文摘
Due to their low visibility, rehabilitation of underground utilities is neglected until a catastrophic failure occurs. This results in costly and difficult rehabilitation options. A key issue governing the selection of appropriate rehabilitation technologies, is the availability of adequate information concerning the condition of infrastructure. This paper presents an overview of the current methods and new developments for sewer line condition assessment. The focus of the paper is on internal inspection technologies, which investigate infiltration/inflow problems, and assess the structural conditions of sewer pipes. The primary internal inspection method is closed-circuit television (CCTV) inspection. The quality of information obtained using traditional CCTV is dependent on the experience and skill of the technician and the reliability of the TV picture. Other non-destructive, remote-sensing diagnostic methods include: infrared thermography system, sonic distance measurement method and ground penetrating radar technique. The features of three new promising multi-sensory systems, namely, KARO, PIRAT and SSET, are explained. The paper also discusses ongoing research efforts for automated interpretation of multi-sensory data.