Calculation of Coupled Stress and Seepage for Dams with a Geotextile/Geomembrane Composite Liner

1995 ◽  
Vol 2 (4) ◽  
pp. 707-721
Author(s):  
T. Tao ◽  
D.F. Li ◽  
J. Yan
Keyword(s):  
Composite Liner ◽  
Coupled Stress

scholarly journals Evaluation of Gingival Microleakage in Class II Composite Restorations with Different Lining Techniques: An In Vitro Study

Scientifica ◽  
2015 ◽  
Vol 2015 ◽  
pp. 1-6
Author(s):  
Vedavathi Bore Gowda ◽  
B. V. Sreenivasa Murthy ◽  
Swaroop Hegde ◽  
Swapna Devarasanahalli Venkataramanaswamy ◽  
Veena Suresh Pai ◽  
...  
Keyword(s):  
Study Groups ◽  
Class Ii ◽  
Composite Liner ◽  
Flowable Composite ◽  
Composite Restorations ◽  
Group 4 ◽  
Group 3 ◽  
Group 2 ◽  
Group 1

Aim. To compare the microleakage in class II composite restorations without a liner/with resin modified glass ionomer and flowable composite liner.Method. Forty standardized MO cavities were prepared on human permanent mandibular molars extracted for periodontal reasons and then divided into 4 groups of ten specimens. The cavity preparations were etched, rinsed, blot dried, and light cured and Adper Single Bond 2 is applied. Group 1 is restored with Filtek P60 packable composite in 2 mm oblique increments. Group 2 is precure group where 1 mm Filtek Z350 flowable liner is applied and light cured for 20 sec. Group 3 is the same as Group 2, but the liner was cocured with packable composite. In Group 4, 1 mm RMGIC, Fuji Lining LC is applied and cured for 20 sec. All the teeth were restored as in Group 1. The specimens were coated with nail varnish leaving 1 mm around the restoration, subjected to thermocycling, basic fuchsin dye penetration, sectioned mesiodistally, and observed under a stereomicroscope.Results. The mean leakage scores of the individual study groups were Group 1 (33.40), Group 2 (7.85), Group 3 (16.40), and Group 4 (24.35). Group 1 without a liner showed maximum leakage. Flowable composite liner precured was the best.

Classification and quantification of downslope erosion from a geosynthetic clay liner (GCL) when covered only by a black geomembrane

2015 ◽  
Vol 52 (4) ◽  
pp. 395-412 ◽  
Author(s):  
R.W.I. Brachman ◽  
A. Rentz ◽  
R.K. Rowe ◽  
W.A. Take
Keyword(s):  
Classification System ◽  
Soil Cover ◽  
Light Transmission ◽  
Test Site ◽  
Field Observations ◽  
Composite Liner ◽  
Geosynthetic Clay Liner ◽  
Clay Liner ◽  
Transmission Technique ◽  
Field Investigations

Field observations of downslope bentonite erosion from a geosynthetic clay liner (GCL) covered by only a black geomembrane are reported for a composite liner left exposed without a protective soil cover for much longer than recommended by the GCL manufacturer. A new nondestructive, light-transmission technique developed to investigate bentonite erosion features in the field is presented. A classification system is developed to describe the type of erosion features observed. Results from five field investigations at the Queen’s University Environmental Liner Test Site (QUELTS II) are reported to quantify the onset, progression, and severity of downslope erosion for one particular geotextile-encased, needle-punched GCL for exposure periods of between 7 weeks and 1.3 years. The first significant erosion feature (type “E”with bentonite loss narrower than 2.5 cm) was observed after 6 months of exposure. Irrecoverable erosion features (type “EE” with bentonite loss wider than 2.5 cm) were observed after 12 months of exposure. These findings highlight the need to follow the manufacturer’s recommendations for timely covering of a composite liner with soil following liner installation.

Exhumation and performance of an Antarctic composite barrier system after 4 years exposure

2020 ◽  
Vol 57 (8) ◽  
pp. 1130-1152 ◽  
Author(s):  
R.S. McWatters ◽  
R.K. Rowe ◽  
V. Di Battista ◽  
B. Sfiligoj ◽  
D. Wilkins ◽  
...  
Keyword(s):  
High Density Polyethylene ◽  
Soil Samples ◽  
Composite Liner ◽  
Subgrade Soil ◽  
And Performance ◽  
Long Term Performance ◽  
Term Performance ◽  
The Antarctic ◽  
Coarse Gravel

An Antarctic biopile using a composite liner (high-density polyethylene geomembrane (GMB) over a geosynthetic clay liner (GCL)) was constructed on a coarse granular subgrade to contain hydrocarbon-contaminated soil and leachate. The soil was remediated after 4 years and the biopile was decommissioned. The liner was exhumed to assess the properties and performance of the GMB and GCL. There was no significant change in the GMB index properties. Although cobbles and coarse gravel of the subgrade had left indentations in the GMB, implying tensile strains that could impact long-term performance, there were no holes. There was significant variability in the hydration of the GCL (from 10% to 220%) and in the underlying subgrade soil water content (from 5% to 30%). This reflects the complexity of the subgrade and groundwater flow in the Antarctic environment. The exhumed GCL specimens had low hydraulic conductivity (1 × 10−11 to 7 × 10−11 m/s) at 13 kPa. Soil samples from below the composite liner showed no detectable hydrocarbons and confirmed no migration through the barrier. It is concluded that the composite barrier contained the leachate and biopile soil over the 4 years in service in the extreme Antarctic conditions.

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