NL2031968A - A device and method for saturation of cohesionless Soil with large grain size in hollow cylindrical torsional shear test - Google Patents

A device and method for saturation of cohesionless Soil with large grain size in hollow cylindrical torsional shear test Download PDF

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Publication number
NL2031968A
NL2031968A NL2031968A NL2031968A NL2031968A NL 2031968 A NL2031968 A NL 2031968A NL 2031968 A NL2031968 A NL 2031968A NL 2031968 A NL2031968 A NL 2031968A NL 2031968 A NL2031968 A NL 2031968A
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specimen
pipeline
valve
sealed space
pressure chamber
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NL2031968A
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Dutch (nl)
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NL2031968B1 (en
Inventor
Zhang Jisheng
Han Shuang
Zhai Qiu
Zhao Hongyi
Wang Huakun
Zheng Jinhai
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Univ Hohai
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N3/24—Investigating strength properties of solid materials by application of mechanical stress by applying steady shearing forces
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L21/00—Vacuum gauges
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L21/00—Vacuum gauges
    • G01L21/02—Vacuum gauges having a compression chamber in which gas, whose pressure is to be measured, is compressed
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N3/02—Details
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N3/22—Investigating strength properties of solid materials by application of mechanical stress by applying steady torsional forces
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/0014—Type of force applied
    • G01N2203/0025—Shearing
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/02—Details not specific for a particular testing method
    • G01N2203/025—Geometry of the test
    • G01N2203/0256—Triaxial, i.e. the forces being applied along three normal axes of the specimen
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/02—Details not specific for a particular testing method
    • G01N2203/026—Specifications of the specimen
    • G01N2203/0284—Bulk material, e.g. powders
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/24—Earth materials

Abstract

A device and method for saturation of cohesionless Soil with large grain size in hollow cylindrical torsional shear test. The present invention falls into the field of 5 Geotechnical Engineering, and specifically relates to a device and method for saturation of cohesionless soil with large grain size in hollow cylinder apparatus torsional shear tests. It includes a hollow cylinder apparatus, a specimen that is installed in the hollow cylinder apparatus, an inner and outer pressure chamber that are formed inside and outside of the specimen, a first seal box to which the top of the specimen is connected 10 through a first pipeline with a valve, a first vacuum pump that is connected to the top of the first seal box through a second pipeline with a valve, a second seal box to which the bottom of the specimen is connected through a third pipeline with a valve, a second vacuum pump that is connected to the top of the second seal box through a fourth pipeline with a valve, a first cell pressure device to which the bottom of the outer 15 pressure chamber is connected through the fifth pipeline with valve, a second cell pressure device to which the bottom of the inner pressure chamber is connected through the seventh pipeline with valve. In the present invention, the difference of vacuum degree between the top and bottom of the specimen is relatively small, which can make the effective confining pressure at different heights of the specimen become more 20 evenly distributed, and can minimise the influence of the saturation process on the subsequent test results. [figure 1]

Description

A device and method for saturation of cohesionless Soil with large grain size in hollow cylindrical torsional shear test
The present invention falls into the research field of Geotechnical Engineering, specifically relates to a saturation device and method for hollow cylindrical torsional shear test of cohesionless soil with large grain size.
Background
With the development in the discipline of geotechnical engineering, cohesionless soils with large grain size such as calcareous sand and sand pebbles become more and more widely used in real-life and production processes as construction materials, dam back-filtration materials and foundation treatment materials. The hollow cylindrical specimens are capable of achieving complex cyclic loading conditions such as continuous rotation of the principal stress axis induced by wave, traffic, earthquake and other loads, which provides a complete experimental technology to explore the static and dynamic properties of dam building materials and foundation treatment materials under various complex stress conditions. The saturation process of the specimen during the test is an essential factor affecting accuracy of the test results.
At present, the saturation method for cohesionless soil specimens in the hollow cylindrical torsional shear test normally uses the backpressure saturation method, in which the air inside the specimen is compressed by increasing the back pressure inside the specimen, meanwhile increasing the cell pressure to keep the effective confining pressure at a low level. Once the air in the specimen has been compressed and stabilized, open the exhaust valve to discharge the gas outward.
Among them, the back pressure saturation method suddenly decrease the back pressure to atmospheric pressure in the process of air bubble discharge, while the cell pressure is still at a high level, so that the effective confining pressure suddenly increased. This will produce pre-solidification process on the specimen, hence affecting the test state of the specimen and the subsequent test results. Moreover, due to the high porosity of large-size cohesionless soil, the effect of removing air bubbles in the process of back-pressure saturation will become less obvious as the degree of saturation increases. This means that it may take a long duration for the complement of the saturation process.
Invention Content
To overcome the above mentioned shortage, the present invention provides a device and method for saturation of cohesionless soil with large grain size in hollow cylindrical torsional shear test, and specify the following technical solutions:
A saturation device for hollow cylindrical torsional shear test of cohesionless soil with large grain size, comprises a hollow cylinder apparatus, a specimen that is mounted between a base and a coupling sensor in the lower and upper part of the mentioned hollow hollow cylinder apparatus, respectively. The mentioned specimen is covered with a rubber membrane. The top and bottom of the mentioned rubber membrane are attached to the coupling sensor and base respectively and sealed by seal rings. The mentioned central cavity of the specimen forms an inner pressure chamber, while the mentioned rubber membrane and the outer wall of the hollow cylindrical torsion shear apparatus form an outer pressure chamber. The top of mentioned specimen is connected to the first seal box outside the hollow cylinder apparatus through the first pipeline with valve. The top of the mentioned first seal box is connected to the first vacuum pump through the second pipeline with valve. The bottom of mentioned specimen is connected to the second seal box outside the hollow cylinder apparatus through the third pipeline with valve. The top end of the mentioned second seal box is connected to the second vacuum pump via a fourth line with valve. The bottom end of the mentioned outer pressure chamber is connected to the first cell pressure device outside the hollow cylinder apparatus via a fifth line with valve while the bottom end of the mentioned inner pressure chamber is connected to the second cell pressure device outside the hollow cylindrical torsion shear apparatus via a seventh line with valve.
Additionally, the mentioned first cell pressure device includes a third seal box. The bottom end of the mentioned outer pressure chamber 1s connected to the third seal box through a fifth line. The top end of the mentioned third seal box is connected to a third vacuum pump through a sixth line with a valve. The mentioned second cell pressure device includes a fourth seal box. The bottom end of the mentioned inner pressure chamber is connected to the fourth seal box through a seventh line. The top end of the mentioned fourth seal box is connected to a fourth vacuum pump through an eighth line with a valve.
Additionally, the mentioned first seal box, second seal box, third seal box, and fourth seal box are all provided with exhaust lines with valves at the top.
Additionally, the mentioned first seal box is connected to the second seal box by a water circulation channel with a valve.
Additionally, the mentioned first pipeline penetrates into the first seal box for a length greater than 80% of the thickness of the first seal box itself. The mentioned third pipeline penetrates into the second seal box for a length greater than 80% of the thickness of the second seal box itself. Both ends of the mentioned water circulation channel penetrate into the first seal box and the second seal box for a length greater than 80% of the thickness of the corresponding seal box, respectively.
Additionally, the mentioned second pipeline, fourth pipeline, sixth pipeline and eighth pipeline are provided with a vacuum pressure gauge and a valve regulator.
A method for saturation of cohesionless soil with large grain size in hollow cylindrical torsional shear test comprises the following procedures: sl Open one of the valves on either the first or the third pipeline while keep the other valve closed, in this way one of the pipeline will be unblocked while the other one will be closed. Open the vacuum pump at the top of the seal box that is directly connected to the unblocked pipeline, then keep vacuumizing for a while. Close the valve between the vacuum pump and the seal box when the vacuum pressure reaches 10-20 kPa and hold for a while. The specimen is completely sealed when there is no change in the readings of the vacuum pressure, otherwise reinstall the specimen and repeat the procedure, i.e, sl, s2 Close the valve on the third pipeline, vacuum until the pressure at the top of the specimen reach the target value. Wait until the vacuum pressure throughout the specimen becomes stable, then vacuum the outer pressure chamber and the inner pressure chamber until their vacuum pressure readings reach the target value. While keeping the valve on the third pipeline closed, pre- adjust the vacuum pressure of the second seal box to be equal to those at the top of the specimen and wait until the pressure becomes stable. Open the valve on the third pipeline, wait until the vacuum pressure throughout the specimen becomes stable then adjust the vacuum pressure at the bottom of the specimen to the target value. On this basis, the first stage of seepage saturation can be carried out, s3 When there are no more bubbles discharged from the pipeline at the outflow end of the specimen or the volume of water discharged from the pipeline at the outflow end of the specimen is larger than the volume of the specimen itself, close the valve on the third pipeline and increase the target value of vacuum pressure at the top of the specimen, the bottom of the specimen, the outer pressure chamber and the inner pressure chamber by 10-30 kPa respectively. Notably, vacuum the top of the specimen, the bottom of the specimen, the outer pressure chamber and the inner pressure chamber in the same way as those in step s2 until they reach the increased magnitude of target value respectively. On this basis, the second stage of seepage saturation can be carried out, s4, Repeat the procedure of the second stage of seepage saturation in step s3 until the final saturation requirement is met.
Additionally, when performing the first stage or the second stage of seepage saturation, ensure that the vacuum target in the inner pressure chamber is greater than that in the outer pressure chamber vacuum target, the vacuum target at the top of the specimen is greater than that at the outer pressure chamber, the vacuum target at the top of the specimen is greater than that in the inner pressure chamber, the vacuum target at the bottom of the specimen is greater than that in the outer pressure chamber, the vacuum target at the bottom of the specimen is greater than that in the inner pressure chamber, the vacuum target at the top of the specimen is not equal to that at the bottom of the specimen.
Compared to the current state of the art, the beneficial effects of the present invention are:
The present invention can create a vacuum pressure state inside and outside the specimen at the same time by adjusting the vacuum degree inside and outside the pressure chamber and the specimen itself. This can effectively expand the volume of bubbles in the specimen, facilitate the discharge of bubbles, and thus greatly improve the efficiency of seepage saturation. Also, the difference of vacuum degree between the top and bottom of the specimen is relatively small, which can make the effective confining pressure at different heights in the specimen become more uniformly distributed, hence avoiding the influence of the saturation process on the subsequent test results.
Graph Supplement
Figure 1 shows a schematic diagram of the device structure of the present invention.
Figure 2 shows a flow chart of the implementation method of the present invention. 1-Hollow cylinder apparatus, 2-Base, 3-Coupling sensor, 4- Specimen, 5-Rubber 5 membrane, 6-Seal, 7-Inner pressure chamber, 8-Outer pressure chamber, 9-First pipeline, 10-First seal box, 11-First vacuum pump, 12-Third pipeline, 13-Second seal box, 14-Second vacuum pump, 15- Fifth pipeline, 16-Third seal box, 17-
Third vacuum pump, 18-Seventh pipeline, 19-Fourth seal box, 20-Fourth vacuum pump, 21-Vacuum pressure gauge, 22-Valve regulator, 23-Exhaust line, 24- Water circulation channel.
Specific Implementation Method
The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. It is noteworthy that the described embodiments are only part of the embodiments of the present invention, and not all of them. Based on the embodiments in the present invention, all other embodiments obtained by a person of ordinary skill in the art without making creative labour will fall within the scope of protection of the present invention.
Refer to Figs. 1-2, a saturation device for hollow cylindrical torsion shear test of cohesionless soil with large grain size, comprise a hollow cylinder apparatus 1. A specimen 4 is installed between a base 2 and a coupling sensor 3 in the lower and upper part of the mentioned hollow cylinder apparatus 1, respectively. The mentioned specimen 4 is equipped with a rubber membrane 5. Both ends of the mentioned rubber membrane 5 are attached to the base 2 and coupling sensor 3 and sealed by a seal ring 6. The mentioned central cavity of the specimen 4 forms the inner pressure chamber 7.
The rubber membrane 5 and the outer wall of the hollow cylinder apparatus 1 form the outer pressure chamber 8. The top of the specimen 4 is connected to the first seal box 10 outside the hollow cylinder apparatus 1 through the first pipeline 9 with valve. The top of the first seal box 10 is connected to the first vacuum pump 11 through the second pipeline with valve. The bottom of the specimen 4 is connected to the first vacuum pump 11 through the third pipeline 12 with valve. The bottom of the mentioned specimen 4 is connected to the second seal box 13 outside the hollow cylinder apparatus 1 through the third line 12 with valve. The top of the mentioned second seal box 13 is connected to the second vacuum pump 14 through the fourth line with valve. The bottom of the mentioned outer pressure chamber 8 is connected to the first cell pressure device outside the hollow cylinder apparatus 1 through the fifth line 15 with valve. The bottom of the mentioned inner pressure chamber 7 is connected to the second cell pressure device outside the hollow cylinder apparatus 1 through the seventh line 18 with valve. The mentioned first cell pressure device includes a third seal box 16. The bottom of the mentioned outer pressure chamber 8 is connected to the third seal box 16 through the fifth line 15. The top of the mentioned third seal box 16 is connected to the third vacuum pump 17 through a sixth line with valve. The mentioned second cell pressure device includes a fourth seal box 19. The top of the mentioned fourth seal box 19 is connected to the fourth vacuum pump 20 through the eighth line with valve. The top of the mentioned first seal box 10, second seal box 13, third seal box 16 and fourth seal box 19 are all provided with the exhaust line 23 with valve. The first and second cell pressure devices can create negative pressure inside and outside the specimen 4 at the same time by adjusting the vacuum level of the inner and outer pressure chambers.
This can effectively expand the volume of air bubbles inside the specimen 4, facilitate the discharge of air bubbles, and thus greatly improve the efficiency of seepage saturation.
In this embodiment, the mentioned first seal box 10 is connected to the second seal box 13 by a water circulation channel 24 with valve. This facilitates the transfer of water between two seal boxes without having to disassemble the device during the process of saturation.
In this embodiment, the mentioned first pipeline 9 penetrates into the first seal box 10 at a length greater than 80% thickness of the first seal box 10 itself.
The mentioned third pipeline 12 penetrates into the second seal box 13 at a length greater than 80% thickness of the second seal box 13 itself. Both ends of the mentioned water circulation channel penetrate into the first seal box 10 and the second seal box 13 at a length greater 80% thickness of the corresponding seal box respectively. This can ensure that the water can still be absorbed by the pipeline and the water circulation channel when the liquid in the seal box falls to a small level.
In this embodiment, the second pipeline, the fourth pipeline, the sixth pipeline and the eighth pipeline are all provided with a vacuum pressure gauge 21 and a valve regulator 22. The vacuum pressure gauge 21 can be used to monitor the vacuum level, while the valve regulator 22 can adjust the pressure of the pipeline.
A method for saturation of cohesionless soil with large grain size in hollow cylindrical torsional shear test comprises the following procedures: sl Open one of the valves on either the first or the third pipeline while keep the other valve closed, in this way one of the pipelines will be unblocked while the other one will be closed. Open the vacuum pump at the top of the seal box that is directly connected to the unblocked pipeline, then keep vacuumizing for a while. Close the valve between the vacuum pump and the seal box when the vacuum pressure reaches 10-20 kPa and hold for a while. The specimen is completely sealed when there is no change in the readings of the vacuum pressure, otherwise reinstall the specimen and repeat the procedure, i.e, sl, s2 Close the valve on the third pipeline, vacuum until the pressure at the top of the specimen reach the target value. Wait until the vacuum pressure throughout the specimen becomes stable, then vacuum the outer pressure chamber and the inner pressure chamber until their vacuum pressure readings reach the target value. While keeping the valve on the third pipeline closed, pre- adjust the vacuum pressure of the second seal box to be equal to those at the top of the specimen and wait for the pressure to become stable. Open the valve on the third pipeline, wait for the vacuum pressure throughout the specimen to become stable then adjust the vacuum pressure at the bottom of the specimen to the target value. On this basis, the first stage of seepage saturation can be carried out, s3 When there are no more bubbles discharged from the pipeline at the outflow end of the specimen or the volume of water discharged from the pipeline at the outflow end of the specimen is larger than the volume of the specimen itself, close the valve on the third pipeline and increase the target value of vacuum pressure at the top of the specimen, the bottom of the specimen, the outer pressure chamber and the inner pressure chamber by 10-30 kPa respectively. Notably, vacuum the top of the specimen, the bottom of the specimen, the outer pressure chamber and the inner pressure chamber in the same way as those in step s2 until they reach the increased magnitude of target value respectively. On this basis, the second stage of seepage saturation can be carried out,
s4 Repeat the procedure of the second stage of seepage saturation in step s3 until the final saturation requirement is met.
In this embodiment, during the first stage of saturation, the difference between the target value of vacuum pressure in the inner and outer pressure chamber is 10-20 kPa. When the difference between the target value of vacuum pressure at the top and bottom of the specimen is 10-40 kPa, the difference between the target value of vacuum pressure at the bottom of the specimen and in the outer pressure chamber is 20-30 kPa, meanwhile the difference between the target value of vacuum pressure at the bottom of the specimen and in the inner pressure chamber is 10-20 kPa. Correspondingly, the direction of water seepage in specimen 4 is from the bottom to the top. When the difference between the target value of vacuum pressure at the top and bottom of the specimen is +10-+40 kPa (the symbols before and after should be kept consistent), the difference between the target value of vacuum pressure at the top of the specimen and in the outer pressure chamber is 20-30 kPa, meanwhile the difference between the target value of vacuum pressure at the top of the specimen and in the inner pressure chamber is 10-20 kPa. Correspondingly, the direction of water seepage in specimen 4 is from the top to the bottom.
In this embodiment, when carrying out the first and second stage of seepage saturation, we have that vacuum target in the inner pressure chamber is greater than that in the outer pressure chamber, the vacuum target at the top of the specimen is greater than that in the outer pressure chamber, the vacuum target at the top of the specimen is greater than that in the inner pressure chamber, the vacuum target at the bottom of the specimen is greater than that in the outer pressure chamber, the vacuum target at the bottom of the specimen is greater than that in the inner pressure chamber, the vacuum target at the bottom of the specimen is greater than that in the inner pressure chamber. This is done mainly for three purposes, the first is to maintain a negative pressure inside the specimen 4, amplifying the air bubbles in the void; the second is to make the value of pressure in the inner and outer chambers become negative as well, meanwhile ensure that the vacuum in the inner and outer pressure chambers are all smaller than that inside the specimen 4 while the pressure difference inside and outside the specimen 4 is relatively small, then the effective confining pressure in the process of seepage saturation can be maintained at a small level,
the third is to make the vacuum at the top and bottom of the specimen become different, so that the amplified air bubbles can be driven out of the specimen by the seepage flow that is formed in the pores of the specimen 4 due to the pressure difference. «
It should be noted that the specific value of the difference between the vacuum target at the top and bottom of the specimen during the saturation process of the second stage can be different from those during the first stage when the effective confining is kept consistent. For example, while the difference between the vacuum target at the top and bottom of the specimen in the first saturation stage is 20 kPa, the difference between the vacuum target at the top and bottom of the specimen in the second saturation stage can be 30 kPa.
Alternatively, the difference between the vacuum target at the top and bottom of the specimen in the first stage can be 20 kPa, whereas the difference between the vacuum target at the top and bottom of the specimen during the second saturation stage can be -20 kPa.
The embodiment mentioned above is only one of the representative examples without confining the technical scope of the present invention. Any minor modifications, equivalent changes and modifications made to the embodiments mentioned above are still within the scope of the technical solution of the present invention.

Claims (8)

ConclusiesConclusions 1. Verzadigings-inrichting voor een torsie-afschuifproef in een holle cilinder van bodemsoorten zonder cohesie met een grote korrelgrootte met het kenmerk dat deze een toestel met een holle cilinder omvat. In dit toestel met een holle cilinder wordt een specimen geïnstalleerd tussen de basis onderaan en de koppelsensor bovenaan. Dit specimen is uitgerust met een rubberen membraan. Beide uiteinden van dit membraan worden bevestigd aan de basis en de koppelsensor, en worden afgedicht met een afdichtring. Deze centrale holte van het specimen vormt een binnenste drukkamer terwijl dit rubberen membraan en de buitenwand van het toestel met een holle cilinder de buitenste drukkamer vormen. De bovenzijde van dit specimen is verbonden met de eerste afgedichte ruimte buiten het toestel met een holle cilinder door middel van de eerste pijpleiding die is voorzien van een klep. De bovenzijde van deze eerste afgedichte ruimte is verbonden met de eerste vacuümpomp door middel van de tweede pijpleiding die is voorzien van een klep. De onderzijde van dit specimen is verbonden met de tweede afgedichte ruimte buiten het toestel met een holle cilinder door middel van de derde pijpleiding die is voorzien van een klep. De bovenzijde van deze tweede afgedichte ruimte is verbonden met de tweede vacuümpomp door middel van de vierde pijpleiding die is voorzien van een klep. De onderzijde van deze buitenste drukkamer is verbonden met de eerste inrichting met drukcellen buiten het toestel met een holle cilinder door middel van de vijfde pijpleiding die is voorzien van een klep. De onderzijde van deze binnenste drukkamer is verbonden met de tweede inrichting met drukcellen buiten het toestel met een holle cilinder door middel van de zevende pijpleiding die is voorzien van een klep.CLAIMS 1. Saturation device for a torsional shear test in a hollow cylinder of non-cohesive soils with a large grain size, characterized in that it comprises an apparatus with a hollow cylinder. In this hollow cylinder device, a specimen is installed between the base at the bottom and the torque sensor at the top. This specimen is equipped with a rubber membrane. Both ends of this diaphragm are attached to the base and the torque sensor, and are sealed with a sealing ring. This central cavity of the specimen forms an inner pressure chamber while this rubber membrane and the outer wall of the hollow cylinder device form the outer pressure chamber. The top of this specimen is connected to the first sealed space outside the hollow cylinder device by means of the first pipeline provided with a valve. The top of this first sealed space is connected to the first vacuum pump by means of the second pipeline, which is provided with a valve. The bottom of this specimen is connected to the second sealed space outside the device with a hollow cylinder by means of the third pipeline equipped with a valve. The top of this second sealed space is connected to the second vacuum pump by means of the fourth pipeline, which is equipped with a valve. The bottom of this outer pressure chamber is connected to the first pressure cell device outside the hollow cylinder device by means of the fifth pipeline provided with a valve. The bottom of this inner pressure chamber is connected to the second pressure cell device outside the hollow cylinder device by means of the seventh pipeline provided with a valve. 2. Verzadigings-inrichting volgens conclusie 1, voor torsie-afschuifproeven in een holle cilinder van bodemsoorten zonder cohesie met een grote korrelgrootte, met het kenmerk dat deze eerste inrichting met drukcellen een derde afgedichte ruimte omvat. De onderzijde van deze buitenste drukkamer is verbonden met de derde afgedichte ruimte door middel van een vijfde pijpleiding. De bovenzijde van deze derde afgedichte ruimte is verbonden met de derde vacuümpomp door middel van een zesde pijpleiding die is voorzien van een klep. Deze tweede inrichting met drukcellen omvat een vierde afgedichte ruimte. De onderzijde van deze binnenste drukkamer is verbonden met de vierde afgedichte ruimte door middel van een zevende pijpleiding. De bovenzijde van deze vierde afgedichte ruimte is verbonden met de vierde vacuümpomp door middel van een achtste pijpleiding die is voorzien van een klep.2. Saturation device according to claim 1, for torsional shear tests in a hollow cylinder of non-cohesive soils with a large grain size, characterized in that this first device with pressure cells comprises a third sealed space. The bottom of this outer pressure chamber is connected to the third sealed space by a fifth pipeline. The top of this third sealed space is connected to the third vacuum pump by a sixth pipeline equipped with a valve. This second pressure cell device includes a fourth sealed space. The bottom of this inner pressure chamber is connected to the fourth sealed space by a seventh pipeline. The top of this fourth sealed space is connected to the fourth vacuum pump by means of an eighth pipeline equipped with a valve. 3. Verzadigings-inrichting volgens conclusie 2, voor torsie-afschuifproeven in een holle cilinder van bodemsoorten zonder cohesie met een grote korrelgrootte, met het kenmerk dat alle van deze eerste afgedichte ruimte, deze tweede afgedichte ruimte, deze derde afgedichte ruimte en deze vierde afgedichte ruimte zijn voorzien van uitlaten die zijn voorzien van kleppen aan de bovenzijde.3. Saturation device according to claim 2, for torsional shear tests in a hollow cylinder of non-cohesive soils with a large grain size, characterized in that all of this first sealed space, this second sealed space, this third sealed space and this fourth sealed space space are equipped with outlets that have valves at the top. 4. Verzadigings-inrichting volgens conclusie 1, voor torsie-afschuifproeven in een holle cilinder van bodemsoorten zonder cohesie met een grote korrelgrootte, met het kenmerk dat de eerste afgedichte ruimte is verbonden met de tweede afgedichte ruimte door middel van een watercirculatieleiding die is voorzien van een klep.4. Saturation device according to claim 1, for torsional shear tests in a hollow cylinder of non-cohesive soils with a large grain size, characterized in that the first sealed space is connected to the second sealed space by means of a water circulation pipe provided with a valve. 5. Verzadigings-inrichting volgens conclusie 4, voor torsie-afschuifproeven in een holle cilinder van bodemsoorten zonder cohesie met een grote korrelgrootte, met het kenmerk dat deze eerste pijpleiding doorloopt tot in de eerste afgedichte ruimte over een lengte die groter is dan 80% van de dikte van de eerste afgedichte ruimte zelf, dat deze derde pijpleiding doorloopt tot in de tweede afgedichte ruimte over een lengte die groter is dan 80% van de dikte van de tweede afgedichte ruimte zelf, en dat beide uiteinden van deze watercirculatieleidingen doorlopen tot in de eerste afgedichte ruimte en de tweede afgedichte ruimte over een lengte die groter is dan 80% van de dikte van de respectieve overeenkomstige afgedichte ruimte.5. Saturation device according to claim 4, for torsional shear tests in a hollow cylinder of non-cohesive soils with a large grain size, characterized in that this first pipeline extends into the first sealed space over a length greater than 80% of the thickness of the first sealed space itself, that this third pipeline extends into the second sealed space over a length greater than 80% of the thickness of the second sealed space itself, and that both ends of these water circulation pipes extend into the first sealed space and the second sealed space over a length greater than 80% of the thickness of the respective corresponding sealed space. 6. Verzadigings-inrichting volgens conclusie 5, voor torsie-afschuifproeven in een holle cilinder van bodemsoorten zonder cohesie met een grote korrelgrootte, met het kenmerk dat deze tweede pijpleiding, vierde pijpleiding, zesde pijpleiding en achtste pijpleiding zijn voorzien van een vacuümdrukmeter and een regelklep.6. Saturation device according to claim 5, for torsional shear tests in a hollow cylinder of non-cohesive soils with a large grain size, characterized in that said second pipeline, fourth pipeline, sixth pipeline and eighth pipeline are provided with a vacuum pressure gauge and a control valve . 7. Verzadigings-inrichting voor een torsie-afschuifproef in een holle cilinder van bodemsoorten zonder cohesie met een grote korrelgrootte, met het kenmerk dat deze de volgende stappen omvat: sl Het openen van één van de kleppen in ofwel de eerste of de derde pijpleiding terwijl de andere klep gesloten wordt gehouden, waardoor een van de pijpleidingen zal worden geopend terwijl de andere wordt gesloten. Het openen van de vacuümpomp aan de bovenzijde van de afgedichte ruimte die direct is verbonden met de geopende pijpleiding, waarna gedurende enige tijd wordt gevacumeerd. Het sluiten van de klep tussen de vacuümpomp en de afgedichte ruimte als de vacuümdruk 10 - 20 kPa bereikt, en het gedurende enige tijd handhaven daarvan. Het specimen is geheel afgedicht als zich geen verandering voordoet in de uitlezingen van de vacuümdruk, anders moet het specimen opnieuw worden geplaatst en moet de procedure, dat wil zeggen s1, worden herhaald. s2 Het sluiten van de klep in de derde pijpleiding, en vacumeren totdat de druk aan de bovenzijde van het specimen de doelwaarde bereikt. Wacht totdat de vacuümdruk door het gehele specimen stabiel wordt, vacumeer dan de buitenste drukkamer en de binnenste drukkamer totdat deze de doelwaarde bereiken. Terwijl de klep in de derde pijpleiding gesloten wordt gehouden, wordt de vacuümdruk van de tweede afgedichte ruimte vooringesteld zodat deze gelijk is aan die aan de bovenzijde van het specimen, en wordt gewacht totdat de druk stabiel wordt. Open de klep in de derde pijpleiding, wacht totdat de vacuümdruk door het gehele specimen stabiel wordt en stel dan de vacuümdruk aan de onderzijde van het specimen in op de doelwaarde. Op deze basis kan de eerste fase van kwelverzadiging worden uitgevoerd. s3 Als er geen bellen meer uit de pijpleiding aan de uitlaatzijde van het specimen komen, of het volume water dat uit de pijpleiding aan de uitlaatzijde van het specimen komt groter is dan het volume van het specimen zelf, sluit dan de klep in de derde pijpleiding en verhoog de doelwaarde van de vacuümdruk aan de bovenzijde van het specimen, de onderzijde van het specimen, de buitenste drukkamer en de binnenste drukkamer met respectievelijk 10 - 30 kPa. Vacumeer met name de bovenzijde van het specimen, de onderzijde van het specimen, de buitenste drukkamer en de binnenste drukkamer op dezelfde wijze als in stap s2 totdat deze de verhoogde respectieve doelwaarden bereiken. Op deze basis kan de tweede fase van kwelverzadiging worden uitgevoerd. s4 Herhaal de procedure van de tweede fase van kwelverzadiging totdat aan de uiteindelijke verzadigingsvereiste wordt voldaan.7. Saturation device for a torsional shear test in a hollow cylinder of non-cohesive soils of large grain size, characterized in that it comprises the following steps: sl Opening one of the valves in either the first or the third pipeline while the other valve is held closed, which will open one of the pipelines while closing the other. Opening the vacuum pump at the top of the sealed space that is directly connected to the opened pipeline, after which vacuuming takes place for some time. Closing the valve between the vacuum pump and the sealed space when the vacuum pressure reaches 10 - 20 kPa and maintaining it for some time. The specimen is completely sealed if there is no change in the vacuum pressure readings, otherwise the specimen must be reseated and the procedure, i.e. s1, repeated. s2 Closing the valve in the third pipeline, and vacuuming until the pressure at the top of the specimen reaches the target value. Wait until the vacuum pressure throughout the specimen becomes stable, then vacuum the outer pressure chamber and the inner pressure chamber until they reach the target value. While the valve in the third pipeline is held closed, the vacuum pressure of the second sealed space is biased to equal that at the top of the specimen and waited for the pressure to become stable. Open the valve in the third pipeline, wait until the vacuum pressure throughout the specimen becomes stable, and then set the vacuum pressure at the bottom of the specimen to the target value. On this basis the first phase of seepage saturation can be carried out. s3 If bubbles no longer come out of the pipeline on the outlet side of the specimen, or the volume of water coming out of the pipeline on the outlet side of the specimen is greater than the volume of the specimen itself, close the valve in the third pipeline and increase the target vacuum pressure at the top of the specimen, the bottom of the specimen, the outer pressure chamber and the inner pressure chamber by 10 - 30 kPa, respectively. In particular, vacuum the top of the specimen, the bottom of the specimen, the outer pressure chamber and the inner pressure chamber in the same manner as in step s2 until they reach the respective increased target values. On this basis the second phase of seepage saturation can be carried out. s4 Repeat the procedure of the second phase of seepage saturation until the final saturation requirement is met. 8. Verzadigingswerkwijze volgens conclusie 7, voor torsie-afschuifproeven in een holle cilinder van bodemsoorten zonder cohesie met een grote korrelgrootte, met het kenmerk dat de doelwaarde voor de vacuümdruk in de binnenste drukkamer groter is dan die in de buitenste drukkamer, dat de doelwaarde voor de vacuümdruk aan de bovenzijde van het specimen groter is dan die in de buitenste drukkamer, dat de doelwaarde voor de vacuümdruk aan de bovenzijde van het specimen groter is dan die in de binnenste drukkamer, dat de doelwaarde voor de vacuümdruk aan de onderzijde van het specimen groter is dan die in de buitenste drukkamer, dat de doelwaarde voor de vacuümdruk aan de onderzijde van het specimen groter is dan die in de binnenste drukkamer, en dat de doelwaarde voor de vacuümdruk aan de bovenzijde van het specimen niet gelijk is aan die aan de onderzijde van het specimen gedurende de eerste en tweede fasen van kwelverzadiging.Saturation method according to claim 7, for torsional shear tests in a hollow cylinder of non-cohesive soils with a large grain size, characterized in that the target value for the vacuum pressure in the inner pressure chamber is greater than that in the outer pressure chamber, in that the target value for the vacuum pressure at the top of the specimen is greater than that in the outer pressure chamber, the target vacuum pressure at the top of the specimen is greater than that in the inner pressure chamber, the target vacuum pressure at the bottom of the specimen is greater than that in the outer pressure chamber, that the target vacuum pressure at the bottom of the specimen is greater than that in the inner pressure chamber, and that the target vacuum pressure at the top of the specimen is not equal to that at the underside of the specimen during the first and second phases of seepage saturation.
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