I received several questions and proposals about this concept in the past two weeks, so I’m providing answers.
There were some questions about the concept alone. (Is this a serious concept? Is it a joke? Is there some research behind it? Is there equipment for this? Do I own patents for this concept?) This answers all those questions.
- This is a concept only. I didn’t do any research to support this concept.
- I’m an experienced tunnel design engineer, which requires me to be well informed about statics, properties of ground materials, technology and mechanisation used underground, so I strongly believe that at least a part of the concept, regarding the underground construction, is without serious flaws. But the concept makes sense when going beyond underground construction, so I have to read a lot of material to get familiar with other areas, like geothermal energy, construction using cob, orbit travel, farming, even 3D printing, etc. I’m far from being an expert in those areas, so there can be some errors along the way, and sometimes solutions are proposed that are impossible to execute. That’s the reason that I’m inviting experts from several areas to comment on parts of the concept which are not valid.
- There is no equipment to execute actions based on this concept yet. The technology is available, but it is used in different ways than what is proposed here. I have a general idea how each piece of equipment should be constructed, how it should work and where there might be problems with it. I strongly believe that a relatively small team of experts and constructors can construct the first generation of equipment for this concept within two to three years.
- It was pointed out in discussion regarding orbit travel and settlements on the Moon and Mars that I made a mistake, calling the “star tram concept” a “space tram concept”. Everything here is related to the classical “star tram concept”.
I was informed that plenty of material is available regarding that concept, and I have to study all of that to provide a more detailed version of the concept. This will take some time. I was also told that some of the solutions might be interesting for constructions of settlements on the Moon or Mars, with certain modifications, of course.
The constructions called molehills, which are described in the chapter “Art of Cob”, also make sense for settlements on the Moon or Mars, if we replaced cob with something which can be printed in circles with 3D printers from material that is found there. The proposed construction has the following advantages:
- It provides simple shapes to be printed.
- Construction can provide relatively large circular shapes, which can be used as rooms.
- Construction is loaded on compression, which requires less strength for printed construction and there is no need for reinforcement.
- Printed construction is underground, which can increase the durability of construction.
So far, I haven’t received opinions that the concept cannot be used for the star tram concept and Moon and Mars settlements, as was proposed.
- 3D printing was proposed as potential technology for molehill construction, with no details. I will explain below what I propose for that technology:
Circular walls are meant to be from cob, which is clay (natural material which is a combination of water, sand, silt and clay minerals) mixed with straw. When you put all ingredients in the right proportions and add straw, the result after drying is new material with solid strength properties, and that is called cob.
Traditional procedures for cob creation are well known and can be upgraded to industrial level, but heavy mechanisation is required for large constructions. To avoid that, 3D printing or similar technology could be used.
The idea is that 3D printing is carried out at the top of circles with a diameter of 6 m, with wall thickness of 0.5-1 m. On both sides of the wall, a formwork would probably be needed, which would also lead printer heads and provide drying and heating. Thin layers no bigger than a cm or two would be added in one phase, adding straw and drying or heating the layer before the print head comes around for another layer installation. The hope is that new material created this way can have solid strength properties.
The idea then is to use 3D printing for adding clay only, and to provide stability of the installed material with formworks, heating, drying and adding straw.
- The molehill, as it is proposed, is not underground without a reason. It is well known that circular shapes can handle a lot of loads if they are loaded from the outside. So, if you build circular towers and bury them, you will get a stabile structure, a circular shaped wall, loaded on compression in a horizontal direction. This is important, because cob can handle only limited force and shear loads.
- Farmers proposed planting weed underground. This begs the question, if you plant weed underground, would it also be possible to construct supply channels deep underground, beneath custom and police checks. Any orders?