INFLUENCE OF GRAVIMETRIC WATER CONTENT ON GEOTEXTILE REINFORCEMENT PULLOUT RESISTANCE IN MSE WALLS WITH MARGINAL QUALITY SOILS

摘要

Pullout capacity of geotextile reinforcement is an important consideration in the internal stabilityanalysis of reinforced soil structures, especially those constructed with marginal soils.Precipitation, ground water infiltration and seasonal variations of moisture content during theconstruction process or service life of the structure could result in significant reductions in thematric suction, leading to a reduction in the soil-geotextile interface strength. Consequently, thereinforced soil structure may experience unacceptable deformations or even failure during itsconstruction or post-construction periods. It should be noted that the loss of matric suction in thesoil influences both the shear strength of the soil and the soil-reinforcement interface. However,the focus of this study is merely on the latter.In this study, a series of pullout and interface shear tests were carried out to measure thepullout resistance of a reinforcement geotextile in a marginal soil which was compacted atdifferent gravimetric water contents (GWC). The marginal soil was selected to meet the limitingrequirements of the National Concrete Masonry Association (NCMA) guidelines for segmentalretaining walls with respect to the fines content, gradation and plasticity. The range of GWCvalues investigated varied from dry to wet side of the soil Optimum Moisture Content (OMC).The matric suction in the soil was measured in order to evaluate its influence on the soilreinforcementinterface shear strength. A Moisture Reduction Factor (MRF) is proposed toaccount for the reduction in the soil-geotextile interface strength as a result of the loss in matricsuction.