ACI 506 5R-2009 Guide for Specifying Underground Shotcrete《确定地下喷浆混凝土的指南》.pdf

1、ACI 506.5R-09Reported by ACI Committee 506Guide for SpecifyingUnderground ShotcreteGuide for Specifying Underground ShotcreteFirst PrintingAugust 2009ISBN 978-0-87031-335-6American Concrete InstituteAdvancing concrete knowledgeCopyright by the American Concrete Institute, Farmington Hills, MI. All r

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10、d together in the annually revised ACI Manual ofConcrete Practice (MCP).American Concrete Institute38800 Country Club DriveFarmington Hills, MI 48331U.S.A.Phone: 248-848-3700Fax: 248-848-3701www.concrete.orgACI 506.5R-09 was adopted and published August 2009.Copyright 2009, American Concrete Institu

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12、em or device, unless permission in writingis obtained from the copyright proprietors.506.5R-1ACI Committee Reports, Guides, Manuals, and Commentariesare intended for guidance in planning, designing, executing,and inspecting construction. This document is intended for theuse of individuals who are co

13、mpetent to evaluate thesignificance and limitations of its content and recommendationsand who will accept responsibility for the application of thematerial it contains. The American Concrete Institute disclaimsany and all responsibility for the stated principles. The Instituteshall not be liable for

14、 any loss or damage arising therefrom.Reference to this document shall not be made in contractdocuments. If items found in this document are desired by theArchitect/Engineer to be a part of the contract documents, theyshall be restated in mandatory language for incorporation bythe Architect/Engineer

15、.Guide for Specifying Underground ShotcreteReported by ACI Committee 506ACI 506.5R-09This document provides a guide for owners, contractors, designers, andtesting, specifying, and inspection organizations engaged in the application ofshotcrete for underground support. The guide provides general info

16、rmation forthe selection of constituent materials, and methods to proportion shotcrete.Typical methods of batching, mixing, and handling of proportionedshotcrete materials are detailed along with shotcrete placement methodsand equipment.Keywords: acceptance criteria; batching; inspection; methods of

17、 payment;mine and tunnel support systems; mixing and placement equipment; mixtureproportioning; preconstruction and construction testing; quality assurance;quality control; safety; shotcrete; shotcrete application.CONTENTSChapter 1Introduction and scope, p. 506.5R-31.1Introduction1.2ScopeChapter 2No

18、tation and definitions, p. 506.5R-52.1Notation2.2DefinitionsChapter 3Submittals, p. 506.5R-63.1Contracts3.2Recommended specificationsChapter 4Materials, p. 506.5R-84.1Accelerators4.2Recommended specificationsJon B. Ardahl Martin Gendreau Jeffrey L. Novak Raymond C. Schallom, III*Lars F. Balck, Jr. J

19、ill E. Glassgold H. Celik Ozyildirim Raymond J. SchutzMichael Ballou*Warren L. Harrison*Harvey W. ParkerPhilip J. SeabrookNemkumar Banthia Merlyn Isaak Ryan E. Poole W. L. Snow, Sr.Chris D. BreedsMarc Jolin*John H. Pye*Curtis WhitePatrick O. Bridger Kristian Loevlie*James A. Ragland Peter T. YenWern

20、-Pink Nick Chen*Mark R. Lukkarilia Venkataswamy Ramakrishnan George Yoggy*Jean-Franois Dufour*Gregory S. McKinnon Michael Rispin*Christopher M. ZyndaJohn R. Fichter*Subcommittee members who produced this report.Subcommittee Co-chairs who produced this report.The Committee acknowledges Bill Edgerton,

21、 Janice Lindell, J. Denis ODonnel, Sr., and Fred Sherrill for their contributions to this report.Peter C. Tatnall*ChairLawrence J. TottenVice ChairDudley R. Morgan*Secretary506.5R-2 ACI COMMITTEE REPORTChapter 5Anchorage and reinforcement,p. 506.5R-115.1Composite support systems5.2Shotcrete with pat

22、tern rock bolts or anchors5.3Shotcrete with rock bolts, friction stabilizers, andwelded wire reinforcement5.4Fiber-reinforced shotcrete5.5Shotcrete with lattice girders5.6Shotcrete with conventional steel sets5.7Recommended specificationsChapter 6Materials handling and storage,p. 506.5R-156.1General

23、6.2Temperature considerations6.3Recommended specificationsChapter 7Shotcrete mixture proportioning,p. 506.5R-167.1General7.2Mixture proportions by trial batching or historicaldata submissions7.3In-place mixture proportions7.4Dry-mix shotcrete7.5Wet-mix shotcrete7.6Recommended specificationsChapter 8

24、Performance requirements,p. 506.5R-208.1General8.2Water-cementitious material ratio8.3Air content8.4Slump8.5Boiled absorption and permeable voids8.6Compressive strength8.7Flexural strength and toughness8.8Early-age strength8.9Other tests8.10Bond strength8.11Explosive spalling protection8.12Recommend

25、ed specificationsChapter 9Quality assurance and quality control,p. 506.5R-239.1General9.2Recommended specificationsChapter 10Preconstruction trials and testing,p. 506.5R-2410.1General10.2Recommended specificationsChapter 11Construction acceptance inspection, p. 506.5R-2711.1General11.2Acceptance ins

26、pection11.3Specific inspection and test quality controlrequirements for underground shotcrete11.4Cold placement conditions11.5Hot placement conditions11.6Shotcrete acceptance and rejection11.7Recommended specificationsChapter 12Batching, mixing, and supply,p. 506.5R-3112.1Handling of bulk bin-bags12

27、.2Quality control considerations12.3Recommended specificationsChapter 13Placing equipment, p. 506.5R-3413.1Pumps13.2Guns13.3Nozzle systems13.4Remote-controlled spraying13.5Recommended specificationsChapter 14Auxilliary equipment, p. 506.5R-3714.1Air supply14.2Recommended specificationsChapter 15Safe

28、ty, p. 506.5R-3915.1General15.2Underground safety15.3Required personal safety equipment15.4View of shotcrete work15.5Communications15.6Nonpersonal safety equipment15.7Recommended specificationsChapter 16Preparation for shotcreting and groundwater control, p. 506.5R-4116.1General16.2Factors affecting

29、 shotcrete adhesion and bonding16.3Surface preparation16.4Groundwater16.5Recommended specificationsChapter 17Ground reinforcement installation,p. 506.5R-4317.1General17.2Rock bolt installation17.3Steel set installation17.4Lattice girder installation17.5Recommended specificationsChapter 18Shotcrete a

30、pplication, p. 506.5R-4418.1Methods used to control thickness18.2Cover, alignment, and tolerance18.3Recommended specificationsChapter 19Curing and protection, p. 506.5R-4619.1General19.2Protection19.3Recommended specificationsChapter 20Shotcrete for repair and rehabilitation of underground structure

31、s, p. 506.5R-4720.1General20.2Materials selection20.3Shotcrete placement methods for repairGUIDE FOR SPECIFYING UNDERGROUND SHOTCRETE 506.5R-320.4Quality assurance requirements for rehabilitationof underground structures20.5Repair considerations20.6Recommended specificationsChapter 21Measurement and

32、 payment,p. 506.5R-5021.1Basis for payment21.2Recommended specificationsChapter 22References, p. 506.5R-5122.1Referenced standards and reports22.2Cited referencesCHAPTER 1INTRODUCTION AND SCOPE1.1IntroductionShotcrete, the method of spraying concrete onto a surface,is ideally suited for the support

33、and construction of under-ground excavations in earth and rock structures. The pneumaticprojection of shotcrete onto a surface at high velocityprovides specific quality enhancements that interact with theground surface and prepared substrates, providing superiorbond characteristics; increased densit

34、y; and resultant strength,durability, and toughness. These qualities are desirable inground support and lining applications. In North America,shotcrete is conventionally defined as pneumatically appliedconcrete, while in Europe it is more commonly referred to assprayed concrete.Although concrete pla

35、ys a very important role in under-ground construction, shotcrete has many advantages overconcrete. Final concrete linings for tunnel and undergroundstructures are typically composed of cast-in-place or precastconcrete sections that provide a structurally sound and durablesubsurface infrastructure. T

36、he principal disadvantage with thesesystems is that they are difficult to install during the excavationphase of tunnel construction. They require formwork orassembly systems that simply cannot be employed in tunnelopenings where the immediate concern is ensuring a safe andstable excavation. Accordin

37、gly, the cast-in-place lining is oftenplaced after excavation is complete, which results in a muchlonger time to complete the tunnel.In contrast, shotcrete in combination with other supportelements can provide early and effective ground support and,therefore, a means of ground control necessary for

38、safe,viable, and economic tunnel construction under a wide rangeof geological conditions.Shotcrete technology has been broadly developed throughoutthe construction industry over the last century. The evolutionof mining and civil tunneling methods has placed uniquedemands on the materials, equipment,

39、 and personnel thatcomprise current concepts of a shotcrete system for under-ground support. With this gradual evolution in technologyand trial and error, came acceptance, adaptation, and newmeans and methods of successful shotcrete application. Thedesign and placement of shotcrete underground is mu

40、chmore challenging than shotcreting above ground.Underground construction and shotcrete application areunique and very demanding. The primary focus is workersafety and the need to provide immediate and effectiveground support. Whereas the industry as a whole wouldaccept the performance associated wi

41、th the compressivestrength developed in shotcrete at 28 days, early 8-hour to 1-daystrength is critical to the performance of underground shotcrete.Much of the shotcrete is applied overhead to irregular tunnelprofiles immediately following blasting or other modes ofexcavation. Geological and groundw

42、ater conditions are notalways predictable; opening stability and rockfalls present aclear hazard to the shotcrete crew. Conditions may be suchthat the window available for shotcrete application isminutes or a few hours. The use of accelerating admixturesis a unique feature of underground shotcrete a

43、pplication inthat it provides a means of controlled and rapid strength gainimmediately following application.Tunnel or mining activities typically take place on acontinuous and cyclical basis. The process of excavation,muck removal or mineral extraction, and ground supportinstallation are repeated.

44、To be viable and acceptable, shotcreteapplication should be an integral part of the overall cycle.This requires that the shotcrete system as a whole be reliable,efficient, and effective.The underground environment can impose significantconstraints and demands on the batching, mixing, handling,and pl

45、acement of shotcrete. The unique logistical demandsassociated with underground shotcrete application mayrequire access to the underground work area via shaft, adit,or ramp, and the subsequent use of long and restrictivehaulage routes or dropping through a borehole or slickline.This frequently result

46、s in extended handling and dischargetimes. At any time, production can be disrupted, and shot-crete installation delayed or disrupted. This is particularlyproblematic if ground conditions deteriorate and the demandfor shotcrete as ground support becomes more critical.Finally, the environment is host

47、ile for worker safety, effi-ciency, and quality control, as well as for quality shotcreteplacement and curing conditions. Figures 1.1 to 1.3 illustratetypical conditions at the heading of tunnels and mines.These types of problems have led to specifically designedsystems for batching and handling of

48、shotcrete materials,admixtures, and placement equipment. These systemsrequire significant investment not only in terms of capital,but also in providing experienced supervisory shotcrete andproduction personnel. Training and supervision have led toimprovements in the quality and consistency of shotcr

49、ete inunderground shotcrete applications. The consequences ofdeficient shotcrete in any ground support application areobvious. Quality assurance, quality control, and the associatedinspection and testing activities are equally important inachieving a successful shotcrete program.A major task faced by the underground shotcrete industryis the ability to demonstrate to owner, designer, specifier,and inspection and testing personnel that high-quality shotcretecan be produced co