An extensive two-dimensional finite element seepage analysis wasconducted to study the parameters affecting the wetting-induced behavior of compacted fills. The results showed that decreasing the placement water content increases the initial suction pressures, which increases the time required for hydrocompression and the magnitude of hydrocompression. The analysis also showed that the time required for hydrocompression increased almost linearly with fill depth. The surface infiltration was found to migrate unevenly through the fill material, resulting in an uneven dissipation of the suction pressures and thus differential ground movements. Because the suction pressures had to be dissipated before a drain could be functional, the installation of a canyon drain or side drain or both did not reduce theamount of hydrocompression or the time required for hydrocompression. However, the drains did cause the wetting front to migrate through the fill in a more uneven pattern than without a drain. To reduce the amount of infiltration and thus hydrocompression, the site should be carefully graded to promote runoff and drains should be installed beneath the irrigation points to intercept the infiltration. If water is allowed to infiltrate the fill, the pavements and structuresshould be designed for the differential ground movements estimated from the procedure described herein. This paper appears in transportation research record no. 1309, Geotechnical engineering 1991.
Abstract