Is it permissible to combine the Asr prayer with the Dhuhr prayer due to time constraints at work and returning home close to the time of Isha?

Every Muslim must perform the prayer at its appointed time, and it is not permissible to intentionally delay it beyond its time, or to combine two prayers without a valid excuse. Some scholars have permitted combining two prayers that share a time due to need. So, if there is a genuine need to combine Asr with Dhuhr because it is impossible to perform it at its due time, and it is not possible to combine them in a merely formal way, then there is no objection to bringing Asr forward to be prayed with Dhuhr.