What is the significance of Great Expectations by Charles Dickens?

For Charles Dickens, Great Expectations was significant because it was semi-autobiographical. It was his revision of his earlier semi-autobiographical novel David Copperfield. Besides the fact that both books are about young boys who have rough upbringings, they are pretty different. David Copperfield is idealized. Great Expectations is darker. Also, Great Expectations takes place in and around Rochester, where Dickens grew up. The places are based on his childhood haunts.
An example of this is the graveyard from the beginning of the book. This is actually based on a real graveyard outside a castle in Rochester which has the same headstones Dickens describes as being Pip’s siblings’ headstones. Dickens grew up looking at them, and incorporated them into Pip’s life.

To five little stone lozenges, each about a foot and a half long, which were arranged in a neat row beside their grave, and were sacred to the memory of five little brothers of mine,—who gave up trying to get a living, exceedingly early in that universal struggle,—I am indebted for a belief I religiously entertained that they had all been born on their backs with their hands in their trousers-pockets, and had never taken them out in this state of existence (Chapter 1).

Dickens even based Satis House on a real house, which you can still visit today. When he was a child, Dickens was enamored with another house called Gad’s Hill Place, and he returned to buy it once he was famous and could afford the house. He was creating his own arc, similar to, but different from, Pip’s. Unlike Pip, Dickens made his own success.
Some of Great Expectations's themes could definitely apply to Dickens's life. Dickens had trouble with relationships, especially when it came to love. He married, but fell out of love with his wife. He loved children and had many, but he was an exacting father. He had high expectations, and often as a result had rocky relationships with his own children. Life didn't turn out to be a fairy tale for Charles Dickens.