Design and Construction of Highway Structures in Karst Terrain

摘要

Bridges, grade separation retaining walls, and noise walls are common structure types in a highway system. Due to the unique subsurface condition of Karst terrain, the stability of residual soils that overlay the cavitose limestone bedrock is often the critical factor to determine the foundation selection. The stability mechanism of residual soil over the karst limestone rock is summarized based on more than 120 field-observed sinkhole collapse events in the eastern United States. Also, factors affecting the stability of residual soils are discussed. The majority of sinkhole events that occurred near the highway structures were triggered by unusual amounts of precipitation. The classification of SPT Low Blow Count material near the soil-carbonate rock interface is important to identify the subsurface sinkhole features.