The SS-18 was deployed in modified SS-9 silos, and employed a cold-launch technique with the missile being ejected from the silo prior to main engine ignition. The rocket was placed in a transport-launch canister made of fiberglass composites. The container was placed into an adapted R-36 silo. The specially hardened silo was 39 meters deep and had a diameter of 5.9 m. Prior to main engine ignition the missile was ejected from the container with the help of a solid-propellant gas generator located in the lower unit of the transport-launch canister.
According to Western estimates, the SS-18 was deployed in a silo with a hardness of at least 4,000 psi (281 kg/sq. cm; 287 bar), and possibly as high as 6,000 psi (422 kg/sq. cm; 430 bar).
http://fas.org/nuke/guide/russia/icbm/r-36m.htm
согласно западным оценкам, шпу сс-18 может выдерживать ув 281-421атм.
A large part of the destruction caused by a nuclear explosion is due to blast effects. Objects within the path of the blast wave are subjected to severe, sharp increases in atmospheric pressure and to extraordinarily severe transient winds.
Most buildings, with the exception of reinforced or blast- resistant structures, will suffer moderate to severe damage when subjected to overpressures of only 35.5 kiloPascals (kPa) (0.35 Atm). The velocity of the accompanying blast wind may exceed several hundred km/hr. Most materiel targets are drag- or wind-sensitive.
The range for blast effects increases significantly with the explosive yield of the weapon. In a typical air burst, these values of overpressure and wind velocity noted above will prevail at a range of 0.7 km for 1 kiloton (Kt) yield; 3.2 km for 100Kt; and 15.0 km for 10 Mt.
http://fas.org/nuke/intro/nuke/blast.htm
при воздушном взрыве 1кт даёт ув в 0,35атм на радиусе 0,7км.