This document provides an overview of underground utility surveys. It discusses the need for such surveys to identify underground utilities in order to avoid damages during construction. Several methods for conducting underground utility surveys are described, including ground penetrating radar, induction utility locators, and acoustic location methods. Case studies from China on developing underground utility tunnels are presented. Advantages of underground utility surveys include safety, cost savings, and minimizing project delays. Disadvantages include limitations related to soil and utility types. The document concludes that underground utility surveys are necessary to identify utilities and avoid accidents and disruption.