If there isn't a subject then there needs to be something that can direct your eyes like a strong pattern. In these, my eyes just wonder pointlessly until they are off the frame. These do not hold my attention and are difficult to keep looking at.
These are patterns. Your photos do not have any strong repetitive shapes. They are random shapes and sizes with random positions. Do not take it personally, my eyes just do not stick to these photos.
The thing that bores me is that in each of your photos it is exactly from the same point of view as if I walked upon the scene, metered, composed, then pressed the shutter. Out of curisoty, how many different shots did you take for each photo? ..... you don't have to be exact, just a round number will do.