Slope Liquefaction Failure of a Rip-Rap Slope during Springtime in a Northern Climate

摘要

A common problem in northern climates during the spring is slope failures occurring on slopes constructed the previous year. The main cause of the failure is a lack of vegetation coupled with ground freezing that prevents water drainage. Typical remediation of failed slopes is to reconstruct the slope back to its original configuration and place rip-rap over the failed section of the slope; a remediation technique that has been found to work well. This case study discusses the construction of a slope adjacent a state highway that utilized a geotextile separator and riprap in the construction of the slope. The following spring, however, the slope dramatically failed resulting in a large amount of soil flowing onto the state highway and a sinkhole forming on the back side of the slope. The primary cause of failure was found to be clogging of the geotextile thus allowing snowmelt and rain to generate pore water pressures behind the geotextile in excess of the rip-rap's ability to prevent failure.