어/아/해 있다 indicates a continued passive state of being after an action is completed.
For instance, compare:
Note that 어/아/해 있다 does not take an object. This is why it is not used with 'wear' verbs.
빈 좌석이 하나도 없어서 남자가 서 있어야 했어요.
There wasn't a single empty seat so he had to stand (and remain standing).
비밀번호를 입력할 때까지 휴대폰이 잠겨 있을 거예요.
Until you enter your password the phone will be locked (it is locked and will remain locked).
우리 시아버지의 댁에는 사슴 머리 장식이 벽에 결려 있어요.
In my father-in-law's house there is a deer head hanging on the wall (it was hung there, and has stayed there to this day).
선생님의 말에 집중 못 할 정도로 깊은 생각에 잠겨 있었어요.
I was so lost in my thoughts (I got lost and stayed lost) that I couldn't focus on my teacher's voice.
새 식당에 가려고 했지만 문이 닫혀 있었어요.
I intended to go to the new restaurant but it was closed (someone closed the doors previously and they are still shut).
교통사고를 당한 탓에 지난주부터 친구가 병원에 입원해 있어요.
Sadly, my friend was in a traffic accident and since last week has been admitted to hospital (he went in and is still there).
큐가든에 가는 게 어때요? 지금 아름다운 꽃이 피어 있어요.
How about going to Kew Gardens? The beautiful flowers are in bloom (they already blossomed and you can still see them now).
로벤섬에서 만델라가 수감되어 있는 동안 편지를 250장 썼어요.
Nelson Mandela wrote 250 letters during his time in prison (he was jailed, and remained in jail when he was writing letters).
냉장고의 문이 열려 있으면 결국 식품이 썩을 거예요.
If the fridge door is left open (if it is opened and remains in that state), the food inside will eventually spoil.
언제나 상하이 지하철은 사람들로 가득 차 있어요.
Whatever time you ride the subway in Shanghai it is crammed full of people (it becomes full and stays that way).
원피스가 차 문에 끼어있는 채로 여자가 출근했어요.
I drove to work with my dress stuck in the car door (the dress got stuck when I closed the door, and it remained stuck as I drove).
그 여자가 다음 저녁에 여전히 술에 취해 있을 정도로 술을 많이 마셨어요.
She drank so much alcohol (last night) that she was still drunk (she remained drunk) the next evening.
제혁씨가 영어를 공부하기 위해 미국에 가 있어요.
Jaehyeok has gone to the USA to study English (he left Korea and is still abroad).
오렌지는 비타민C가 많이 들어 있는 과일이에요.
Oranges are a fruit that contains a lot of vitamin C (it continues to hold those nutrients).
거창이란 산으로 둘러싸여 있는 작은 도시에서 아내를 처음 만났어요.
I first met my wife in Geochang, a small town surrounded by mountains (the town was built -- and continues to be -- in the mountains).
지난 주말부터 제가 서울에 와 있어요.
I came to Seoul last weekend (that's when I first arrived, and I am still here).
시간이 많이 남아 있으니까 서두르지 마세요.
There's enough time to spare (there was -- and continues to be -- sufficient time left), so don't rush.
눈이 쌓여 있어서 보도가 너무 미끄러우니까 조심하세요.
The snow has piled up (and is still sitting there); please be careful as the pavement is very slippery.
불이 꺼져있는 채로 영화를 봤어요.
I watched a movie with the lights off (they were turned off beforehand and stayed off for the duration of the movie).
리야드에 사는 사람들이 금요 기도에 갈 때 길들이 텅 비어 있어요.
When people in Riyadh go to Friday prayers, the streets are completely empty (people vacate the streets and they remain vacant).
폭설 때문에 많은 차가 눈에 파묻혀 있어요.
Due to heavy snowfall, many cars are buried in the snow (the snow fell and buried them, and are still covered in it).
허리 통증 때문에 소파에서 앉아 있는 것보다 마루에 누워 있는 게 더 편하더라고요.
Because of back pain, I find it easier to lie on the floor (to lower myself onto the floor and stay there) than sit on a sofa (to lower myself into a chair and stay there).