The foot makes contact with the Ground.
How do we approach that contact?
There are different approaches which can also depend upon the Tai Chi style you practise.
Here is one to try. Be aware of the sole of the foot contacting the ground and soften it. There is no seperation of foot and ground. Notice how you walk. Is your foot hammering into the ground?
Soften. Relax. Be kind to yourself and the ground.