Landfill2015. Advantages of Geosynthetics over Natural Materials in Landfills with Composite Liner Systems. Kent von Maubeuge.

Transcription

1 Advantages of Geosynthetics over Natural Materials in Landfills with Composite Liner Systems Kent von Maubeuge Main author Andy Post Co-author, presenter Stephan Westhus Co-author

2 Landfill TOP Liner with Geosynthetics Geocomposite Gas Drain Geosynthetic Clay Liner Geomembrane Geogrid Geocomposite Draina

3 General Advantages of Geosynthetics: direct material cost savings airspace savings reduction of excavation volumes faster installation rates possibility of steeper slope applications

4 Requirements for steep capping sealing systems Slope Geometry 35

5 Requirements for steep capping sealing systems Design of Sealing System (Original) Mineral layers / GM Cover Soil, t 1 m Grain Filter, t = 20 cm Drainage Layer, t = 30 cm (Gravel 16/32 mm) Sand Protection Layer, d = 10 cm HDPE-GM (t = 2.5 mm) Compacted Clay Liner (CCL), t = 50 cm d = 2.10 m

6 Requirements for steep capping sealing systems 50 cm CCL installation and compaction? 30 cm Gravel 16/32 mm?

7 Requirements for steep capping sealing systems Cover Soil, t 150 cm Cover Soil, t 70 cm Geogrid (Uniaxial, F k = 400 kn/m) Geos. Drainage Layer HDPE Geomembrane (textured) GCL

8 Requirements for steep capping sealing systems Anchor trench for load transfer Pay attention to frictional forces in the shear planes (critical shear plane)! d G 4 G 2 G 1 T G T R1,u E a G 32 G 31 L 2 L 4 T 32,o/u T 31,o/u Dichtungssystem Geogitter L 32 L 31 L 1

9 Requirements for steep capping sealing systems Alternative to anchor trench Plateau Slope

10 However: the correct selection of the product is crucial the proper installation of the product is decisive Poor selection or installation can have the effect of negating the economic and technical benefits focus mainly on GCLs and the recent development of multicomponent GCLs

11 GCLs versus CCLs in Landfill Caps Leakage Leakage through a needle-punched GCL Darcy's Law states that leakage may be expressed as Q = k x i x A, where Q = total liner leakage in m³/ha/day k = 1.5 x E-11m/s (@ 200kPa i = Gradient = (hydraulic head + GCL thickness)/liner thickness i = (300mm + 10mm)/10mm = 31 A = 1 ha = 10,000m² Q = 1.5 x E-11m/s x 31 x 10,000m² x (60s x 60min x 24hours) = 0.4 m³/ha/day Leakage Through Compacted Clay Liner Again, Q = k i A, where Q = total liner leakage in m3/ha/day k = 1 x E-9m/s i = (hydraulic head + liner thickness)/liner thickness = ( )/50 = 1.6 A = 1ha = 10,000m² Q = 1 x E-9m/s x 1.6 x 10,000m² x (60s x 60min x 24hours) = 1.38 m³/ha/day

12 Permeability Variations in a Compacted Clay Liner (Rowgowski, 1986) 1 x 10-7 m/s 1 x 10-8 m/s 1 x 10-9 m/s 1 x m/s 10 m 22 m

13 In-Situ Testing of Compacted Clay (Germany) Degree of efficiency of 3 CCLs at the hazardous waste dump site Hamburg-Georgswerder, test fields S1, S3 und F1 (capping system) Precipitation and percolation through CCL [mm] % 90% 80% 70% 60% 50% 40% Degree of efficiency [%] precipitation seepage flow S3 seepage flow F1 seepage flow S1 effectivity S3 effectivity S1 effectivity F1

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15 Powder has less air space than granular bentonite NAUE GmbH & Co. KG, Espelkamp, Germany Kent von Maubeuge NAUE GmbH & Co. KG, Espelkamp, Germany Kent von Maubeuge Therefore powder bentonite closes during the hydration period air space quicker than granular bentonite.

16 Conclusion in the GSI Report

17 General Advantages of GCLs versus CCLs: take up less airspace resistant to freeze/thaw and wet/dry cycles can be installed quicker at substantially lower costs reduce on site QC/QA offer at least equivalent hydraulic characteristics

18 Introduction Coated GCLs In all industries we improve products and add safety factors

19 Multi-Component GCLs So we decided to give the clay geosynthetic barrier an additional barrier with add-on-value. multicomponent GCL, n - GCL with an attached film, coating, or membrane decreasing the hydraulic conductivity or protecting the clay core or both

20 Manufacturing Schematic Needle-punched GCL Sodium Bentonite Geotextile Roll Nonwoven Geotextile Roll Back Lights Finished GCL Roll Bentonite Deposition Needlepunching Boards Coating Needle Detector

21 Coating The Add-on Value Example coating solution: Coating with HDPE Fibres are integrated into the coating through the melting process GCL Coated Ensuring a long-term bond The consequence: Safe slopes

22 Comparison lamination vs coating : lamination Bentofix X2 coating Resin PE PE (DIBt quality) Thickness approx. 0.1mm approx. 0.2mm upto 1mm Resistance vs damage very low good Peel very low very good Interface friction very low, very good, (against GBR-C) bonded in rows entirely attached 22

23 Stormwater Retention Pond, Lederhose, Germany

24 Stormwater Retention Pond, Lederhose, Germany

25 Stormwater Retention Pond, Lederhose, Germany

26 Stormwater Retention Pond, Lederhose, Germany Completed filled stromwater retention pond

27 Project Water Storage Application Overview of finalised project, Reden, Germany

28 Project Water Storage Application Coated GCL in a Pond Application, Reden, Germany

29 Millar Road Landfill, Australia GCL placement - 70,000 m² coated Bentofix X2

30 Millar Road Landfill, Australia

31 Current project in RSA: Klerksdorp Landfill

32 Advantages of Multi-component GCLs 1. Resistance against desiccation 2. Enhanced chemical resistance 3. Reduction of root penetration 4. Gas, radon barrier 5. hydraulic conductivity improvement 6. Improves additionally the good bentonite erosion stability at high water pressures and gravel soils Drainage level layer solid waste 2, 3, 6 1, 5 4

33 The GCL IQ Design Manual

34 The GCL IQ Design Manual

35 All the News in 2 Minutes Conclusions In general look at design issues when specifying a GCL Coated GCLs are the next generation and opens a new range of applications without replacing the current GCL types but improving them A Coating does not replace a geomembrane. Multicomponent clay geosynthetic barriers bring add-on values On-site quality control is important

36 Thank you for your attention. Any questions? Kent von Maubeuge Main author Andy Post Co-author, presenter Stephan Westhus Co-author