A precise subbase width that is matched to the expected fill strength helps to prevent pumping and rutting.

https://www.scribd.com/document/978890988/Concrete-Companies-Reveal-The-3-Hour-Window-Secrets-That-Ensure-Strong-Slabs-160910

Maintaining tendons restricted and areas stable over time by having a subbase diameter that is accurate and matched to pile expectations helps avoid rutting and pumping.