1、Designation: D 6230 98 (Reapproved 2005)Standard Test Method forMonitoring Ground Movement Using Probe-TypeInclinometers1This standard is issued under the fixed designation D 6230; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, th
2、e year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the use of inclinometers tomonitor the internal movement of ground. The test method
3、covers types of instruments, installation procedures, operatingprocedures and maintenance requirements. It also providesformulae for data reduction.1.2 The values stated in SI units are to be regarded as thestandard. The inch-pound units given in parentheses are forinformation only.1.3 This standard
4、 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 health and safety practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM
5、Standards:2D 653 Terminology Relating to Soil, Rock, and ContainedFluidsD 4622 Test Method for Rock Mass Monitoring UsingInclinometers33. Significance and Use3.1 An inclinometer is a device for measuring deformationnormal to the axis of a pipe by passing a probe along the pipeand measuring the incli
6、nation of the probe with respect to theline of gravity. Measurements are converted to distances usingtrigonometric functions. Distances are summed to find theposition of the pipe. Successive measurements give differencesin position of the pipe and indicate deformation normal to theaxis of the pipe.
7、In most cases the pipe is installed in anear-vertical hole. Measurements indicate subsurface horizon-tal deformation. In some cases the pipe is installed horizontallyand the measurements indicate vertical deformation.3.2 Inclinometers are also called slope inclinometers orslope indicators. Typical a
8、pplications include measuring therate of landslide movement and locating the zone of shearing,monitoring the magnitude and rate of horizontal movementsfor embankments and excavations, monitoring the settlementand lateral spread beneath tanks and embankments, and moni-toring the deflection of bulkhea
9、ds, piles or structural walls.4. Apparatus4.1 The probe type inclinometer uses sensors inside a probeto indicate the orientation of the probe relative to the pull ofgravity. The complete system consists of:4.1.1 A permanently installed pipe, called casing, with testmethod grooves. The casing is made
10、 of plastic, aluminumalloy, or fiberglass.4.1.2 The ProbeMost probes use force balance acceler-ometers which give a voltage output that is proportional toinclination of the probe. Biaxial probes contain two sensorsoriented 90 apart to permit readings in orthogonal directionsat the same time.4.1.3 A
11、portable readout unit with power supply for thesensors and display to indicate probe inclination. The readoutunit may have internal memory to record data.4.1.4 An electrical cable connecting the probe and readoutunit with distance markings. Fig. 1 shows a typical set ofcomponents.5. Procedure5.1 Ins
12、tallation of Casing in a Borehole:5.1.1 Select casing materials that are compatible with theenvironmental conditions at the installation. Select casing sizeconsistent with the specific measurement requirements andconditions for the job. Store casing materials in a safe, secureplace to prevent damage
13、. Sunlight may damage plastic casing.High and low pH may damage metal casing. Note that a specialprobe may be required for non-vertical boreholes.5.1.2 Assemble all components required for the casing,including casing, joints, connectors, and end cap. Examineeach component for defects. Do not use def
14、ective componentssince they may later cause problems with readings that aredifficult to diagnose and impossible to correct. Keep all1This test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.23 on Field Instrumen-tation.Curre
15、nt edition approved Nov. 1, 2005. Published December 2005. Originallyapproved in 1998. Last previous edition approved in 1998 as D 6230 98.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume
16、 information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United Sponents clean and free of foreign matter during assembly.Follow the manufacturers instructions for ass
17、embly of thecasing. If required, use sealing mastic and tape to seal allcouplings to prevent later flow of soil particles into the casing.This is especially important when using grout to seal the casingin the hole. Exercise care to keep the casing grooves free ofobstructions. When assembling couplin
18、gs, use procedures toprevent spiraling of the casing grooves. Twist adjacent cou-plings in alternate directions before fixing to minimize spiral-ing. Examine the casing during assembly to confirm thatspiraling is not occurring. Place a cap on the bottom end andseal it to prevent inflow.5.1.3 Create
19、the borehole using procedures to keep italigned within the range of the readout equipment. Extend theborehole at least 5 m (16 ft) beyond the zone of expectedmovement. It may be necessary to use casing, hollow-stemaugers, or drilling mud to keep the hole open and stable. Flushthe hole until clear of
20、 drilling cuttings.5.1.4 Insert the casing into the borehole. Establish thereference orientation for the casing and align one set of groveswith this reference. This orientation is commonly referred to asthe A direction. It should align with the direction of greatestanticipated movement. Add clean wa
21、ter to the casing ifnecessary to overcome buoyancy. Use care to minimize anytwist of the casing during installation. Care should be exercisedto maintain orientation without twisting from the first piece ofcasing to the last. Twisting the top of the casing may causespiraling of casing at depth.5.1.5
22、Backfill the annular space between the borehole walland the inclinometer casing with a suitable filling material.Borehole can be pre-grouted or post-grouted. If post-grouted,grouting can be through a tremie placed in the annulus of theinclinometer casing and the boreholes walls or via an internaltre
23、mie connected to a one-way bottom grout valve. Optionsinclude cement grout, sand and pea gravel.Alean cement groutbackfill is preferable unless the surrounding ground is toopervious to hold the grout. Place grout with a tremie. Buoyancymust be overcome with grout backfills. Add a weight to thebottom
24、 of the inclinometer casing, temporarily place clean drillpipe inside the casing, or place the first 3 m (10 ft) of groutaround the bottom of the casing and let it set, then complete thegrouting. Place sand and gravel backfills slowly and withtechniques to prevent leaving large voids in the backfill
25、. Suchvoids can later lead to erratic readings. Place backfill andwithdraw drill casing or augers in sequence to prevent anysqueezing off of the borehole. Withdraw drill casing andhollow-stem augers without rotation to prevent damage to theinclinometer casing. Use measures to prevent backfill fromsp
26、illing into the inclinometer casing.5.2 Installation on The Ground Surface of Horizontal Cas-ing:NOTE 1A practical limit for installing horizontal casing is about 100m. Beyond 100 m cable friction makes it difficult to pull the inclinometerprobe through the casing. Special TFE-fluorocarbon inserts o
27、n the cablealleviate the problem to some degree.5.2.1 Select casing materials that are compatible with theenvironmental conditions at the installation. Select casing sizeconsistent with the specific measurement requirements andconditions for the job. Store casing materials in a safe, secureplace to
28、prevent damage. Sunlight may damage plastic casing.High and low pH may damage metal casing. Note that a specialprobe is required for horizontal casing. If one end of the casingis to be buried then the end cap contains a pulley to carry a wirethat is used to pull the probe into the inclinometer casin
29、g.Special care must be taken to insure that the pulley is correctlyassembled, free to turn and has the wire in place. Takeprecautions at all times during installation to keep the wireclean.5.2.2 Create a near-level surface over the length where thecasing is to be installed. Cover with a bed of at le
30、ast 50-mm(2-in.) deep and 300-mm (12-in.) wide of clean sand, peagravel or a lean grout.5.2.3 Assemble all components required for the casing,including casing joints, connectors, and end cap. Examine eachcomponent for defects. Do not use defective components sincethey may later cause problems with r
31、eadings that are difficult todiagnose and impossible to correct. Keep all components cleanand free of foreign matter during assembly. Follow the manu-facturers instructions for assembly of the casing. If requireduse sealing mastic and tape to seal all couplings to prevent laterflow of soil particles
32、 into the casing. This is especiallyimportant when using grout to seal the casing in the borehole.Exercise care to keep the casing grooves free of obstructions.When assembling couplings, use procedures to prevent spiral-ing of the casing grooves. Twist adjacent couplings in alternatedirections befor
33、e fixing to minimize spiraling. Examine thecasing during assembly to confirm that spiraling is not occur-ring.5.2.4 Place the casing onto the bed and adjust its positionuntil it is within the tolerances required by the readout device.Establish the reference orientation for the casing and align onese
34、t of groves with this reference. This orientation is commonlyreferred to as the A direction. It aligns with the direction ofgreatest anticipated movement. Visually check for and removeany spiraling. Determine that the pull cable is in position andmoves freely through the inclinometer casing.FIG. 1 T
35、ypical Components of Inclinometer SystemD 6230 98 (2005)25.2.5 Use hand tools or light construction equipment toplace clean sand, pea gravel or lean grout evenly, at least150-mm (6-in.) wide, on both sides of the casing. Cover theinclinometer casing with at least 50 mm (2 in.) of clean sand,pea grav
36、el or lean grout. Place fill over casing in 150-mm(6-in.) lifts. Fill for the first lift should not contain any particleslarger than 25 mm (1 in.). If compaction is required, use handcompactors for the first two lifts.5.3 Calibration:5.3.1 Inclinometers are factory calibrated and supplied witha cali
37、bration factor, K, that is specific to the probe and thereadout unit. Some manufacturers provide standardized read-out units that can be used with multiple probes. However itshould be noted that electronic variations in the readoutequipment may cause conditions where different probes willgive differ
38、ent readings. It is recommended that a calibrationcheck be performed any time a probe and readout unitcombination is changed. For applications involving small butimportant changes over several years, recalibrate the instru-ment to the precision of the device at least once per year.5.3.2 Perform a ca
39、libration check before each set of incli-nometer readings. Field checks can be made using a test stand,a test casing, or a section of field casing in material that doesnot move. Test stands are available from most manufacturers.They employ a short piece of inclinometer casing preset at afixed angle.
40、 The test stand must be set on a stable base andproperly aligned by the manufacturers instructions. A testcasing is a short piece of casing installed in a fixed positionwith the grooves at angles of 0 to 10 from the vertical. Asection of field casing that is placed in fixed material can beused to ch
41、eck calibrations. This last method is the leastpreferable since most field casings are near-vertical (or near-horizontal). Calibration checks on vertical casing can indicatemalfunctioning equipment but cannot provide an accuratecalibration.5.3.3 Perform a calibration check by assembling the probe,ca
42、ble and readout equipment and allowing it to equilibrate toambient temperature for at least 10 min. The probe is posi-tioned in the test stand or casing and readings taken. The probeis removed, rotated 90, reinserted and read. This operation isrepeated to obtain readings at 180 and 270. Consult them
43、anufacturers instructions to determine if your readings arewithin the recommended ranges for the equipment. Anyobvious malfunctioning of the equipment, such as drift in thereading with time, inability to reproduce a reading, should becorrected before using the instrument.5.4 Measurement Method:5.4.1
44、 The probe is inserted into the casing oriented in thereference direction (that is, a direction) to the bottom of avertical or inclined casing or to the far end of a horizontalcasing. A measurement traverse is made by holding the probestationary at each depth interval and recording depth andreading.
45、 Recommended practice is to use a reading intervalequal to the wheel spacing on the probe. After each reading,raise the probe by the reading interval and take the next set ofreadings. Repeat the procedure to the top of the casing tocomplete the traverse. Remove the probe from the casing,rotate it 18
46、0, and lower it to the bottom of the casing. Startreadings for this traverse from exactly the same depth as thefirst traverse and make each reading at exactly the same depthas the first traverse. For biaxial probes, two traverses completethe set of readings. For uniaxial probes, two more traversesmu
47、st be made for the B direction the same way as for the Adirection.5.4.2 Check the set of readings by summing the readings forthe A and A8 directions at each depth and the readings for theB and B8 direction. These sums are called check-sums andshould equal a constant value that is a characteristic of
48、 theprobe. Refer to the manufacturers literature for information onallowable variation in the check-sum. A single deviation in acheck-sum probably indicates a bad reading. Erratic behaviorof the check-sums generally indicates a poor electrical connec-tion or a malfunctioning probe or readout.5.5 Ini
49、tial Readings:5.5.1 Make initial observations after allowing sufficient timefor the grout around the casing to set or for the backfill tostabilize. Since computation of all displacements is based onthe initial readings, it is important to have a valid set. Verify theinitial set of readings with at least two sets of readings, takenon the same day. Check these readings for stability of thecheck-sums and for displacement within the accuracy of theequipment. Repeat observations until satisfactory agreement isobtained. From all initial readings taken, one set should
