title: Variation of crack intensity factor in three compacted clay liners exposed to annual cycle of atmospheric conditions with and without geotextile cover.
abstract: Performance of compacted clay liners commonly used as landfill barrier systems can be subject to decline in terms of hydraulic conductivity if left exposed to atmospheric conditions for an extended period of time prior to placement of overlaying layers. The resulting desiccation cracking can lead to increased hydraulic conductivity. Desiccation crack intensity was studied for three clayey soils commonly used for construction of landfill barrier system in a relatively large scale test setup exposed to real time atmospheric conditions over a complete annual cycle. A white separator geotextile cover was presumed to be capable of reducing the intensity of desiccation cracking through absorbing and maintaining higher amounts of moisture and reducing the temperature of the soil surface in comparison to a directly exposed soil surface. Desiccation cracking was monitored using a digital imaging technique for three compacted clay liners in two sets, one open to air and the second covered with the white geotextile. Crack intensity factor approached a relatively stable phase after certain cycles corresponding to atmospheric dry wet cycles. The results indicated that the white separator geotextile was capable of reducing the crack intensity factor by 37.4-45.9% throughout the experiment including the cyclic phase of desiccation cracking. During the stable phase, the maximum reduction in crack intensity factor of 90.4% as a result of applying geotextile cover was observed for the soil with the lowest plastic index and clay content and therefore the lowest magnitude of crack intensity factor. The other two soils with similar clay content but different plastic index showed 23.6% and 52.2% reductions in crack intensity factor after cyclic phase when covered with geotextile.
authors.affiliation: Department of Environmental Engineering, Graduate Faculty of Environment, University of Tehran, Tehran, Iran. Electronic address: ensafari@ut.ac.ir.
authors.forename: E
authors.initials: E
authors.lastname: Safari
authors.affiliation: Department of Environmental Pollutants, Environmental Sciences Research Institute, Shahid Beheshti University, Tehran, Iran. Electronic address: ma_jalili@sbu.ac.ir.
authors.forename: M
authors.initials: M
authors.lastname: Jalili Ghazizade
authors.affiliation: Department of Environmental Engineering, Graduate Faculty of Environment, University of Tehran, Tehran, Iran. Electronic address: mabdoli@ut.ac.ir.
authors.forename: M A
authors.initials: MA
authors.lastname: Abduli
authors.affiliation: Department of Civil Engineering, School of Civil Engineering, University of Tehran, Tehran, Iran; Ecole Nationale des Ponts et Chaussees, Paris, France(1). Electronic address: gatmiri@ut.ac.ir.
authors.forename: B
authors.initials: B
authors.lastname: Gatmiri
mesh_terms: D000538:Aluminum Silicates; D001272:Atmosphere; D000077215:Clay; D002980:Climate; D003890:Desiccation; D004867:Equipment Design; D007492:Iran; D010969:Plastics; D012037:Refuse Disposal / Q000379:methods*; D012621:Seasons; D012987:Soil; D012989:Soil Pollutants / Q000737:chemistry*; D013696:Temperature; D013784:Textiles; D013997:Time Factors; D064091:Waste Disposal Facilities; D014874:Water Pollutants, Chemical / Q000032:analysis
chemical_list: D000538:Aluminum Silicates; D010969:Plastics; D012987:Soil; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical; D000077215:Clay
keywords: Compacted clay liner; Crack intensity factor; Desiccation cracking; Geotextile; Landfill barrier