The explosive charge is heavily shielded from damage (titanium alloy and carbon fiber) and propelled through the solid rock, reinforced concrete, whatever by a rocket motor. It then detonates based on either a timer (X seconds after impact) or a predetermined distance of penetration (X meters farther from the GPS satellite than point of impact.)
It doesn’t sound that complicated but it IS Rocket Science.
Thanks.
Amazing that they can design something that is strong enough to smash through concrete while still protecting the warhead.