CN113155701B

CN113155701B - Bentonite penetration-diffusion-expansive force combined test device and test method thereof

Info

Publication number: CN113155701B
Application number: CN202110450375.8A
Authority: CN
Inventors: 曾智磊; 廖饶平; 张婷婷; 余闯; 吴则祥; 叶昌鹏
Original assignee: Wenzhou Transportation Bureau; Wenzhou University
Current assignee: Wenzhou Transportation Bureau; Wenzhou University
Priority date: 2021-04-25
Filing date: 2021-04-25
Publication date: 2022-11-08
Anticipated expiration: 2041-04-25
Also published as: CN113155701A

Abstract

The invention relates to a bentonite permeation-diffusion-expansive force combined test device and a test method thereof, belonging to the technical field of geotechnical engineering test instruments and comprising the following steps: soil body lateral confinement device, temperature regulating device, diffusion device, penetrant unit. By adopting the bentonite permeation-diffusion-swelling force combined test device and the test method thereof, a permeation-diffusion-swelling force continuous test under a temperature control state can be realized; the evolution law of core retardation parameters such as permeation, diffusion and expansion of high-compaction bentonite under the heat-effect action can be effectively tested and evaluated, and a basis is further provided for design and evaluation of the buffer material of the high-level radioactive waste deep geological disposal library.

Description

Bentonite penetration-diffusion-expansive force combined test device and test method thereof

Technical Field

The invention belongs to the field of geotechnical engineering tests, and particularly relates to a combined test device and a test method for permeation-diffusion-expansive force of high-compaction bentonite.

Background

The problem of safe treatment of nuclear waste has always been one of the most critical factors restricting the sustainable development of the nuclear industry, in particular the long-term safe disposal of high-level radioactive waste with high radioactivity, high concentration, high toxicity, high heat release and long half-life. Compared with the research and disposal schemes for many years, the deep disposal reservoir for storing high-level waste by establishing multiple barriers in the geologic body with the depth of 500-1000 m from the earth surface to permanently isolate and bury the high-level waste from the living environment of human beings is the most generally accepted and technically feasible scheme at present. The multiple barrier system includes a natural barrier system composed of surrounding rock and an engineered barrier system filled with a cushioning/backfill material. The buffer backfill material in the engineering barrier plays an important role in maintaining the stable structure of the disposal reservoir, preventing the seepage of underground water, retarding the migration of nuclides, diffusing nuclear radiant heat and the like.

In the deep geological disposal concept, in order to ensure safe and effective operation of a deep geological disposal warehouse, the bentonite serving as a buffering/backfilling material is generally designed by splicing high-compaction blocks, and has the functions of generating hydration expansion after meeting water so as to heal/seal construction gaps among the high-compaction bentonite blocks, between the blocks and surrounding rocks and cracks caused by excavation and unloading of the disposal warehouse in the surrounding rocks, and meanwhile, the expansion force generated by meeting water can also buffer the influence of the pressure of the surrounding rocks on a waste tank and maintain the stability of the structure of the disposal warehouse; the bentonite is hydrated to form a crystal layer to expand and a diffusion double electric layer is thickened, so that the inner and outer pores of the soil particle assembly are gradually reduced, the permeability of the bentonite is reduced, and the infiltration of underground water in the surrounding rock to a disposal reservoir is delayed, thereby preventing nuclides from migrating outwards through the underground water. It can be said that the water swelling action of bentonite is the most central function of engineering, hydraulic and chemical barriers. As a buffer material, the expansibility, the impermeability and the adsorbability of high-compaction bentonite are important for maintaining the stable structure of a disposal reservoir and retarding the migration and diffusion of nuclides. Therefore, the evolution of the expansive force, the permeability coefficient and the diffusion parameter of the high-compaction bentonite in the nuclide solution environment needs to be researched so as to evaluate the chemical buffer performance of the engineering barrier system.

In the prior art, CN 109655599A (university of three gorges) provides a high compaction bentonite expansive force-osmotic coupling tester and a using method thereof, the tester comprises a combined sample ring, the upper part of the combined sample ring is fixed with a top disk through a threaded rod, the middle part of the top disk is provided with a sensor, an induction probe at the lower part of the sensor is contacted with a long piston, the long piston is positioned in the combined sample ring, a circular knife is embedded in the combined sample ring, and the circular knife is positioned below the long piston; metal permeable stones are respectively placed on the upper part and the lower part of the cutting ring, spiral grooves are arranged below the metal permeable stones on the lower part of the cutting ring, and a water inlet pipe and a first water outlet pipe are respectively arranged at two ends of each spiral groove; both sides of the metal permeable stone are provided with spiral grooves.

The invention relates to a CN 110160883A osmotic pressure device and a test method for a high-compaction bentonite test, wherein the osmotic pressure device comprises a bottom water injection and exhaust mechanism, a side surface sealing mechanism arranged on the bottom water injection and exhaust mechanism and a piston inserted in the side surface sealing mechanism and connected with the side surface sealing mechanism in a sliding manner, a bentonite test cavity is enclosed among the bottom water injection and exhaust mechanism, the side surface sealing mechanism and the piston, the bentonite test cavity is square, and the height of the bentonite test cavity is smaller than the width; during the test, a bentonite sample parallel to the compaction direction and a bentonite sample perpendicular to the compaction direction are respectively placed in a bentonite test cavity for testing. The advantages of this document are: the thickness of the bentonite sample in the direction of measuring the expansive force and the permeability coefficient can be reduced, the influence of nonuniform hydration of the bentonite is avoided, and the method is suitable for measuring the expansive force and the permeability coefficient of the high-compaction bentonite in the direction parallel to the compaction direction and the direction perpendicular to the compaction direction.

In conclusion, aiming at the problem of retardation parameter evolution in engineering barriers, the existing research mainly aims at developing indoor static experiments and researches the expansibility, the adsorption performance, the saturation permeability and the diffusion property of different high-compaction soil samples. However, because the evolution period of the high-compaction bentonite under different environments is long, parameters obtained by experiments under different environments are often different. At present, a combined test device aiming at the permeation-diffusion-expansion force of high-compaction bentonite with controllable environmental temperature is not available.

Disclosure of Invention

The invention aims to provide a combined test device and a test method for permeation-diffusion-expansive force of high-compaction bentonite, so as to overcome the defects of the prior art.

An ambient temperature controllable testing high compaction bentonite penetration-diffusion-expansive force combination device, comprising: the device comprises a soil body side limiting device, a temperature control device and a diffusion device;

wherein, soil body lateral confinement device include: the first center perforated cover plate and the second center perforated cover plate are respectively arranged on the upper side and the lower side of the center steel cylinder; the center of the first center perforated cover plate is provided with a plurality of through holes, the lower surface of the middle part of the first center perforated cover plate is provided with a first circumferential groove, and the upper surface and the lower surface of the edge part of the first center perforated cover plate are both provided with second circumferential grooves; the first circumferential groove and the second circumferential groove are concentric, and the radius of the first circumferential groove is smaller than that of the second circumferential groove; the center of the second center perforated cover plate is provided with a plurality of through holes, the upper surface of the middle part of the second center perforated cover plate is provided with a first circumferential groove, and the upper surface and the lower surface of the edge part of the second center perforated cover plate are both provided with second circumferential grooves; the first circumferential groove and the second circumferential groove are concentric, and the radius of the first circumferential groove is smaller than that of the second circumferential groove; the first center perforated cover plate and the second center perforated cover plate are all connected with the center steel cylinder in a nested mode, specifically, protrusions are arranged at the top end and the bottom end of the cylinder wall of the center steel cylinder, and the protrusions arranged at the top end and the bottom end of the cylinder wall of the center steel cylinder are respectively matched with a first circumferential groove arranged on the lower surface of the first center perforated cover plate and a first circumferential groove arranged on the upper surface of the second center perforated cover plate;

wherein, temperature regulating device include: the middle part of the outer side of the organic glass cylinder is provided with a temperature control chamber and a temperature control system; the top end and the bottom end of the outer middle organic glass cylinder are respectively provided with a protrusion, and the protrusions arranged at the top end and the bottom end of the outer middle organic glass cylinder are respectively matched with a second circumferential groove arranged on the lower surface of the first center perforated cover plate and a second circumferential groove arranged on the upper surface of the second center perforated cover plate; the space among the lower surface of the first center perforated cover plate, the upper surface of the second center perforated cover plate, the inner surface of the organic glass cylinder in the middle of the outer side and the outer surface of the center steel cylinder forms a temperature control chamber;

the temperature control system includes: a hot water circulating pump, a connecting pipeline and a water source; the hot water pump is connected with a water source, the hot water pump is connected with a temperature control chamber connecting pipeline of the first center perforated cover plate through a liquid supply pipeline, a temperature control chamber connecting pipeline is arranged in the first center perforated cover plate, one end of the temperature control chamber connecting pipeline in the first center perforated cover plate is a liquid inlet, and a liquid outlet at the other end of the temperature control chamber connecting pipeline is connected with the temperature control chamber; a temperature control chamber connecting pipeline is also arranged in the second center perforated cover plate, a liquid inlet of the temperature control chamber connecting pipeline in the second center perforated cover plate is connected with the control chamber, a liquid outlet is arranged at the other end of the temperature control chamber connecting pipeline, and the liquid outlet is connected with a water source through a liquid outlet pipeline;

wherein, the diffusion device includes: an outer top organic glass cylinder, an outer bottom organic glass cylinder, a top cover plate and a bottom cover plate; a second circumferential groove is formed in the lower surface of the top cover plate; a second circumferential groove is formed in the upper surface of the bottom cover plate; the top end and the bottom end of the outer top organic glass cylinder are both provided with a protrusion, and the protrusions arranged at the top end and the bottom end of the outer top organic glass cylinder are respectively matched with a second circumferential groove arranged on the upper surface of the first center perforated cover plate and a second circumferential groove arranged on the lower surface of the top cover plate; the top end and the bottom end of the outer bottom organic glass cylinder are both provided with a protrusion, and the protrusions arranged at the top end and the bottom end of the outer bottom organic glass cylinder are respectively matched with a second circumferential groove arranged on the lower surface of a second center perforated cover plate and a second circumferential groove arranged on the upper surface of a bottom cover plate; the space among the top cover plate, the outer top organic glass cylinder and the first center perforated cover plate forms an upper solution diffusion chamber; the space among the bottom cover plate, the outer bottom organic glass cylinder and the second center perforated cover plate forms a lower solution diffusion chamber; diffusion liquid connecting pipelines are also arranged in the top cover plate and the bottom cover plate, and the diffusion liquid connecting pipelines of the top cover plate are used for filling solution into the solution diffusion chamber at the upper part; the diffusion liquid connecting pipeline of the bottom plate cover plate is used for filling the recovery solution into the solution diffusion chamber at the lower part;

wherein the permeation device comprises: a penetrating fluid connecting pipeline arranged inside the first center perforated cover plate, a penetrating fluid connecting pipeline arranged inside the second center perforated cover plate, a first GDS controller, a first solution source, a second GDS controller and a second solution source;

a penetrating fluid connecting pipeline is also arranged inside the first center perforated cover plate, one end of the penetrating fluid connecting pipeline inside the first center perforated cover plate is a fluid inlet, and a fluid outlet at the other end of the penetrating fluid connecting pipeline is connected with the center steel cylinder;

a penetrating fluid connecting pipeline is also arranged inside the second center perforated cover plate, the penetrating fluid inside the second center perforated cover plate is connected with the center steel cylinder of the pipeline, the other end of the second center perforated cover plate is a liquid outlet, and the liquid outlet of the second center perforated cover plate is connected with a first solution source through a liquid outlet pipeline;

a liquid outlet of a penetrating fluid connecting pipeline is also arranged in the first center perforated cover plate, and a liquid inlet of a penetrating fluid connecting pipeline is also arranged in the second center perforated cover plate and can be plugged through a plug;

the first solution source and the first GDS controller are connected with a liquid inlet of a penetrating fluid connecting pipeline in the first center perforated cover plate;

and the second solution source is connected with a liquid outlet of a penetrating fluid connecting pipeline in the second center perforated cover plate.

Furthermore, the through holes of the first center perforated cover plate and the second center perforated cover plate are provided with threaded holes or non-threaded holes, and the through holes can be plugged by plugs.

Furthermore, a plurality of threaded holes are uniformly distributed in the top cover plate and the bottom cover plate, the threaded holes are formed in the outer side of the upper solution diffusion chamber and the outer side of the lower solution diffusion chamber, and the top cover plate and the bottom cover plate are clamped through the long threaded column-nut assembly, so that the overall stability of the device is improved.

Furthermore, a plurality of threaded holes are uniformly distributed in the first center perforated cover plate and the second center perforated cover plate, the threaded holes are arranged outside the temperature control chamber, the first center perforated cover plate and the second center perforated cover plate are clamped by the short threaded column-nut assembly, and spaces allowing the long threaded columns to pass through are formed in the first center perforated cover plate and the second center perforated cover plate.

Further, a sealing ring is arranged between the first circumferential groove and the second circumferential groove and the bulge.

A test method of a solution penetration test under a temperature control state comprises the following steps:

s1, firstly placing a bottom cover plate, and then inserting a bulge at the bottom of the bottom organic glass cylinder at the outer side into a second circumferential groove on the upper surface of the bottom cover plate so as to connect the bottom organic glass cylinders at the outer side of the bottom cover plate;

s2, installing an organic glass cylinder at the bottom of the outer side and a second center perforated cover plate: a second circumferential groove on the lower surface of the second center perforated cover plate corresponds to a bulge on the top of the bottom organic glass cylinder on the outer side, and the second center perforated cover plate is pressed, so that the bottom organic glass cylinder on the outer side of the bottom cover plate is connected with the second center perforated cover plate;

s3, mounting a central steel cylinder: inserting the protrusion at the bottom of the central steel cylinder into the first circumferential groove on the upper surface of the second central perforated cover plate;

s4, installing an organic glass cylinder in the middle of the outer side: inserting the bulge at the bottom of the organic glass cylinder in the middle of the outer side into a second circumferential groove in the upper surface of a second central perforated cover plate;

s5, putting permeable stones, test soil samples and permeable stones in the central steel cylinder in sequence, keeping through holes of a first central perforated cover plate and a second central perforated cover plate in a closed state, and keeping a liquid outlet of a penetrating fluid connecting pipeline arranged in the first central perforated cover plate and a liquid inlet of a penetrating fluid connecting pipeline arranged in the second central perforated cover plate in an open state;

s6, installing a first center perforated cover plate: pressing the first center perforated cover plate, and inserting the bulge at the top of the center steel cylinder and the bulge at the top of the organic glass cylinder in the middle of the outer side into the first circumferential groove and the second circumferential groove on the lower surface of the first center perforated cover plate;

s7, installing an outer top organic glass cylinder: a second circumferential groove in the upper surface of the first center perforated cover plate corresponds to a bulge at the bottom of the outer top organic glass cylinder, and the outer top organic glass cylinder is pressed to connect the outer top organic glass cylinder with the first center perforated cover plate;

s8, installing a top cover plate: a second circumferential groove formed in the lower surface of the top cover plate corresponds to a protrusion at the top of the outer top organic glass cylinder, and the top cover plate is pressed, so that the protrusion at the top of the outer top organic glass cylinder is inserted into the second circumferential groove formed in the lower surface of the top cover plate;

s9, then starting a hot water circulating pump, and filling the temperature control chamber with a solution so as to control the temperature of the soil body;

and S10, the first GDS pressure volume controller and the second GDS pressure volume controller respectively control the upper water head and the lower water head, and when the liquid change amount of the two GDS controllers per hour is close, the permeability coefficient can be calculated by reading the volume change amount in unit time and the osmotic water pressure difference.

In the step S9, the permeability coefficient of the saturated soil body at different temperatures can be obtained by adjusting the temperature in the temperature control chamber 4.

A test method of a solution diffusion test under a temperature control state comprises the following steps:

s2, installing an organic glass cylinder at the bottom of the outer side and a second center perforated cover plate: a second circumferential groove on the lower surface of the second center perforated cover plate corresponds to a bulge on the top of the bottom organic glass cylinder at the outer side, and the second center perforated cover plate is pressed, so that the bottom organic glass cylinder at the outer side of the bottom cover plate 7-2 is connected with the second center perforated cover plate;

s3, installing a central steel cylinder: inserting the protrusion at the bottom of the central steel cylinder into the first circumferential groove on the upper surface of the second central perforated cover plate;

s5, putting permeable stones, saturated test soil samples and permeable stones in the central steel cylinder in sequence, and keeping through holes of the first central perforated cover plate and the second central perforated cover plate in an open state;

a liquid outlet of a penetrating fluid connecting pipeline which is also arranged in the first center perforated cover plate and a liquid inlet of a penetrating fluid connecting pipeline which is also arranged in the second center perforated cover plate are kept in a closed state;

s7, installing an outer top organic glass cylinder: a second circumferential groove on the upper surface of the first central perforated cover plate corresponds to a bulge at the bottom of the outer top organic glass cylinder, and the outer top organic glass cylinder is pressed to connect the outer top organic glass cylinder with the first central perforated cover plate;

s10, filling a solution diffusion chamber at the lower part of the bottom plate cover plate with a diffusion solution connecting pipeline; filling solution into the solution diffusion chamber at the upper part by using a diffusion solution connecting pipe arranged in the top cover plate; the solution diffusion chamber at the lower part is filled in sequence, and then the solution diffusion chamber at the upper part is filled in sequence;

the solution diffusion chamber at the upper part and the solution diffusion chamber at the lower part are filled with solutions with different concentrations, and the diffusion parameters of the high-compaction bentonite are calculated by testing the concentration of the solutions in the diffusion tanks at two sides at fixed time intervals.

And S9, adjusting the temperature in the temperature control chamber to obtain the diffusion coefficients of the saturated soil body at different temperatures.

A test method of an expansion force test under a temperature control state comprises the following steps:

s5, putting permeable stones, test soil samples and axial pressure sensors in the central steel cylinder in sequence, wherein the through hole of the first central perforated cover plate is kept in a closed state, and the through hole of the second central perforated cover plate is kept in a closed state;

the penetrating fluid connecting pipeline arranged in the first center perforated cover plate is kept closed; a penetrating fluid connecting pipeline of a penetrating fluid connecting pipeline arranged inside the second center perforated cover plate is kept open;

s10, the device is placed in a solution tank, moisture enters a soil sample from a through hole of a second center perforated cover plate, an axial pressure sensor is arranged above the soil sample, permeable stones are arranged below the soil sample, the through hole of the second center perforated cover plate enables the axial pressure sensor to be externally connected with a wire conveniently, and the second center perforated cover plate ensures that the solution can smoothly pass through the second center perforated cover plate and then enters a soil body to cause soil body expansion through the permeable stones.

An environmental temperature controllable testing high compaction bentonite infiltration-diffusion-expansive force combination device, comprising: the device comprises a soil body side limiting device, a temperature control device and a diffusion device;

wherein, soil body lateral confinement device include: the central steel cylinder, the first central perforated cover plate and the second central perforated cover plate are provided with openings at the upper side and the lower side, and the first central perforated cover plate and the second central perforated cover plate are respectively arranged at the upper side and the lower side of the central steel cylinder; the center of the first center perforated cover plate is provided with a plurality of through holes, the lower surface of the middle part of the first center perforated cover plate is provided with a first circumferential groove, and the upper surface and the lower surface of the edge part of the first center perforated cover plate are both provided with second circumferential grooves; the first circumferential groove and the second circumferential groove are concentric, and the radius of the first circumferential groove is smaller than that of the second circumferential groove; the center of the second center perforated cover plate is provided with a plurality of through holes, the upper surface of the middle part of the second center perforated cover plate is provided with a first circumferential groove, and the upper surface and the lower surface of the edge part of the second center perforated cover plate are both provided with second circumferential grooves; the first circumferential groove and the second circumferential groove are concentric, and the radius of the first circumferential groove is smaller than that of the second circumferential groove; the first center perforated cover plate and the second center perforated cover plate are all connected with the center steel cylinder in a nested mode, specifically, protrusions are arranged at the top end and the bottom end of the cylinder wall of the center steel cylinder, and the protrusions arranged at the top end and the bottom end of the cylinder wall of the center steel cylinder are respectively matched with a first circumferential groove arranged on the lower surface of the first center perforated cover plate and a first circumferential groove arranged on the upper surface of the second center perforated cover plate;

wherein, temperature regulating device include: the middle part of the outer side of the organic glass cylinder is provided with an organic glass cylinder, a temperature control chamber and a temperature control system; the top end and the bottom end of the outer middle organic glass cylinder are respectively provided with a protrusion, and the protrusions arranged at the top end and the bottom end of the outer middle organic glass cylinder are respectively matched with a second circumferential groove arranged on the lower surface of the first center perforated cover plate and a second circumferential groove arranged on the upper surface of the second center perforated cover plate; the space among the lower surface of the first center perforated cover plate, the upper surface of the second center perforated cover plate, the inner surface of the organic glass cylinder in the middle of the outer side and the outer surface of the center steel cylinder forms a temperature control chamber;

wherein the permeation device comprises: a first GDS controller, a first solution source, a second GDS controller, a second solution source;

a first penetrating fluid connecting pipeline is arranged in the first center perforated cover plate, a T-shaped second penetrating fluid connecting pipeline is matched with the upper part of the wall part of the center steel cylinder, one side opening of the second penetrating fluid connecting pipeline is arranged on the upper surface of the center steel cylinder, the other two openings are respectively arranged on the side surface of the wall part, and the first penetrating fluid connecting pipeline is in adaptive communication with the second penetrating fluid connecting pipeline; the opening of the T-shaped second penetrating fluid connecting pipeline at the upper part of the wall part of the central steel cylinder corresponds to the permeable stone at the upper part;

a first penetrating fluid connecting pipeline is arranged in the second center perforated cover plate, a T-shaped third penetrating fluid connecting pipeline is matched with the lower part of the wall part of the center steel cylinder, one side opening of the third penetrating fluid connecting pipeline is arranged on the lower surface of the center steel cylinder 8, the other two openings are respectively arranged on the side surface of the wall part, and the first penetrating fluid connecting pipeline arranged in the second center perforated cover plate is in adaptive communication with the third penetrating fluid connecting pipeline; the upper part of the wall part of the central steel cylinder is matched with a permeable stone at the lower part corresponding to the opening of a T-shaped third penetrating fluid connecting pipeline;

further comprising: 2 closing rods; the closing rod includes: a rotating rod, a threaded rod, a closed end member; the rotary rotating rod, the threaded rod and the closed end component are sequentially connected;

the openings of the wall of the central steel cylinder and the wall of the organic glass cylinder in the middle of the outer side are provided with threaded openings, and the threaded rod of the sealing rod is respectively matched with the threaded opening of the wall of the central steel cylinder and the threaded opening of the wall of the organic glass cylinder in the middle of the outer side; the size of the rotary rotating rod is matched with the size of a horizontal connecting pipeline of the T-shaped third penetrating fluid connecting pipeline; a rotating rod 20-1 is provided outside the plexiglas cylinder in the middle of the outer side, by which the closed end member can be moved from the inside of the wall of the central steel cylinder to the outside of the wall of the central steel cylinder.

One end of a first penetrating fluid connecting pipeline of the first center perforated cover plate is a liquid inlet; one end of the first penetrating fluid connecting pipeline of the second center perforated cover plate is a liquid outlet, and the liquid outlet is connected with a first solution source through a liquid outlet pipeline; the first solution source and the first GDS controller are connected with a liquid inlet of a penetrating fluid connecting pipeline in the first center perforated cover plate; and the second solution source is connected with a liquid outlet of a penetrating fluid connecting pipeline in the second center perforated cover plate.

A test method of a solution expansion force and permeation continuous type test under a temperature control state comprises the following steps:

meanwhile, the center steel cylinder is rotated, so that a first penetrating fluid connecting pipeline arranged inside the second center perforated cover plate is communicated with a T-shaped third penetrating fluid connecting pipeline arranged at the lower part of the wall part of the center steel cylinder;

s5, putting permeable stones, test soil samples, permeable stones and axial pressure sensors in the central steel cylinder in sequence, wherein the through holes of the first central perforated cover plate are kept in an open state, and the through holes of the second central perforated cover plate are kept in a closed state;

a liquid outlet of a penetrating fluid connecting pipeline which is also arranged in the first center perforated cover plate and a liquid inlet of a penetrating fluid connecting pipeline which is also arranged in the second center perforated cover plate are kept in an open state;

s6, installing a first center perforated cover plate: pressing the first center perforated cover plate, and inserting a bulge at the top of the center steel cylinder and a bulge at the top of the organic glass cylinder in the middle of the outer side into a first circumferential groove and a second circumferential groove on the lower surface of the first center perforated cover plate;

meanwhile, rotating the first center perforated cover plate to enable a first penetrating fluid connecting pipeline arranged inside the first center perforated cover plate to be communicated with a T-shaped second penetrating fluid connecting pipeline arranged on the upper part of the wall part of the center steel cylinder;

s10, a first stage: the first GDS pressure volume controller adopts pulse type water drainage:

firstly, the closing rod at the upper part is rotated to enable the closing end component to be close to the outer side of the wall part of the central steel cylinder 8, namely, the second permeate pipeline is kept communicated;

rotating the lower closing rod so that the closed end member is close to the inside of the wall of the central steel cylinder 8, i.e. keeping the third permeate line closed;

next, the measurement of the expansion force below different water contents was started:

at the beginning, a certain amount of water is put in, and after the numerical value of the axial pressure sensor is stable, the expansion force under the water content is obtained;

then, a certain amount of water is added, and after the numerical value of the axial pressure sensor is stable, the expansion force under the water content is obtained;

then, measuring the expansion force under different water contents according to the content until the measured expansion force tends to be stable;

in the second stage, the closing rod at the lower part is rotated, so that the closing end component is close to the outer side of the wall part of the central steel cylinder 8, namely, the third permeate pipeline is kept communicated;

the first GDS pressure volume controller and the second GDS pressure volume controller respectively control an upper water head (solution inflow) and a lower water head (solution outflow), and when liquid change amounts (inflow and outflow) of the two GDS controllers are close to each other per hour, the permeability coefficient can be calculated by reading the volume change amount per unit time and the osmotic water pressure difference.

Further, the organic glass cylinder at the top of the outer side and the organic glass cylinder at the bottom of the outer side are provided with doors.

A method for operating a continuous test of solution expansibility, permeability and diffusivity in a temperature control state comprises the following steps:

s2, installing an organic glass cylinder at the bottom of the outer side and a second center perforated cover plate: a second circumferential groove on the lower surface of the second center perforated cover plate corresponds to a bulge on the top of the organic glass cylinder at the bottom of the outer side, and the second center perforated cover plate is pressed, so that the organic glass cylinder at the bottom of the outer side of the bottom cover plate is connected with the second center perforated cover plate;

s5, putting permeable stones, radial pressure sensors, test soil samples and permeable stones in the central steel cylinder in sequence, wherein the through holes of the first central perforated cover plate are kept in a closed state, and the through holes of the second central perforated cover plate are kept in a closed state;

a liquid outlet of a penetrating fluid connecting pipeline which is also arranged in the first center perforated cover plate and a liquid inlet of a penetrating fluid connecting pipeline which is also arranged in the second center perforated cover plate keep an opening state;

s10, in the first stage, measuring the expansion force: the first GDS pressure volume controller adopts pulse type water drainage:

firstly, rotating the upper closing rod to enable the closing end component to be close to the outer side of the wall of the central steel cylinder, namely keeping the second permeate pipeline communicated;

rotating the lower closing rod so that the closed end member is close to the inside of the wall of the central steel cylinder, i.e. keeping the third permeate line closed;

at the beginning, a certain amount of water is put in, and after the numerical value of the radial pressure sensor is stable, the expansion force under the water content is obtained;

then, a certain amount of water is added, and after the numerical value of the radial pressure sensor is stable, the expansion force under the water content is obtained;

then, measuring the expansion force under different water contents according to the mode until the measured expansion force tends to be stable;

in the second stage, the permeability coefficient is measured: rotating the lower closing rod to make the closing end component close to the outer side of the wall of the central steel cylinder, namely keeping the third permeate pipeline communicated;

the first GDS pressure volume controller and the second GDS pressure volume controller respectively control the upper water head and the lower water head, and when the liquid change amount of the two GDS controllers per hour is close, the permeability coefficient can be calculated by reading the volume change amount in unit time and the osmotic water pressure difference;

in the third stage, the diffusion coefficient is measured:

rotating the upper closing rod to make the closed end component close to the inner side of the wall of the central steel cylinder, namely keeping the second permeate pipeline closed;

opening a door on the top of the outer side of the organic glass cylinder and on the bottom of the outer side of the organic glass cylinder, and taking away the through hole of the first center perforated cover plate and the plug of the through hole of the second center perforated cover plate, so that the through hole of the first center perforated cover plate is kept in an open state and the through hole of the second center perforated cover plate is kept in an open state; then closing a door on the organic glass cylinder at the top of the outer side and the organic glass cylinder at the bottom of the outer side;

a diffusion liquid connecting pipe arranged in the bottom plate cover plate is used for filling solution into a solution diffusion chamber at the lower part; a solution diffusion chamber 6-1 at the upper part is filled with solution by using a diffusion solution connecting pipe arranged in the top cover plate;

the solution diffusion chamber at the upper part and the solution diffusion chamber at the lower part are filled with solutions with different concentrations, solution concentration sensors are arranged in the solution diffusion chamber at the upper part and the solution diffusion chamber at the lower part, and the diffusion parameters of the highly compacted bentonite are calculated by testing the concentration of the solutions in the diffusion cells at two sides at fixed time intervals.

Further, the GDS controller is a GDS pressure volume controller.

By adopting the technical scheme, compared with the prior art, the method has the advantages of the following points.

First, the present application includes three points: which correspond to the first, second and third embodiments, respectively.

Second, the first embodiment of the present application can implement: and testing the expansion force, the penetration and the diffusion under the temperature control state, namely, the expansion force, the penetration and the diffusion can be tested by adopting the same equipment. However, the above test cannot realize a continuous type test in the test.

Third, the second embodiment of the present application can implement: the continuous type of expansive force-osmotic solution test under the temperature-controlled condition, compared to example one, does not require re-preparation of the osmotic test.

Fourth, one of the inventive points of the present application is (corresponding to example three): the testing device for the continuous test of the swelling power, the permeation and the diffusion of the solution in the temperature control state is provided, and the concept that the swelling power-permeation-diffusion continuous test in the temperature control state can be carried out is creative. In particular, wherein:a radial pressure sensor 2-2,The first center perforated cover plate 5-1 is internally provided withFirst penetrating fluid connecting pipeline 5-1-4 (L type)The upper part of the wall part of the central steel cylinder 8 is matched withT Type two penetrating fluid connecting pipeline(one side is opened on the upper surface of the central steel cylinder 8, and the other two sides are opened on the upper surface of the central steel cylinderThe openings are respectively arranged on the side surface of the wall part), and the first penetrating fluid connecting pipeline 5-1-4 is in adaptive communication with the second penetrating fluid connecting pipeline; the upper part of the wall part of the central steel cylinder 8 is matched withThe opening of the T-shaped second penetrating fluid connecting pipeline corresponds to the permeable stone 3 at the upper part(ii) a A first penetrating fluid connecting pipeline (L-shaped) is arranged inside the second center perforated cover plate 5-2, a T-shaped third penetrating fluid connecting pipeline is matched at the lower part of the wall part of the center steel cylinder 8 (one opening is arranged on the lower surface of the center steel cylinder 8, and the other two openings are respectively arranged on the side surface of the wall part),what is needed is A first penetrating fluid connecting pipeline and a third penetrating fluid connecting pipeline which are arranged in the second center perforated cover plate 5-2 are connected in a matching way Tong (Chinese character of 'tong')；The upper part of the wall part of the central steel cylinder 8 is matched with a permeable stone 3 at the lower part corresponding to the opening of a T-shaped third penetrating fluid connecting pipeline;further comprising:2 closing rods 20; the closing rod 20 comprises: a rotating rod 20-1, a threaded rod 20-2 and a closed end component 20-3 are rotated; rotary wrench The rotary rotating rod 20-1, the threaded rod 20-2 and the closed end component 20-3 are connected in sequence(ii) a The openings of the wall of the central steel cylinder 8 and the wall of the outer middle organic glass cylinder 9-1 are arranged asScrew thread mouthOf the threaded rod 20-2 of the closing rod 20 with the wall of the central steel cylinder 8, respectivelyScrew thread mouthThe screw thread opening of the wall part of the organic glass cylinder 9-1 at the middle part of the outer side is matched; the size of the rotary rotating rod 20-1 is matched with the size of a horizontal connecting pipeline of a T-shaped third penetrating fluid connecting pipeline (vertical and horizontal); that is to say that the first and second electrodes,by rotating Turning the rotating rod 20-1 (which is located outside the plexiglas barrel 9-1 in the middle of the outside) allows the closed end piece 20-3 to be closed Can move from the front side of the wall of the center steel cylinder 8 to the rear side of the wall of the center steel cylinder 8；The top of the outer side is an organic glass cylinder 9-2 A door is arranged on the organic glass cylinder 9-3 at the side bottom, which is convenient for technicians to reach to close or open the first central perforated cover plate 5-1 and a second center perforated cover plate 5-2(the through hole is generally plugged by a threaded plug), all belong to necessary technical characteristics, namely technically belong to a whole.

Description of the drawings:

FIG. 1 is a diagram of the environment temperature controlled test high compacted bentonite infiltration-diffusion-expansion force combination device of example 1 in the state of infiltration or diffusion.

Fig. 2 is a schematic design diagram of a first center-piercing cover plate of example 1.

Fig. 3 is a state diagram of the test high compacted bentonite permeation-diffusion-expansion force combination device with controllable environmental temperature and a design diagram of a solution circulation system in the process of permeation or diffusion in the embodiment 1.

FIG. 4 is a schematic structural view of the temperature-controlled diffusion apparatus of example 1.

Figure 5 is a state diagram of the ambient temperature controlled test high compacted bentonite infiltration-diffusion-expansion force combination device of example 2 when infiltration or diffusion is performed.

Figure 6 is a schematic design drawing of the first center perforated cover plate, center steel cylinder permeate connection of example 2.

Fig. 7 is a design illustration of the closing rod 20.

Fig. 8 is a schematic diagram of the state design of the environmental temperature controlled test high compacted bentonite infiltration-diffusion-expansive force combination device of example 2 when infiltration is performed.

Figure 9 is a graph of the ambient temperature controlled test high compacted bentonite infiltration-diffusion-expansive force combination of example 3 under the conditions of expansive force-infiltration-diffusion.

The reference numerals in fig. 1-9 are illustrated as follows:

test soil sample 1;

an axial pressure sensor 2, a radial pressure sensor 2-2;

permeable stone 3

A temperature control chamber 4;

the temperature control chamber comprises a first center perforated cover plate 5-1, a first circumferential groove 5-1-1 of the first center perforated cover plate, a second circumferential groove 5-1-2 of the first center perforated cover plate, a temperature control chamber connecting pipeline 5-1-3 arranged in the first center perforated cover plate and a second center perforated cover plate 5-2;

a top cover plate 7-1 and a bottom cover plate 7-2;

the central steel cylinder 8 is a hollow cylinder with a central hole,

an organic glass cylinder 9-1 at the middle part of the outer side, an organic glass cylinder 9-2 at the top of the outer side and an organic glass cylinder 9-3 at the bottom of the outer side;

a hot water circulating pump 15;

a closing rod 20;

a water source 23.

Detailed Description

The first embodiment is as follows: as shown in fig. 1 to 6, the present invention provides an environmental temperature controllable permeation-diffusion-expansion force combination device for testing high compaction bentonite, comprising: a soil body side limiting device, a temperature control device and a diffusion device;

wherein, soil body lateral confinement device include: the central steel cylinder 8 with openings at the upper side and the lower side, a first central perforated cover plate 5-1 and a second central perforated cover plate, wherein the first central perforated cover plate 5-1 and the second central perforated cover plate 5-2 are respectively arranged at the upper side and the lower side of the central steel cylinder 8;

the first center perforated cover plate 5-1 includes: the center is provided with 3 rows by 3 columns (9 in total) of through holes with the diameter of 10mm, the lower surface of the middle part of the center is provided with a first circumferential groove 5-1-1, and the upper surface and the lower surface of the edge part of the center are both provided with a second circumferential groove 5-1-2; the first circumferential groove 5-1-1 and the second circumferential groove 5-1-2 are concentric, and the radius of the first circumferential groove is smaller than that of the second circumferential groove;

the second center perforated cover plate 5-2 includes: the center of the frame is provided with 3 rows by 3 columns (9 in total) of through holes with the diameter of 10mm, the upper surface of the middle part of the frame is provided with a first circumferential groove, and the upper surface and the lower surface of the side part of the frame are both provided with a second circumferential groove; the first circumferential groove and the second circumferential groove are concentric, and the radius of the first circumferential groove is smaller than that of the second circumferential groove;

the first center perforated cover plate 5-1 and the second center perforated cover plate 5-2 are both connected with the center steel cylinder in a (hollow) nested manner, specifically, protrusions are arranged at the top end and the bottom end of the cylinder wall of the center steel cylinder, and the protrusions arranged at the top end and the bottom end of the cylinder wall of the center steel cylinder are respectively matched with a first circumferential groove 5-1-1 arranged on the lower surface of the first center perforated cover plate 5-1 and a first circumferential groove arranged on the upper surface of the second center perforated cover plate 5-2;

the through holes of the first center perforated cover plate 5-1 and the second center perforated cover plate 5-2 are provided with threaded holes or non-threaded holes, and the through holes can be plugged by plugs (when the non-threaded holes are adopted, the plugs can adopt T-shaped plugs);

wherein, temperature regulating device include: the middle part of the outer side of the organic glass cylinder 9-1, a temperature control chamber 4 and a temperature control system;

the top end and the bottom end of the outer middle organic glass cylinder 9-1 are both provided with a bulge, and the bulges arranged at the top end and the bottom end of the outer middle organic glass cylinder 9-1 are respectively matched with a second circumferential groove 5-1-2 arranged on the lower surface of the first center perforated cover plate 5-1 and a second circumferential groove arranged on the upper surface of the second center perforated cover plate 5-2;

the space among the lower surface of the first center perforated cover plate, the upper surface of the second center perforated cover plate, the inner surface of the organic glass cylinder 9-1 in the middle of the outer side and the outer surface of the center steel cylinder 8 forms a temperature control chamber 4;

the temperature control system includes: a hot water circulating pump 15, a connecting pipeline, a water source 23;

the hot water pump 15 is connected with a water source 23, the hot water pump 15 is connected with a temperature control chamber connecting pipeline of a first center perforated cover plate 5-1 through a liquid supply pipeline, a temperature control chamber connecting pipeline 5-1-3 is arranged inside the first center perforated cover plate, one end of the temperature control chamber connecting pipeline inside the first center perforated cover plate is a liquid inlet, and a liquid outlet at the other end is connected with the temperature control chamber 4;

a temperature control chamber connecting pipeline is also arranged in the second center perforated cover plate, a liquid inlet of the temperature control chamber connecting pipeline in the second center perforated cover plate is connected with the control chamber 4, a liquid outlet is arranged at the other end of the temperature control chamber connecting pipeline, and the liquid outlet is connected with a water source 23 through a liquid outlet pipeline;

wherein, the diffusion device includes: an outer top organic glass cylinder 9-2, an outer bottom organic glass cylinder 9-3, a top cover plate 7-1 and a bottom cover plate 7-2;

the lower surface of the top cover plate 7-1 is provided with a second circumferential groove; a second circumferential groove is formed in the upper surface of the bottom cover plate 7-2;

the top end and the bottom end of the outer top organic glass cylinder 9-2 are both provided with a protrusion, and the protrusions arranged at the top end and the bottom end of the outer top organic glass cylinder 9-2 are respectively matched with a second circumferential groove 5-1-2 arranged on the upper surface of the first center perforated cover plate 5-1 and a second circumferential groove arranged on the lower surface of the top cover plate 7-1;

the top end and the bottom end of the outer bottom organic glass cylinder 9-3 are both provided with a protrusion, and the protrusions arranged at the top end and the bottom end of the outer bottom organic glass cylinder 9-3 are respectively matched with a second circumferential groove 5-1-2 arranged on the lower surface of a second center perforated cover plate 5-1 and a second circumferential groove arranged on the upper surface of a bottom cover plate 7-2;

the space among the top cover plate 7-1, the outer top organic glass cylinder 9-2 and the first center perforated cover plate 5-1 forms an upper solution diffusion chamber 6-1;

the space among the bottom cover plate 7-2, the outer bottom organic glass cylinder 9-3 and the second center perforated cover plate 5-2 forms a lower solution diffusion chamber 6-2;

diffusion liquid connecting pipelines are also arranged inside the top cover plate 7-1 and the bottom cover plate 7-2, and the diffusion liquid connecting pipeline of the top cover plate 7-1 is used for filling solution into the solution diffusion chamber 6-1 at the upper part; the diffusion liquid connecting pipeline of the bottom plate cover plate 7-2 is used for filling the solution diffusion chamber 6-2 at the lower part with a recovery solution;

wherein the permeation device comprises: a penetrating fluid connecting pipeline arranged inside the first center perforated cover plate 5-1, a penetrating fluid connecting pipeline arranged inside the second center perforated cover plate 5-2, a first GDS controller, a first solution source, a second GDS controller and a second solution source;

a penetrating fluid connecting pipeline 5-1-4 is also arranged inside the first center perforated cover plate 5-1, one end of the penetrating fluid connecting pipeline inside the first center perforated cover plate is a liquid inlet, and a liquid outlet at the other end is connected with a center steel cylinder 8;

a penetrating fluid connecting pipeline is also arranged inside the second center perforated cover plate 5-2, the penetrating fluid inside the second center perforated cover plate is connected with the center steel cylinder 8 of the pipeline, the other end of the second center perforated cover plate is a liquid outlet, and the liquid outlet of the second center perforated cover plate is connected with a water source 23 through a liquid outlet pipeline;

a liquid outlet of a penetrating fluid connecting pipeline is also arranged in the first center perforated cover plate 5-1, and a liquid inlet of a penetrating fluid connecting pipeline is also arranged in the second center perforated cover plate 5-2 and can be plugged by a plug;

In addition, in order to improve the structural integrity, a plurality of threaded holes (arranged outside the upper solution diffusion chamber 6-1 and the lower solution diffusion chamber 6-2) are uniformly distributed on the top cover plate 7-1 and the bottom cover plate 7-2, and the top cover plate 7-1 and the bottom cover plate 7-2 are clamped by adopting a long threaded column-nut assembly, so that the integral stability of the device is improved.

In addition, in order to improve the structural integrity, a plurality of threaded holes (arranged outside the temperature control chamber 4) are uniformly distributed in the first center perforated cover plate 5-1 and the second center perforated cover plate 5-2, and the first center perforated cover plate 5-1 and the second center perforated cover plate 5-2 are clamped by adopting a short threaded column-nut assembly, so that the overall stability of the device is improved.

In addition, spaces allowing the long threaded columns to pass through are arranged on the first center perforated cover plate 5-1 and the second center perforated cover plate 5-2.

In addition, a sealing ring is arranged between the first circumferential groove and the second circumferential groove and the bulge.

The application of the device of the present application is the core inventive concept of the present application, and specifically, the device can realize the following functions:

first, operating method of temperature-controlled state-solution permeation test (without considering diffusion and expansion force):

s1, firstly placing a bottom cover plate 7-2, and then inserting a bulge at the bottom of an organic glass cylinder 9-3 at the outer side bottom into a second circumferential groove on the upper surface of the bottom cover plate 7-2, so as to connect the organic glass cylinder 9-3 at the outer side bottom of the bottom cover plate 7-2;

s2, installing an organic glass cylinder 9-3 at the bottom of the outer side and a second center perforated cover plate 5-2: a second circumferential groove on the lower surface of the second center perforated cover plate 5-2 corresponds to a bulge on the top of the outer bottom organic glass cylinder 9-3, and the second center perforated cover plate 5-2 is pressed, so that the outer bottom organic glass cylinder 9-3 of the bottom cover plate 7-2 and the second center perforated cover plate 5-2 are connected;

s3, installing a central steel cylinder 8: inserting the bulge at the bottom of the central steel cylinder 8 into the first circumferential groove on the upper surface of the second central perforated cover plate 5-2;

s4, installing an organic glass cylinder 9-1 in the middle of the outer side: inserting the bulge at the bottom of the organic glass cylinder 9-1 at the middle part of the outer side into a second circumferential groove on the upper surface of a second center perforated cover plate 5-2;

s5, putting permeable stones 3, a test soil sample 1 and the permeable stones 3 in the central steel cylinder 8 in sequence, keeping through holes of a first central perforated cover plate 5-1 and a second central perforated cover plate 5-2 in a closed state, and keeping a liquid outlet of a penetrating fluid connecting pipeline arranged in the first central perforated cover plate 5-1 and a liquid inlet of a penetrating fluid connecting pipeline arranged in the second central perforated cover plate 5-2 in an open state;

s6, mounting a first center perforated cover plate 5-1: pressing the first center perforated cover plate 5-1, and inserting the bulge at the top of the center steel cylinder 8 and the bulge at the top of the organic glass cylinder 9-1 in the middle of the outer side into the first circumferential groove and the second circumferential groove on the lower surface of the first center perforated cover plate 5-1;

s7, installing an organic glass cylinder 9-2 at the top of the outer side: a second circumferential groove in the upper surface of the first center perforated cover plate 5-1 corresponds to a protrusion at the bottom of the outer top organic glass cylinder 9-2, and the outer top organic glass cylinder 9-2 is pressed, so that the outer top organic glass cylinder 9-2 and the first center perforated cover plate 5-1 are connected;

s8, mounting a top cover plate 7-1: a second circumferential groove formed in the lower surface of the top cover plate 7-1 corresponds to a protrusion in the top of the outer top organic glass cylinder 9-2, and the top cover plate 7-1 is pressed, so that the protrusion in the top of the outer top organic glass cylinder 9-2 is inserted into the second circumferential groove formed in the lower surface of the top cover plate 7-1;

s9, then a hot water circulating pump 15 is started, and the temperature control chamber 4 is filled with solution, so that the temperature of the soil body is controlled (the permeability coefficients of the soil body at different temperatures can be measured);

and S10, the first GDS pressure volume controller and the second GDS pressure volume controller respectively control an upper water head (solution inflow) and a lower water head (solution outflow), and when liquid change amounts (inflow and outflow) of the two GDS controllers are close to each other per hour, the permeability coefficient can be calculated by reading the volume change amount per unit time and the osmotic water pressure difference.

The permeability coefficient calculation formula is as follows:

k＝QL/AHt

in the formula: k-permeability coefficient;

q-volume of liquid penetrating through the sample (unit: cm) ³ )；

L-the height of the sample (the height of the sample in the patent is 2 cm);

a-sample cross-sectional area (this patent sample cross-sectional area is 3.14X 3.09) ² cm ² )；

H-head difference (water pressure of 100m head is 1 MPa);

the GDS pressure controller can accurately record the change Q of the volume, and the permeability coefficient of the sample can be calculated by substituting the Q value into the formula.

In the step S9, the permeability coefficients of the saturated soil body at different temperatures can be obtained by adjusting the temperature in the temperature control chamber 4.

In the penetration test (without considering diffusion and expansive force) of the soil, the upper solution diffusion chamber 6-1 and the lower solution diffusion chamber 6-2 were not opened.

Second, the operation method of the solution diffusion test under the temperature control state is as follows:

s5, sequentially placing a permeable stone 3, a saturated test soil sample 1 and a permeable stone 3 in a central steel cylinder 8, and keeping through holes of a first central perforated cover plate 5-1 and a second central perforated cover plate 5-2 in an open state;

the liquid outlet of the penetrating fluid connecting pipeline which is also arranged in the first center perforated cover plate 5-1 and the liquid inlet of the penetrating fluid connecting pipeline which is also arranged in the second center perforated cover plate 5-2 are kept in a closed state;

s6, mounting a first center perforated cover plate 5-1: pressing the first center perforated cover plate 5-1, and inserting a bulge at the top of the center steel cylinder 8 and a bulge at the top of the organic glass cylinder 9-1 in the middle of the outer side into a first circumferential groove and a second circumferential groove on the lower surface of the first center perforated cover plate 5-1;

s7, installing an organic glass cylinder 9-2 at the top of the outer side: a second circumferential groove on the upper surface of the first center perforated cover plate 5-1 corresponds to a bulge at the bottom of the outer top organic glass cylinder 9-2, and the outer top organic glass cylinder 9-2 is pressed to connect the outer top organic glass cylinder 9-2 with the first center perforated cover plate 5-1;

s9, then a hot water circulating pump 15 is started, and the temperature control chamber 4 is filled with solution, so that the temperature of the soil body is controlled (the diffusion coefficients of the soil body at different temperatures can be measured);

s10, filling a solution into the solution diffusion chamber 6-2 at the lower part by using a diffusion solution connecting pipeline arranged in the bottom plate cover plate; a solution diffusion chamber 6-1 at the upper part is filled with solution by using a diffusion solution connecting pipeline arranged in the top cover plate 7-1; (the order of filling the solution is first the lower solution diffusion chamber 6-2, and then the upper solution diffusion chamber 6-1).

The upper solution diffusion chamber 6-1 and the lower solution diffusion chamber 6-2 are filled with solutions with different concentrations, and the diffusion parameters of the highly compacted bentonite are calculated by testing the concentration of the solutions in the diffusion cells at fixed intervals (solution concentration sensors can be arranged in the upper solution diffusion chamber 6-1 and the lower solution diffusion chamber 6-2).

In the step S9, the diffusion coefficient of the saturated soil body at different temperatures can be obtained by adjusting the temperature in the temperature control chamber 4.

The diffusion parameters can be calculated by adopting a one-dimensional steady-state diffusion model, and the plane flow J passing through the thickness L is expressed by Fick's first law as follows:

if the concentration in the system changes, i.e., the diffusion process is unstable, fick's second law is as follows:

while

In the formula, D _a Is the apparent diffusion coefficient (m) ² /s)；D _e Is the effective diffusion coefficient (m) ² S); alpha is a capacity factor (dimensionless) which is a measure of the nuclide capacity. α is defined as follows:

α＝ε+ρ·K _d

wherein, K _d To balance the distribution coefficient (m) ³ /kg) showing the interaction between solute and adsorption phase. ρ is the compacted density (kg/m) ³ ) (ii) a ε is the porosity.

In the safety evaluation of highly radioactive waste disposal libraries, porosity is one of the important parameters in modeling the radionuclide migration process. In the compacted buffer/backfill, only the part of the pores through which the water flows contributes to the diffusion of the radionuclide, and the ratio of this part of the pores to the total pores, called porosity (epsilon), can be used to describe the migration behavior of the radionuclide. The porosity calculation equation is as follows:

in the formula, ρ _r (kg/m ³ ) The density of the particles can be obtained by conversion of the product of the specific gravity and the density of water.

If Fick's second law is adopted to calculate D of one-dimensional unsteady state penetration diffusion _e The values, initial, boundary conditions and analytical expressions are as follows:

c(0,t)＝C ₀ ,x＝0；t≥0，

c(L,t)＝0,x＝L；t≥0

wherein A is _cum Is the total amount of all nuclides that cross the x = L boundary (g) over time t; l is the soil sample thickness (m); s is the cross-sectional area (m) of the soil sample ² )；C ₀ Is the initial concentration of nuclide (g/m) ³ )。

Instantaneous diffusion flux J (g/cm) of diffusion cell (low concentration end x = L) ² D) calculated as follows:

wherein J (L, t) is the radioactive flux (ug/cm) with the boundary x = L ² ·d)。

Based on the above defined formula of diffusion flux, the effective diffusion coefficient De and the capacity factor α of solute diffusion can be obtained by fitting experimental data.

Thirdly, the operation method of the expansion force test under the temperature control state comprises the following steps:

s5, putting a permeable stone 3, a test soil sample 1 and an axial pressure sensor 2 into the central steel cylinder 8 in sequence, wherein the through hole of the first central perforated cover plate 5-1 is kept in a closed state, and the through hole of the second central perforated cover plate 5-2 is kept in a closed state;

the penetrating fluid connecting pipeline arranged in the first center perforated cover plate 5-1 is kept closed; a penetrating fluid connecting pipeline of a penetrating fluid connecting pipeline arranged in the second center perforated cover plate 5-2 is kept open;

s10, the device is placed in a solution pool, moisture enters a soil sample from a through hole of a second center perforated cover plate 5-2, an axial pressure sensor is arranged above the soil sample, a permeable stone is arranged below the soil sample, the through hole of the second center perforated cover plate 5-2 is convenient for the axial pressure sensor to be externally connected with a wire, and the second center perforated cover plate 5-2 ensures that the solution can smoothly pass through the second center perforated cover plate 5-2, passes through the permeable stone 3 and then enters a soil body to cause the soil body to expand.

That is, when the saturated soil expansive force test is carried out alone (the expansive soil expansive force is measured by constant volume measurement in the application), S1, S2, S7, S8 and S9 in the permeation and diffusion test are not needed.

In the second embodiment, the device in the first embodiment can not realize the measurement of the expansive force of unsaturated expansive soil; meanwhile, the expansion force of the saturated soil is measured, and the upper solution diffusion chamber 6-1 and the lower solution diffusion chamber 6-2 are not required.

In order to realize the combined test device of the penetration-diffusion-expansive force of the high-compaction bentonite, the improvement is as follows:

a first penetrating fluid connecting pipeline 5-1-4 (L-shaped) is arranged in the first center perforated cover plate 5-1, a T-shaped second penetrating fluid connecting pipeline is matched with the upper part of the wall part of the center steel cylinder 8 (one side opening is arranged on the upper surface of the center steel cylinder 8, and the other two openings are respectively arranged on the side surface of the wall part), and the first penetrating fluid connecting pipeline 5-1-4 is in adaptive communication with the second penetrating fluid connecting pipeline;

the upper part of the wall part of the central steel cylinder 8 is matched with a permeable stone 3 with an opening of a T-shaped second penetrating fluid connecting pipeline corresponding to the upper part;

a first penetrating fluid connecting pipeline (L-shaped) is arranged inside the second center perforated cover plate 5-2, a T-shaped third penetrating fluid connecting pipeline is matched with the lower part of the wall part of the center steel cylinder 8 (one side opening is arranged on the lower surface of the center steel cylinder 8, and the other two openings are respectively arranged on the side surface of the wall part), and the first penetrating fluid connecting pipeline arranged inside the second center perforated cover plate 5-2 is in adaptive communication with the third penetrating fluid connecting pipeline;

the upper part of the wall part of the central steel cylinder 8 is matched with a permeable stone 3 at the lower part corresponding to the opening of a T-shaped third penetrating fluid connecting pipeline;

further comprising: 2 closing rods 20; the closing rod 20 comprises: a rotating rod 20-1, a threaded rod 20-2 and a closed end component 20-3 are rotated; the rotary rotating rod 20-1, the threaded rod 20-2 and the closed end component 20-3 are connected in sequence;

openings of the wall of the central steel cylinder 8 and the wall of the outer middle organic glass cylinder 9-1 are provided with threaded openings, and the threaded rod 20-2 of the sealing rod 20 is respectively matched with the threaded opening of the wall of the central steel cylinder 8 and the threaded opening of the wall of the outer middle organic glass cylinder 9-1;

the size of the rotary rotating rod 20-1 is matched with the size of a horizontal connecting pipeline of a T-shaped third penetrating fluid connecting pipeline (vertical and horizontal);

that is, by rotating the rotating lever 20-1 (which is disposed outside the outer middle plexiglass cylinder 9-1), the closed end member 20-3 can be made to move from the front side of the wall of the center steel cylinder 8 to the rear side of the wall of the center steel cylinder 8.

That is, in the second embodiment, the penetrating fluid connection pipelines of the first center perforated cover plate 5-1 and the second center perforated cover plate 5-1 are modified, so that the use performance of the device is greatly improved.

The device of the second embodiment can realize the saturation-expansive force test of the unsaturated soil expansive force and the penetration test of the expansive soil at the same time through one test.

As shown in the figure 5 of the drawings,

the operation method of the solution expansion force and permeation continuous test under the temperature control state comprises the following steps:

s1, firstly placing a bottom cover plate 7-2, and then inserting a protrusion at the bottom of an organic glass cylinder 9-3 at the outer side into a second circumferential groove on the upper surface of the bottom cover plate 7-2, so as to connect the organic glass cylinder 9-3 at the outer side of the bottom cover plate 7-2;

s2, installing an organic glass cylinder 9-3 at the bottom of the outer side and a second center perforated cover plate 5-2: a second circumferential groove on the lower surface of the second center perforated cover plate 5-2 corresponds to a bulge on the top of the bottom organic glass cylinder 9-3 at the outer side, and the second center perforated cover plate 5-2 is pressed to connect the bottom organic glass cylinder 9-3 at the outer side of the bottom cover plate 7-2 and the second center perforated cover plate 5-2;

s3, installing a central steel cylinder 8: inserting the bulge at the bottom of the central steel cylinder 8 into a first circumferential groove on the upper surface of the second central perforated cover plate 5-2;

meanwhile, the central steel cylinder 8 is rotated, so that a first penetrating fluid connecting pipeline 5-1-4 arranged inside the second central perforated cover plate 5-2 is communicated with a T-shaped third penetrating fluid connecting pipeline arranged at the lower part of the wall part of the central steel cylinder 8;

s5, putting a permeable stone 3, a test soil sample 1, a permeable stone 3 and an axial pressure sensor 2 into a central steel cylinder 8 in sequence, wherein a through hole of a first central perforated cover plate 5-1 is kept in an open state (used for threading of the axial pressure sensor), and a through hole of a second central perforated cover plate 5-2 is kept in a closed state;

a liquid outlet of a penetrating fluid connecting pipeline is also arranged in the first center perforated cover plate 5-1, and a liquid inlet of a penetrating fluid connecting pipeline is also arranged in the second center perforated cover plate 5-2, and the liquid inlets are kept in an open state;

meanwhile, the first center perforated cover plate 5-1 is rotated, so that a first penetrating fluid connecting pipeline 5-1-4 arranged inside the first center perforated cover plate 5-1 is communicated with a T-shaped second penetrating fluid connecting pipeline arranged on the upper part of the wall part of the center steel cylinder 8;

s8, mounting a top cover plate 7-1: a second circumferential groove formed in the lower surface of the top cover plate 7-1 corresponds to a protrusion at the top of the outer top organic glass cylinder 9-2, and the top cover plate 7-1 is pressed, so that the protrusion at the top of the outer top organic glass cylinder 9-2 is inserted into the second circumferential groove formed in the lower surface of the top cover plate 7-1;

s9, then the hot water circulating pump 15 is started, and the temperature control chamber 4 is filled with solution, so that the temperature of the soil body is controlled;

firstly, the closing rod of the upper part is rotated so that the closing end component is close to the outer side of the wall of the central steel cylinder 8, namely, the second permeate pipeline is kept communicated;

Before the test, the water content of the soil sample was measured.

The third embodiment and the second embodiment realize that: the one-stop test of the expansive force-osmotic force of the highly compacted bentonite still needs to be carried out twice (the original test device needs to be disassembled and cleaned) when the bentonite is treated and diffused, and the test is not universal and inconvenient.

The application is improved:

the axial pressure sensor 2 (in the first and second embodiments, both: axial pressure sensor) is changed into a radial pressure sensor 2-2.

The design of the third embodiment can realize one-stop measurement of the penetration-diffusion-expansion force of the high-compaction bentonite.

The operation method of the solution expansion force, infiltration and diffusion continuous test under the temperature control state comprises the following steps:

s5, putting a permeable stone 3, a radial pressure sensor 2-2, a test soil sample 1 and a permeable stone 3 in the central steel cylinder 8 in sequence, wherein the through hole of the first central perforated cover plate 5-1 is kept in a closed state, and the through hole of the second central perforated cover plate 5-2 is kept in a closed state;

in the second stage, the permeability coefficient is measured: rotating the lower closing rod to make the closing end component close to the outer side of the wall of the central steel cylinder 8, namely keeping the third permeate pipeline communicated;

the first GDS pressure volume controller and the second GDS pressure volume controller respectively control an upper water head (solution inflow) and a lower water head (solution outflow), and when liquid change amounts (inflow and outflow) of the two GDS controllers per hour are close, the permeability coefficient can be calculated by reading the volume change amount per unit time and the osmotic water pressure difference;

and a third stage, measuring diffusion coefficient:

rotating the upper closing rod so that the closed end member is close to the inside of the wall of the central steel cylinder 8, i.e. keeping the second permeate line closed;

opening doors on the top organic glass cylinder 9-2 at the outer side and the bottom organic glass cylinder 9-3 at the outer side, and taking away plugs of the through hole of the first center perforated cover plate 5-1 and the through hole of the second center perforated cover plate 5-2, so that the through hole of the first center perforated cover plate 5-1 is kept in an open state, and the through hole of the second center perforated cover plate 5-2 is kept in an open state; then closing and sealing the doors on the organic glass cylinder 9-2 at the top of the outer side and the organic glass cylinder 9-3 at the bottom of the outer side;

a solution diffusion chamber 6-2 at the lower part is filled with solution by using a diffusion solution connecting pipe arranged in the bottom plate cover plate; a solution diffusion chamber 6-1 at the upper part is filled with solution by using a diffusion solution connecting pipeline arranged in the top cover plate 7-1;

In step S9, by adjusting the temperature in the temperature control chamber 4, the expansion force variation law, the permeability coefficient variation law, and the diffusion coefficient variation law of the soil at different temperatures can be obtained.

Before the test, the water content of the soil sample was measured.

While the preferred embodiments of the present invention have been described in detail, it should be understood that various changes and modifications of the invention may be effected therein by those skilled in the art after reading the foregoing teachings. Such equivalents are intended to fall within the scope of the claims appended hereto.

Claims

1. An environmental temperature controllable bentonite penetration-diffusion-expansive force testing combination device is characterized by comprising: the device comprises a soil body side limiting device, a temperature control device, a diffusion device and a radial pressure sensor;

the radial pressure sensor is used for measuring the expansive force of the soil body;

the soil body lateral confinement device comprises: the central steel cylinder, the first central perforated cover plate and the second central perforated cover plate are provided with openings at the upper side and the lower side, and the first central perforated cover plate and the second central perforated cover plate are respectively arranged at the upper side and the lower side of the central steel cylinder; the center of the first center perforated cover plate is provided with a plurality of through holes, the lower surface of the middle part of the first center perforated cover plate is provided with a first circumferential groove, and the upper surface and the lower surface of the edge part of the first center perforated cover plate are both provided with second circumferential grooves; the first circumferential groove of the first center perforated cover plate and the second circumferential groove of the first center perforated cover plate are concentric, and the radius of the first circumferential groove of the first center perforated cover plate is smaller than that of the second circumferential groove of the first center perforated cover plate;

the center of the second center perforated cover plate is provided with a plurality of through holes, the upper surface of the middle part of the second center perforated cover plate is provided with a first circumferential groove, and the upper surface and the lower surface of the edge part of the second center perforated cover plate are both provided with second circumferential grooves; the first circumferential groove of the second center perforated cover plate and the second circumferential groove of the second center perforated cover plate are concentric, and the radius of the first circumferential groove of the second center perforated cover plate is smaller than that of the second circumferential groove of the second center perforated cover plate; the first center perforated cover plate and the second center perforated cover plate are all connected with the center steel cylinder in a nested manner, protrusions are arranged at the top end and the bottom end of the cylinder wall of the center steel cylinder, and the protrusions arranged at the top end and the bottom end of the cylinder wall of the center steel cylinder are respectively matched with a first circumferential groove arranged on the lower surface of the first center perforated cover plate and a first circumferential groove arranged on the upper surface of the second center perforated cover plate;

the temperature control system includes: a hot water circulating pump, a connecting pipeline and a water source; the hot water circulating pump is connected with a water source, the hot water circulating pump is connected with a liquid inlet of a temperature control chamber connecting pipeline of the first center perforated cover plate through a liquid supply pipeline, the temperature control chamber connecting pipeline is arranged in the first center perforated cover plate, one end of the temperature control chamber connecting pipeline in the first center perforated cover plate is a liquid inlet, and a liquid outlet at the other end of the temperature control chamber connecting pipeline is connected with the temperature control chamber; a temperature control chamber connecting pipeline is also arranged in the second center perforated cover plate, a liquid inlet of the temperature control chamber connecting pipeline in the second center perforated cover plate is connected with the control chamber, a liquid outlet is arranged at the other end of the temperature control chamber connecting pipeline, and the liquid outlet is connected with a water source through a liquid outlet pipeline;

wherein, the diffusion device includes: an outer top organic glass cylinder, an outer bottom organic glass cylinder, a top cover plate and a bottom cover plate; a second circumferential groove is formed in the lower surface of the top cover plate; a second circumferential groove is formed in the upper surface of the bottom cover plate; the top end and the bottom end of the outer top organic glass cylinder are both provided with a protrusion, and the protrusions arranged at the top end and the bottom end of the outer top organic glass cylinder are respectively matched with a second circumferential groove arranged on the upper surface of the first center perforated cover plate and a second circumferential groove arranged on the lower surface of the top cover plate; the top end and the bottom end of the outer bottom organic glass cylinder are both provided with a protrusion, and the protrusions arranged at the top end and the bottom end of the outer bottom organic glass cylinder are respectively matched with a second circumferential groove arranged on the lower surface of a second center perforated cover plate and a second circumferential groove arranged on the upper surface of a bottom cover plate; the space among the top cover plate, the outer top organic glass cylinder and the first center perforated cover plate forms an upper solution diffusion chamber; the space among the bottom cover plate, the outer bottom organic glass cylinder and the second center perforated cover plate forms a lower solution diffusion chamber; diffusion liquid connecting pipelines are also arranged inside the top cover plate and the bottom cover plate, and the diffusion liquid connecting pipelines of the top cover plate are used for filling solution into the solution diffusion chamber at the upper part; the diffusion liquid connecting pipeline of the bottom cover plate is used for filling the recovery solution into the solution diffusion chamber at the lower part;

further comprising: an osmotic device, wherein the osmotic device comprises: a first GDS controller, a first solution source, a second GDS controller, a second solution source;

an L-shaped first penetrating fluid connecting pipeline is arranged in the first center perforated cover plate, a T-shaped second penetrating fluid connecting pipeline is matched with the upper part of the wall part of the center steel cylinder, an opening on one side of the second penetrating fluid connecting pipeline is arranged on the upper surface of the center steel cylinder, the other two openings are respectively arranged on the side surface of the wall part, and the first penetrating fluid connecting pipeline is in adaptive communication with the second penetrating fluid connecting pipeline; the opening of the T-shaped second penetrating fluid connecting pipeline at the upper part of the wall part of the central steel cylinder corresponds to the permeable stone at the upper part;

an L-shaped first penetrating fluid connecting pipeline is arranged inside the second center perforated cover plate, a T-shaped third penetrating fluid connecting pipeline is matched with the lower portion of the wall portion of the center steel cylinder, an opening on one side of the third penetrating fluid connecting pipeline is formed in the lower surface of the center steel cylinder, the other two openings are respectively formed in the side surface of the wall portion, and the first penetrating fluid connecting pipeline arranged inside the second center perforated cover plate is in adaptive communication with the third penetrating fluid connecting pipeline; the lower part of the wall part of the central steel cylinder is matched with a permeable stone of which the opening of a T-shaped third penetrating fluid connecting pipeline corresponds to the lower part;

the openings of the wall of the central steel cylinder and the wall of the organic glass cylinder in the middle of the outer side are provided with threaded openings, and the threaded rod of the sealing rod is respectively matched with the threaded opening of the wall of the central steel cylinder and the threaded opening of the wall of the organic glass cylinder in the middle of the outer side; the size of the rotary rotating rod is matched with the size of the horizontal connecting pipeline of the T-shaped second penetrating fluid connecting pipeline and the size of the horizontal connecting pipeline of the T-shaped third penetrating fluid connecting pipeline; the rotating rod is arranged outside the organic glass cylinder in the middle of the outer side, and the closed end part component can move from the inner side of the wall part of the central steel cylinder to the outer side of the wall part of the central steel cylinder by rotating the rotating rod;

one end of a first penetrating fluid connecting pipeline of the first center perforated cover plate is a liquid inlet; one end of the first penetrating fluid connecting pipeline of the second center perforated cover plate is a liquid outlet, and the liquid outlet is connected with a first solution source through a liquid outlet pipeline; the first solution source and the first GDS controller are connected with a liquid inlet of a penetrating fluid connecting pipeline in the first center perforated cover plate; a second GDS controller, wherein a second solution source is connected with a liquid outlet of a penetrating fluid connecting pipeline inside the second center perforated cover plate;

and the top of the outer side of the organic glass cylinder and the bottom of the outer side of the organic glass cylinder are provided with doors.

2. The environmental temperature controllable bentonite penetration-diffusion-expansion force testing combination device as claimed in claim 1, wherein the through holes of the first and second center perforated cover plates are provided with threaded holes or non-threaded holes, and can be plugged by plugs;

the top cover plate and the bottom cover plate are uniformly distributed with a plurality of threaded holes, the threaded holes are arranged outside the upper solution diffusion chamber and the lower solution diffusion chamber, and the long threaded column-nut assembly is adopted to clamp the top cover plate and the bottom cover plate, so that the overall stability of the device is improved;

a plurality of threaded holes are uniformly distributed in the first center perforated cover plate and the second center perforated cover plate, the threaded holes are formed outside the temperature control chamber, the first center perforated cover plate and the second center perforated cover plate are clamped tightly by adopting a short threaded column-nut assembly, and spaces allowing long threaded columns to pass through are formed in the first center perforated cover plate and the second center perforated cover plate.

3. A method for testing a continuous test of swelling power, permeation and diffusion of a solution under a temperature-controlled state, which is characterized by using the apparatus of claim 2, wherein:

firstly, rotating the closing rod at the upper part to enable the closing end component to be close to the outer side of the wall part of the central steel cylinder, namely, keeping the second permeate pipeline communicated;

and a third stage, measuring diffusion coefficient:

rotating the lower closing rod so that the closed end member is close to the inner side of the wall of the central steel cylinder, namely keeping the third permeate pipeline closed;

a solution diffusion chamber at the lower part is filled with solution by using a diffusion solution connecting pipe arranged in the bottom cover plate; filling solution into the solution diffusion chamber at the upper part by using a diffusion solution connecting pipe arranged in the top cover plate;