Temperature and moisture effects on GCL and textured geomembrane interface shear strength

Abstract

This investigation was conducted to determine the effects of temperature and moisture on the shear strength of a double nonwoven geosynthetic clay liner (GCL) and a high-density polyethylene textured geomembrane (T-GM) interface for municipal solid waste landfills. Interface direct shear tests were conducted at normal stresses representative of cover liners (10, 20 and 30 kPa) and bottom liners (100, 200 and 300 kPa). Tests were conducted at temperatures of 2, 20 and 40°C (cover liner) and 20 and 40°C (bottom liner); and at moisture contents of as-received (19%), 50 and 100%. Both peak and large-displacement (50 mm) shear strength parameters were determined. For cover liners, temperature was determined to have a greater influence on interface shear strength than moisture content, whereas bottom liner shear strength was influenced more by moisture than temperature. Measured interface shear strengths varied by up to 54% with temperature and up to 43% with moisture content. Interface friction angles were greatest at 20°C for both cover and bottom liners. Variations in the interface shear strength parameters were attributed to geosynthetic damage including surface texture of the geomembranes (quantified with optical interferometry) and bentonite extrusion. Overall, results of this testing programme indicated that both peak and large displacement GCL/T-GM interface shear strengths were influenced by temperature and moisture content representative of field service conditions.

Effect of Temperature on Internal Shear Strength Mechanism of Needle-Punched GCL

“…GCL internal strength was measured by direct shear, ring shear, and inclined plate [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. The direct shear apparatus with displacement control and stress control has some advantages and disadvantages.…”

A unit-cell model for thermal regulation of degradation of organics in solid waste

“…The existing test results have shown that the optimum range of temperature for the rapid degradation of organics is between 30°C and 40°C (Cecchi et al, 1993; DeWalle et al, 1978; Hartz et al, 1982). The degradation of organics in solid waste produces heat (El-Faddel et al, 1996; Faitli et al, 2015; Hanson et al, 2015; Hubert et al, 2016; Jafari et al, 2014; Meegoda et al, 2016; Pirt, 1978; Yasumasa et al, 2015; Yoshida and Rowe, 2003; Zanetti et al, 1997). The temperature in solid waste landfills varies in a wide range typically between 4°C and 50°C (Dach and Jager, 1995; Hanson et al, 2015; Jafari et al, 2014; Yoshida and Rowe, 2003).…”

“…The degradation of organics in solid waste produces heat (El-Faddel et al, 1996; Faitli et al, 2015; Hanson et al, 2015; Hubert et al, 2016; Jafari et al, 2014; Meegoda et al, 2016; Pirt, 1978; Yasumasa et al, 2015; Yoshida and Rowe, 2003; Zanetti et al, 1997). The temperature in solid waste landfills varies in a wide range typically between 4°C and 50°C (Dach and Jager, 1995; Hanson et al, 2015; Jafari et al, 2014; Yoshida and Rowe, 2003). It may even rise above 70°C (Lefebvre et al, 2000), at which the degradation of organics would be inhibited.…”

Temperature Effects on the Swelling and Bentonite Extrusion Characteristics of GCLs

“…Vukelic et al (2008) reported bentonite extrusion to be more extensive during shearing of prehydrated GCL/GM than for non-prehydrated GCL/GM interfaces. Hanson et al (2015) identified threshold water contents and normal stress levels for onset of significant bentonite extrusion. In addition, fluid transfer characteristics of GCLs (i.e., containment effectiveness) are expected to be affected by bentonite extrusion due to the resulting reduction in the amount of bentonite in GCLs.…”