Study on evaluation technique for ground settlement by decrepit sewer using CCTV monitoring and GPR exploration in Korea

Abstract

Ground settlement and road sinking such as sinkhole have been increasingly occurred in urban area of Korea, causing the people to suffer from an anxiety and socioeconomic loss as well. Ground settlement in urban area results from various factors and deteriorated sewer and neighboring construction site were known to mostly have caused such settlement. This study is intended to investigate the cases of ground settlement caused by deteriorated sewer, thereby analyzing the mechanism of ground settlement and furthermore, a basic study to develop the technique to evaluate the sewer-causing ground settlement and the cavity was conducted. This study also includes CCTV monitoring and GPR (Ground Penetrating Radar) exploration of deteriorated sewer. In CCTV monitoring, examination to determine the deterioration of the sewer and potential causes of ground settlement was carried out using high-definition CCTV equipment (1.2 million pixels) and evaluation of correlative characteristics of ground behavior signal caused by deteriorated sewer was conducted. As a result of HD CCTV monitoring and GPR exploration of deteriorated sewer, loosened ground was monitored around soil sedimentation layer from the analysis of GPR exploration and anomaly zone was monitored at soil sedimentation caused by damaged sewer. Using CCTV monitoring and GPR exploration, ground settlement due to deformed sewer would possibly be predicted and investigation database is expected to help develop the reliable ground settlement evaluation technique. © Copyright 2016 by the International Society of Offshore and Polar Engineers (ISOPE).