Abstract

The East Tennessee landscape consists of varied topography that reflects the lithology and geologic structure of the area. Karst makes up a large part of the East Tennessee landscape and is very problematic in locating, designing, and constructing highways. Instead of a reactive approach to dealing with karst in highway planning, design, and construction, this paper proposes a proactive methodology that is needed in karst terrain. Types of karst problems include sinkholes, caves and karren, collapse incidents, and groundwater contamination. Typical reactive remedial measures used in correcting karst-related highway problems include bridging, drainage alteration, and relocation. Proactive concepts implemented by the Tennessee Department of Transportation include avoidance measures such as relocation of the roadway and drainage design methods including impervious lined drainage ditches and highway runoff filtering systems. Additional proactive drainage measures include the use of graded rock pads, overflow channels from sinkholes to free-draining areas, sinkhole opening improvement and protection, and curbs for embankment sections. Innovative and cost-effective remedial concepts for solving karst-related geotechnical problems include avoidance, using lined ditches and graded rock pads, and other bridging- and drainage-related concepts. Stringent land use and building codes for karst areas are required to ensure the success of karst-related remedial design concepts proposed for highways.

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