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Developing an “engineering approach” to design and selection of lining systems for irrigation canals. Part 1 - Analysing results of long term trials to.

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Presentation on theme: "Developing an “engineering approach” to design and selection of lining systems for irrigation canals. Part 1 - Analysing results of long term trials to."— Presentation transcript:

1 Developing an “engineering approach” to design and selection of lining systems for irrigation canals. Part 1 - Analysing results of long term trials to understand failure modes of canal lining systems. - Geosynthetic Consulting - Third Party Geomembrane CQA 2012 IAL Conference Adelaide By Nick Kastoumis BEng Civil Geosynthetics Consultant 1

2 1.Why do we need this presentation ? - Geosynthetic Consulting - Third Party Geomembrane CQA The size of water conservation expenditure is huge A lot of systems on the market – how do we assess them? Long service life requirements + 25yrs Conserving water is vital - getting it wrong - is very costly 2 Developing an “engineering approach” to design and selection of lining systems for irrigation canals

3 2.The objectives of this presentation – 5 goals - Geosynthetic Consulting - Third Party Geomembrane CQA 1.Educate decision makers on the body of knowledge available 2.Identify forces in canals and liner failure mechanisms - through analysis of these trials 3.Prompt designers and decision makers to consider these forces when selecting a lining system 4.Call out to other organisations to share experiences with canal lining 5.Find funding for research into quantifying the forces and developing an engineering approach to canal lining design 3 Developing an “engineering approach” to design and selection of lining systems for irrigation canals

4 3.The 2 main reports that were looked at - Geosynthetic Consulting - Third Party Geomembrane CQA – Deschutes Canal Lining Demonstration Project; USBR – Evaluation of canal lining projects Rio Grande; TWRI Also considered 2004 – Open Channel Seepage and Control – Guidelines by ANCID o Done in Australia o 3 year period of trials o Installation procedures were assessed o Long term durability was not assessed – would like to follow up with these irrigators to get updates on performance !! Performance of plastic canal liners – PVC and HDPE 4 Developing an “engineering approach” to design and selection of lining systems for irrigation canals

5 Deschutes canal lining Demonstration Project - Geosynthetic Consulting - Third Party Geomembrane CQA Funded by USBR – United States Bureau of Reclamation 34 different lining systems were trialled, installed from 1991 o exposed membranes (16) o Armour/covered systems (11) o Spray ons (7) Lining systems were evaluated/followed up During installation 7yrs on in the yr Report 10yrs on in the yr Report 2011 I have ed the irrigations districts for feedback on performance Some 20yr old coupon samples have been taken and tested in Developing an “engineering approach” to design and selection of lining systems for irrigation canals

6 Deschutes canal lining Demonstration Project - Geosynthetic Consulting - Third Party Geomembrane CQA 6 Developing an “engineering approach” to design and selection of lining systems for irrigation canals

7 – Evaluation of Canal Lining Projects in Rio Grande valley - Geosynthetic Consulting - Third Party Geomembrane CQA Conducted by TWRI – Texas Water Research Institute Two stage of trials and reports were published TR353 – 2009 Report o 6 different liners were installed in 1999 o PET, PVC, PP, EIA-R, EPDM, PU o Performance was evaluated after 10yrs TR412 – 2011 Report o Follow up on previously evaluated liners from 2009, now 12yrs old o New liners were trialled, TPO-R, EPDM-R, PP-R 7 Developing an “engineering approach” to design and selection of lining systems for irrigation canals

8 1999 – Evaluation of Canal Lining Projects in Rio Grande valley - Geosynthetic Consulting - Third Party Geomembrane CQA 8 Developing an “engineering approach” to design and selection of lining systems for irrigation canals

9 6.Identifying forces on canal liners - Geosynthetic Consulting - Third Party Geomembrane CQA 9 1.Point out an anomaly We are good at designing liquid containment o Dams, ponds, reservoirs, lagoons, even landfills o We usually get some leaks o Complete system failure is rare When it comes to canal liners we have much more failures even complete removal But its not some “aggressive liquid” Its ONLY WATER!!!!! Developing an “engineering approach” to design and selection of lining systems for irrigation canals

10 Question: Why do we continue to design canal liners as if they are pond liners ? - Geosynthetic Consulting - Third Party Geomembrane CQA 10 Developing an “engineering approach” to design and selection of lining systems for irrigation canals

11 7.Forces acting on canal liners vs. pond liners - Geosynthetic Consulting - Third Party Geomembrane CQA 11 Forces to resistLiquid containmentLiquid transportation Dams, ponds, reservoirs, lagoonsCanals, channels UV and weathering Exposed areas must resist UV and weathering Exposed areas must resist UV and weathering Hydrostatic forces Can be very deep, >3m so puncture is one of the main failure mechanism of containment liners Generally shallow < 3m so subgrade puncture resistance is not important to consider Hydrokinetic forces Generally only considered for the inlet and outlet structures, spillways The main failure mechanism of flexible canal liners Mechanical damage Can be avoided by fencing or armouring of the liner and or prompt repairs Can be avoided by fencing or armouring of the liner and or prompt repairs Abrasion Generally only considered for the inlet and outlet structures, spillways Must be considered for the life of the lining system, including any armour or coverings Developing an “engineering approach” to design and selection of lining systems for irrigation canals

12 The moment when the light bulb went on - Geosynthetic Consulting - Third Party Geomembrane CQA 12 Developing an “engineering approach” to design and selection of lining systems for irrigation canals

13 8.All of these Canal lining reports – support tearing and abrasion as the most important failure mechanisms of canal liners - Geosynthetic Consulting - Third Party Geomembrane CQA 13 Developing an “engineering approach” to design and selection of lining systems for irrigation canals

14 9.How did the exposed liners go ? - Geosynthetic Consulting - Third Party Geomembrane CQA 14 Developing an “engineering approach” to design and selection of lining systems for irrigation canals

15 How did the exposed liners go ? - Geosynthetic Consulting - Third Party Geomembrane CQA 15 This is puncture - Hypalon shows excellent puncture resistance. The puncture has NOT progressed for 4 yrs. pg. 94 Deschutes 7yr report Developing an “engineering approach” to design and selection of lining systems for irrigation canals

16 - Geosynthetic Consulting - Third Party Geomembrane CQA 16 But, unable to resist tearing Hypalon suffers severe Tear Damage: 0.9mm Hypalon + geotextile 7yrs old – pg. 96 Deschutes 7yr report Developing an “engineering approach” to design and selection of lining systems for irrigation canals

17 - Geosynthetic Consulting - Third Party Geomembrane CQA 17 This is NOT a PUNCTURE, this is a TEAR - This is NOT a PUNCTURE, this is a TEAR - Severe Tear Damage: 2mm textured HDPE after 6 ½ yrs. service – pg. 87 Deschutes 7yr report Developing an “engineering approach” to design and selection of lining systems for irrigation canals

18 - Geosynthetic Consulting - Third Party Geomembrane CQA 18 This is NOT a PUNCTURE, this is a TEAR This is NOT a PUNCTURE, this is a TEAR Severe Tear Damage: 1.14mm unreinforced EPDM rubber, less than 8yrs service – pg. 16 TWRI Report 2008 Developing an “engineering approach” to design and selection of lining systems for irrigation canals

19 Life prediction of exposed liners – be careful !! - Geosynthetic Consulting - Third Party Geomembrane CQA 19 SectionMaterialAge Visual Assessment Physical Property Testing Service Life Prediction A~3 80-mil Textured HOPE 10 yearsExcellent Elongation down 90% OIT down 30% years A-4 30-mil PVC with Bonded Geotextile 10 yearsVery Good Tensile up 30% Modulus up 140% Elongation down 70% years A-5 45-mil Hypalon10 yearsFair to PoorTear strength down 60%10-15 years A-6 36-mil Hypalon10 yearsFairTear strength down 60%10-15 years mil EPDM2 yearsExcellent Elongation down 30% Tear strength down 50% years mil LLDPE2 yearsExcellent Tensile down 10% Tear Strength down 10% years Table 13.-Coupon Testing of Exposed Geomembrane test sections. From Deschutes 10yr Report pg 191

20 Developing an “engineering approach” to design and selection of lining systems for irrigation canals Life prediction of exposed liners – be careful !! - Geosynthetic Consulting - Third Party Geomembrane CQA 20 Table of lining performance. TWRI Report TR412 pg 13

21 Developing an “engineering approach” to design and selection of lining systems for irrigation canals Life expectancy vs Tear, is there a correlation ? - Geosynthetic Consulting - Third Party Geomembrane CQA 21

22 10.How did the spray on liners go? - Geosynthetic Consulting - Third Party Geomembrane CQA 22 Developing an “engineering approach” to design and selection of lining systems for irrigation canals

23 How did the spray on liners go? - Geosynthetic Consulting - Third Party Geomembrane CQA 23 Some points on membranes spray applied to geotextile I have worked with some spray on membranes and even failed at developing my own The main problem is LACK OF SATURATION The liquid is made up of 2 parts o Solvent – the carrier o Solids – the final membrane 2 main plains of failure o Bonding to substrate – does not occur o Solvent penetrates geotextile but solids remain on the top o No solids saturate the geotextile. The result is  Thin bonding interface between film and geotextile  Porous surface of 3D geotextile Solids must saturate the geotextile to take advantage of its mechanical strength !!

24 Developing an “engineering approach” to design and selection of lining systems for irrigation canals 11.How did the covered liners go? - Geosynthetic Consulting - Third Party Geomembrane CQA 24 There were 4 types of cover 1.Unreinforced shotcrete 2.Reinforced shotcrete 3.Grout mattresses 4.Soil – we wont cover this here

25 Developing an “engineering approach” to design and selection of lining systems for irrigation canals Unreinforced shotcrete - main failure mechanism of unreinforced shotcrete was cracking – typical of local settlements and inconsistent thickness - Geosynthetic Consulting - Third Party Geomembrane CQA 25 Photograph 122.— Importance of Tensile strength. Close up of 300mm diameter hole in shotcrete lining. Shotcrete is less than 25mm thick.

26 Developing an “engineering approach” to design and selection of lining systems for irrigation canals Reinforced shotcrete - main failure mechanism of fibre reinforced shotcrete was cracking – typical of shrinkage and inconsistent thickness - Geosynthetic Consulting - Third Party Geomembrane CQA 26 Importance of flexibility. Transverse crack is running all the way across the channel

27 Developing an “engineering approach” to design and selection of lining systems for irrigation canals Grout Mattresses - main failure mechanism of grout mattresses is abrasion - Geosynthetic Consulting - Third Party Geomembrane CQA 27 Photograph 103.— Severity of abrasion in canals. Geotextile is deteriorated by abrasion. Note that some of the grout bricks are also missing in this area.

28 Developing an “engineering approach” to design and selection of lining systems for irrigation canals 12.In summary - Geosynthetic Consulting - Third Party Geomembrane CQA 28 Next time you consider a lining system for a canal, past experience shows that to meet long term durability requirements 1.Exposed membranes – need to be assessed for o abrasion and tearing strength o UV and weathering o For the whole service life !! 2.Amor and cover systems have issues too Shotcrete lacks flexibility so a designer must consider o subsurface drainage o Long term differential settlement Grout mattresses must consider o long term abrasion 3.Spray on membranes – are yet to be proven as long term effective lining systems

29 Developing an “engineering approach” to design and selection of lining systems for irrigation canals Thank you - Geosynthetic Consulting - Third Party Geomembrane CQA 29 Any questions ?


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