since youre running a sim ill assume its p5/p6

i dont think its possible to delete the ground, just to make it invis or invisible to the renderer.
go to your figure dropdown in the viewport, and click props > GROUND
in the properties tab of your parameter dials window, make sure both visible and visible in raytracer are checked.
when you set up your lighting, click on each of your light globes and make sure shadows are checked and switch them to ray trace shadows. if you have one of my recent products skim over the PDF readme included with them to set up your shadow min bias, render settings, etc. if not then try a generic 0.15 for your shadow min. bias.
in your render settings make sure to enable raytracing and cast shadows.