Citation

Black B, Machan G, Poelma M. Transp. Res. Rec. 2009; 2116: 35-40.

Copyright

(Copyright © 2009, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

10.3141/2116-05

PMID

unavailable

Abstract

During highway construction, a large ancient landslide was discovered within the Cattaraugus Creek Valley in western New York State. An active landslide was contained within this ancient landslide complex. The depth of the slide is approximately 30 m (100 ft). The purpose of the horizontal drain installation test program was to determine the feasibility of reducing pore-water pressures within a clay stratum by using dewatering techniques. The test demonstrated that horizontal drains could be installed with moderate difficulty. More than 90% of the installed horizontal drains produced discharge water. Flow rates were low but consistent with horizontal drain experience in clayey soils. Most of the original working drains were still discharging water 6 months after installation. Several of the piezometers appeared to have responded to the horizontal drains. One piezometer showed a gradual drawdown of 3.8 m (12 ft) during the first 6 months. A reduction in the rate of slide movement was also observed.