[aerohead]

Our community's founder had built a ferro-cement yacht,and it occurred to him that one could invert such a structure to create a robust earth-sheltered structure.
Ours are created from an armature of rebar,remesh,and hardware cloth (or expanded metal lath) which is united to the rebar in the slab,then hand plastered with an 8-sack sand mix concrete containing a vinyl bonding agent.
At the time (1981) I did mine the rough structure was costing about $10 /sq-ft.
I had mine foamed with 20-lb/cu-ft density polyurethane.If it ever gets finished and buried it will have the equivalent of around R-90,factoring the thermal flywheel.
It's a 'tiny home' before such things existed.
The dome in your photo,no doubt is from the Monolith folks.They were (are) inflating rubber domes under the reinforcements which allows a continuous 'pour'.It's a slick setup!
I've enjoyed mine.Hope to die there with or without boots.