ASTM D4553-2018 Standard Test Method for Determining In Situ Creep Characteristics of Rock.pdf

1、Designation: D4553 18Standard Test Method forDetermining In Situ Creep Characteristics of Rock1This standard is issued under the fixed designation D4553; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A

2、number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers the preparation, equipment, testprocedure, and data documentation for determining in situcreep characteristics

3、 of a rock mass using a rigid plate loadingmethod.1.2 This test method is designed to be conducted in an aditor small underground chamber; however, with suitablemodifications, this test could be conducted at the surface.1.3 The test is usually conducted parallel or perpendicular tothe anticipated ax

4、is of thrust, as dictated by the design load orother orientations, based upon the application.1.4 Flexible plate apparatus can be used if the anticipatedcreep displacement is within the tolerance of the travel of theflat jacks.1.5 UnitsThe values stated in inch-pound units are to beregarded as stand

5、ard. The values given in parentheses aremathematical conversions to SI units that are provided forinformation only and are not considered standard. Reporting oftest results in units other than inch-pound shall not be regardedas nonconformance with this standard.1.5.1 The gravitational system of inch

6、-pound units is usedwhen dealing with inch-pound units. In the system, the pound(lbf) represents a unit of force (weight), while the units formass is slugs. The slug unit is not given, unless dynamic (F =ma) calculations are involved.1.6 All observed and calculated values shall conform to theguideli

7、nes for significant digits and rounding established inPractice D6026, unless superseded by this test method.1.6.1 For purposes of comparing a measured or calculatedvalue(s) with specified limits, the measured or calculatedvalue(s) shall be rounded to the nearest decimal of significantdigits in the s

8、pecified limit.1.6.2 The procedures used to specify how data are collected/recorded and calculated in the standard are regarded as theindustry standard. In addition, they are representative of thesignificant digits that generally should be retained. The proce-dures used do not consider material vari

9、ation, purpose forobtaining the data, special purpose studies, or any consider-ations for the users objectives; and it is common practice toincrease or reduce significant digits of reported data to becommensurate with these considerations. It is beyond the scopeof these test methods to consider sign

10、ificant digits used inanalysis methods for engineering data.1.7 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety, health, and environmental practices and deter-m

11、ine the applicability of regulatory limitations prior to use.For specific precaution statements, see Section 8.1.8 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of I

12、nternational Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D653 Terminology Relating to Soil, Rock, and ContainedFluidsD3740 Practice for Minimum Requirements for AgenciesEngaged in

13、Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD4394 Test Method for Determining In Situ Modulus ofDeformation of Rock Mass Using Rigid Plate LoadingMethodD4403 Practice for Extensometers Used in RockD4879 Guide for Geotechnical Mapping of Large Under-ground

14、Openings in Rock (Withdrawn 2017)3D6026 Practice for Using Significant Digits in GeotechnicalData3. Terminology3.1 Definitions:1This test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.12 on Rock Mechanics.Current edition ap

15、proved July 1, 2018. Published August 2018. Originallyapproved in 1985. Last previous edition approved in 2008 as D4553 08, whichwas withdrawn January 2017 and reinstated July 2018. DOI: 10.1520/D4553-18.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Se

16、rvice at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.*A Summary of Changes section appears at the end of this standardCopyrigh

17、t ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International

18、 Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.13.1.1 For definitions of common technical terms used in thisstandard, refer to Terminology D653.3.2 Definitions of Terms Specific to This Standard:3.2.1 creepa time-dependent di

19、splacement of a platepushed into the surface of the rock by a constant normal load.It is not directly related with laboratory creep data because ofthe nonuniformity of stress within the rock mass underneaththe plate.3.2.2 displacementmovement of the rigid plate, grout pad,or rock in response to and

20、in the same direction as the appliedload.3.2.3 loadtotal force acting on the rock face.3.2.4 rigid plateplate with a deflection of less than 0.0005in. (0.0127 mm) from the center to the edge of the plate whenmaximum load is applied.4. Summary of Test Method4.1 Areas on two opposing faces of a test a

21、dit undergroundchamber are flattened and smoothed.4.2 A grout pad and rigid metal plate are installed againsteach face and a hydraulic loading system is placed between therigid plates.4.3 The two faces are rapidly loaded to the desired creepload, without shock, the load maintained, and the displacem

22、entof the plate measured as a function of time.5. Significance and Use5.1 Results of this test method are used to predict time-dependent deformation characteristics of a rock mass resultingfrom loading. It is a test that may be required depending onrock type or anticipated loads, or both.5.2 This te

23、st method may be useful in structural designanalysis where loading is applied over an extensive period.5.3 This test method is normally performed at ambienttemperature in the field, but equipment can be modified orsubstituted for operations at other temperatures.5.4 Results of this test method may b

24、e useful in verifyinglaboratory creep data and structural mathematical modelinganalyses.5.5 Creep characteristics are determined under a nonuni-form state of stress within the rock mass underneath the plate.5.6 If during a field investigation, time-dependent charac-teristics are detected, then an in

25、 situ creep test shall beperformed.NOTE 1The quality of the result produced by this standard isdependent on the competence of the personnel performing it, and thesuitability of the equipment and facilities used. Agencies that meet thecriteria of Practice D3740 are generally considered capable of com

26、petentand objective testing/sampling/inspection/etc. Users of this standard arecautioned that compliance with Practice D3740 does not in itself assurereliable results. Reliable results depend on many factors; Practice D3740provides a means of evaluating some of those factors.6. Interferences6.1 A co

27、mpletely inflexible plate used to load the rock faceis difficult to construct. However, if the plate is constructed asrigid as feasible, the rock face is smoothed, and a thin,high-modulus material is used for the pad, the error in themeasured displacements will be minimal.6.2 The rock under the load

28、ed area is generally nothomogeneous, as assumed in theory. The rock will respond tothe load according to its local deformational characteristics andorientation of discontinuities. The use of the average platedisplacement will mitigate this problem. If this creep test isperformed immediately after a

29、plate loading testTest MethodD4394, for instance, the results of the creep test will bedifferent than if it had been performed on virgin rock.7. Apparatus7.1 Surface Preparation EquipmentTest site preparationequipment shall include an assortment of excavation tools,such as drills and chipping hammer

30、s. Blasting shall not beallowed during a preparation of the test site.7.2 Instrumentation:7.2.1 Displacement Measuring EquipmentFor displace-ment measurements, dial gauges or linear variable differentialtransformers (LVDTs) are generally used. An accuracy of atleast 60.0001 in. (0.0025 mm), includin

31、g the error of thereadout equipment, and a sensitivity of at least 0.00005 in.(0.0013 mm) is recommended. Errors in excess of 0.0004 in.(0.01 mm) can invalidate test results when the modulus of rockmass exceeds 5 106psi (3.5 104MPa).7.2.2 Load CellA load cell is recommended to measurethe load on the

32、 bearing plate. An accuracy of 61000 lbf (4.4kN) or 65 % of maximum test load, including errors intro-duced by the readout system, and a sensitivity of at least 500lbf (2.2 kN) are recommended. Long-term stability of theinstrumentation system shall be verified throughout the test.7.3 Loading Equipme

33、nt:7.3.1 Hydraulic Ram or Flat JacksThis equipment, ca-pable of applying and maintaining desired pressures to within63 %, is usually used to apply the load.Aspherical bearing ofsuitable capacity shall be coupled to one of the bearing plates.If a hydraulic ram is used, the load shall be corrected toa

34、ccount for the effects of ram friction. If flat jacks are used, thejacks shall not be expanded beyond a thickness equal to 3 % ofthe diameter of a metal jack and care shall be taken that thejacks do not operate at the upper end of their range.7.3.2 The loading equipment includes a device for applyin

35、gthe load and the reaction members, usually thick-walledaluminum or steel pipes, to transmit the load.7.3.3 Load Maintaining EquipmentEquipment such as aservo-control system or air over hydraulic oil is required.7.3.4 Bearing PadsThe bearing pads shall have a modulusof elasticity of around 4 106psi

36、(3 104MPa) and shall becapable of conforming to the rock surface and bearing plate.High early strength grout or molten sulfur bearing pads arerecommended.7.3.5 Bearing PlatesThe bearing plates shall approximatea rigid die as closely as practical. A bearing plate that has beenfound satisfactory is sh

37、own in Fig. 1.Although the exact designand materials may differ, the stiffness of the bearing plate shallD4553 182be the minimum stiffness necessary to not produce measurabledeflection of the plate under maximum load.8. Safety Hazards8.1 Enforce safety by applicable safety standards.8.2 Pressure lin

38、es should be bled of air to preclude violentfailure of the pressure system.8.3 Total displacement should not exceed the expansioncapabilities of the flatjacks; normally this is approximately 3 %of the diameter of a metal jack.9. In Situ ConditionsNOTE 2The guidelines presented in this section are th

39、e domain of theagency or organization requesting the testing and are intended to facilitatedefinition of the scope and development of site-specific requirements forthe testing program as a whole.9.1 Test each structurally distinctive zone of rock massselecting areas that are geologically representat

40、ive of the mass.Test those portions of the rock mass with features such asfaults, fracture zones, cavities, inclusions, and the like toevaluate their effects. Design the testing program so that effectsof local geology can be clearly distinguished and the impact ofexcavation minimized.9.2 The size of

41、 the bearing plate will be determined by thelocal geology, pressures to be applied, and the size of the aditto be performed. These parameters should be considered priorto excavation of the adit. Acceptable adit dimensions areapproximately six times the plate diameter; recommended platediameter is co

42、mmonly 112 to 314 ft (0.5 to 1 m). Other sizesare used depending upon site specifics. A map of the adit andtest site shall be prepared in accordance with Guide D4879.9.3 The effects of anisotropy should be investigated byappropriately oriented tests; for example, parallel and perpen-dicular to the b

43、edding of a sedimentary sequence, or paralleland perpendicular to the long axes of columns in a basalt flow.9.4 Tests shall be performed at a site not affected bystructural changes resulting from excavations of the adit. Thezone of rock that contributes to the measured displacementduring the plate l

44、oading depends on the diameter of the plateand the applied load. Larger plates and higher loads measurethe response of rock further away from the test adit.Thus, if therock around the adit is damaged by the excavation process, andthe deformational/creep properties of the damaged zone are theprimary

45、objective of the test program, small-diameter platetests on typically excavated surfaces are adequate.9.5 Site conditions may dictate that site preparation and padconstruction be performed immediately after excavation.10. Procedure10.1 Verify the compliance of equipment and apparatus withthe perform

46、ance specifications in Section 7. If requirements arenot stated, the manufacturers specifications for the equipmentmay be appropriate as a guide, however, care should be takenFIG. 1 Rigid Bearing Plate for 12 in. (30.5 cm) Diameter In Situ Creep TestD4553 183for sufficient performance. Performance v

47、erification is gener-ally done by calibrating the equipment and measurementsystem. Accomplish calibration and documentation in accor-dance with the quality assurance procedures in Annex A1.10.2 Ensure that the test results are defensible and traceableby following at least the minimum guidelines for

48、personnelqualifications, calibrations, test setup, test procedure, equip-ment performance and verification, and vetting of test data arefollowed in Annex A1.10.3 Conduct the test across a “diameter” or chord of theadit with the two test surfaces nearly parallel and in planesoriented perpendicular to

49、 the thrust of the loading assembly. Aschematic of an acceptable test setup is shown in Fig. 2.Awooden platform (not shown) allows for ease of constructionand alignment of test components.NOTE 3The procedure shown is generalized but the user should not beconfined by this procedure with regards to the actual testing portion. Theuser of this standard needs to realize that this is an expensive timeconsuming test and that running the test is a small part comparted to thesetup of the test. Therefore, if possible it may be prudent to collect asmuch data as po