Structure and Interpretation of 走得到吗？
'走'(to walk) is the verb 

'到'(arrive/ to) in '走到'(to walk to) is the resultative verb particle

Resultative verb particle completes the verb action. in this case- you walk to/ you walk and arrive. 

'得'(able to) in '走得到' is the potential particle 

There are only two potential particles. They are 得(can) and 不(cannot). You are either potentially can or cannot walk there.

'吗' in '走得到吗？' is the final interrogative particle (indicates the phrase is a question)


  "走得到吗？" means "can (I) walk to (that place)?"