This is overcome by using concrete.
Make underground roof support systems without collapse.
So i have 15x15 interior rooms on either side of a 3x15 walkway that i use for my killbox in my mountain base.
This article describes explains the directions of forces in roof structures illustrating downwards force horizontal thrust and the causes of rafter sags rafters that disconnect from the ridge or top plate and why a sagging roof pushes the building walls outwards at the wall top.
Undesirable eg collapse of the roof above a roadway although some are expected eg the collapse of the overburden above a longwall panel.
Extreme weather conditions are the most common cause of roof collapses.
While some earth sheltered homes are built completely beneath ground level many are constructed using a technique known as berming.
Construction plastic sheeting is laid out in the hole of depth where the roof shall rest.
Earth bermed homes are built largely above ground but piles of soil are then pushed up against the walls all the way to the top to form a protective cocoon of earth and vegetation that will separate the outer shell of the home from the open air.
These lining systems add a major cost to the tunnel construction.
In your blog about using a membrane as an underground roof you suggested laying a sheet of rigid foam below the surface to keep the ground warm.
Rock on the other hand behaves a little bit differently in that it does have some tensile strength.
Kms uses the roof instability rating rir system along with the latest in proprietary finite element modeling to provide precise and accurate analysis prediction and site specific ground control design.
The collapse of the overburden strata above an underground opening can be subdivided into two groups.
It is therefore very crucial for homeowners to identify and act on signs that a roof is in danger of collapse.
While this is a good idea it has its drawbacks.
The 15x15 rooms where i plan to plce my turrets keep caving in in the middle.
Reinforcing rods mesh is then laid on top which is covered by concrete.
Provide analyses to develop ground support systems for the most challenging conditions.
For both cases mine designers need to be able to predict if and how the failure will occur.
The cheapest roof making method is leaving it round a square house don t care what shape roof it sits under.
We include photographs of collapsing wood framed roofs and photo sequences.
This is why many tunnels are lined with materials like steel or concrete to provide support to the tunnel walls and transfer the stresses in the subsurface around the tunnel.