1McDonald S E,Zhao J Q.Condition assessment and rehabilitation of large sewers.International conference on underground infrastructure research,University of Waterloo,Waterloo,Ontario,2001
2Siggins A F.Ground probing radar in geotechnical applications.Exploration Geophysics,1990,21:175～186
3Andrews M E.Large diameter sewer condition assessment using combined sonar and CCTV equipment.Session Ⅲ/Trunk sewersmaintenance now prevents problems later.NRCC/CPWA Seminar Series"Innovations in Urban Infrastructure".APWA International Public Works Congress.Las Vegas,1998
