Heat olive oil in a large pot or Dutch oven over medium heat.
Add the diced onion and sauté for about 3-4 minutes until softened.
Stir in the minced garlic and cook for an additional minute until fragrant.
Add the ground beef to the pot, breaking it up with a spoon. Cook until browned, about 5-7 minutes. Drain excess fat if necessary.
Add the carrots, celery, and bell pepper to the pot. Sauté for another 5 minutes, stirring frequently.
Stir in the diced tomatoes (with juice), beef broth, green beans, corn, oregano, thyme, salt, pepper, and the bay leaf.
Bring the soup to a boil, then reduce heat to low and let it simmer for 20-25 minutes, allowing the flavors to meld and the vegetables to become tender.
Taste and adjust seasoning if needed, then remove the bay leaf before serving.