DE102021134241A1 - Unconsolidated rock specimens and method for producing the unconsolidated rock specimens - Google Patents

Abstract

The invention relates to a method for producing a cylindrical, completely liquefied test body (12, 15) whose internal structure corresponds to a soft rock structure which is established after demonstrably complete liquefaction and subsequent consolidation. Furthermore, a test body arrangement is described, which is used to carry out the method.

Description

The field of application of the invention is in soil physics, the production of cylindrical loose rock specimens that are used in particular for triaxial tests.

Soft rock behaves like a liquid when the pore water pressure increases to such an extent that the effective stresses become zero and the load on the liquefied soil element is completely absorbed by the pore fluid.

In situ, loosely bedded, water-saturated soils liquefy when dynamically excited by earthquakes, blasting, etc., or soils with zero residual shear strength when the ultimate strength has been exceeded.

From soil-physical testing practice, the active expert is well aware that soils with the same material and condition-descriptive characteristics with the same stress state can exhibit qualitatively different settlement, sagging, water permeability and strength behavior depending on the genesis.

Key figures describing the material are, for example, grain density, grain size distribution, the number of pores in loose and dense storage, the proportion of organic components and the rounding and texture coefficients.

Indicators that describe the condition are, for example, the proportion of pores, the density, the water content and the saturation number. The state of stress is characterized by the size of the effective principal stresses and the pore water pressure.

The genesis of the soft rock includes the way in which the structure was built up through deposition and the development of the main stresses, the point in time at which the groundwater rose and, if applicable, external events influencing the condition of the soft rock, such as compaction measures or the like.

For a laboratory investigation of the settlement, subsidence, water permeability and strength properties at one point in a soil layer, an undisturbed soil sample can be taken right there and examined in the laboratory. The test results apply exactly to the soft rock sample of this soft rock in the present state and for the stress state set in the laboratory test.

A soil sample taken from a different location, i.e. a sample of loose rock, will usually have other material and condition-descriptive characteristics for a laboratory test with a comparatively set same stress state.

This means that it is not immediately possible to determine the settlement, sagging, water permeability and strength behavior of a soil.

Such a determination only ever applies to soil with the same material-descriptive key figures and the same structure.

This means that for a more precise determination, several tests must be carried out on one soil at different conditions and stresses.

When using undisturbed samples for such tests, identical key figures describing the material cannot be guaranteed due to the different sampling locations. An undisturbed sample or soil sample is obtained from the surrounding soil structure without disturbing the soil structure. Taking the undisturbed sample requires a special technique, such as hammering in or pressing in hollow cylinders of a defined volume or taking soil samples using freezing methods.

In particular, anthropogenically produced heaps such as dumps are usually very inhomogeneously structured with regard to the local distribution of the material-descriptive key figures. In addition, the indicators describing the condition of the undisturbed samples only cover a small part of the possible range of variation of the indicators describing the condition.

This means that undisturbed soil samples are unsuitable as loose rock specimens for tests to determine the settlement, subsidence, water permeability and strength behavior, also because the variation in the characteristic numbers describing the condition is too small.

For this reason, a large number of manufacturing processes for triaxial loose rock specimens, i.e. for loose rock specimens on which triaxial tests are carried out, have already been developed, which are intended to reproduce the defined genesis of a structure.

These manufacturing processes mostly relate to man-made fills, since such fills pose a risk to the public excluded and therefore mostly laboratory tests have to be carried out.

State-of-the-art are manufacturing processes that have not been published by the laboratories, which simulate the structure build-up by earth-moist collapse, flushing into sinks or dumping in water.

Proceeding from this state of the art, the object of the invention is to produce a loose rock specimen whose inner structure corresponds to a completely liquefied loose rock. In other words, a manufacturing process is used to produce verifiably liquefied loose rock specimens suitable for further investigation of settlement, subsidence, water permeability and strength behavior in the static triaxial device.

Such a production method for the production of an “artificial loose rock test body”, the internal structure of which corresponds to a completely liquefied loose rock and the described use of a triaxial device for carrying out the production method, is not known to date.

It is known that only loosely packed, water-saturated, cohesive sands are liquefiable at all. Thus, only these loosely stored, water-saturated, non-cohesive sands can be the starting point for the production of test specimens, the aim of which is a completely liquefied test specimen.

It is also known that loose, non-cohesive soft ground specimens are not able to stand on their own, so the soft ground specimens have to be supported.

In the following the invention will be explained in more detail, with the 1 a triaxial device 100 with an unliquefied loose rock specimen 12 and the 2 shows the triaxial device 100 with a completely liquefied loose rock specimen 15.

In the figures, the same reference numbers are used for the same components. It is asked that 1 and 2 to be considered in a synopsis. In addition, for the sake of simplicity, the sample material of the unconsolidated rock test body is only referred to below as non-liquefied test body 12 or completely liquefied test body 15 ).

A triaxial device 100, known per se, in which settlement, subsidence, water permeability and strength behavior is carried out in a known manner, is used according to the invention to produce a fully liquefied test body 15 in the laboratory with the internal structure of a loose rock sample of a loose rock structure, which according to after complete liquefaction and subsequent consolidation.

• Aus einem verflüssigungsfähigen Lockergestein wird durch Einrieseln des erdfeuchten Materials, wenn nötig zur Entfernung von groben Bestandteilen über ein grobes Sieb, ein sehr lockerer, makroporenhaltiger unverflüssigter zylindrischer Probekörper 12 gefertigt, in dem das Material in einen Zylinder mit einer elastische Hülle 13, insbesondere einer Gummihülle verbracht wird.

The procedure is as follows:

• A very loose, non-liquefied cylindrical specimen 12 containing macropores is produced from a liquefiable loose rock by trickling in the earth-moist material, if necessary to remove coarse components via a coarse sieve, in which the material is placed in a cylinder with an elastic sleeve 13, in particular a rubber sleeve is spent.

First, the sample base plate 11 shown in the figures is connected to a lower open end of the elastic sleeve 13 .

Fastening elements 6 are used for this purpose, with elastic rings, in particular rubber rings, being used in a preferred embodiment, as a result of which the elastic sleeve 13 is sealed in a gas-tight manner.

A static filling support element (not shown) is attached to the lateral surface of the at least one test body base plate 11 by means of at least one further fastening element (not shown), which is later removed again. For example, two cylindrical half-shells are used as the filling support element. The upper open end of the elastic sleeve 13 is also temporarily connected to the upper end of the filling support element, in particular the two cylindrical half-shells, by means of at least one other fastening element, also not shown.

The cavity of the cylinder thus formed, which is still open at the top and closed at the bottom, is then filled with the sample material.

Then a specimen head plate 3 is put on, with the elastic sleeve 13 preferably being fastened in a gas-tight manner to the lateral surface of the at least one specimen head plate 3 by means of a similar at least one fastening element 6 (elastic rings, in particular rubber rings).

The specimen top plate 3 has a filter stone 16 which is connected to an openable line 17A shown in the figures creates a connection between the otherwise gas-tight cavity or the sample material arranged therein and the environment.

It is essential that the filling support element, in particular the two cylindrical half shells, have an inner diameter which corresponds to the outer diameter of the test body bottom plate 11 and the test body top plate 3 formed by the lateral surfaces. This ensures that the sample material is statically supported in the cylinder designed as an elastic sleeve 13 and the elastic sleeve 13 with the filled sample material does not collapse and has the predetermined geometric shape of a cylinder.

The top surface of the cylindrical specimen 12 is thus formed by the specimen top plate 3 . The base of the cylindrical specimen 12 is formed by the specimen base plate 11 . The outer surface of the cylindrical specimen 12 is formed by the elastic sleeve 13, which is supported by the filling support element.

The thus formed precursor of a desired specimen arrangement is without the filling support element in a 1 and 2 shown triaxial cell 2, 5, 8 of the triaxial device 100 installed, the triaxial cell top plate 2 is still open, as will be explained below.

The triaxial device 100 essentially comprises a triaxial device wall 5 and the triaxial cell top plate 2 as well as a triaxial cell bottom plate 8, which when closed adjoins the triaxial device wall 5 and a closed gas-tight working space in the so-called triaxial cell 2, 5, 8 of the Form triaxial device 100.

Provision is made for a vacuum to be drawn outside the triaxial cell 2, 5, 8 via the filter block 16 arranged in the test body head plate 3 and the line 17A arranged on it in the cylinder surrounding the test body 12, which vacuum creates the specified geometric shape of the cylinder between the specimen head plate 3 and the specimen base plate 11 is statically stabilized in such a way that the preliminary stage of the desired specimen arrangement - now without a filling support element - can be arranged in the triaxial cell 2, 5, 8 of the triaxial device 100, with the the filling support element is not lost through the generated vacuum.

After installation of the cylindrical specimen 12, located in the envelope 13 and supported by vacuum, in the triaxial cell 2, 5, 8 of the triaxial apparatus 100, another static support element, referred to as the test support element 4, is again placed.

That in the 1 and 2 The test support element 4 shown forms a test support hollow cylinder which is mounted in the triaxial cell 2, 5, 8 of the triaxial device 100 on the triaxial cell base plate 8.

Two cylindrical half-shells are preferably provided as the test support element 4, which, in contrast to the filling support element, are not arranged directly on the cylindrical lateral surface of the elastic sleeve 13 of the cylindrical test body 12, but on the cylindrical lateral surface of the elastic sleeve 13 of the cylindrical test body 12 can be located remotely, as will be explained in more detail below.

After installing the test support element 4 designed as a test support cylinder or the cylindrical half-shells used for this purpose, the desired test specimen arrangement is available.

The test specimen arrangement is characterized by the geometrically specified and statically stable cylinder, the test specimen 12 in the elastic sleeve 13 with the non-liquefied sample material arranged therein and the test specimen top plate 3 arranged above and the test specimen base plate 11 arranged below, with the Test support element 4 designed as a hollow cylinder (half shells) is arranged in such a way that its inner diameter d _i,z is larger than the outer diameter of the cylindrical body of the test specimen 12.

The inner diameter d _i,z of the test supporting hollow cylinder is slightly larger than the outer diameter formed by the fastening elements 6, in particular the elastic rings, in particular rubber rings and by the elastic sleeve 13, or by the test specimen top plate 3 and the test specimen bottom plate 11 .

It is intended that the inner radius r _i,z or the inner diameter d _i,z = 2r _i,z of the test support element 4 is greater than the outer radius r of the earth-moist test specimen 12 supported with negative pressure.

According to 1 the outer radius r and the height h of the earth-moist test body 12 supported with negative pressure in the starting position of the test body 12 are known. $${\mathrm{right}}_{i,\mathrm{e.g}}\ge \sqrt{\frac{{\mathrm{right}}^2\cdot H}{H-\mathrm{\Delta }{H}_v}}$$

The amount Δh _v (compare 2 ) corresponds in this equation (1) to a sample height difference, which differs from a sample height Δh _{in front of} the earth-moist test body 12 supported with negative pressure (cf 1 ) before complete liquefaction and subsequent consolidation in the starting position and a sample height Δh _after reaching an end position of the sample 15 ( 2 ) after complete liquefaction and subsequent consolidation.

The sample height difference Δh _v is determined by a preliminary test, the sample height difference Δh _v , for example the difference in the distances Δh _after - Δh _before (Δh _after > Δh _before ) according to the 1 and 2 is equivalent to.

From the 1 and 2 is further clear that the specimen head plate 3 within the test support hollow cylinder with respect to the 1 and 2 can move vertically, the vertical direction of the direction of movement (compare the double arrows P1) of a plunger 1 of the triaxial device 100 within the triaxial cell top plate 2 of the triaxial device 100 corresponds. The plunger 1 is firmly connected to the head plate 3 of the specimen. A central axis of the test specimen arrangement, which is transverse to the plates 3, 11 in the longitudinal extension of the specimen 12, corresponds to a central axis of the pressure stamp 1 of the triaxial device 100. The in the triaxial cell head plate 2 according to the illustrated double arrow P1 arranged reversibly movable plunger 1 engages in the embodiment, like the 1 and 2 point into an indentation of the specimen head plate 3.

The triaxial cell 2, 5, 8 of the triaxial device 100 is sealed gas-tight by placing the triaxial cell top plate 2 on it. The line 17 is led out of the triaxial cell 2, 5, 8 of the triaxial device 100, as is not shown in detail.

To the triaxial cell 2, 5, 8 of the triaxial device 100, a ventilation line 14A with a shut-off valve 14 that can be opened is also connected.

A cell pressure line 9A with a shut-off valve 9 that can be opened is connected to the triaxial cell 2, 5, 8 of the triaxial device 100.

A pore water pressure line 7A with an openable shut-off valve 7 is also connected to the triaxial cell 2, 5, 8 of the triaxial device 100, the pore water pressure line 7A being connected to a further filter stone 10 which is arranged in the test specimen base plate 11.

The use of the pore water pressure line 7A within the scope of this invention will be explained below.

After all lie according to 1 the structural and procedural prerequisites in order to produce the inner structure of the earth-moist specimen 12, which corresponds to a specific loose rock structure, which is established after demonstrably complete liquefaction and subsequent consolidation.

The manufactured internal structure of the fully liquefied test body with the reference number 15 according to 2 corresponds to the structure of completely liquefied unconsolidated rock, which is formed after liquefaction from the liquefied gas-water-solid suspension (solid = sample material) through consolidation as a result of the decreasing pore water pressure.

In other words, 2 illustrates the cylindrical, completely liquefied loose rock specimen 15, the internal structure of which corresponds to a loose rock structure that has been proven to occur after complete liquefaction and subsequent consolidation.

This desired internal structure of the liquefied specimen 15 is produced as follows.

• Nach dem Einbau in die Triaxialzelle 2, 5, 8 des Triaxialgerätes 100 ist vorgesehen, dass der Probekörper 12 gemäß 1, insbesondere anisotrop konsolidiert wird. Dazu werden mittels des Druckstempels 1 geringe Spannungen vorzugsweise im Bereich zwischen 40 kPa und 100 kPa auf den Probekörper 12 aufgebracht, die durch eine Bewegung des Druckstempels 1 in Richtung des Probekörpers 12 aufgebracht werden.

Consolidating Specimen 12 in Static Triaxial Apparatus 100:

• After installation in the triaxial cell 2, 5, 8 of the triaxial device 100, it is provided that the specimen 12 according to FIG 1 , in particular anisotropically consolidated. For this purpose, low stresses, preferably in the range between 40 kPa and 100 kPa, are applied to the test specimen 12 by means of the pressure stamp 1 , which stresses are applied by moving the pressure stamp 1 in the direction of the test body 12 .

In a preferred embodiment of the method, provision is made for the proportion of air in the sample material in the test body 12 to be replaced by carbon dioxide before, during or after this consolidation. For this purpose it is provided that the test body 12 is flowed through with carbon dioxide.

For supplying carbon dioxide, the pore water pressure line 7A of the triaxial device 100 is used, which is provided with the openable shut-off valve 7 which is brought into an open state. The by the carbon dioxide from the Air displaced by the pores can escape from the test specimen 12 via the filter stone 16 and the line 17A leading out of the triaxial device 100 to the outside, in which the openable shut-off valve 17 is arranged.

• Anschließend ist vorgesehen, dass der Probekörper 12 von unten (über die Probekörper-Bodenplatte 11) nach oben (in Richtung der Probekörper-Kopfplatte 3) mit einem flüssigen Fluid, insbesondere Wasser (auf)gesättigt wird.

Saturating the specimen 12 with water, the saturation being increased by applying a counter-pressure in the triaxial cell 2, 5, 8 surrounding the specimen 12:

• It is then provided that the specimen 12 is saturated from below (via the specimen bottom plate 11) upwards (in the direction of the specimen head plate 3) with a liquid fluid, in particular water.

The pore water pressure line 7A of the triaxial device 100, which is provided with the shut-off valve 7 that can be opened and is then in the open state, is again used to supply water.

When the shut-off valve 17 is in the open state, the gas displaced from the pores can escape from the test specimen 12 via the filter stone 16 and the line 17A leading out of the triaxial device 100 and in which the openable shut-off valve 17 is arranged.

After the gas has been displaced from the pores, the check valves 7 and 17 are closed.

After the test body 12 has been saturated with water, a back pressure is generated in the test body 12 . It is provided that the total principal stresses σ ₁ and σ ₃ including the pore water pressure are increased by the same amount. The effective principal stresses σ′ ₁ and σ′ ₃ acting on the grain structure of the test specimen 12 thus remain constant.

The procedure for generating the back pressure within the specimen 12 in a triaxial device 100 is generally known to the person skilled in the art and is not explained in more detail here.

The increasing higher pore water pressure in the specimen 12 compresses the gas fractions still present in the specimen 12, as a result of which the saturation number in the specimen 12 increases. Advantageously, the liquefaction capacity of the specimen 12 increases.

• Im nächsten Verfahrensschritt wird der Probekörper 12 bis zur vollständigen Verflüssigung des Probekörpers 12 undräniert passiv gestaucht. Die Stauchung findet wiederum mittels des Druckstempels 1 statt.

Undrained passive compression of the specimen 12 until complete liquefaction, the liquefaction of the specimen 12 being controlled by measuring the principal stresses:

• In the next method step, the test body 12 is passively compressed until the test body 12 has completely liquefied and does not drain. The upsetting takes place in turn by means of the pressure die 1 .

With the desired complete liquefaction, the effective principal stresses σ′ ₁ and σ′ ₃ in the specimen 15 are equal to zero. The total vertical principal stress, the total horizontal principal stress and the pore water pressure are the same.

It is determined metrologically that when all principal stresses σ′ ₁ and σ′ ₃ are the same, the desired complete liquefaction of the test body 15 has occurred.

it will be in 2 It is particularly clear that the test support element 4 prevents the test specimen 15 arranged in the elastic sleeve 13 from flowing away.

The test body 15, which has been completely liquefied as a result of the upsetting, assumes the geometric hollow-cylindrical inner contour of the test support element 4 with the inner radius r _i,z .

The grains of the test body 15 settle in the soil/water mixture. Since the sample body 15 is still in an undrained state, a layer of water forms above the grains that have settled due to the constant volume of the sample body 15 .

• Anschließend wird der Probekörper 15 zum Zwecke des Abbaus des Porenwasserdruckes mit einer geringen Spannung konsolidiert.

Consolidate the liquefied specimen 15:

• The test specimen 15 is then consolidated with a low level of stress for the purpose of reducing the pore water pressure.

Consolidation is effected via line 17A by opening shut-off valve 17 that isolates line 17A from the atmosphere.

The water layer is pressed out of the test specimen 15 in the process. Due to the consolidation, the outer radius r of the test body 15 can again (slightly) decrease depending on the specific material properties of the sample material of the test body 15 .

The total principal stress σ ₃ (the cell pressure in the test piece 15) should suitably correspond to the absolute value of the negative pressure supporting the test piece 15 during consolidation, as explained below.

• Anschließend erfolgt das Schließen der Leitung 17A durch Schließen des Absperrventils 17, sodass der Probekörper 15 wieder von der Atmosphäre getrennt ist.

Supporting the specimen 15 after consolidation by applying a vacuum in the fully liquefied test body 15 designed as a closed cylinder:

• The line 17A is then closed by closing the shut-off valve 17 so that the test specimen 15 is isolated from the atmosphere again.

After completion of the consolidation, a supporting negative pressure is introduced into the completely liquefied sample body 15 via the line 7 by opening the associated shut-off valve 7A. At the same time, the total principal stress (σ ₃ (the cell pressure in the specimen 15) is reduced to atmospheric pressure. The effective principal stress σ' ₃ acting on the grain structure of the specimen 15 thus remains constant.

• Danach wird die Probekörper-Anordnung 4, 15 aus dem Triaxialgerät 100 nach dem Öffnen des Triaxialgerätes 100 ausgebaut.

Removal of the specimen arrangement 4, 15 from the triaxial device 100:

• After that, the specimen arrangement 4, 15 is removed from the triaxial device 100 after the triaxial device 100 has been opened.

After dismantling the test support element 4, in particular the two half-shells of the support hollow cylinder, there is a statically stable cylindrical test body 15 supported by the negative pressure in the elastic sleeve 13, the structure of which demonstrably arose after soil liquefaction. Instead of undisturbed soil samples taken on site, this specimen 15 can now be examined analogously as a fully liquefied soil sample in a laboratory, i.e. the actual laboratory investigation of the settlement, sagging, water permeability and strength properties can be carried out using this "artificially" produced, fully liquefied specimen 15 are carried out so that an on-site removal of an undisturbed soil sample is advantageously unnecessary.

Reference List

100

triaxial device

1

pressure stamp

2

Triaxial headstock

3

Specimen headstock

4

experimental support element

5

Triaxial device wall

6

fastener

7

shut-off valve

7A

pore water pressure line

8th

Triaxial device base plate

9

shut-off valve

9A

cell pressure line

10

filter element

11

Specimen floor plate

12

non-liquefied specimen [ 1 ]

13

elastic sleeve

14

shut-off valve

14A

vent line

15

completely liquefied specimen [ 2 ]

16

filter stone

17

shut-off valve

17A

vent line

2, 5, 8

triaxial cell

P1

direction of movement

Δhv

Height deformation of the specimen up to liquefaction

Δhvor

Distance before height deformation

Δhafter

Distance after height deformation

ri, z

Inner radius of the test support element 4

tue, e.g

Inner diameter of the test support element 4

right

Outer radius of specimen 12

H

Height of specimen 12

Claims (4)

Method for producing a cylindrical, completely liquefied test body (12, 15), the internal structure of which corresponds to a loose rock structure which is established after demonstrably complete liquefaction and subsequent consolidation, characterized by the steps of - placing an earth-moist, loose and macroporous non-liquefied sample material in a one-sided open cylindrical cavity which is formed by a cylindrical test body base plate (11) arranged at one end of a hollow-cylindrical elastic sleeve (13), the elastic sleeve (13) being filled by a hollow-cylindrical filling arranged on the outer lateral surface of the elastic sleeve (13). - the supporting element is held in a hollow-cylindrical form, the inside diameter of the hollow cylinder of the filling-support element corresponding to the outside diameter of the elastic sleeve (13), - closing the elastic sleeve (13) on the other end with a cylindrical test body head plate (3) forming a cylindrical test body (12), - applying a negative pressure in the test body (12) designed as a closed cylinder, - removing the filling support element, - arranging a test body designed as a hollow cylinder supporting element (4), on the outer lateral surface formed by the elastic sleeve (3), of the test body (12) designed as a closed cylinder, the inside diameter d _i,z of the hollow cylinder of the test supporting element (4) being larger than the outside diameter of the elastic sleeve (13), - inserting the closed cylinder filled with the sample material and the test support element (4) into a triaxial cell (2, 5, 8) of a static triaxial device (100), - consolidating the test specimen (12) in the static triaxial device (100), - saturating the test specimen (12) with water, the saturation being increased by applying counter-pressure in the triaxial cell (2, 5, 8) surrounding the test specimen (12), - undrained passive compression of the test specimen (12) to for complete liquefaction, whereby the liquefaction of the fully liquefied specimen (15) is controlled by measuring the principal stresses, - consolidating the fully liquefied specimen (15) liquefied specimen (15), - supporting the fully liquefied specimen (15) after consolidation Application of a negative pressure in the liquefied test body (15) designed as a closed cylinder, - removal of the test body (15) from the triaxial device (100), - removal of the test support element (4). procedure after claim 1 , characterized in that the specimen (12) is flowed through with carbon dioxide before, during or after the anisotropic consolidation. procedure after claim 1 , characterized in that the inner diameter d _i,z = 2r _i,z of the test support element (4) as a function of the outer radius r and the height h of the earth-moist test specimen (12) supported with negative pressure in a starting position of the test specimen (12) according to an equation (1) ${\mathrm{right}}_{i,\mathrm{e.g}}\ge \sqrt{\frac{{\mathrm{right}}^2\cdot H}{H-\mathrm{\Delta }{H}_v}}$

is determined, where Δh _v in this equation (1) corresponds to a sample height difference, which differs from a sample height Δh _{in front} of the earth-moist test body (12) supported with negative pressure before complete liquefaction and subsequent consolidation in the starting position of the test body (12) and a Sample height Δh _after reaching an end position of the test specimen (15) after complete liquefaction and the subsequent consolidation of the test specimen (15), with the inner diameter d _i,z = 2r _i,z of the test support element (4) being at least the outer diameter corresponds to the fastening elements (4) by means of which the elastic sleeve (13) is fastened to the cylindrical specimen top plate (3) and the cylindrical specimen bottom plate (11). Test body arrangement of a test body (12) filled with a sample material, which can be arranged in the triaxial cell (2, 5, 8) of a static triaxial device (100), characterized in that a cylindrical cavity, open on one side, of a hollow cylindrical elastic sleeve (13) has a test body base plate (11) arranged at one end is closed and can be filled with the sample material, the elastic sleeve (13) being held in a hollow cylindrical shape by a hollow-cylindrical filling support element arranged on the outer surface of the elastic sleeve (13), the inner diameter of the hollow cylinder of the filling support element corresponds to the outer diameter of the elastic sleeve (13), the elastic sleeve (13) being closed at its other end with a test body head plate (3) to form a cylindrical test body (12) and under negative pressure is set, as a result of which the hollow-cylindrical filling support element can be exchanged for a test support element (4) designed as a hollow cylinder, which is also arranged on the outer lateral surface formed by the elastic sleeve (3) of the test body (12) designed as a closed cylinder, the inner diameter d _i,z of the hollow cylinder of the test support element (4) being greater than the outer diameter of the elastic sleeve (13).

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