Two ways to do it.
1) Dig a hole 1m (50cm) and use the spade to pull and dig it out. Or hire a small shovel car (machine digger of sorts)
2) Cut out as much you can and add weed killer to the roots, don’t give it time to regrow because bamboo grows fast!
3) keep cutting the roots even after adding weed killer so it prevents from growing again.
If your dealing with the actual bamboo shoots, you’ll need to cut them 1 inch above soil and add the weed killer inside the shoots. Keep cutting the shoots each day because it will grow again and again and within a month it will be tall again.