Purity: Minor Invalidator After Tayammum for Ghusl
Practical Laws of Islam as per the teachings of Ayatullah Sistani
Ruling 713:
If someone performs tayammum in place of ghusl and afterwards something happens that invalidates wuḍūʾ, in the event that he cannot perform ghusl for subsequent prayers, he must perform wuḍūʾ. And the recommended precaution is that he should also perform tayammum; and if he cannot perform wuḍūʾ, he must perform tayammum instead.
-Ayatullah Sistani, Practical Laws of Islam, Purification (Taharah)