I'm trying to describe my thoughts on a novel process of "continuous helical tunnel boring". I think this kind of concept could speed the construction of a 3dimensional tunnel system that Elon Musk described exponentially. If there is anyone you could think of to share this idea with I would appreciate that. . Working from the premises that it is better to continuously "pour" the structural concrete tunnel walls rather than pausing the tunneling process to lay precast sections of wall. The area of operations we are then focusing on is the area directly behind the boring machine face and within the tunnel shield wall where we will have to transport materials for forming our tunnel wall from without the tunnel dig to the area of operations. These materials being a role of sandwiched basalt fiber fabric pre impregnated with high strength Portland cement, configured into a sleeve that when injected with wet concrete will create a continuous form laid in a spiral or helical manor along the tunnel wall and forming a negative worm gear. These roles can be transported to the area of operations by autonomous electric vehicle conveyance. The roles being of a fixed length must be connected end to end by a process of stitching by which the two ends are laid open and sown together as the material is being fed to the work surface. To do this without interrupting the whole process slack has to be fed towards the wall end in an inch worm fashion and then taken up again until the next seam is necessary. These rolls of basalt fiber fabric have a structural cross threading in a manner in which when filled with concrete they form a roughly T shaped extrusion creating both a structural concrete form and the inner teeth of the negative worm gear. These preimpregnated basalt fabric roles which both give structural form and act as structural forms for the wet concrete mix are key to continuously forming the walls of the tunnel. Two other main elements in this process are water and wet concrete mix both separately conveyed to the area of operations through high pressure hoses. It's important to note that ideally a concrete batching plant will be located at the entrance to the tunnel and raw materials stockpiled so as to avoid delays in pouring that come from concrete mixing trucks being ironically stuck in traffic that the boring company is attempting to alleviate. Also that ideally spoil material from the tunnel would be mixed with this concrete and reconstituted as the walls of the tunnel. Raw water is needed to activate the impregnated basalt fabric and applying it is a tricky problem. I'm going to try to use an analogy to describe this process and the process of injecting the wet concrete into the fabric sleeve. We should all by now as I write this in the beginning of 2021 be familiar with the image of an intubation tube being inserted down the esophagus of a patient. In this case the intubation tube is the nozzle end of the concrete hose which is inserted in the fabric sleeve which is the esophagus of our patient. The nozzle is a two pant system with an inner hose reaching farther into the sleeve and an outer jacket evenly applying water to the inside of the fabric sleeve. Directionality of this tunnel wall system is achieved by the flexible nature of the fabric sleeved poured concrete rather than the traditional precast concrete block systems used today. I am attaching a picture of the commonly used flexible corrugated conduit because this is essentially the engineering form I am describing in the system. The means of conveyance of the tunnel boring machine is achieved by an articulated tunnel shield which locks into the worm gear of the tunnel, screwing itself along with a multitude of industrial in-hub electric drive wheels. These drive wheels are relatively low speed compared to electric car motors but harness the high torque and flexible geometry of electric drive systems. Working on this idea. The current limiting factor to tunnel construction is the placing of precast concrete tunnel segments. The above concept is an attempt to break from that system. If the process of CO2 curing could be incorporated in this system, hopefully it would speed the curing process and facilitate a massive amount of carbon sequester in underground tunnels. David Elze dvdelze@gmail.com
A wonderful and insightful talk. Thank you!
Where is Mark now? What a genius of a man!
I'm trying to describe my thoughts on a novel process of "continuous helical tunnel boring". I think this kind of concept could speed the construction of a 3dimensional tunnel system that Elon Musk described exponentially. If there is anyone you could think of to share this idea with I would appreciate that.
.
Working from the premises that it is better to continuously "pour" the structural concrete tunnel walls rather than pausing the tunneling process to lay precast sections of wall.
The area of operations we are then focusing on is the area directly behind the boring machine face and within the tunnel shield wall where we will have to transport materials for forming our tunnel wall from without the tunnel dig to the area of operations.
These materials being a role of sandwiched basalt fiber fabric pre impregnated with high strength Portland cement, configured into a sleeve that when injected with wet concrete will create a continuous form laid in a spiral or helical manor along the tunnel wall and forming a negative worm gear. These roles can be transported to the area of operations by autonomous electric vehicle conveyance. The roles being of a fixed length must be connected end to end by a process of stitching by which the two ends are laid open and sown together as the material is being fed to the work surface. To do this without interrupting the whole process slack has to be fed towards the wall end in an inch worm fashion and then taken up again until the next seam is necessary. These rolls of basalt fiber fabric have a structural cross threading in a manner in which when filled with concrete they form a roughly T shaped extrusion creating both a structural concrete form and the inner teeth of the negative worm gear. These preimpregnated basalt fabric roles which both give structural form and act as structural forms for the wet concrete mix are key to continuously forming the walls of the tunnel.
Two other main elements in this process are water and wet concrete mix both separately conveyed to the area of operations through high pressure hoses. It's important to note that ideally a concrete batching plant will be located at the entrance to the tunnel and raw materials stockpiled so as to avoid delays in pouring that come from concrete mixing trucks being ironically stuck in traffic that the boring company is attempting to alleviate. Also that ideally spoil material from the tunnel would be mixed with this concrete and reconstituted as the walls of the tunnel. Raw water is needed to activate the impregnated basalt fabric and applying it is a tricky problem. I'm going to try to use an analogy to describe this process and the process of injecting the wet concrete into the fabric sleeve. We should all by now as I write this in the beginning of 2021 be familiar with the image of an intubation tube being inserted down the esophagus of a patient. In this case the intubation tube is the nozzle end of the concrete hose which is inserted in the fabric sleeve which is the esophagus of our patient. The nozzle is a two pant system with an inner hose reaching farther into the sleeve and an outer jacket evenly applying water to the inside of the fabric sleeve.
Directionality of this tunnel wall system is achieved by the flexible nature of the fabric sleeved poured concrete rather than the traditional precast concrete block systems used today. I am attaching a picture of the commonly used flexible corrugated conduit because this is essentially the engineering form I am describing in the system.
The means of conveyance of the tunnel boring machine is achieved by an articulated tunnel shield which locks into the worm gear of the tunnel, screwing itself along with a multitude of industrial in-hub electric drive wheels. These drive wheels are relatively low speed compared to electric car motors but harness the high torque and flexible geometry of electric drive systems.
Working on this idea. The current limiting factor to tunnel construction is the placing of precast concrete tunnel segments. The above concept is an attempt to break from that system. If the process of CO2 curing could be incorporated in this system, hopefully it would speed the curing process and facilitate a massive amount of carbon sequester in underground tunnels.
David Elze
dvdelze@gmail.com