A laboratory investigation was conducted to determine the effects of temperature and moisture on the shear strength of textured geomembrane (T-GM) and geosynthetic clay liner (GCL) interface. Several landfill slope failures involving geosynthetics have occurred within the past three decades. Interface shear strength of T-GM/GCL is well documented for testing conducted at laboratory temperatures and at moisture contents associated with GCLs in submerged conditions. However, in-service conditions for landfill liner systems include a wide range of temperatures (extending from below 0 °C to above 40 °C) and a wide range of moisture conditions. Large-scale interface direct shear tests were performed at normal stresses of cover liners (10, 20, and 30 kPa) and bottom liners (100, 200, and 300 kPa). Cover liner specimens were subjected to temperatures of 2, 20 and 40 °C; and bottom liner specimens were subjected to temperatures of 20 and 40 °C. Both cover and bottom liner specimens were prepared at moisture contents of as-received (approx. 18-19%), 50%, and 100%.
Cover liner specimens exhibited decreased peak interface shear strength (tp) with increasing temperature. Specimens sheared at 2 °C exhibited greater tp than those sheared at 20 °C by as much as 27%. Specimens sheared at 20 °C exhibited greater tp than those sheared at 40 °C by as much as 16%. Large-displacement interface shear strength (tld) generally exhibited a bell-shaped relationship with increasing temperature with the greatest tld at 20 °C. A bell-shaped relationship was exhibited between temperature and peak and large-displacement interface friction angle (dp and dld). dp ranged from 17.4 to 26.3°, 23.8 to 29°, and 20.4 to 22.2° for 2, 20, and 40 °C, respectively. dld ranged from 12.7 to 18.2°, 18.2 to 20.6°, and 15.9 to 16.7° for 2, 20, and 40 °C, respectively. Decreased d at 2 and 40 °C were largely attributed to increased geosynthetic damage. Bottom liner specimens exhibited decreased tp and tld with increasing temperature by up to 12% and 16%, respectively. Bottom liner specimens exhibited decreased tp and tld with increasing moisture content by up to 14% and 36%, respectively. For bottom liner specimens, a trend of decreased dp with increased temperatures was exhibited. dp ranged from 20 to 24.7° and 19.5 to 22.2° for 20 °C and 40 °C, respectively. dld ranged from 10.4 to 15.6° and 8.9 to 13.9° for 20 °C and 40 °C, respectively. Decreased d at 40 °C was largely attributed to increased geosynthetic damage and increased bentonite extrusion. Increased moisture content resulted in decreased dp and dld by up to 4.7 and 5.1°, respectively. Results of this testing program indicated that T-GM/GCL interface shear strengths are influenced by temperature and moisture content within ranges representative of field conditions. Interpolation factors and reduction factors were developed for use to avoid overestimation of d when determined at standard laboratory temperatures. For cover liners, reduction factors of 0.8 and 0.85 are recommended for dp and dld, respectively. For bottom liners, reduction factors of 0.9 and 0.85 are recommended for dp and dld, respectively.
","abstract_html":"<p>A laboratory investigation was conducted to determine the effects of temperature and moisture on the shear strength of textured geomembrane (T-GM) and geosynthetic clay liner (GCL) interface. Several landfill slope failures involving geosynthetics have occurred within the past three decades. Interface shear strength of T-GM/GCL is well documented for testing conducted at laboratory temperatures and at moisture contents associated with GCLs in submerged conditions. However, in-service conditions for landfill liner systems include a wide range of temperatures (extending from below 0 °C to above 40 °C) and a wide range of moisture conditions. Large-scale interface direct shear tests were performed at normal stresses of cover liners (10, 20, and 30 kPa) and bottom liners (100, 200, and 300 kPa). Cover liner specimens were subjected to temperatures of 2, 20 and 40 °C; and bottom liner specimens were subjected to temperatures of 20 and 40 °C. Both cover and bottom liner specimens were prepared at moisture contents of as-received (approx. 18-19%), 50%, and 100%.</p> <p>Cover liner specimens exhibited decreased peak interface shear strength (t<sub>p</sub>) with increasing temperature. Specimens sheared at 2 °C exhibited greater t<sub>p</sub> than those sheared at 20 °C by as much as 27%. Specimens sheared at 20 °C exhibited greater t<sub>p</sub> than those sheared at 40 °C by as much as 16%. Large-displacement interface shear strength (t<sub>ld</sub>) generally exhibited a bell-shaped relationship with increasing temperature with the greatest t<sub>ld</sub> at 20 °C. A bell-shaped relationship was exhibited between temperature and peak and large-displacement interface friction angle (d<sub>p</sub> and d<sub>ld</sub>). d<sub>p</sub> ranged from 17.4 to 26.3°, 23.8 to 29°, and 20.4 to 22.2° for 2, 20, and 40 °C, respectively. d<sub>ld</sub> ranged from 12.7 to 18.2°, 18.2 to 20.6°, and 15.9 to 16.7° for 2, 20, and 40 °C, respectively. Decreased d at 2 and 40 °C were largely attributed to increased geosynthetic damage. Bottom liner specimens exhibited decreased t<sub>p</sub> and t<sub>ld</sub> with increasing temperature by up to 12% and 16%, respectively. Bottom liner specimens exhibited decreased t<sub>p</sub> and t<sub>ld</sub> with increasing moisture content by up to 14% and 36%, respectively. For bottom liner specimens, a trend of decreased d<sub>p </sub>with increased temperatures was exhibited. d<sub>p</sub> ranged from 20 to 24.7° and 19.5 to 22.2° for 20 °C and 40 °C, respectively. d<sub>ld</sub> ranged from 10.4 to 15.6° and 8.9 to 13.9° for 20 °C and 40 °C, respectively. Decreased d at 40 °C was largely attributed to increased geosynthetic damage and increased bentonite extrusion. Increased moisture content resulted in decreased d<sub>p</sub> and d<sub>ld</sub> by up to 4.7 and 5.1°, respectively. Results of this testing program indicated that T-GM/GCL interface shear strengths are influenced by temperature and moisture content within ranges representative of field conditions. Interpolation factors and reduction factors were developed for use to avoid overestimation of d when determined at standard laboratory temperatures. For cover liners, reduction factors of 0.8 and 0.85 are recommended for d<sub>p </sub>and d<sub>ld</sub>, respectively. For bottom liners, reduction factors of 0.9 and 0.85 are recommended for d<sub>p </sub>and d<sub>ld</sub>, respectively.</p>","abstract_has_math":false,"creators":["Chrysovergis, Taki Stavros"],"institution":null,"degree_name":"MS in Civil and Environmental Engineering","degree_level":null,"degree_discipline":"Civil and Environmental Engineering","degree_department":null,"school":null,"contributors":["James Hanson"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2012,"date_issued":"2012-12-01T08:00:00Z","date_published":"2012-12-01T08:00:00Z","updated_at":"2026-07-24T01:31:17Z","subjects":["Geosynthetics","Interface shear strength","Temperature","Geomembrane","Geosynthetic clay liner","Environmental Engineering","Geotechnical Engineering","Other Civil and Environmental Engineering"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["10.15368/theses.2012.220"],"render_values":[{"text":"10.15368/theses.2012.220","href":"https://doi.org/10.15368/theses.2012.220","code":true}]}]},"links":{"outbound_url":"https://digitalcommons.calpoly.edu/theses/899","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["James Hanson"]},{"key":"dc:creator","label":"Author","values":["Chrysovergis, Taki Stavros"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.available","label":"Dc Date Available","values":["2012-12-12T08:00:00Z"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Civil and Environmental Engineering"]},{"key":"thesis:degree_name","label":"Degree Name","values":["MS in Civil and Environmental Engineering"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Geosynthetics","Interface shear strength","Temperature","Geomembrane","Geosynthetic clay liner","Environmental Engineering","Geotechnical Engineering","Other Civil and Environmental Engineering"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://digitalcommons.calpoly.edu/theses/899","10.15368/theses.2012.220"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["A laboratory investigation was conducted to determine the effects of temperature and moisture on the shear strength of textured geomembrane (T-GM) and geosynthetic clay liner (GCL) interface. Several landfill slope failures involving geosynthetics have occurred within the past three decades. Interface shear strength of T-GM/GCL is well documented for testing conducted at laboratory temperatures and at moisture contents associated with GCLs in submerged conditions. However, in-service conditions for landfill liner systems include a wide range of temperatures (extending from below 0 °C to above 40 °C) and a wide range of moisture conditions. Large-scale interface direct shear tests were performed at normal stresses of cover liners (10, 20, and 30 kPa) and bottom liners (100, 200, and 300 kPa). Cover liner specimens were subjected to temperatures of 2, 20 and 40 °C; and bottom liner specimens were subjected to temperatures of 20 and 40 °C. Both cover and bottom liner specimens were prepared at moisture contents of as-received (approx. 18-19%), 50%, and 100%.
Cover liner specimens exhibited decreased peak interface shear strength (tp) with increasing temperature. Specimens sheared at 2 °C exhibited greater tp than those sheared at 20 °C by as much as 27%. Specimens sheared at 20 °C exhibited greater tp than those sheared at 40 °C by as much as 16%. Large-displacement interface shear strength (tld) generally exhibited a bell-shaped relationship with increasing temperature with the greatest tld at 20 °C. A bell-shaped relationship was exhibited between temperature and peak and large-displacement interface friction angle (dp and dld). dp ranged from 17.4 to 26.3°, 23.8 to 29°, and 20.4 to 22.2° for 2, 20, and 40 °C, respectively. dld ranged from 12.7 to 18.2°, 18.2 to 20.6°, and 15.9 to 16.7° for 2, 20, and 40 °C, respectively. Decreased d at 2 and 40 °C were largely attributed to increased geosynthetic damage. Bottom liner specimens exhibited decreased tp and tld with increasing temperature by up to 12% and 16%, respectively. Bottom liner specimens exhibited decreased tp and tld with increasing moisture content by up to 14% and 36%, respectively. For bottom liner specimens, a trend of decreased dp with increased temperatures was exhibited. dp ranged from 20 to 24.7° and 19.5 to 22.2° for 20 °C and 40 °C, respectively. dld ranged from 10.4 to 15.6° and 8.9 to 13.9° for 20 °C and 40 °C, respectively. Decreased d at 40 °C was largely attributed to increased geosynthetic damage and increased bentonite extrusion. Increased moisture content resulted in decreased dp and dld by up to 4.7 and 5.1°, respectively. Results of this testing program indicated that T-GM/GCL interface shear strengths are influenced by temperature and moisture content within ranges representative of field conditions. Interpolation factors and reduction factors were developed for use to avoid overestimation of d when determined at standard laboratory temperatures. For cover liners, reduction factors of 0.8 and 0.85 are recommended for dp and dld, respectively. For bottom liners, reduction factors of 0.9 and 0.85 are recommended for dp and dld, respectively.
"]},{"key":"dc:title","label":"Title","values":["Laboratory Investigation of the Effects of Temperature and Moisture on Interface Shear Strength of Textured Geomembrane and Geosynthetic Clay Liner"]}]}],"canonical_facts":{"dc:contributor":["James Hanson"],"dc:creator":["Chrysovergis, Taki Stavros"],"dc:date.available":["2012-12-12T08:00:00Z"],"dc:description.abstract":["A laboratory investigation was conducted to determine the effects of temperature and moisture on the shear strength of textured geomembrane (T-GM) and geosynthetic clay liner (GCL) interface. Several landfill slope failures involving geosynthetics have occurred within the past three decades. Interface shear strength of T-GM/GCL is well documented for testing conducted at laboratory temperatures and at moisture contents associated with GCLs in submerged conditions. However, in-service conditions for landfill liner systems include a wide range of temperatures (extending from below 0 °C to above 40 °C) and a wide range of moisture conditions. Large-scale interface direct shear tests were performed at normal stresses of cover liners (10, 20, and 30 kPa) and bottom liners (100, 200, and 300 kPa). Cover liner specimens were subjected to temperatures of 2, 20 and 40 °C; and bottom liner specimens were subjected to temperatures of 20 and 40 °C. Both cover and bottom liner specimens were prepared at moisture contents of as-received (approx. 18-19%), 50%, and 100%.
Cover liner specimens exhibited decreased peak interface shear strength (tp) with increasing temperature. Specimens sheared at 2 °C exhibited greater tp than those sheared at 20 °C by as much as 27%. Specimens sheared at 20 °C exhibited greater tp than those sheared at 40 °C by as much as 16%. Large-displacement interface shear strength (tld) generally exhibited a bell-shaped relationship with increasing temperature with the greatest tld at 20 °C. A bell-shaped relationship was exhibited between temperature and peak and large-displacement interface friction angle (dp and dld). dp ranged from 17.4 to 26.3°, 23.8 to 29°, and 20.4 to 22.2° for 2, 20, and 40 °C, respectively. dld ranged from 12.7 to 18.2°, 18.2 to 20.6°, and 15.9 to 16.7° for 2, 20, and 40 °C, respectively. Decreased d at 2 and 40 °C were largely attributed to increased geosynthetic damage. Bottom liner specimens exhibited decreased tp and tld with increasing temperature by up to 12% and 16%, respectively. Bottom liner specimens exhibited decreased tp and tld with increasing moisture content by up to 14% and 36%, respectively. For bottom liner specimens, a trend of decreased dp with increased temperatures was exhibited. dp ranged from 20 to 24.7° and 19.5 to 22.2° for 20 °C and 40 °C, respectively. dld ranged from 10.4 to 15.6° and 8.9 to 13.9° for 20 °C and 40 °C, respectively. Decreased d at 40 °C was largely attributed to increased geosynthetic damage and increased bentonite extrusion. Increased moisture content resulted in decreased dp and dld by up to 4.7 and 5.1°, respectively. Results of this testing program indicated that T-GM/GCL interface shear strengths are influenced by temperature and moisture content within ranges representative of field conditions. Interpolation factors and reduction factors were developed for use to avoid overestimation of d when determined at standard laboratory temperatures. For cover liners, reduction factors of 0.8 and 0.85 are recommended for dp and dld, respectively. For bottom liners, reduction factors of 0.9 and 0.85 are recommended for dp and dld, respectively.
"],"dc:identifier":["https://digitalcommons.calpoly.edu/theses/899","10.15368/theses.2012.220"],"dc:subject":["Geosynthetics","Interface shear strength","Temperature","Geomembrane","Geosynthetic clay liner","Environmental Engineering","Geotechnical Engineering","Other Civil and Environmental Engineering"],"dc:title":["Laboratory Investigation of the Effects of Temperature and Moisture on Interface Shear Strength of Textured Geomembrane and Geosynthetic Clay Liner"],"thesis:degree_discipline":["Civil and Environmental Engineering"],"thesis:degree_name":["MS in Civil and Environmental Engineering"]},"updated_at":"2026-07-24T01:31:17Z"}