Effects of Poorly Draining Backfill on Geotextiles for Earth Reinforcement of Vertical Soil Slopes

摘要

Sixty models of geotextile reinforced and unreinforced vertical walls were constructed and tested to catastrophic failure on the geotechnical centrifuge to examine failure mechanisms of reinforced soil retaining walls built of cohesive soils. All walls were built on rigid foundations. Forty-three models were constructed using Speswhite kaolin to examine the influence of wall reinforcement geometry on wall stability and seventeen were constructed from six other soils to examine the influences of soil type. The following conclusions were drawn: Geotextiles can be used to clear advantage to construct reinforced cohesive soil retaining walls. In these tests reinforcement increased equivalent full scale wall height at failure to three times that of an unreinforced vertical cut in partially saturated kaolin. The failure modes observed depended on the soil and the reinforcement configuration. In plastic Speswhite kaolin, failures in reinforced walls were characterized by a vertical tension crack intersecting an inclined failure plane emerging above the toe of the wall. All such failures occurred by reinforcement breakage and never by reinforcement pullout, regardless of reinforcement length. In less plastic reinforced cohesive soil walls, vertical tension cracks also opened but failure occurred by overturning. Two dimensional limit equilibrium analysis was used with success to explain behavior of walls failing by sliding. It was unsuccessful and unconservative when applied to walls failing by overturning.