Applicability and accuracy of the initially dry and initially wet contact filter paper tests for matric suction measurement of geosynthetic clay liners

An initially wet contact filter paper test (IW-CFPT) and an initially dry contact filter paper test (ID-CFPT) were used to examine the wetting paths of geosynthetic clay liners, including non-contact filter paper tests for comparative purposes. The CFPTs were applied to both geosynthetic clay liner faces to examine the effect of geotextile type on capillary contact. The non-woven geotextile face was found to be more likely to cause capillary breaks than the woven geotextile face. Both IW- and ID-CFPTs were found to be applicable to geosynthetic clay liners within their accurate upper matric suction measurement limits of 146 kPa and 66 kPa, respectively.