Efficient method of eliminating accidental damage of sewer tunnel Dmitriy Goncharenko, Olga Starkova, Alevtyna Aleinikova, Yulyia Kolomiiets and Oksana Greenchuk MATEC Web Conf., 230 (2018) 02011 Published online: 16 November 2018 DOI: 10.1051/matecconf/201823002011