Underground polymeric l-shaped pipeline vibrations under seismic effect Nematilla Nishonov, Diyorbek Bekmirzaev, Akbar Ergashov, Ziyoviddin Rakhimjonov and Asror Khurramov E3S Web Conf., 264 (2021) 02037 Published online: 02 June 2021 DOI: 10.1051/e3sconf/202126402037