Discussion of “Comparison of Interface Shear Strength of Soil Nails Measured by Both Direct Shear Box Tests and Pullout Tests” by Lok-Man Chu and Jian-Hua Yin

2007 ◽  
Vol 133 (3) ◽  
pp. 344-346 ◽  
Author(s):  
K. S. Li ◽  
S. R. Lo
Keyword(s):  
Shear Strength ◽  
Direct Shear ◽  
Interface Shear Strength ◽  
Interface Shear ◽  
Soil Nails ◽  
Pullout Tests ◽  
Shear Box

scholarly journals The influence of saturation on the interface shear strength of clay and nonwoven geotextile

2021 ◽  
Vol 15 (1) ◽  
pp. 41-54
Author(s):  
Minh-Duc Nguyen ◽  
Minh-Phu Ho
Keyword(s):  
Shear Strength ◽  
Clayey Soil ◽  
Water Pressure ◽  
Strength Analysis ◽  
Direct Shear ◽  
Interface Shear Strength ◽  
Interface Shear ◽  
Shear Box ◽  
Nonwoven Geotextile ◽  
Adhesion Factor

The paper presents a series of modified direct shear tests to investigate the interface shear strength between clay and nonwoven geotextile under different normal stresses and degrees of saturation. The modified direct shear apparatus consists of a 60 mm × 60 mm square shear box assembly with a 60 mm × 60 mm acrylic block inserted in the bottom shear box. A woven geotextile layer was glued to the top of the acrylic block, while the top shear box was filled by the compacted clayey soil. The results revealed that the interface shear strength of clay and nonwoven geotextile reduced by 13.4-27.7% when changing from optimum moisture content (OMC) of the soil to saturation condition. The high permeability of nonwoven geotextile induced the dissipation of excess pore water pressure at the interface when shearing. As a result, the adhesion factor of the clay-geotextile interface increased from about 0.6 for the specimens at OMC to over 0.8 for consolidated saturated specimens. In contrast, for the impermeable reinforcement, the interface shear strength analysis of previous studies shows that the adhesion factor of the reinforcement and clayey soil would be reduced when increasing the water content of the clay specimens. Keywords: adhesion factor; clay; nonwoven geotextile, interface shear strength; saturation.

scholarly journals The Significant Effect of Interface Shear Strength Between Soil Liner and Geotextile with Different Percentages of Bentonite and Sodium Bentonite with Geosynthetic

2018 ◽  
Vol 150 ◽  
pp. 02009
Author(s):  
Roslizayati Razali ◽  
Nor Azizah Che Azmi ◽  
Diana Che Lat ◽  
Mazidah Mukri ◽  
Farah Hafifie Ahamad
Keyword(s):  
Shear Strength ◽  
Direct Shear ◽  
Interface Shear Strength ◽  
Interface Shear ◽  
Sodium Bentonite ◽  
Liner Material ◽  
Fine Soil ◽  
Shear Performance ◽  
Soil Liner ◽  
Shear Box

This research focuses on the interface shear performance between geotextile and soil with various percentages of bentonite and sodium bentonite for landfill stability by using Direct Shear Test. Admixtures are mixed with clay to improve its performance as a liner material due to their ability to fill the voids between soil particles and also the most effective sealants. The aim of this study is focused on evaluating the effectiveness of bentonite and sodium bentonite on improving interface shear strength of fine soil. In this study, direct shear box was used to measure the interface shear strength of soil with different percentages of bentonite and sodium bentonite at optimum moisture content. Analysis shows that the most suitable percentage is of 5 % of bentonite and 2.5 % of sodium bentonite due to the highest interface shear strength of the mixture with geosynthetic. It is clearly shown that 2.5 % sodium bentonite is the most suitable percentage to be used as admixture for landfill stability as it gives higher interface shear strength.

Influence of degree of saturation on soil nail pull-out resistance in compacted completely decomposed granite fill

2007 ◽  
Vol 44 (11) ◽  
pp. 1314-1328 ◽  
Author(s):  
Li-Jun Su ◽  
Terence C.F. Chan ◽  
Y.K. Shiu ◽  
Tony Cheung ◽  
Jian-Hua Yin
Keyword(s):  
Shear Strength ◽  
Degree Of Saturation ◽  
Interface Shear Strength ◽  
Interface Shear ◽  
Soil Nails ◽  
Soil Nail ◽  
Pull Out ◽  
Decomposed Granite ◽  
Soil Interface ◽  
Completely Decomposed Granite

The nail–soil interface shear strength is a key parameter in the design and stability assessment of soil nailing systems. A number of factors will influence the nail–soil interface shear strength. Among these factors, the degree of saturation (Sr) of the soil is an important one especially for permanent soil nail structures. To study the influence of Sr on soil nail pull-out shear resistance, a series of laboratory pull-out tests have been conducted on soil nails in compacted completely decomposed granite (CDG) fill prepared to different Sr. The tests were conducted using two specially designed pull-out boxes (with same specifications). In the near-saturated tests, a high Sr (about 98%) was achieved using two special features of the apparatus: a waterproof front cap and back-water pressure pipes at the bottom of the pull-out box. Test results showed that the nail–soil shearing plane migrated outwards into the soil when the Sr of the soil increased. Also, peak pull-out strengths of soil nails were strongly influenced by the Sr of the soil. Among the tested Sr, the highest values of peak pull-out shear strength were obtained at Sr values between 50% and 75%.

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