pound the pavement - Phrases/Idioms
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Walk the streets, especially in search of employment. For example, He was fired last year and he's been pounding the pavement ever since. A similar usage is pound a beat, meaning “to walk a particular route over and over”; it is nearly always applied to a police officer. [Early 1900s]