Shear Response of Geogrid-Unsaturated Marginal Soil Interface Based on Effective Stress Approach -Abbas Mahboobi

Shear Response of Geogrid-Unsaturated Marginal Soil Interface Based on Effective Stress Approach

Abbas Mahboobi 1 Mahmoud Ghazavi 2

1- Ph. D Student, Faculty of Civil Engineering, K. N. Toosi University of Technology, Tehran, Iran. 2- Professor, Faculty of Civil Engineering, K. N. Toosi University of Technology, Tehran, Iran.

Abstract:

Unsaturated marginal soils can be used as an economical alternative to engineered soils reinforced with geosynthetics. This report investigates the shear behavior of the marginal soil-geogrid interface. Since exploring the impact of the reduction in the effective stress of the interface caused by wetting on its shear response has received little attention, in this research, large-scale direct shear tests (DST) were performed on unsaturated specimens under different stresses and moisture contents. In this research, for the first time, effective stress was employed for the shear resistance response of the unsaturated soil-reinforcement interface. The results indicated that the development of the failure envelope on the effective stress plane could have merit over the other approach (i.e., independent stress variables), given its accuracy in predicting internal and interface shear strength and parameters. The observation reveals that at a constant stress level, by increasing suction, the shear behavior of the soil changes from the contractive mode to the dilative mode. Analyzing the interface shear strength ratio and interface friction coefficients shows that wetting the soil-geogrid interface, even at a moisture content of 2% less than the optimum moisture content, the sliding potential of the reinforcement increases significantly.

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تاریخ:

1402/09/20

تعداد بازدید:

203

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