It's widely known that Sylvia Plath's father died of untreated diabetes when she was very young. So, many have said that her many poems about the loss of a father were inspired by this. She's also often lumped into the "confessional" school of poetry, whose poets were all about directly dredging up the joys and horrors (mostly horrors) of their lives as fuel for their work. All that said, it's hardly ever a good idea think of the poet as the speaker, because poets tend to embellish and push past themselves in their writing. (Hey, it's their job to be poetic, right?) For example, Sylvia Plath never spent a lot of time hanging around the ruined remains of a giant statue (that we know of).
So, what do we know about the speaker in this particular poem? Well, she certainly is dutiful to this toppled Colossus. (We wonder what Dr. Phil would have to say about her life choices.) She spends every day "Scaling little ladders with glue pots and pails of Lysol" to try to put ruin back together and keep it clean (11). Still, she's not exactly optimistic about her project. She even kicks the poem off by telling the statue, "I shall never get you put together entirely, / Pieced, glued, and properly jointed (1-2). So, if she knows there's no use in fretting about it anymore, why does she spend all day every day doing just that? Toward the end of the poem, the speaker says that her "hours are married to shadow" (28). This seems to really sum up her situation. She's tied to this dark event from her past, and she just can't seem to let herself escape. Sad, right?