Forschungsgesellschaft für Straßen- und Verkehrswesen Earthworks and Foundation Engineering Task Force
Supplementary Technical
Terms and Conditions of Contract and Guidelines
for
Earthworks in Road Construction
ZTVE-StB 94
Issue 1994 as amended in 1997
14.2.5Indirect testing methods
Where it is difficult or excessively time-consuming to perform compaction
measurements and standard Proctor tests pursuant to Sections 14.2.2 and
14.2.3, e.g. because of the material properties, or such measurements and
tests cannot be conducted to the required extent because of the specified
laying performance, the following test methods which indirectly characterise
the compaction status may be adopted:
(1)Static plate pressure test to DIN 18134;
(2)Dynamic plate pressure test to TP-BF Part B 8.3
(3)Subsidence test using Benkelman's beam to TP-BF Part 9;
(4)Penetration resistance tests using ramming or pressure penetration to
DIN 4094, while special vibratory sounding rods too may be employed
for services trenches;
(5)Testing by settlement measurements following the individual compacting
passes for rockfills and soils with stones in excess of 200 mm or those
containing a major percentage of gravel and stones;
(6)Dynamic measurement of the acceleration performance of the work roller
used for compacting, or of a special gauge roller.
The test methods to be adopted in the particular case shall be indicated in
the specification.
Usually, test methods (2) and (4) can be quickly employed. Therefore, when
these methods are used, the minimum scope of testing can be increased
when compared to test methods pursuant to Sections 14.2.2 or 14.2.3, thus
adding to the statistical meaningfulness and reliability of the test results. The
scope shall be indicated in the specification.
On commencement of testing, calibration tests shall be conducted to
determine the relationship between the outcome of the test method chosen
and the required value indicated in the specification. Where this is not
required or impractical, the owner and the contractor may agree and resort to indicative figures based on own experience or accepted experience of
others, for the test method chosen, as a reference for the tests.
The following tests are recommended for testing in service trenches and in
confined workplaces:
(1)The dynamic plate pressure test to TP-BF Part B 8.3 for placement in
layers of backfill materials of all kind, or for shallow service trenches;
(2)Penetration resistance testing for preferably non-cohesive backfill
materials, using special service-trench sounding rods, for placement in
layers or for shallow service trenches (0.7 metres deep);
(3)Penetration resistance testing by means of ramming penetration to
DIN 4094, for preferably non-cohesive backfill materials and deep
service trenches.
14.3Testing the modulus of resilience on the formation
To test the bearing and deformation performance of the formation as a
supporting medium for the pavement, compliance with the requirements
applicable to the modulus of resilience Eν2 pursuant to Section 3.4.7.2 shall
be demonstrated. To this end, the methods M 1, M 2 or M 3 as per Section
14.1 shall be adopted by analogy.
characterise
Testing shall be conducted by employing the static plate pressure test to
DIN 18134 or, alternatively, by means of the following test methods:
(1)Dynamic plate pressure test to TP-BF Part B 8.3
(2)Subsidence test using Benkelman's beam to TP-BF Part 9;
(3)Dynamic measurement of the acceleration performance of the work roller
used for compacting, or of a special gauge roller.
The dynamic moduli or subsidence derived from the alternative test methods call for prior calibration using the modulus of resilience Eν2, or reference to
existing and accepted empirical values. Application of these test methods
shall be subject to prior agreement between the owner and the contractor.
Reference to alternative test methods called for or to be ruled out shall be
included in the specification.
Testing the modulus of resilience on the formation shall not be required
where
(1)the foundation or the substructure is consolidated by means of binders,
or
(2)it is ensured on the grounds of local experience or through compaction
tests that the required moduli of resilience are achieved.
Forschungsgesellschaft für Straßen- und Verkehrswesen Local Road Construction Working Committee
Supplementary Technical
Terms and Conditions of Contract and Guidelines
for
Excavations and Digging-up in Traffic Areas
ZTVA-StB 97
Issue 1997
1.7.2Testing the compaction in earthworks
1.7.
2.1Test methods
The test method to be employed to verify the compaction shall be
coordinated jointly with the contracting body and the relevant transport
department or authority.
1.7.
2.1.3Dynamic plate pressure test as an indirect test method
Instead of performing a static plate pressure test, an investigation may be
conducted using the dynamic plate pressure test to TP BF-StB Part B 8.3.
The setup is particularly suited for service-trench construction as the test
can be quickly performed by an operator. The scope of testing can be
increased as necessary; also, tests of the individual layers placed
(thickness not greater than 30 cm) can be readily performed.
Assessment of the E vd value measured is a function of the backfill
material. Correlation values relating to the static plate pressure test for the
soil prevailing or intended to be backfilled shall be determined by way of
attempt.
To this end, one may resort to correlation values regionally available with
road construction offices, civil engineering offices, public utility
undertakings, or earthworks testing institutes.
For non-cohesive backfill materials, correlation values can be readily
determined (Annex 14).
For cohesive soils, checking the moisture content is an additional
requirement.
1.7.
2.1.4Penetration resistance tests as an indirect test method
Assessment of trench backfilling is also possible by penetration resistance
tests using ramming or pressure penetration to DIN 4094 or other
equipment developed for this purpose.
The minimum required number of impacts shall be determined for the
required degree of compaction for the types of soils involved.
To this end, empirical values available with the relevant transport
department or public utility undertaking may be used as a basis. When the
lightweight sounding rod is driven displacement of soil causes the top
zone to loosen. Therefore, the numbers of impacts within the upper 50 cm
are not suited for comparison. It is recommended to load the bottom plate
by means of an appropriate equivalent load (concrete rings or the like) so
that comparable figures are achieved at from the top edge of trench
backfill.