 --> 00:20:36,399
Speaker 1: the pipe that it was pushing into the tunnel. You

339
00:20:36,400 --> 00:20:39,480
Speaker 1: would pull the auger boring machine back to its starting position.

340
00:20:40,080 --> 00:20:43,960
Speaker 1: You would then lower into the digging pit a new

341
00:20:44,119 --> 00:20:49,400
Speaker 1: length of pipe inside, which is another length of auger blade,

342
00:20:50,440 --> 00:20:52,960
Speaker 1: and then you would connect the two lengths of auger

343
00:20:53,000 --> 00:20:55,600
Speaker 1: blade together the one that's already in the tunnel and

344
00:20:55,680 --> 00:20:58,119
Speaker 1: the new length of auger blade that you've just lowered

345
00:20:58,160 --> 00:21:01,159
Speaker 1: into the pit. You would connect the other side to

346
00:21:01,240 --> 00:21:04,960
Speaker 1: the auger boring machine, and now you've essentially doubled the

347
00:21:05,119 --> 00:21:08,200
Speaker 1: length of your auger blade and you can start up again.

348
00:21:08,680 --> 00:21:12,240
Speaker 1: A full dig job might require you do this several times,

349
00:21:12,800 --> 00:21:15,440
Speaker 1: and essentially you would keep doing it until the dig

350
00:21:15,520 --> 00:21:18,360
Speaker 1: job was done. Uh, if the dig job was super long,

351
00:21:18,480 --> 00:21:21,200
Speaker 1: this is problematic because eventually you're going to get to

352
00:21:21,240 --> 00:21:23,359
Speaker 1: a length where the auger boring machine is not going

353
00:21:23,400 --> 00:21:26,200
Speaker 1: to be able to generate the torque necessary to turn

354
00:21:26,600 --> 00:21:29,399
Speaker 1: that long of a blade and the cutting head. But

355
00:21:29,480 --> 00:21:32,240
Speaker 1: generally speaking, that's how it works. You just keep on

356
00:21:32,359 --> 00:21:35,800
Speaker 1: lowering extensions into the pit, connecting it to the part

357
00:21:35,840 --> 00:21:38,960
Speaker 1: that's already been pushed into the tunnel, and start up again.

358
00:21:39,840 --> 00:21:41,240
Speaker 1: It's actually kind of neat. There are a lot of

359
00:21:41,320 --> 00:21:45,040
Speaker 1: videos on YouTube that show this process. I watched tons

360
00:21:45,200 --> 00:21:47,879
Speaker 1: of them because it was I don't know, I was

361
00:21:47,920 --> 00:21:51,240
Speaker 1: turned into like a little kid again watching construction videos. Now,

362
00:21:51,240 --> 00:21:53,560
Speaker 1: for the larger boring machines, the really big ones that

363
00:21:53,600 --> 00:21:56,680
Speaker 1: are digging tunnels for like, you know, cars, or trains

364
00:21:56,760 --> 00:22:01,160
Speaker 1: or whatever. There's a really cool method for building out

365
00:22:01,160 --> 00:22:04,680
Speaker 1: a tunnel. These machines are way too big to draw

366
00:22:04,800 --> 00:22:08,040
Speaker 1: thrust or rotational power from an auger boring machine. You

367
00:22:08,119 --> 00:22:12,600
Speaker 1: would not have just a truly enormous auger boring machine

368
00:22:12,600 --> 00:22:16,800
Speaker 1: outside in a deep pit. So instead they have all

369
00:22:16,800 --> 00:22:20,880
Speaker 1: the mechanical elements incorporated into this enormous tunneler, and there's

370
00:22:20,920 --> 00:22:22,920
Speaker 1: so many moving parts that it's hard to keep track

371
00:22:22,920 --> 00:22:26,119
Speaker 1: of them all. They have their own rotational motor to

372
00:22:26,200 --> 00:22:32,120
Speaker 1: generate that incredible torque needed to turn the cutting heads that,

373
00:22:32,480 --> 00:22:34,919
Speaker 1: like I said, can be meters in diameter. Bertha was

374
00:22:35,240 --> 00:22:38,520
Speaker 1: seventeen nearly seventeen and a half meters in diameter. You

375
00:22:38,560 --> 00:22:40,960
Speaker 1: need a really powerful motor to be able to turn

376
00:22:41,040 --> 00:22:44,080
Speaker 1: that with the force necessary for it to start cutting

377
00:22:44,119 --> 00:22:48,040
Speaker 1: through the earth. Behind the cutting head, typically you have

378
00:22:48,119 --> 00:22:50,560
Speaker 1: a chamber. There are a couple of different major types

379
00:22:50,560 --> 00:22:54,359
Speaker 1: of tunneling machines, so these chambers can serve slightly different purposes,

380
00:22:54,720 --> 00:22:56,560
Speaker 1: And I guess I should go ahead and break them

381
00:22:56,600 --> 00:22:58,399
Speaker 1: down because it all has to do with the type

382
00:22:58,440 --> 00:23:02,479
Speaker 1: of material your dig through. If it's pretty much solid

383
00:23:02,600 --> 00:23:05,000
Speaker 1: rock you're digging through, you could use what's called an

384
00:23:05,000 --> 00:23:08,920
Speaker 1: open tunnel boring machine. These do not have the protective

385
00:23:08,960 --> 00:23:14,120
Speaker 1: shielding cylinder that extends back from the cutting head. They're

386
00:23:14,160 --> 00:23:19,080
Speaker 1: just open because they're cutting through essentially stone, and they

387
00:23:19,960 --> 00:23:22,200
Speaker 1: the rest of the machine is just straight behind it,

388
00:23:23,119 --> 00:23:26,600
Speaker 1: unprotected for the most part, and the machine would use

389
00:23:26,720 --> 00:23:29,840
Speaker 1: hydraulic grippers to brace against the walls of the tunnel

390
00:23:29,880 --> 00:23:33,480
Speaker 1: it was building and to provide the forward thrust needed

391
00:23:33,560 --> 00:23:37,080
Speaker 1: for it to make contact with the cutting face to

392
00:23:37,200 --> 00:23:41,040
Speaker 1: keep on cutting crews behind it would add support systems

393
00:23:41,080 --> 00:23:44,040
Speaker 1: to the tunnel like rock bolts and wire mesh, and

394
00:23:44,160 --> 00:23:47,720
Speaker 1: that would help support the tunnel as it was being dug.

395
00:23:48,640 --> 00:23:52,359
Speaker 1: But otherwise you don't have to have any additional stuff.

396
00:23:52,400 --> 00:23:54,800
Speaker 1: You know, you you have like a conveyor to move

397
00:23:54,880 --> 00:23:59,480
Speaker 1: the spoil away from the cutting head and down the tunnel,

398
00:23:59,560 --> 00:24:01,880
Speaker 1: but otherwise eyes you don't need all the other bits

399
00:24:01,880 --> 00:24:05,600
Speaker 1: and pieces. For soft ground, however, you might need something

400
00:24:05,640 --> 00:24:08,800
Speaker 1: like an earth pressure balance machine. These machines have a

401
00:24:08,840 --> 00:24:12,119
Speaker 1: shield to keep the tunnel supported around the end of

402
00:24:12,240 --> 00:24:14,320
Speaker 1: the boring machine. So this is that cylinder I was

403
00:24:14,359 --> 00:24:17,840
Speaker 1: talking about that extends back from the cutting head. They

404
00:24:17,920 --> 00:24:22,639
Speaker 1: hold up the tunnel from uh that that's made immediately

405
00:24:22,720 --> 00:24:25,080
Speaker 1: behind the cutting head, otherwise it would just collapse in

406
00:24:25,119 --> 00:24:30,280
Speaker 1: on itself. Behind the cutting head, there's a chamber and

407
00:24:30,760 --> 00:24:34,879
Speaker 1: that's where the muck or spoil comes into the tunneler.

408
00:24:35,680 --> 00:24:38,240
Speaker 1: There's a screw conveyor that then can take that stuff

409
00:24:38,400 --> 00:24:42,400
Speaker 1: out of this chamber, and the screw conveyor can turn

410
00:24:42,440 --> 00:24:45,240
Speaker 1: at different speeds, and the reason why you would want

411
00:24:45,240 --> 00:24:49,960
Speaker 1: to alter the speed of the conveyor is to control

412
00:24:50,000 --> 00:24:54,720
Speaker 1: the amount of pressure inside that chamber. The pressure can

413
00:24:54,760 --> 00:24:58,879
Speaker 1: help keep the cutting face stable. So if you need

414
00:24:58,920 --> 00:25:01,760
Speaker 1: more pressure to keep the cutting face stable, maybe there's

415
00:25:02,160 --> 00:25:05,919
Speaker 1: water that would otherwise come into the system, then the

416
00:25:05,920 --> 00:25:09,040
Speaker 1: screw conveyor can slow down. It can remove material more

417
00:25:09,160 --> 00:25:13,800
Speaker 1: slowly from the chamber, and it creates more pressure so

418
00:25:14,000 --> 00:25:17,920
Speaker 1: that the tunnel doesn't just flood and collapse in on itself.

419
00:25:18,400 --> 00:25:21,200
Speaker 1: If less pressure is needed, the screw conveyor can speed

420
00:25:21,280 --> 00:25:23,920
Speaker 1: up and remove more material from the chamber and that

421
00:25:24,160 --> 00:25:28,000
Speaker 1: decreases the pressure behind the cutting head. There's another soft

422
00:25:28,040 --> 00:25:31,760
Speaker 1: ground tunneling machine type called a slurry shield, which is

423
00:25:31,800 --> 00:25:34,879
Speaker 1: for ground that has really high water pressure inside it,

424
00:25:35,000 --> 00:25:38,000
Speaker 1: or is made up of very granular particles like sand

425
00:25:38,119 --> 00:25:40,920
Speaker 1: or gravel or some types of clay. And with these

426
00:25:40,920 --> 00:25:45,919
Speaker 1: boring machines you create a pressurized slurry. You use a

427
00:25:46,040 --> 00:25:50,200
Speaker 1: material called bentonite clay and you suspend it in water

428
00:25:50,640 --> 00:25:53,760
Speaker 1: and this helps create the hydrostatic pressure needed to keep

429
00:25:53,800 --> 00:25:57,080
Speaker 1: the cutting face stable during tunneling, and it also acts

430
00:25:57,080 --> 00:26:00,800
Speaker 1: as away to transport muck back away in the cutting head.

431
00:26:01,240 --> 00:26:04,200
Speaker 1: In this case, the muck ends up being almost liquid

432
00:26:04,280 --> 00:26:09,040
Speaker 1: or gelatinous in nature, so this mixture can be injected

433
00:26:09,119 --> 00:26:12,400
Speaker 1: into the cutting face through pressurized nozzles. It's like it's

434
00:26:12,440 --> 00:26:16,639
Speaker 1: like you're squirting out this bentnite stuff in front of

435
00:26:16,720 --> 00:26:19,760
Speaker 1: the tunneler and this creates a sort of membrane that

436
00:26:19,800 --> 00:26:22,880
Speaker 1: protects against the exterior water pressure and it keeps water

437
00:26:22,920 --> 00:26:26,560
Speaker 1: from rushing into the tunneling machine. The excavated material and

438
00:26:26,600 --> 00:26:29,760
Speaker 1: slurry mixture can be pumped back out of the tunnel.

439
00:26:29,920 --> 00:26:32,800
Speaker 1: Instead of using a screw conveyor, you're actually using pipes

440
00:26:32,840 --> 00:26:35,240
Speaker 1: and pumps to pump it out the back. Then you

441
00:26:35,280 --> 00:26:37,800
Speaker 1: can process it, and some of that material you might

442
00:26:37,840 --> 00:26:41,199
Speaker 1: even use in construction, so you might reclaim some of that,

443
00:26:41,280 --> 00:26:45,080
Speaker 1: not just dump it as spoil. Now next I'm gonna

444
00:26:45,080 --> 00:26:48,240
Speaker 1: explain how these large tunneling machines could keep digging underground

445
00:26:48,320 --> 00:26:51,360
Speaker 1: even in soft earth, and how they build the solid

446
00:26:51,520 --> 00:26:54,679
Speaker 1: tunnel behind them. But first let's take another quick break

447
00:26:54,760 --> 00:27:05,520
Speaker 1: to thank our sponsor. So in these soft earth tunneling machines,

448
00:27:06,080 --> 00:27:10,520
Speaker 1: there's an apparatus that is just inside the shielded section

449
00:27:10,600 --> 00:27:13,760
Speaker 1: near the cutting head, so it's protected by that cylinder

450
00:27:13,840 --> 00:27:17,879
Speaker 1: I was talking about. This device is an erector. It

451
00:27:17,920 --> 00:27:23,159
Speaker 1: puts up rings of concrete in segments uh there. The

452
00:27:23,200 --> 00:27:25,879
Speaker 1: segments can be several meters in length. That all depends

453
00:27:25,920 --> 00:27:28,960
Speaker 1: upon the diameter of the tunnel you're digging. So what

454
00:27:29,000 --> 00:27:32,960
Speaker 1: the erector does is there's a conveyor that will pull

455
00:27:33,520 --> 00:27:40,080
Speaker 1: prefabricated segments of concrete rings to the erector. The erector

456
00:27:40,280 --> 00:27:44,919
Speaker 1: comes down, picks up each segment and then places them

457
00:27:44,960 --> 00:27:47,159
Speaker 1: as part of the tunnel wall. So it does this

458
00:27:47,240 --> 00:27:50,439
Speaker 1: piece by piece, and it ends with a wedge shape

459
00:27:50,480 --> 00:27:54,600
Speaker 1: piece called the keystone. The segments of concrete ring essentially

460
00:27:54,640 --> 00:27:58,280
Speaker 1: snapped together. They use things like dowels and holes to

461
00:27:58,359 --> 00:28:02,119
Speaker 1: snap together, and they also are bolted together. And the

462
00:28:02,160 --> 00:28:05,760
Speaker 1: concrete ring acts as a tunnel interior. And it's also

463
00:28:06,119 --> 00:28:09,280
Speaker 1: while the tunneling machine uses to push off of to

464
00:28:09,720 --> 00:28:13,399
Speaker 1: use as thrust when tunneling. So the small borders I

465
00:28:13,400 --> 00:28:18,119
Speaker 1: talked about earlier do this in too processes two stages really,

466
00:28:18,240 --> 00:28:20,600
Speaker 1: so do the large ones. So first, let's say that

467
00:28:20,640 --> 00:28:24,560
Speaker 1: you've been tunneling for a while, right, You've set up

468
00:28:24,560 --> 00:28:28,280
Speaker 1: several meters of tunnel, so the process has been going

469
00:28:28,280 --> 00:28:33,720
Speaker 1: on for a few days. Hydraulic arms on the tunneling

470
00:28:33,760 --> 00:28:38,840
Speaker 1: machine press against the edge, the outer edge of the ring,

471
00:28:38,960 --> 00:28:41,520
Speaker 1: the one that's furthest inside the tunnel. So it's as

472
00:28:41,560 --> 00:28:46,560
Speaker 1: far as you've gone, and in constructing this tunnel, this

473
00:28:46,680 --> 00:28:50,880
Speaker 1: is still under the protective shielding of that cylinder I

474
00:28:50,920 --> 00:28:53,720
Speaker 1: was talking about. So you have these hydraulic arms that

475
00:28:53,760 --> 00:28:57,800
Speaker 1: are pressing on that outer edge. Those hydraulic arms exert

476
00:28:57,840 --> 00:29:01,400
Speaker 1: pressure and create force to put the cutting head against

477
00:29:01,400 --> 00:29:05,880
Speaker 1: the cutting face. So they as they extend, they're at

478
00:29:06,000 --> 00:29:09,120
Speaker 1: their creating that forward thrust for the cutting head, so

479
00:29:09,160 --> 00:29:13,120
Speaker 1: it's actually pushing the cutting head against the earth. Now,

480
00:29:13,160 --> 00:29:15,800
Speaker 1: this tends to go really really slowly, and once all

481
00:29:15,840 --> 00:29:19,440
Speaker 1: those hydraulic arms have extended all the way, they can't

482
00:29:19,520 --> 00:29:21,120
Speaker 1: go any further. That means you're not going to get

483
00:29:21,200 --> 00:29:25,840
Speaker 1: any more forward thrust, the tunneling phase ends and the

484
00:29:25,880 --> 00:29:29,560
Speaker 1: erector moves into place, and now we move into the

485
00:29:29,600 --> 00:29:34,200
Speaker 1: second phase, the building phase. So for each segment of ring,

486
00:29:34,600 --> 00:29:37,880
Speaker 1: the respective hydraulic arms that are pushing against that outer

487
00:29:38,080 --> 00:29:42,000
Speaker 1: edge will withdraw, and that gives the erector the enough

488
00:29:42,120 --> 00:29:46,800
Speaker 1: room to snap the next ring section into place. Once

489
00:29:46,840 --> 00:29:49,680
Speaker 1: it has done that, the hydraulic arms can extend again

490
00:29:50,120 --> 00:29:54,120
Speaker 1: and brace against this new section of ring. And once

491
00:29:54,120 --> 00:29:57,760
Speaker 1: you've completed a whole ring segment, you've extended the tunnel

492
00:29:58,400 --> 00:30:01,880
Speaker 1: by one more ring. Now each ring might be you know,

493
00:30:02,240 --> 00:30:05,880
Speaker 1: a meter or so in with so you've just extended it.

494
00:30:06,560 --> 00:30:09,720
Speaker 1: Then the next tunneling phase can begin. All the hydraulic

495
00:30:09,840 --> 00:30:15,320
Speaker 1: arms are now closer in their one ring segment further contracted,

496
00:30:15,680 --> 00:30:18,280
Speaker 1: so they can start extending again and they can create

497
00:30:18,280 --> 00:30:21,640
Speaker 1: thrust again. And so you do this in this sort

498
00:30:21,680 --> 00:30:25,840
Speaker 1: of seesaw approach. You tunnel, you stop, you build, the

499
00:30:25,920 --> 00:30:28,840
Speaker 1: building creates the space you need in order to create

500
00:30:28,880 --> 00:30:32,479
Speaker 1: the thrust, and you tunnel again. It's actually pretty interesting,

501
00:30:32,480 --> 00:30:34,880
Speaker 1: and there's a lot of videos that show this. I

502
00:30:34,880 --> 00:30:37,920
Speaker 1: know it's kind of hard to envision from audio, but

503
00:30:38,000 --> 00:30:40,240
Speaker 1: I highly recommend if you want to check this out,

504
00:30:40,600 --> 00:30:43,120
Speaker 1: you can look for tunneling machine videos to see the

505
00:30:43,160 --> 00:30:46,480
Speaker 1: process I'm talking about. So what happens though if you

506
00:30:46,520 --> 00:30:49,760
Speaker 1: need to turn as you're tunneling, Because what I've been

507
00:30:49,800 --> 00:30:52,800
Speaker 1: describing works really well if you're going in a straight line.

508
00:30:53,080 --> 00:30:54,840
Speaker 1: But if you're in one of these big machines and

509
00:30:54,880 --> 00:30:58,440
Speaker 1: you need to make that tunnel curve a bit, well,

510
00:30:58,480 --> 00:31:04,320
Speaker 1: for those sections, you might use ring segments that are conical,

511
00:31:04,640 --> 00:31:08,520
Speaker 1: which means that by changing the direction of this cone

512
00:31:08,960 --> 00:31:13,200
Speaker 1: shape you can create a curve. And plus you have

513
00:31:13,360 --> 00:31:17,120
Speaker 1: these hydraulic arms behind the cutting head that can exert

514
00:31:17,160 --> 00:31:20,840
Speaker 1: different levels of thrust and turn the direction of the

515
00:31:20,880 --> 00:31:24,720
Speaker 1: cut just slightly so like the left side is pushing

516
00:31:24,720 --> 00:31:27,360
Speaker 1: out a little further than the right side. That starts

517
00:31:27,400 --> 00:31:30,120
Speaker 1: to create the curve that you need in order to

518
00:31:30,840 --> 00:31:34,320
Speaker 1: meet whatever the shape of the tunnel needs to be.

519
00:31:34,920 --> 00:31:37,960
Speaker 1: Over time, this creates these really long curves. Now, these

520
00:31:38,000 --> 00:31:41,240
Speaker 1: machines do not go very fast. The cutting head might

521
00:31:41,280 --> 00:31:45,040
Speaker 1: only turn two or three times per minute, and according

522
00:31:45,120 --> 00:31:49,320
Speaker 1: to the Boring Company, your average snail is a speed

523
00:31:49,680 --> 00:31:53,719
Speaker 1: demon compared to a tunnel boring machine can move fourteen

524
00:31:53,880 --> 00:31:57,560
Speaker 1: times faster than a tunneling machine as it travels a

525
00:31:57,600 --> 00:32:01,720
Speaker 1: straight line, and tunneling also is really expensive and again

526
00:32:01,760 --> 00:32:04,720
Speaker 1: according to the boring Company, a mile of tunnel could

527
00:32:04,760 --> 00:32:08,920
Speaker 1: cost up to one billion dollars depending upon the project.

528
00:32:09,560 --> 00:32:11,960
Speaker 1: These are really big obstacles that stand in the way

529
00:32:11,960 --> 00:32:14,960
Speaker 1: of building out tunnel systems to allow for underground travel

530
00:32:15,000 --> 00:32:17,640
Speaker 1: in some of the busiest cities in the world. So

531
00:32:17,800 --> 00:32:20,960
Speaker 1: the boring Company hopes to bring both the time it

532
00:32:21,000 --> 00:32:24,240
Speaker 1: takes to complete a project down and the cost down.

533
00:32:25,080 --> 00:32:28,160
Speaker 1: To increase speed, the Boring Company is increasing the cutting

534
00:32:28,160 --> 00:32:31,840
Speaker 1: speed of the cutting head, so they're increasing the number

535
00:32:31,840 --> 00:32:35,120
Speaker 1: of rotations it does per minute. This also requires building

536
00:32:35,160 --> 00:32:37,880
Speaker 1: out other systems like cooling systems to help keep the

537
00:32:37,920 --> 00:32:43,560
Speaker 1: bearings and other components at the right nominal operating temperatures.

538
00:32:44,240 --> 00:32:47,040
Speaker 1: The company is also developing machines that will not have

539
00:32:47,120 --> 00:32:51,200
Speaker 1: to alternate between digging and the building phases, so that

540
00:32:51,240 --> 00:32:53,840
Speaker 1: they can just keep cutting continuously. They don't have to

541
00:32:54,320 --> 00:32:58,240
Speaker 1: cut stop, build a segment of ring, cut stop, build

542
00:32:58,240 --> 00:33:01,640
Speaker 1: a segment of ring. The company also proposes using the

543
00:33:01,720 --> 00:33:05,360
Speaker 1: excavated earth when possible, to make bricks, which might then

544
00:33:05,400 --> 00:33:08,160
Speaker 1: be used to line the tunnel itself, which would cut

545
00:33:08,160 --> 00:33:12,400
Speaker 1: down the need for making concrete, and that's environmentally a

546
00:33:12,440 --> 00:33:15,800
Speaker 1: good thing because concrete production causes a lot of pollution.

547
00:33:15,960 --> 00:33:19,760
Speaker 1: Nearly five percent of the world's greenhouse gas emissions comes

548
00:33:19,920 --> 00:33:25,120
Speaker 1: from concrete production. In early November two eighteen, Elon Musk

549
00:33:25,400 --> 00:33:28,920
Speaker 1: tweeted out a video of the Hawthorne Test tunnel. That's

550
00:33:28,960 --> 00:33:32,080
Speaker 1: a route that leads from SpaceX Is parking lot and

551
00:33:32,160 --> 00:33:37,040
Speaker 1: moves under street near Los Angeles for about two miles.

552
00:33:37,480 --> 00:33:40,040
Speaker 1: And the tunnel is supposed to open on December tenth,

553
00:33:40,240 --> 00:33:43,280
Speaker 1: two eighteen, and they're supposed to be a big opening

554
00:33:43,400 --> 00:33:46,720
Speaker 1: celebration event that day and on the following day, the

555
00:33:46,760 --> 00:33:49,760
Speaker 1: boring company will offer free rides to the public in

556
00:33:49,800 --> 00:33:53,920
Speaker 1: the tunnel, which sounds pretty exciting. Meanwhile, these sorts of

557
00:33:53,960 --> 00:33:57,040
Speaker 1: tunneling machines are being used all over the world to

558
00:33:57,120 --> 00:34:00,880
Speaker 1: dig out subway systems. The tunnel Bertha Ug in Seattle

559
00:34:01,240 --> 00:34:04,640
Speaker 1: is a replacement for the Alaskan Way Viaduct that's an

560
00:34:04,640 --> 00:34:08,040
Speaker 1: elevated highway in Seattle, so instead of building up, they're

561
00:34:08,080 --> 00:34:11,399
Speaker 1: building down. The project was originally supposed to take two

562
00:34:11,440 --> 00:34:14,280
Speaker 1: and a half years to complete. Instead it took nearly

563
00:34:14,400 --> 00:34:18,400
Speaker 1: four years due to various setbacks, one of which happened

564
00:34:18,400 --> 00:34:21,560
Speaker 1: early early on in the progress project when um they

565
00:34:21,640 --> 00:34:27,000
Speaker 1: encountered a steel rod that was underground. And UM they've

566
00:34:27,080 --> 00:34:30,799
Speaker 1: also had a few attempts by various Washington politicians to

567
00:34:31,000 --> 00:34:33,480
Speaker 1: kill the whole project. They were saying that it was

568
00:34:34,000 --> 00:34:37,600
Speaker 1: um an embarrassment, it was a waste. But it kept

569
00:34:37,600 --> 00:34:40,479
Speaker 1: on going and it did complete. The tunneling process ended

570
00:34:41,040 --> 00:34:44,880
Speaker 1: in April. The tunnel as of the recording of this

571
00:34:44,920 --> 00:34:48,480
Speaker 1: podcast isn't open yet. It's not scheduled for use until

572
00:34:48,520 --> 00:34:52,800
Speaker 1: February twenty nineteen. But once Bertha finished the digging process,

573
00:34:53,520 --> 00:34:57,359
Speaker 1: it broke through into what was called a disassembly pit,

574
00:34:57,640 --> 00:35:01,719
Speaker 1: where it was well, just a bold Bertha would not

575
00:35:01,800 --> 00:35:04,520
Speaker 1: be used to dig any more tunnels. Instead, anything that

576
00:35:04,560 --> 00:35:07,759
Speaker 1: could be melted down and recycled was and everything else

577
00:35:07,800 --> 00:35:10,640
Speaker 1: was kind of, you know, thrown away. The massive machine

578
00:35:10,680 --> 00:35:14,400
Speaker 1: was cut up into twenty ton pieces, but since the

579
00:35:14,440 --> 00:35:19,120
Speaker 1: machine weighed seven thousand two tons, that took a long time.

580
00:35:20,160 --> 00:35:23,239
Speaker 1: Since tunneling ended, engineers have been building a double deck

581
00:35:23,400 --> 00:35:28,080
Speaker 1: highway inside the tunnel that Bertha dug. And that's all

582
00:35:28,120 --> 00:35:30,799
Speaker 1: I have to say about these tunneling machines. They are

583
00:35:31,000 --> 00:35:34,719
Speaker 1: really interesting. Uh. The more I looked into them, the

584
00:35:34,760 --> 00:35:38,240
Speaker 1: more I was fascinated by how enormous the big ones

585
00:35:38,360 --> 00:35:41,600
Speaker 1: are and the fact that it's a machine that also

586
00:35:41,880 --> 00:35:45,640
Speaker 1: is like a construction site all by itself is pretty phenomenal.

587
00:35:45,840 --> 00:35:48,760
Speaker 1: And just seeing how simple things like the Archimedes screw

588
00:35:49,200 --> 00:35:52,560
Speaker 1: could be incorporated into these machines to move massive amounts

589
00:35:52,560 --> 00:35:56,319
Speaker 1: of earth. It also speaks to the ingenuity of the

590
00:35:56,480 --> 00:36:01,120
Speaker 1: ancient designers like Archimedes who came up with these ideas

591
00:36:01,120 --> 00:36:04,320
Speaker 1: that we're still finding uses for today, These these simple

592
00:36:04,360 --> 00:36:07,480
Speaker 1: machines that are still the best way to do certain things.

593
00:36:07,520 --> 00:36:09,960
Speaker 1: I think it's pretty interesting and I really look forward

594
00:36:09,960 --> 00:36:14,280
Speaker 1: to finding out how Elon Musk's boring company is able

595
00:36:14,400 --> 00:36:18,160
Speaker 1: to advance the technology. And maybe pretty soon we'll have

596
00:36:18,400 --> 00:36:22,120
Speaker 1: underground tunnels in all major cities that make getting around

597
00:36:22,280 --> 00:36:25,040
Speaker 1: much much easier. I would look forward to that too.

598
00:36:25,480 --> 00:36:27,800
Speaker 1: If you guys have any suggestions for future topics I

599
00:36:27,800 --> 00:36:31,000
Speaker 1: should cover in tech Stuff, why not visit our website.

600
00:36:31,040 --> 00:36:34,319
Speaker 1: It is text stuff podcast dot com that has all

601
00:36:34,360 --> 00:36:36,319
Speaker 1: the different ways to get in touch with me. You

602
00:36:36,360 --> 00:36:38,319
Speaker 1: can let me know what you would like me to

603
00:36:38,360 --> 00:36:40,960
Speaker 1: cover in a future episode. There also don't forget to

604
00:36:41,080 --> 00:36:44,120
Speaker 1: visit t public dot com slash tech Stuff. That's our

605
00:36:44,160 --> 00:36:47,160
Speaker 1: merchandise store. Every purchase you make goes to help the show,

606
00:36:47,200 --> 00:36:50,120
Speaker 1: and we're always adding nude designs over there, so go

607
00:36:50,239 --> 00:36:54,239
Speaker 1: check that out. Don't forget. My Heart Radio has the

608
00:36:54,320 --> 00:36:57,719
Speaker 1: upcoming podcast Awards and you can vote in them. My

609
00:36:57,840 --> 00:37:00,080
Speaker 1: show is one of the ones nominated. It's nominated it

610
00:37:00,120 --> 00:37:04,759
Speaker 1: in the science and Technology category, So go check out

611
00:37:04,800 --> 00:37:07,920
Speaker 1: the I Heart Radio Podcast Awards. If you go online,

612
00:37:07,960 --> 00:37:10,640
Speaker 1: you can vote up to five times per day. And

613
00:37:10,680 --> 00:37:12,760
Speaker 1: don't forget to look around at all the other categories.

614
00:37:12,800 --> 00:37:14,600
Speaker 1: There might be some other shows you really love that

615
00:37:14,640 --> 00:37:17,840
Speaker 1: you would like to support. It's always nice for creators

616
00:37:17,880 --> 00:37:21,759
Speaker 1: to get that message from their listeners. It's very rewarding.

617
00:37:22,040 --> 00:37:26,400
Speaker 1: It's something that that just feels nice. So go support

618
00:37:26,440 --> 00:37:29,680
Speaker 1: the shows you love. And that's it for me. I'll

619
00:37:29,680 --> 00:37:37,719
Speaker 1: talk to you again really soon for more on this

620
00:37:37,880 --> 00:37:40,400
Speaker 1: and thousands of other topics. Because it how staff works

621
00:37:40,400 --> 00:37:50,719
Speaker 1: dot Com