ASTM D4719-00
(Test Method)Standard Test Method for Prebored Pressuremeter Testing in Soils
Standard Test Method for Prebored Pressuremeter Testing in Soils
SCOPE
1.1 This test method covers pressuremeter testing of soils. A pressuremeter test is an in-situ stress-strain test performed on the wall of a borehole using a cylindrical probe that is expanded radially. To obtain viable test results, disturbance to the borehole wall must be minimized.
1.2 This test method includes the procedure for drilling the borehole, inserting the probe, and running pressuremeter tests in both granular and cohesive soils, but does not include high pressure testing in rock. Knowledge of the type of soil in which each pressuremeter test is to be made is necessary for assessment of (1) the method of boring or probe placement, or both, and (2) the reasonableness of results and interpretation of the test.
1.3 This test method does not cover the self-boring pressuremeter, for which the hole is drilled by a mechanical tool inside the hollow core of the probe. This test method is limited to the pressuremeter which is inserted into predrilled boreholes or, under certain circumstances, is inserted by driving.
1.4 Two alternate testing procedures are provided as follows:
1.4.1 Procedure A -The Equal Pressure Increment Method.
1.4.2 Procedure B -The Equal Volume Increment Method. Note 1-A standard for the self-boring pressuremeter is scheduled to be developed separately. Pressuremeter testing in rock may be standardized as an adjunct to this test method.
1.5 The values stated in SI units are to be regarded as the standard.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. See Note 5.
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Designation:D4719–00
Standard Test Method for
Prebored Pressuremeter Testing in Soils
This standard is issued under the fixed designation D 4719; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope * priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. See Note 6.
1.1 Thistestmethodcoverspressuremetertestingofsoils.A
pressuremeter test is an in situ stress-strain test performed on
2. Referenced Documents
the wall of a borehole using a cylindrical probe that is
2.1 ASTM Standards:
expanded radially. To obtain viable test results, disturbance to
D 1587 Practice for Thin-Walled Tube Sampling of Soils
the borehole wall must be minimized.
D 2113 Practice for Diamond Core Drilling for Site Inves-
1.2 This test method includes the procedure for drilling the
tigation
borehole, inserting the probe, and conducting pressuremeter
tests in both granular and cohesive soils, but does not include
3. Terminology
high pressure testing in rock. Knowledge of the type of soil in
3.1 Definitions—Fordefinitionsoftermsinthistestmethod,
which each pressuremeter test is to be made is necessary for
refer to Terminology D 653.
assessment of (1) the method of boring or probe placement, or
–2
3.1.1 limit pressure, P [FL ], n—the pressure at which the
l
both, (2) the interpretation of the test data, and (3) the
probe volume reaches twice the original soil cavity volume.
reasonableness of the test results.
–2
3.1.2 pressuremeter modulus, E [FL ], n—the modulus
p
1.3 This test method does not cover the self-boring pres-
calculated from the slope of the pseudo-elastic portion of the
suremeter, for which the hole is drilled by a mechanical or
corrected pressure-volume curve experiencing little to no
jetting tool inside the hollow core of the probe. This test
creep.
method is limited to the pressuremeter which is inserted into
–2
3.1.3 unload-reload modulus, E [FL ], n—the modulus
R
predrilledboreholesor,undercertaincircumstances,isinserted
calculated from an unload-reload loop.
by driving.
3.1.3.1 Discussion—Theunload-reloadmodulusvarieswith
1.4 Two alternate testing procedures are provided as fol-
stress, or strain level, or both, and thus, the modulus values
lows:
should be reported with the pressure and volume at the start of
1.4.1 Procedure A—The Equal Pressure Increment Method.
the unloading, at the bottom of the loop and at the crossover
1.4.2 Procedure B—The Equal Volume Increment Method.
point.
NOTE 1—A standard for the self-boring pressuremeter is scheduled to
3.2 Abbreviations:
be developed separately. Pressuremeter testing in rock may be standard-
3.2.1 PBP—prebored pressuremeter test
ized as an adjunct to this test method.
NOTE 2—Strain-controlled tests also can be performed, whereby the
4. Summary of Test Method
probe volume is increased at a constant rate and corresponding pressures
4.1 A pressuremeter cavity is prepared either by drilling a
are measured. This method shall be applied only if special requirements
must be met and is not covered by this test method. Strain-controlled tests borehole, or by advancing some type of sampler. Under certain
may yield different results than the procedure described in this test
circumstances, the pressuremeter probe is driven into place,
method.
usually within a casing. The various tools and methods
available to prepare the cavity produce different degrees of
1.5 The values stated in SI units are to be regarded as the
disturbance. The recommended methods to be used at a site
standard.
depend on the soil and the conditions met. The proper choice
1.6 This standard does not purport to address all of the
of tools and methods is covered by this test method.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
NOTE 3—It is recommended that several drilling techniques be avail-
able on the site to determine which method will provide the most suitable
test hole.
This test method is under the jurisdiction of ASTM Committee D-18 on Soil
and Rock and is the direct responsibility of Subcommittee D18.02 on Sampling and
Related Field Testing for Soil Investigations.
Current edition approved Feb. 10, 2000. Published May 2000. Originally
e1 2
published as D 4719 – 87. Last previous edition D 4719 – 87(1994) . Annual Book of ASTM Standards, Vol 04.08.
*A Summary of Changes section appears at the end of this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D4719
4.2 The pressuremeter test basically consists of placing an
inflatable cylindrical probe in a predrilled hole and expanding
thisprobewhilemeasuringthechangesinvolumeandpressure
in the probe. The probe is inflated under equal pressure
increments (Procedure A) or equal volume increments (Proce-
dure B) and the test is terminated when yielding in the soil
becomes disproportionately large. A conventional limit pres-
sure is estimated from the last few readings of the test and a
pressuremeter modulus is calculated from pressure-volume
changes read during the test. It is of basic importance that the
probe be inserted in a borehole with a diameter close to that of
the probe to ensure adequate volume change capability. If this
requirement is not met, the test could terminate without
reaching sufficient probe expansion in the soil to permit
evaluation of the limit pressure. The instrument may be either
of the type where the change in volume of the probe is directly
FIG. 1 a) Basic Principles of the Triple Cell Design Pressuremeter
measured by an incompressible liquid or the type where feelers
(Baguelin, Jézéquel and Shields, 1978, b) Slotted Tube with
are used to determine the change in diameter in the probe. The
Probe
volume measuring system must be well protected and cali-
brated against any volume losses throughout the system while
both systems, the nominal hole diameter shall not be more than
the feeler operated probe must be sensitive enough to measure
1.2 times the nominal probe diameter. Typical probe dimen-
relatively small displacements.
sions and corresponding borehole diameters are indicated in
NOTE 4—This test method is based on the type of apparatus where Table 1.
volume changes are recorded during the test. For the system measuring
6.1.1 Probe Walls—The flexible walls of the probe may
probe diameters, alternate evaluation methods are given in the notes.
consist of a single rubber membrane (single cell design) or of
an inner rubber membrane fitted with an outer flexible sheath
5. Significance and Use
or cover (triple cell design) which will take up the shape of the
5.1 This test method provides a stress-strain response of the
borehole as pressure is applied. In a coarse-grained material
soil in situ. A pressuremeter modulus and a limit pressure is
like gravel, a steel sheath made of thin overlapping metal strips
obtained for use in geotechnical analysis and foundation
is often used. The accuracy of the test will be impaired when
design.
the probe cannot take up the shape of the borehole accurately.
5.2 The results of this test method are dependent on the
NOTE 5—Various membrane and sheath, or cover, materials may be
degree of disturbance during drilling of the borehole and
used to better accommodate soil types; identify the membrane and sheath,
insertion of the pressuremeter probe. Since disturbance cannot
or cover, used in the report.
be completely eliminated, the interpretation of the test results
6.1.2 Measuring Devices—Changes in volume of the mea-
should include consideration of conditions during drilling.This
suring portion of the probe are measured in the hydraulic
disturbance is particularly significant in very soft clays and
apparatus, and alternatively, the probe diameter can be mea-
very loose sands. Disturbance may not be eliminated com-
sured by the use of feelers in the electric apparatus. Provisions
pletelybutshouldbeminimizedforthepreboredpressuremeter
to measure the diameter in directions at a 120° angle shall be
design rules to be applicable.
provided with the electric apparatus. The measuring cell shall
6. Apparatus be prevented from expanding in the vertical direction by guard
cellsorothereffectiverestraintsinthehydraulicapparatus.The
6.1 Hydraulic or Electric Probe—The apparatus shall con-
accuracy of the readout device shall be such that a change of
sist of a probe to be lowered in the borehole and a measuring
0.1 % in the probe diameter is measurable.
or readout device to be located on the ground adjacent to the
6.2 Lines—Lines connecting the probe with the readout
boring. The probe may be either the hydraulic type or the
device consist of plastic tubing in the hydraulic apparatus. To
electric type. The hydraulic probe may be of a single cell or
reduce measuring errors, a coaxial tubing is used, whereby the
triple cell design. In the latter case, the role of which is to
inner tubing is prevented from expanding by a gas pressure at
provide effective end restraint and ensure radial expansion of
its perimeter. By applying the correct gas pressure, expansion
the central cell (Fig. 1a ). The combined height of the
of the inner tubing is reduced to a minimum. Single tubing can
measuring and guard cells, if any, shall be at least six
diameters. The design of the probe shall be such that the
drilling liquid may flow freely past the probe without disturb-
TABLE 1 Typical Probe and Borehole Dimensions
ing the sides of the borehole during insertion or removal. For
Probe
Borehole Diameter
Hole Diameter
Diameter,
Designation
Nominal, mm Max., mm
mm
Ax 44 45 53
Baguelin, F., Jézéquel, J.F., and Shields, D.H., “The Pressuremeter and
Bx 58 60 70
Foundation Engineering,” Trans Tech Publications, Series on Rock and Soil Nx 74 76 89
Mechanics, Vol 2, No. 4, 1978, p 617.
D4719
also be used. In both cases, requirement for volume losses
given in 7.3 should apply. Electric lines need special protection
against groundwater.
6.3 Readout Device—The readout device includes a mecha-
nism to apply pressure (ProcedureA) or volume (Procedure B)
in equal increments to the probe and readout of volume change
(Procedure A) or pressure change (Procedure B). The equip-
ment using the hydraulic system and guard cells shall also
include a regulator whereby the pressure in the gas circuit is
kept below the fluid pressure in the measuring cell. The
magnitudeofpressuredifferencebetweengasandfluidmustbe
adjustable to compensate for hydrostatic pressures developing
in the probe. In the electrical system the volume readings are
substituted by an electrical readout on the diameter of the
probe.
6.4 Slotted Tube—Asteel tube, (Fig. 1b) that has a series of
longitudinalslots(usuallysix)cutthroughittoallowforlateral
NOTE 1—The schematic graphs are not to scale; each calibration
expansion, sometimes is used as a protective housing when the
requires different volumes and pressures.
probe is driven, vibrodriven, or pushed into deposits that
FIG. 2 Calibration for Volume and Pressure Losses
cannot be prevented from caving by drilling mud alone. The
PBP test is performed within the slotted tube.
duty steel casing or pipe. A suggested procedure is to increase
7. Calibration
the pressure in steps of 100 kPa or 500 kPa depending if the
7.1 The instrument shall be calibrated before each use to
probe is designed for a maximum expansion pressure of 2.5
compensate for pressure losses (P ) and volume losses (V ).
c c
MPa or 5.0 MPa, respectively. Each pressure increment should
7.2 Pressure Losses—Pressure losses (P ) occur due to the
c
be reached within 20 s and once in contact with the steel tube,
rigidity of the probe walls. The pressure readings obtained
held constant for 1 minute. The resulting graph of injected
during the test on the readout device include the pressure
volume (V ) at the end of each pressure increment (P)isthe
r r
required to expand the probe walls; this membrane resistance
volume calibration curve. The zero volume calibration is
must be deducted to obtain the actual pressure applied to the
obtained by first fitting a straight line extension of the curve to
soil. Calibrations for membrane resistance shall be performed
zero pressure, as shown in Fig. 2.The resulting intercept V can
i
by inflating the probe, completely exposed to the atmosphere,
be used to estimate the deflated volume of the probe measuring
with the probe placed at the level of the pressure gage.
cell (V ) as follows:
o
NOTE 6—Warning: The performance of the pressuremeter test, and
V 5 p/4! LD – V (1)
~
o i i
particularly the calibration procedures, may present a safety hazard to the
operator and persons assisting in the test. The blowout of the probe if on
where:
the ground or at shallow depth in the hole may cause injuries from flying
D 5 inside diameter of the heavy duty steel casing or pipe,
i
debris. Wearing protective devices over the eyes and face or other
and
measures such as putting the probe in a protective cylinder during
L 5 length of the measuring cell.
calibration are recommended.
The volume loss (V ) of the instrument for a particular
c
7.2.1 Apply pressures in 10-kPa increments for ProcedureA
pressure is obtained by using the factor a corresponding to the
and hold for 1 min. Make volume readings after 1-min elapsed
slope of the volume versus pressure calibration plot (Fig. 2) as
time. When Procedure B is used, increase the volume of the
follows:
probe in increments equal to 5% of the nominal volume of the
V 5 V –aP (2)
c r r
measuring portion of the uninflated probe (V ). Apply the
volume increase in about 10 s and hold constant for 1 min. This volume loss correction (V ) must be deducted from the
c
Continue steps in both procedures until the maximum probe measured volumes during the test. This correction is relatively
volume is reached. Plot results using a pressure versus volume small in soils and can be neglected if the correction is less than
plot. The obtained curve is the pressure calibration curve. The 0.1 % of the nominal volume of the measuring portion of the
pressure correction (P )is the pressure loss obtained from the uninflated probe (V ) per 100 kPa (1 tsf) of pressure. In very
c 0
calibration for the volume reading (V ) (Fig. 2). hard soils or rock, the correction is significant and must be
r
7.2.2 The pressure correction (P ) must be deducted from applied. In no case should this correction exceed 0.5 % of the
c
the pressure readings obtaine
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