This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
塧 combines 土 (earth) with 益, but the exact historical development and original meaning are uncertain.
The left side is earth 土 and the right side is 益 (benefit). Without a clear meaning, picture earth that might be beneficial or steep, but the exact idea is unclear.
For アイ, imagine an eye (アイ) looking at the earth 土 and wondering what benefit 益 it holds: eye -> アイ.