A case study of a ground slip during installation of an HDPE pipe

This paper presents a case study of a slide that occurred during the construction of the initial starter dam for a planned four-stage coal refuse impoundment located in Eastern Kentucky. During the installation of 1700 linear feet of 36-inch HDPE decant pipe, loading from coarse refuse placement on a side hill adjacent to the pipe alignment and future embankment initiated a slide in natural ground prior to the construction of the dam embankment. This slide caused a 300 foot section of pipe to displace laterally and vertically. This paper presents the lessons learned from the remediation of this slide and the repairs made to the decant pipe. It also presents the challenges that developed as construction progressed and operation commenced as well as challenges that developed as later stages were proposed and constructed. This paper also examines the economic, regulatory, and maintenance and inspection challenges created in later stages of the permitting and design process as a result of the initial remedial efforts and the course of action taken.