They do hit the ground!
UV rays actually hit the earth all the time. Most get blocked by the ozone in our atmosphere, but some manage to get through. UV is actually important for animals to produce vitamin D. However, too much exposure can increase a person's risk of skin cancer.
However, hitting the ground won't really do too much damage. The danger of UV radiation is that it is very high energy, so for living tissues, it can cause damage - e.g. to DNA, causing mutations.
For the ground, it's not going to overwhelm it with energy, in the same way. It will transfer the energy and maybe make it a bit warmer, but we won't see it damaging the ground like it would DNA.
Hope this helps; let me know if I can do anything else:)