1、Designation: D4506 131Standard Test Method forDetermining In Situ Modulus of Deformation of Rock MassUsing Radial Jacking Test1This standard is issued under the fixed designation D4506; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisio
2、n, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1NOTEEditorial corrections were made throughout in February 2014.1. Scope*1.1 This test method is used to determine
3、 the in situmodulus of deformation of rock mass by subjecting a testchamber of circular cross section to uniformly distributedradial loading; the consequent rock displacements aremeasured, from which elastic or deformation moduli may becalculated. The anisotropic deformability of the rock can alsobe
4、 measured and information on time-dependent deformationmay be obtained.1.2 This test method is based upon the procedures devel-oped by the U.S. Bureau of Reclamation featuring longextensometers (1).2An alternative procedure is also availableand is based on a reference bar (2). More information on ra
5、dialjacking and its analysis is presented in References (3-8).1.3 Application of the test results is beyond the scope of thistest method, but may be an integral part of some testingprograms.1.4 UnitsThe values stated in inch-pound units are to beregarded as standard. The values given in parentheses
6、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 test method.1.4.1 The gravitational system of inch-pound units is usedwhen dealing w
7、ith inch-pound units. In this system, the pound(lbf) represents a unit of force (weight), while the unit for massis slugs.1.5 All observed and calculated values shall conform to theguidelines for significant digits and rounding established inPractice D6026.1.5.1 The procedures used to specify how da
8、ta are collected/recorded or calculated, in this 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 variation, purpose forobtaining the data, special purpose stu
9、dies, 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 this standard to consider significant digits used in analyticalmethods for engineering desig
10、n.1.6 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 and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced
11、 Documents2.1 ASTM Standards:3D653 Terminology Relating to Soil, Rock, and ContainedFluidsD3740 Practice for Minimum Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD4403 Practice for Extensometers Used in RockD6026 Practice
12、 for Using Significant Digits in GeotechnicalData3. Terminology3.1 Definitions:3.1.1 For definitions of common technical terms in thisstandard, refer to Terminology D653.3.2 Definitions of Terms Specific to This Standard:3.2.1 deformationthe change in the diameter of the exca-vation in rock (test ch
13、amber).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 approved Nov. 1, 2013. Published December 2013. Originallyapproved in 1985. Last previous edition approved in 2008 as D450
14、6 08. DOI:10.1520/D4506-13E01.2The boldface numbers in parentheses refer to the list of references appended tothis standard.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, r
15、efer to the standards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14. Summary of Test Method4.1 A circular test chamber is ex
16、cavated and a uniformlydistributed pressure is applied to the chamber surfaces bymeans of flat jacks positioned on a reaction frame. Rockdeformation is measured by extensometers placed in boreholesperpendicular to the chamber surfaces. Pressure is measuredwith a standard hydraulic transducer. During
17、 the test, thepressure is cycled incrementally and deformation is read ateach increment. The modulus is then calculated. The pressureis held constant and deformation is observed over time todetermine time-dependent behavior.5. Significance and Use5.1 In this test method a volume of rock large enough
18、 totake into account the influence of discontinuities on theproperties of the rock mass is loaded. This test method shouldbe used when values are required which represent the true rockmass properties more closely than can be obtained through lessexpensive uniaxial jacking tests or other procedures.N
19、OTE 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 competentand objective testing/sampling
20、/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. Apparatus6.1 Chamber Excavation EquipmentIncluding drilli
21、ngand “smooth wall” blasting equipment or mechanical excava-tion equipment capable of producing typically a 9-ft (3-m)diameter tunnel with a length about three times that dimension.6.2 Concreting EquipmentConcreting materials andequipment for lining the tunnel, together with strips of weakjointing m
22、aterials for segmenting the lining.6.3 Reaction FrameThe reaction frame shall be com-prised of steel rings of sufficient strength and rigidity to resistthe force applied by flat jacks, as depicted in Fig. 1. For load1. Measuring profile. 2. Distance equal to the length of active loading. 3. Control
23、extensometer. 4. Pressure gauge. 5. Reference beam. 6. Hydraulic pump. 7. Flat jack.8. Hardwood lagging. 9. Shotcrete. 10. Excavation diameter. 11. Measuring diameter. 12. Extensometer drillholes. 13. Dial gauge extensometer. 14. Steel rod. 15.Expansion wedges. 16. Excavation radius. 18. Inscribed C
24、ircle. 19. Rockbolt anchor. 20. Steel ring.FIG. 1 Radial Jacking TestD4506 1312application by flat jacks, the frame must be provided withsmooth surfaces; hardwood planks are usually inserted be-tween the flat jacks and the metal rings.6.4 Loading EquipmentTo apply a uniformly distributedradial press
25、ure to the inner face of the concrete lining,including:6.4.1 Hydraulic PumpWith all necessary hoses,connectors, and fluid, capable of applying the required pressureand of holding this pressure constant to within 5 % over aperiod of at least 24 h.6.4.2 Flat JacksUsed for load application (Fig. 1), an
26、d areof a practicable width and of a length equal at least to thediameter of the tunnel (9 ft (3 m). The jacks should bedesigned to load the maximum of the full circumference of thelining with sufficient separation to allow displacementmeasurements, and should have a bursting pressure and travelcons
27、istent with the anticipated loads and displacements. Stain-less steel flat jacks in effective contact with 90 % of the area arerecommended, with the maximum pressure capacity twice thedesign pressure.6.5 Load Measuring EquipmentLoad measuring equip-ment shall consist of one or more hydraulic pressur
28、e gages ortransducers of suitable range, capable of measuring the appliedpressure with an accuracy better than 62 %. Measurements areusually made by means of mechanical gages. Particular care isrequired to guarantee the reliability of electric transducers andrecording equipment, when used.6.6 Displa
29、cement Measuring EquipmentDisplacementmeasuring equipment to monitor rock movements radial to thetunnel shall have an accuracy of at least 60.0003 in. (0.1 mm)and resolution of at least 0.0001 in. (0.0025 mm). Multiple-position (six anchor points) extensometers in accordance withPractice D4403 shoul
30、d be used. The directions of measurementshould be normal to the axis of the tunnel. Measurements ofmovement should be related to reference anchors rigidlysecured in rock, well away from the influence of the loadedzone. The multiple-position extensometers should have thedeepest anchor as a reference
31、situated at least 3 test-chamberdiameters from the chamber lining.7. Verification7.1 The compliance of all equipment and apparatus with theperformance specifications in Section 6 shall be verified. Theequipment and measurement systems should be included aspart of the verification and documentation s
32、hall be accom-plished in accordance with standard quality assurance proce-dures8. Procedure8.1 Test Chamber:8.1.1 Select the test chamber location taking into consider-ation the rock conditions, particularly the orientation of therock mass elements such as joints, bedding, and foliation inrelation t
33、o the orientation of the proposed tunnel or opening forwhich results are required.8.1.2 Excavate the test chamber by smooth (presplit) blast-ing to the required diameter of 9 ft (3 m), with a length equalto at least three diameters.8.1.3 Record the geology of the chamber and specimenstaken for index
34、 testing, as required. Core and log all instru-mentation holes as follows:8.1.3.1 Cored BoreholesDrill the boreholes using dia-mond core techniques. Continuous core shall be obtained.8.1.3.2 Core LoggedCompletely log the recovered core,with emphasis on fractures and other mechanical nonhomoge-neitie
35、s.8.1.4 Accurately mark out and drill the extensometer holes,making sure no interference between loading and measuringsystems. Install six-point extensometers and check the equip-ment. Place two anchors deep beyond the tunnel influence,appropriately spacing the other four anchors as close to thesurf
36、ace of the tunnel as possible.8.1.5 Assemble the reaction frame and loading equipment.8.1.6 Line the chamber with concrete to fill the spacebetween the frame and the rock.8.2 Loading:8.2.1 Perform the test with at least three loading andunloading cycles, a higher maximum pressure being applied ateac
37、h cycle. Typically, the maximum pressure applied is 1000psi (7 MPa), depending on expected design loads.8.2.2 For each cycle, increase the pressure at an average rateof 100 psi/min (0.7 MPa/min) to the maximum for the cycle,taking not less than 10 intermediate sets of load-displacementreadings in or
38、der to define a set of pressure-displacementcurves (see Fig. 2). The automation of data recording isrecommended.8.2.3 On reaching the maximum pressure for the cycle, holdthe pressure constant for 10 minutes. Complete each cycle byreducing the pressure to near zero at the same average rate,taking thr
39、ee additional sets of pressure-displacement readings.8.2.4 For the final cycle, hold the maximum pressureconstant for 24 h to evaluate creep. Complete the cycle byunloading in stages, taking readings of pressure and corre-sponding displacements similar to the loading cycle.9. Calculation9.1 Correct
40、the applied load values to give an equivalentdistributed pressure, p1, on the test chamber lining, as follows:p15(b2r1pm(1)FIG. 2 Typical Graph of Applied Pressure Versus DisplacementD4506 1313where:p1= distributed pressure on the lining at r1, to the nearest 1psi ( 0.007 MPa)r1= radius, to the near
41、est 0.5 ft ( 0.15 m)pm= pressure in the flat jacks, to the nearest 1 psi ( 0.007MPa)b = flat jack width (see Fig. 3), to the nearest 0.5 ft (0.15 m)9.1.1 Calculate the equivalent pressure P2at a “measuringradius” r2just beneath the lining; this radius being outside thezone of irregular stresses bene
42、ath the flat jacks and the liningand loose rock (see Fig. 3).P25r1r2P15(b2r2Pm(2)Pm(b 5 P12r1P15Pm(b2r1P25 P1r1r2where:P2= the equivalent pressure at measuring radius r2,tothenearest 1 psi (0.007 MPa)r2= measuring radius, to the nearest 0.5 ft (0.15 m)9.2 Superposition is only strictly valid for ela
43、stic deforma-tions but also gives a good approximation if the rock ismoderately plastic in its behavior. Superposition of displace-ments for two fictitious loaded lengths is used to give theequivalent displacements for an “infinitely long test chamber.”This superposition is made necessary by the com
44、parativelyshort length of the test chamber in relation to its diameter.9.3 Plot the result of the long duration test, dundermaximum pressure, p2, which is the maximum P2value, on thedisplacement graph (Fig. 4). Proportionally correct test data foreach cycle to give the complete long-term pressure-di
45、splacement curve. The elastic component, e, and the plasticcomponent, p, of the total deformation, t, are obtained fromthe deformation at the final unloading:t5 p1esee Fig. 4! (3)where:e= elastic componentt= total deformationp= plastic component9.4 The elastic modulus, E, and the deformation modulus
46、,D, are obtained from the pressure-displacement graph (Fig. 2)using the following formulae based on the theory of elasticity:E 5p2r2e11!(4)D 5p2r2t11!where:p2= maximum test pressure, to the nearest 1 psi ( 0.007MPa) = estimated value for Poissons RatioE = elastic modulusD = deformation modulus9.4.1
47、As an alternative to 9.4, the moduli of intact rock maybe obtained, taking into account the effect of a fissured andloosened region, by using the following formulae:E 5p2r2eS111lnr3r2D(5)D 5p2r2tS111lnr3r2Dwhere:r3= radius to the limit of the assumed fissured and loosenedzone, to the nearest 0.5 ft
48、(0.15 m).FIG. 3 Scheme of Loading Showing Symbols Used in the Calcu-lationsFIG. 4 Typical Graph Showing Total and Plastic Displacementsas a Function of Direction Perpendicular to the Test ChamberAxisD4506 13149.4.2 AssumptionsThis solution is given for the case of asingle measuring circle with exten
49、someter anchors immedi-ately behind the lining. The solution assumes linear-elasticbehavior for the rock and is usually adequate in practice,although it is possible to analyze more complex test configu-rations (using, for example, a finite element analysis).10. Report: Test Data Sheet(s)/Form(s)10.1 The methodology used to specify how data are re-corded on the test data sheet(s)/form(s) as given below, iscovered in 1.5 and Practice D6026.10.2 Record as a minimum the following general informa-tion (data):10.
