How to get rid of burrowing animals living under concrete pool deck?

We first had this problem 20 yrs ago. pest Conrol Co. Removed the ground hogs , then installed a "rat wall" around the outside edge of the pool deck....sturdy metal wire mesh fastened to concrete with screws /washers. mesh goes down approx 6" then bends out at 90 angle for about 12". back fill the trench with dirt and top with beach stone.... Landscape fabric is a good idea to add. Last week a ground hog prob disturbed by nearby roadworks, arrived and found the end of the wire rat wall. We have used the 20 year old solution and installed 6' of rat wall ourselves. First, harass the gh into leaving for quieter pastures. Then dig a 12 to 18" trench. I bought an 8x4 sheet of metal, diamond mesh floor tile underlay ($5). It's easy to bend. Cut with metal snips. Need a hammer drill to screw in screws/washers every foot or so then cover everything up. Voila!