1、2023 China-Europe Trenchless Technology ConferenceJinan,China,2024/03/21On the Advances of Trenchless TechnologiesKeh-Jian ShouChairman,International Society for Trenchless Technology(ISTT)CONTENTSI.Introduction Trenchless Technologies II.The Trenchless Rehabilitation Method-CIPP1.About ISTTThe Inte

2、rnational Society for Trenchless Technology(ISTT)was established in September 1986 as a United Kingdom private limited company with the object to advance the science and practice of trenchless technology for the public benefit.and to promote education,training,study and research in the said science

3、and practice for the public benefit,and to publish the useful results of the same.In the years that followed,ISTT affiliated with regional trenchless societies located throughout the world to advance these objectives globally.ISTT has 28 Affiliated Societies.All recorded members of an Affiliated Soc

4、iety are members of ISTT.In addition to Affiliated Society members,ISTT has a limited number of members who reside in regions where no Affiliate Society exits.I.Introduction Trenchless Technologieshttps:/ Technologies A set of technologies for the remote installation,rehabilitation and repair of uti

5、lities,pipelines and small tunnels-linked by their lack of need for digging a continuous trenchlack of need for digging a continuous trenchfor the installation of new pipes or the repair of old pipesWhat is Trenchless Technology(NoWhat is Trenchless Technology(No-Dig)?Dig)?Problems with Open Cut Tra

6、ffic congestion growing Street pavement damage Cost of surface restoration Direct/indirect business loss CO2emissionTrenchless Technology provides modern solutions to underground utility problemsUnderground Construction TechniquesUnderground Construction TechniquesCommon trenchless technologies for

7、inspection and condition assessment include CCTV,laser,sonar,flow CCTV,laser,sonar,flow monitoring,gas monitoring and leak detectionmonitoring,gas monitoring and leak detection.i.Condition Assessmenti.Condition Assessmentii.New Installationii.New InstallationAgeing infrastructure and increasing popu

8、lations have resulted in the development of pipe rehabilitation as a fundamental concern in the maintenance of essential underground services.This category encompasses methods of restoring integrity to defective pipelines and underground structures and extending their operational life.Renovation is

9、a method in which all or part of the original fabric of a pipeline is incorporated and its current performance improved.Replacement is the rehabilitation of an existing pipeline system by the installation of a new system,either on or off the existing line without incorporating the original fabric.Re

10、pair entails the rectification of local damage.iii.Rehabilitationiii.RehabilitationRehabilitation is divided into three sections;renovationrenovation,replacementreplacement and repairrepair.replacementreplacementiii.Rehabilitationiii.Rehabilitationis divided into three sections;renovationrenovation,

11、replacementreplacement and repairrepair.renovationrenovation3.ISTT Technical Guidelineshttps:/ No Dig 2025,Vancouver,CanadaInternational No Dig 2026,Auckland,New ZealandISTT Educational Webinar 2022 II.The Trenchless Rehabilitation Method-CIPP1.What is CIPP2.The applications of CIPP3.The design anal

12、ysis of CIPP4.Further development and considerationISTT Educational Webinar 2022 1.What is Cured In Place Pipe(CIPP)https:/ Educational Webinar 2022 Cured in Place pipe(CIPP)can be used to rehabilitate sanitary sewers,storm drains and pressure pipelines for water,gas and process effluents.Circular p

13、ipe from 100-2,700mm and a variety of noncircularpipe such as egg shapes,ovoids,and box culverts can be lined.ISTT Educational Webinar 2022 Lining with CIPP removes the pipe from service for the duration of the installation and reinstatement process so overpumping or provision of an alternate source

14、 of supply may be necessary.Prior to lining,the pipe must be cleaned by jetting to remove corrosion debris and detritus.Protruding lateral connections also must be removed.Local repairs may be required where the existing pipe is substantially deformed or damaged.Lined water mains must be disinfected

15、 before returning to service.ISTT Educational Webinar 2022 CIPP liners of non-woven polyester felt or fibre reinforced fabric are manufactured to fit the host pipe.The liners are impregnated with a polymer resin,which when cured(by heat or light)will form a close fitting liner pipe within the host p

16、ipe.The liner may be designed with sufficient thickness when cured to sustain the loads imposed by external groundwater and internal service pressure,and soil and traffic over the pipe.ISTT Educational Webinar 2022 ISTT Educational Webinar 2022 The liner is thoroughly saturated with polyester,vinyl

17、ester epoxy or silicate resin using vacuum,gravity or other applied pressure.The resin includes a chemical catalyst or hardener to facilitate curing.The outermost layer of the liner tube is coated with a polymer film to protect the liner during handling and installation.The impregnated liner may be

18、chilled for transportation to maintain stability until installed.ISTT Educational Webinar 2022 CIPP liners may be installed using the inversion method as shown above.The inversion method employs a scaffold tower or pressure vessel to apply air or water pressure to turn the liner inside out and push

19、it along the host pipe.CIPP liners also may be installed by winching into place through a manhole or specially prepared access point and inflated to come into close contact with the circumference of the existing pipe.The liner is restrained in any intermediate manhole.CIPP liners may be inflated or

20、inverted with air or water pressure.ISTT Educational Webinar 2022 Lengths installed may vary from short sections over a joint or defect,to full length linings typically 30-150m.Lengths of up to 900m have been installed in a single shot.The resin impregnated liner may cure at ambient temperature but

21、the cure is more usually accelerated by application of heat by circulation of inversion water through a boiler,blending steam with inflation air or by pulling through a UV light train.A sample of the CIPP may be taken from pipe ends or from a mould cured under the conditions of manufacture for testi

22、ng and verification that the liner met performance specifications.ISTT Educational Webinar 2022 ISTT Educational Webinar 2022 2.Applications of CIPPDeformationCorrosionCrackBreakageJoint SeparationThe Consequences of Void,Soil Penetration,Water Inflow,etc.ISTT Educational Webinar 2022 ISTT Education

23、al Webinar 2022 ISTT Educational Webinar 2022 ISTT Educational Webinar 2022 3.Design Analysis Numerical analysis such as FEA can be used to simulate different geometries of underground pipelines,i.e.straight line and curved pipeline,damaged by corrosion and the performance of the Cured-In-Place-Pipe

24、(CIPP).The analysis results can be used to confirm that CIPP can reinforce the damaged pipe by reducing the stress concentration and reducing the differential displacement.The design of the CIPP liner could be further optimized in terms of its design,i.e.,thickness and material properties.ISTT Educa

25、tional Webinar 2022 Straight-line caseCurved caseISTT Educational Webinar 2022 Typical pipe diameters were chosen based on Chinese National Standard(CNS)4626G3111 of Taiwan(2012),that defines the specifications of carbon steel pipes foroperation under pressure.The size of the modeled soil mass diffe

26、red according to the size of the pipes.Thedistances from the left and right boundaries of the soil mass to the center of the pipewere about six times the diameter of the pipe.The distances from the bottom boundaryof the soil mass to the center of the pipe were about five times the diameter of the pi

27、pe.Both the soil and the pipe were 10m in length.Detailed dimensions of the models are listed in Table 2.CaseShape of pipeArea of Damage(mm2)Location of Damage1Straight-line2826TopCurved15133Inner and outer side2Straight-line7850TopCurved55296Inner and outer sideCurved-small18432Inner sideISTT Educa

28、tional Webinar 2022 Before liner installationThe stress fields before and after the installation of liner for the straight-line case with internal pressure 588.4 kPa.After liner installationISTT Educational Webinar 2022 The stress and displacement at the void center before and after the installation

29、 of liner for the straight-line case with surface loadingISTT Educational Webinar 2022 The stress fields and the stress at the void center before and after the installation of liner for the curved case without internal pressureISTT Educational Webinar 2022 The stress at the void center before and af

30、ter the installation of liner for the curved case with surface loading.ISTT Educational Webinar 2022 The stress fields and the stress at the void center before and after the installation of liner for the curved case with different liner deformation propertyISTT Educational Webinar 2022 Copyright 201

31、9 IATT.All rights reserved.Full or partial reproduction is prohibited.ISTT Educational Webinar 2022 ISTT Educational Webinar 2022 From the parametric study for the corrosion damaged buried pipe,itshows that the thickness of the pipe wall in the most critical factor.A larger diameter to thickness rat

32、io(D/t),i.e.,a small pipe wallthickness,resulted in a greater increase of stress and displacementat the corrosion void.And the increase in stress and displacementwas positively correlated to the size of the void.The results also suggest that the liner could be designed toeconomicallyoptimizeitsthick

33、ness.Inaddition,morecomprehensive analysis are necessary for the typical problemsabout the CIPP construction quality,such as the imperfect adhesionof the liner to the old pipe,etc.SummaryISTT Educational Webinar 2022 4.Further Development and Considerations Applications of CIPP for more complicated

34、scenarios Detailed considerations of the conditions,such as wrinkles,backfill,etc.The influence of the interface properties and material property contrast.Laboratory testing and numerical analysis can be applied to perform the design analysis of the above conditions and influence factor The design c

35、an be optimized based on the above design analysisISTT Educational Webinar 2022 Laboratory testing_CIPP for Connector The test specimens consisted of two 800-mm-long RCP pipes,arranged with 20mm separation distance,and then the liners were inserted by inversion.After the liner cured using hot water,

36、the specimens were cut accordingly.The CIPP liners were made of EP resin provided by Yutaifeng Company,Taiwan.The flexural and tensile strength of liner after curing meets the test requirements of ASTM D790 and ASTM D638.The thickness of liner is calculated according to ASTM F1216 specifications,and

37、 is 7.5mm after calculation.The preparation of test specimensISTT Educational Webinar 2022 Numerical model_CIPP for connector3.1 Mesh information and Boundary conditions.Mesh information：Three types of elements used in the numerical model:C3D8R for concrete and liner,R3D4 for load cell beam and lower bearing support,and T3D2 for steel cage.Total number of elements are 32,660.Boundary conditions：Bottom bearing supports were restrained in y direction,and the load cell beam was restricted in all directions except the y-axis.ISTT Educational Webinar 2022