AKHSHTYR, Russia (AP) — Trucks rumble to the edge of a gigantic pit filled with spray cans, tires and foam sheets and dump a stream of concrete slabs that send up a cloud of limestone dust. Other trucks pile clay on top and a bulldozer mixes everything together in a rudimentary effort to hide the mess. This landfill outside Sochi, which will host the Winter Olympics in 100 days, is smack in the middle of a water protection zone where dumping industrial waste is banned.As a centerpiece of its Olympic bid, Russia trumpeted a “Zero Waste” program that promised the cleanest games ever, saying it would refrain from dumping construction waste and rely on reusable materials.