Here’s a game of mine from the Llandudno Major last week in which I won in a Queen’s Gambit Declined Exchange Variation. After 17…Bxc5 18.bxc5 I got pressure against Black’s weak pawn on b7, but it was difficult to win the position when Black defended the pawn. What I had to do was open a second front on the other side of the board, and this happened with 34.g4.
My Dad showed me this game of Anatoly Karpov, which is quite similar. But Karpov even brought his king to the queenside before opening the second front: