Wal-Mart is to open its biggest chain store in Dalian, a coastal city in northeast China's Liaoning Province, the Xinhua News Agency reported today.This will be the retailer's ninth chain store in China and its second in Dalian City. The new store, scheduled to open in April next year, is 21,000 sq m, making it Wal-Mart's largest store in the world.Wal-Mart has opened eight chain stores in China's Shenzhen, Dongguan, Kunming, and Dalian with a total investment of 1.1 billion yuan ($132.5m).