In a Dutch oven or large stockpot, heat vegetable oil over medium heat. Add beef and sear. Remove beef to a plate.
Add carrots, celery, and onion, and cook for 4-5 minutes. Add the garlic, parsley, oregano, and thyme and cook for 1 minute, stirring constantly. Add the beef broth, diced tomatoes, bay leaf, and beef back to the pot. Reduce heat and simmer for 1 1/2 hours or until the roast is fork-tender. Add barley and corn; cover with a lid for 30 minutes. Remove the lid and continue simmering for 15 minutes.
Remove the roast from the pot and trim the beef away from any gristle or fat. Cut or shred into bite-size chunks and return to the pot.