Longitudinal vibrations of underground pipelines of finite length in medium surrounded by soil with different properties along pipeline lengthR. B. Khusainov, B. Sh. Yuldoshev, D. Abdullaev and S. B. KhusainovE3S Web of Conf., 401 (2023) 04060DOI: https://doi.org/10.1051/e3sconf/202340104060