Is it permissible to combine the Asr prayer with the Dhuhr prayer due to extreme exhaustion after finishing work, knowing that the workplace is about one hundred kilometers away from home, and is this considered a travel distance that permits combining prayers?

Work is not considered an excuse to delay prayer beyond its prescribed time, or to combine it with another, or to miss congregational prayer. Rather, prayer must be performed at its due time and in congregation if you hear the call. Allah Almighty says: "Indeed, prayer has been decreed upon the believers a time-bound ordinance" (Quran 4:103). And the Prophet, peace and blessings be upon him, said: "Perform prayer at its prescribed time." There is no obedience to a creature in disobedience to the Creator. As for combining the Dhuhr and Asr prayers, it is permissible if the distance between your workplace and the last urban area of the city is 83 kilometers or more, because in that case, you are considered a traveler.