POKASEEDES:
Good morning. There are many reasons why your pound cake ends up with tunnels in the interior. I will only mention two today just 2 reasons. Please next time post your recipe & it's directions so that I can see if the recipe is properly balanced or not. Many times it is the sugar that is the culprit. Here's how & why. Sugar doesn't always get melted during baking. If the sugar granules are coarse it will not melt & as a result it doesn't get into all parts of the batter evenly. As a precaution measure out the sugar & place it in your food processor or blender & give it a 40 second twirl. It will be about 1/4 the size of what it was. If this doesn't take cake of your problem I will then post another fix for you if you post the recipe. Good luck & have a nice day.

~CHEF DUNASK.