It looks like they have blown up the road and rail bridge across the top of the dam.
They have probably also disabled the sluice gates so that the Ukrainians cannot lower the water level in the Kakhovka Reservoir below the entrance to the Crimean canal.
They have blown all the rail and road bridges south of the Kakhovka Reservoir in order to make it hard for the Ukrainians to attack the eastern part of Kherson province.
There are probably a dozen rail and road bridges at Zaporizhzhia, Dnipro, Kremenchuck, Cherkasy and Kaniv. I’ve never understood why the Russians have not destroyed them all to make supply of the Ukrainian army east of the Dnipro more difficult.