Hi Ellanor,
The pole bean vines will grow on the ground usually just fine, only problem is, so will the beans. The bean pods growing on the ground means most of your beans will be in contact with soil or medium that grows pathogens, that can cause disease, plus hungery bugs and slugs can more easily access the bean pods, which opens the pods up to infection. This usually drastically reduces the bean harvest.
The peas depending on mature height, can sometimes be grown in close
enough proximity, that they act as trellis for each other. If your variety is 40 inches tall, a 40 inch wide row would be needed, with the vines planted close enough they can all lock tendrils, but like I said, this tends to work better with the shorter varieties. Some support is always best advised, even if its just two end row steaks with a string running down the row for support, as certian weather events can blow soft tissue plants over. Once your peas are on the grownd, they face the same problems as beans do.
Hope that helps!