Physical model test on the effect of geosynthetic reinforcement on embankment constructed with modified lateritic soil under wetting-vibration.

Abstract

Geosynthetic reinforcement has been widely used in the construction of embankment. However, the effect of reinforcement on embankment constructed with modified lateritic soil under wetting-vibration is still understudied. Lime was added into a typical high-liquid-limit lateritic soil at a mass ratio of 9% to prepare a mixture of modified lateritic soil, which was then used to construct three embankment models: unreinforced, partially and fully reinforced. A model test system designed by the authors was used to carry out the comparative test under wetting-vibration. White noise was excited on the three models to compare the variations of dynamic property parameters with wetting degree for the three types of embankments. Under three wetting conditions of no wetting, low wetting and high wetting, seismic waves of San Fernando, San Simeon_CA and Trinidad were acted on each of the three embankments to compare and study the variations of PGA amplification factor, dynamic earth pressure and dynamic pore water pressure with the input acceleration amplitude. The test results indicate that the reinforcement significantly enhanced the properties of embankments constructed with modified lateritic soil under wetting-vibration. When the wetting degree is in the range of 0% to 50%, the natural frequencies of the partially and fully reinforced embankments are increased by 11.77% to 12.74% and 29.01% to 35.53% respectively compared with that of the unreinforced embankment, and the damping ratios of the partially and fully reinforced embankments are reduced by 7.78% to 30.49% and 13.20% to 41.80% respectively. At different wetting degrees and under the three seismic waves, compared with the unreinforced embankment, the PGA amplification factors of the partially and fully reinforced embankments are reduced by 6.69% to 18.16% and 12.47% to 31.73%; the peak dynamic pore water pressures are reduced by 22.72% to 30.14% and 38.58% to 50.27%; and the peak dynamic earth pressures are reduced by 7.78% to 30.49% and 13.20% to 41.80%. The test result is a theoretical support for the revision of specifications of reinforced lateritic soil embankments.