Hey mate!
I'm playing Tank myself with 1H + shield, lv 66 and doing lv88 expeditions. So our situations are pretty similar =D
Tho, I don't get oneshoted at all. Bosses and Elites sometimes drive me very very low, but it's not oneshot and I have time to react and heal or dodge.
About your stats compared to mine:
I'm currently 45K hp, with 100% chance to block and 55% Efficiency. I don't understand what you're meaning by "50% to 100% chance to block" but you should really aim for permanent 100% block. Reroll your stuff and make it able to be geared by multiples Alexandrites in order to increase block chance, and then block efficiency. 30% is by far not enough at this level.
My resistances are a little bit less than yours, around 55% in average, but it's still running very well with the block chance to balance that.
And then, of course some Elites and Bosses can kill you. But unlike my friends that are playing Mage or Gunner and get oneshoted, we as tank have a small window to take damage before dodging. Still, we need to dodge. You just can't tank that demon laser-beam face to face, you just have a little more time than others to react and dodge around.
And do not hesitate to tempo for you Juggernaut shield, this one make you able to tank anything so use it as much as possible and sometimes just run between cooldowns.
Also, as stuff, if ever you have it, the unique ring Seven Sister Pact is damn powerful imo, giving you life, lifeleech and regen, if ever you have it in stash. It's a bis at our level, in my opinion. And I don't know what your main damage skill is, but I use Bleeding Edge with lifeleech modifier, work very well to tempo and regen between 2 Juggernaut shields.
See ya my friend! =D