CN117250219A - Rock freeze-thawing cycle test equipment and method for monitoring frost heaving pressure and freeze-thawing damage - Google Patents

Abstract

The invention discloses rock freeze-thawing cycle test equipment for monitoring frost heaving pressure and freeze-thawing damage, which comprises the following components: the total control analysis system is used for controlling the whole freeze thawing test process and carrying out integrated analysis on all data; the visual freeze thawing environment box body is used for performing freeze thawing cycle treatment on the placed rock sample; the ice-containing crack frost heaving pressure monitoring system is used for monitoring the frost heaving pressure of the ice-containing crack in the freeze thawing process in real time; the temperature acquisition system is used for acquiring temperature signals of all positions of the box body in the visual freeze thawing environment in the freeze thawing process in real time; the rock damage detection system is used for transmitting the series of quality data to the total control analysis system to quantitatively analyze the freeze-thawing damage degree of the sample; the water level control system is used for controlling the water supplementing and backwater levels in the box body in the visual freeze thawing environment; the invention also discloses a rock freeze-thawing cycle test method for monitoring the frost heaving pressure and the freeze-thawing damage, which is simple in operation and full-process automation, and can monitor the frost heaving pressure of the ice-containing crack in real time and quantitatively evaluate the freeze-thawing damage.

Description

Rock freeze-thaw cycle testing equipment and methods for monitoring frost heave pressure and freeze-thaw damage

Technical field

The invention relates to the technical field of geotechnical mechanics, in particular to a rock freeze-thaw cycle test equipment and method for monitoring frost heave pressure and freeze-thaw damage.

Background technique

Due to the huge temperature differences between day and night and seasonal temperature differences in alpine areas, the problem of freezing and thawing disasters in rock engineering is particularly prominent. Under the action of day and night or seasonal freeze-thaw cycles, water-ice phase changes and water migration phenomena occur frequently alternately within the engineering rock mass, resulting in significant deterioration of the physical and mechanical properties of the engineering rock mass and easily inducing freeze-thaw erosion of rock slopes. , collapse or even landslide, which greatly threatens the safety and stability of rock engineering in alpine areas. Therefore, it is of great significance to develop a freeze-thaw test device and method that can automatically and quantitatively evaluate the degree of freeze-thaw damage of rocks.

Under the action of freeze-thaw cycles, water-saturated cracks in engineering rock masses will experience the repeated effects of "initiation-development-dissipation" of frost-heaving forces, which in turn will cause the cracks inside the rock mass to gradually expand and penetrate. Frost heave pressure is the core driving force for frost heave cracking and freeze-thaw damage in rock mass. However, the magnitude of the frost heave force in cracks and its evolution mechanism have been controversial, and there is still a lack of effective experimental testing methods. Therefore, it is crucial to develop a test device and method that can accurately measure the frost heave pressure of ice-containing cracks in real time.

Contents of the invention

In order to solve the problems existing in the prior art, the purpose of the present invention is to provide a rock freeze-thaw cycle test equipment and method for monitoring frost heave pressure and freeze-thaw damage. The present invention is simple to operate, fully automated, and can monitor ice content in real time. Fracture frost heave pressure and quantitative assessment of freeze-thaw damage.

In order to achieve the above purpose, the technical solution adopted by the present invention is: a rock freeze-thaw cycle test equipment for monitoring frost heave pressure and freeze-thaw damage, including a total control analysis system, a visual freeze-thaw environment box, and ice-containing cracks frost heave Pressure monitoring system, temperature acquisition system, rock damage detection system and water level control system. The total control analysis system is used to control the entire freeze-thaw test process and integrate and analyze all data; the visual freeze-thaw environment box includes a stainless steel box body, a stainless steel sample rack located in the stainless steel box, a double-layer insulated glass cover located on the top of the stainless steel box, and a heating and cooling component located at the bottom of the stainless steel box. The freeze-thaw environment box can be viewed It is used to perform freeze-thaw cycle processing on the placed rock samples; the ice-containing crack frost heave pressure monitoring system monitors the ice content in the freezing and thawing process in real time through a distributed membrane pressure sensor located inside the visible freeze-thaw environment box. The frost heave pressure of the cracks; the temperature acquisition system collects temperature signals in real time throughout the visible freeze-thaw environment box during the freezing and thawing process through a temperature sensor installed inside the visual freeze-thaw environment box; the rock damage detection system uses a scale The heavy instrument transmits a series of quality data to the total control analysis system to quantitatively analyze the degree of freeze-thaw damage of the sample; the water level control system includes a water storage chamber and a water level sensor located in the water storage chamber for controlling visual freezing. The water supply and return water levels inside the melt environment box.

As a further improvement of the present invention, the total control analysis system includes a parameter control module, a pressure data analysis module, a temperature curve display module, a damage data analysis module and a water level control module; wherein:

The parameter control module is used to pre-set freeze-thaw cycle related parameters, and is connected to the power control end of the heating and refrigeration component to control the work of the heating and refrigeration component;

The pressure data analysis module is connected to the signal output port of the ice-containing fissure frost heave pressure monitoring system, and is used to display the evolution curve of the ice-containing fissure frost heave pressure over time in real time;

The temperature curve display module is connected to the port of the temperature acquisition system for real-time display of the temperature curve of each control point inside the visual freeze-thaw environment box;

The damage data analysis module is connected to the signal output port of the weighing instrument in the rock damage detection system, and is used to collect the dry mass m _dry and saturated mass m _sat of the rock sample, and automatically calculate the pores of the rock sample based on this. rate n, mass loss rate M and damage variable S;

The water level control module is connected to the control port of the water level control system. When the water level control module switches to the air-frozen water thawing mode, the water level control system will be in an open state, that is, the water in the water storage chamber is being heated during the thawing process. Then it will be extracted into the visible freezing and thawing environment box. On the contrary, when the water level control module switches to the air-freezing, air-thawing and freezing-thawing mode, the water level control system is in a closed state, so that the air-freezing, water-thawing or air-freezing and thawing mode can be set as needed. Two freezing and thawing modes: freeze and gas thawing.

As a further improvement of the present invention, the porosity n is calculated as follows:

In the formula, m _sat is the mass of saturated rock, m _dry is the mass of dry rock, ρ _w is the density of water, and V is the volume of the rock sample;

The calculation of mass loss rate M is characterized by the dry mass of the sample:

In the formula, m ₁ is the mass of the dry rock sample before the freeze-thaw cycle, and m ₂ is the mass of the dry rock sample after the freeze-thaw cycle;

Freeze-thaw damage variable S based on sample porosity n:

In the formula, S _i is the damage variable of the rock sample after i freeze-thaw cycles; n _i and n ₀ are respectively the porosity of the rock sample after i freeze-thaw cycles and the porosity of the rock sample that has not experienced freeze-thaw cycles. Porosity.

As a further improvement of the present invention, the stainless steel sample rack is divided into three layers: upper, middle and lower. It is placed in the middle of the visual freezing and thawing environment box and consists of uprights and partitions. The partitions are hollow partitions to facilitate the air circulation. Water circulation in frozen water thawing mode.

As a further improvement of the present invention, the heating and refrigeration assembly is composed of a heating machine and a refrigeration compressor. The heating machine is used to heat the water inside the water storage chamber to a specified melting water temperature. The refrigeration compressor is used to reduce freezing and thawing. The indoor temperature reaches the designated freezing temperature; the heating and cooling components are connected to the parameter control module of the total control analysis system, and control the operation of the heating machine and the refrigeration compressor according to the set parameters related to the freeze-thaw cycle.

As a further improvement of the present invention, the distributed film pressure is located in a sealed bag and installed on the surface of the rock sample to be tested. The sealed bag is pasted on the crack surface of the rock sample to convert the pressure signal received by the sensing area into electrical energy. The signal is transmitted to the frost heave pressure monitoring system of ice-containing fissures through Dupont lines. The bottom of the fissures of the rock specimens is equipped with waterproof and thermal insulation materials.

As a further improvement of the present invention, the rock damage detection system includes a drying chamber and a saturated chamber; the drying chamber includes a transmission crawler and a weighing instrument, and the transmission crawler is used to transfer rock samples after a specified number of freeze-thaw cycles from frozen to The melting chamber is transported to the drying chamber of the damage detection system, and the weighing instrument is used to weigh the quality of the frozen-thaw samples dried in the drying chamber in real time; the saturated chamber includes a transmission crawler and a saturated area, and the transmission crawler is used to The dried rock samples are transported from the drying chamber to the saturated chamber. The saturated area is used to dry the frozen-thawed rock samples after different freeze-thaw cycles and perform saturated treatment according to specifications.

The present invention also provides a rock freeze-thaw cycle test method for monitoring frost heave pressure and freeze-thaw damage, which is characterized in that the rock freeze-thaw cycle test equipment for monitoring frost heave pressure and freeze-thaw damage is used as described above; The method includes the following steps:

①Set the relevant parameters of the freeze-thaw cycle on the operating system and whether to monitor the frost heave pressure of ice-containing cracks and detect freeze-thaw damage;

②Put the sample to be tested into the sample rack in the freezing and thawing chamber;

③ If you want to monitor the frost heave pressure of ice-containing cracks, install the distributed film pressure sensor on the surface of the sample to be tested before starting the freeze-thaw cycle test;

④ If you want to conduct freeze-thaw damage detection, place the sample on the transmission track;

⑤ According to the set freeze-thaw cycle test plan, carry out freeze-thaw cycle tests on rocks, frost heave pressure monitoring of ice-containing fissures, and freeze-thaw damage detection tests.

The beneficial effects of the present invention are:

This invention has the characteristics of simple equipment structure, full automation, low operating difficulty, reliable detection results, and strong practicability. It can monitor the evolution process of frost heave pressure in ice-containing fissure rocks in real time and accurately, and quantitatively characterize the freeze-thaw damage of rocks with dual parameters. Provide effective data support for the study of rock freeze-thaw degradation.

Description of drawings

Figure 1 is a schematic three-dimensional structural diagram of the experimental equipment in the embodiment of the present invention;

Figure 2 is a front view of the experimental equipment in the embodiment of the present invention;

Figure 3 is a top view of the experimental equipment in the embodiment of the present invention;

Figure 4 is a schematic diagram of frost heave pressure monitoring in ice-containing cracks in the embodiment of the present invention.

Reference signs:

1. General control analysis system, 2. Visual freezing and thawing environment box, 3. Ice crack frost heave pressure monitoring system, 4. Temperature acquisition system, 5. Rock damage detection system, 6. Water level control system, 7. Stainless steel Sample rack, 8. Heating and cooling components, 9. Double-layer insulated glass cover, 10. Distributed film pressure sensor, 11. Temperature sensor, 12. Drying chamber, 13. Saturated water chamber, 14. Weighing instrument, 15. Transmission track, 16. Water-saturated area, 17. Water level sensor, 18. Water storage chamber, 19. Sealed bag, 20. Rock sample, 21. Fissure surface, 23. Waterproof and thermal insulation material.

Detailed ways

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

Example 1

As shown in Figures 1 to 4, a rock freeze-thaw cycle test equipment for monitoring frost heave pressure and freeze-thaw damage includes a general control analysis system 1, a visual freeze-thaw environment box 2, and ice-containing crack frost heave pressure monitoring System 3, temperature acquisition system 4 and rock damage detection system 5, the total control analysis system 1 is located in the upper left position of the entire test equipment. This system controls the entire freeze-thaw test process and integrates analysis of all data; visual freeze-thaw environment box 2 Located in the center of the test equipment, it includes a stainless steel box, a stainless steel sample rack 7, a heating and cooling component 8 and a double-layer insulated glass cover 9, which is used to perform freeze-thaw cycles on the placed rock samples; frost heaving of cracks containing ice The pressure monitoring system 3 is located at the bottom of the total control analysis system 1. The frost heave pressure of ice cracks during the freezing and thawing process relies on the distributed membrane pressure sensor 10 installed inside the visual freezing and thawing environment box 2 for real-time monitoring; the temperature acquisition system 4 Located at the bottom of the ice-containing crevice frost heave pressure monitoring system 3, the temperature signals throughout the visible freeze-thaw environment box during the freezing and thawing process rely on the temperature sensor 11 installed inside the box 2 for real-time collection; the rock damage detection system 5 is located at the Looking at the right side of the freeze-thaw environment box 2, the series of quality data is transmitted to the total control analysis system 1 through the weighing instrument 14 for quantitative analysis of the degree of freeze-thaw damage of the sample.

The total control analysis system 1 is the core part of the test equipment, used to control the entire freeze-thaw test process and data integration during the test process, including a parameter control module, a pressure data analysis module, a temperature curve display module, and a damage data analysis module. and a water level control module. The parameter control module is used to preset freeze-thaw cycle related parameters (freezing and thawing mode, freezing temperature, freezing speed, freezing time, thawing temperature, thawing speed, thawing time, number of freezing and thawing cycles, etc.), and The power control end of the heating and refrigeration component 8 is connected to control the work of the heating and refrigeration component 8; the pressure data analysis module is connected to the signal output port of the ice-containing crack frost heave pressure monitoring system 3 for real-time display of the ice-containing crack frost heave pressure. Evolution curve over time; the temperature curve display module is connected to the port of the temperature acquisition system 4 for real-time display of the temperature curve at each control point inside the visual freeze-thaw environment box 2; the damage data analysis module is connected to the rock damage The signal output port of the weighing instrument 14 in the detection system 5 is connected to collect the dry mass m _dry and the saturated mass m _sat of the rock sample, and based on this, automatically calculate the porosity n and mass loss rate M of the rock sample. And the damage variable S; the water level control module is connected to the control port of the water level control system 6. When the water level control module switches to the air-frozen water thawing mode, the water level control system 6 will be in an open state, that is, the water level control system 6 will be in an open state, that is, the water level control module will be in the open state during the thawing process. The water in the water chamber 18 will be pumped into the visual freezing and thawing environment box 2 after heating. On the contrary, when the water level control module switches to the air-freezing air-thawing freezing-thawing mode, the water level control system 6 is in a closed state, so that You can set two freezing and thawing modes of air-frozen water-thawing or air-frozen air-thawing according to your needs; if you do not need to measure the frost heave pressure and freeze-thaw damage of ice-containing cracks during the freeze-thaw cycle, you can directly close the total control analysis system. The pressure data analysis module and damage data analysis module in 1.

The water level control system is located at the bottom of the visible freeze-thaw environment box 2 and includes a water level sensor 17 and a water storage chamber 18. The system control port is connected to the water level control module of the total control analysis system 1. According to the set freeze-thaw mode To control the water level control system 6, and then control the water replenishment and return water levels inside the visible freeze-thaw environment box.

The stainless steel sample rack 7 is divided into three layers: upper, middle and lower. It is placed in the middle of the visible freezing and thawing environment box. It is composed of uprights and partitions. The partitions are hollow partitions to facilitate the freezing and thawing in air. Circulation of sewer water.

The heating and cooling assembly 8 is composed of a heating machine and a refrigeration compressor. The heating machine is used to heat the water inside the water storage chamber 18 to a specified melting water temperature. The refrigeration compressor is used to reduce the temperature in the freezing and thawing chamber to a specified temperature. Freezing temperature; the heating and refrigeration component 8 is connected to the parameter control module of the total control analysis system 1, and controls the operation of the heating machine and the refrigeration compressor according to the parameters related to the freezing and thawing cycle.

The double-layer heat-insulating glass cover 9 is composed of double-layer heat-insulating glass and sealing strips. The cover not only has heat-insulating and sealing features to ensure the temperature stability in the freeze-thaw environment box 1, but also has transparency. Visualization features that allow changes in the appearance of rocks during freeze-thaw cycles or frost heave and cracking processes to be recorded in real time with external industrial cameras.

The distributed membrane pressure sensor 10 includes the sensor itself and a series of Dupont lines. By installing the sensor on the surface of the rock sample to be tested, the pressure signal received in the sensing area is converted into an electrical signal and transmitted to the ice-containing fissure through the Dupont line. In the frost heave pressure monitoring system 3, the system will convert this electrical signal into a pressure signal again and transmit it to the total control analysis system for analysis, and then obtain the frost heave pressure evolution curve inside the ice-containing crack during the freeze-thaw cycle.

The temperature sensor 11 includes a series of sub-temperature sensors. The sub-temperature sensors are placed on the side of the visible freeze-thaw environment box 2 to monitor the temperature curve in the box during the freeze-thaw cycle. The sub-temperature sensors are installed on the rock samples. The surface can monitor the temperature curve of the rock sample surface, and installing the sub-temperature sensor on the surface of the ice-containing crack can monitor the temperature curve inside the rock sample crack.

The working principle of the rock damage detection system 5 is to first dry and then saturate the rock sample after a specified number of freeze-thaw cycles, measure the dry and saturated quality of the rock sample, and transmit a series of quality data to The overall control analysis system 1 performs processing to obtain the rock sample porosity n, mass loss rate M and damage variable S. The rock damage detection system 5 includes two parts: a drying chamber 12 and a saturated chamber 13.

The drying chamber is composed of a transmission crawler 15 and a weighing instrument 14. The function of the transmission crawler 15 is to transport the rock sample after a specified number of freeze-thaw cycles from the freezing and thawing chamber to the drying chamber of the damage detection system. The weighing instrument 14 Its function is to weigh the mass of freeze-thaw samples dried in the drying chamber in real time.

The saturated chamber is composed of a transmission crawler 15 and a saturated area 16. The function of the transmission crawler 15 is to transport the dried rock sample from the drying chamber to the saturated chamber. The function of the saturated area 16 is to wait for different freeze-thaw cycles. The freeze-thaw rock samples after several times are dried and then saturated with water according to specifications.

Add water at 1/3, 2/3, and 3/3 of the height of the rock to the dry sample every 6 hours, and finally immerse the sample for 6 hours. The sample after this treatment is considered to be a saturated sample.

Each of the systems is separated by stainless steel plates with appropriate thickness to ensure temperature stability in the visible freeze-thaw environment box 2 . Since the temperature data and ice-containing crack frost heave pressure data need to be collected inside the visual freeze-thaw environment box 2, the side wall of the visual freeze-thaw environment box 2 is provided with a cable opening to facilitate the temperature sensor and distributed membrane After the arrangement of the pressure sensor and the sensor and its connecting wires are completed, a sealing cover is used to insulate and seal the wire opening.

This embodiment also provides a rock freeze-thaw cycle test method for monitoring frost heave force and freeze-thaw damage. The method includes the following steps: ① Set freeze-thaw cycle related parameters on the operating system and whether to perform frost heave of ice-containing fissures Pressure monitoring and freeze-thaw damage detection; ② Place the sample to be tested on the sample rack of the freeze-thaw chamber; ③ If you want to monitor the frost heave pressure of ice-containing cracks, place the distributed film pressure sensor before starting the freeze-thaw cycle test. Installed on the surface of the sample to be tested; ④ If you want to perform freeze-thaw damage detection, place the sample on the transmission track; ⑤ According to the set freeze-thaw cycle test plan, carry out freeze-thaw cycle tests of rocks, ice-containing fissure freeze Expansion pressure monitoring and freeze-thaw damage detection test.

Example 2

As shown in Figure 1-3, a rock freeze-thaw cycle test equipment capable of real-time monitoring of frost heave pressure and freeze-thaw damage in ice-containing fissures, including a general control analysis system 1, a visual freeze-thaw environment box 2, and ice-containing fissures Frost heave pressure monitoring system 3, temperature acquisition system 4 and rock damage detection system 5. The total control analysis system 1 is the core part of the rock freeze-thaw cycle test equipment. This system is connected to the other five systems to overall control the freeze-thaw cycle test process and the integrated analysis of characteristic index data. The visual freezing and thawing environment box 2 is used to place rock samples that require freezing and thawing treatment and to perform repeated freezing and thawing tests on the samples. One end of the ice-containing fissure frost heave pressure monitoring system 3 is connected to the distributed membrane pressure sensor 10 installed inside the fissure rock, and the other end is connected to the pressure data analysis module of the general control analysis system 1 to convert the electrical signal input by the sensor 10 into a pressure signal. Then it is transmitted to the pressure data analysis module for analysis and display. One end of the temperature acquisition system 4 is connected to the temperature sensor 11 inside the visual freeze-thaw environment box, and the other end is connected to the temperature curve display module of the total control analysis system 1 to realize real-time collection and recording of the temperature signals at each control point, and communicate with The combined action of the total control analysis system 1 ensures the smooth progress of the freeze-thaw cycle test. The rock damage detection system 5 measures the dry and saturated quality of the rock sample through the drying chamber 12 and the saturated chamber 13, and transmits a series of quality data to the damage data analysis module of the total control analysis system 1 for quantitative analysis and display of freeze-thaw damage.

As shown in Figures 1 and 4, the ice-containing crack frost heave pressure monitoring system 3 includes the ice-containing crack frost heave pressure monitoring system 3, a distributed film pressure sensor 10, a sealed bag 19, and a DuPont line 22. By combining the distributed film pressure sensor 10 is installed on the crack surface 21 of the rock sample to be tested, converts the pressure signal received in the sensing area into an electrical signal and transmits it to the ice-containing crack frost heave pressure monitoring system 3 through the Dupont line 22, and the monitoring system 3 will use this electrical signal The pressure signal is again converted to the pressure data analysis module of the total control analysis system 1, and then the frost heave pressure evolution curve inside the ice-containing crack during the freeze-thaw cycle is obtained; the function of the sealing bag is to stick the sealing bag to the rock sample 20 of the crack surface 21 to ensure that the position of the distributed film pressure sensor 10 relative to the crack surface 21 of the rock sample remains unchanged during the freeze-thaw cycle test, and inserting the distributed film pressure sensor 10 into the sealed bag 19 can ensure that the sensor 10's of high accuracy and multiple uses.

As shown in Figures 1 and 3, the working principle of the rock damage detection system 5 is to measure the dry and saturated quality of the rock sample by first drying and then saturated the rock sample after a specified number of freeze-thaw cycles. The series of quality data are transmitted to the damage data analysis module of the general control analysis system 1 for processing, and the rock sample porosity n, mass loss rate M and damage variable S are obtained. The rock damage detection system 5 includes a drying chamber 12 and saturated water. The chamber 13 has two parts, these two parts are connected by a transmission crawler 15.

The controlled freeze-thaw cycle test process is as follows:

①First add an appropriate amount of clean water into the water storage tank 18 until the water level reaches the requirement;

② Place the water-saturated rock sample into the stainless steel sample rack 7 of the visible freeze-thaw environment box 2;

③After setting the freeze-thaw cycle related parameters in the total control analysis system 1 (freeze-thaw mode, freezing temperature, freezing speed, freezing time, thawing temperature, thawing speed, thawing time, number of freeze-thaw cycles, etc.), start the freeze-thaw cycle test;

④ Freezing and thawing cycle process: First, use the refrigeration compressor of the heating and refrigeration component 8 to reduce the temperature in the freezing and thawing chamber to the freezing temperature. After the set freezing time, use the heating machine of the heating and refrigeration component 8 to remove the water in the water storage chamber 18. Heated to the specified melting water temperature, and then the water in the water storage chamber 18 is extracted to the visible freezing and thawing environment box 2 to immerse the sample (air freezing and water thawing mode). After the set thawing time, a freezing and thawing cycle is completed. .

The process of the ice-containing crack frost heave pressure monitoring system 3 is as follows:

① First, pre-prepare the rock sample cracks, paste the sealing bag 19 of appropriate size on the rock sample crack surface 21 with glue, and keep it for 6-12 hours until the glue dries;

② Use waterproof and insulating material 23 to seal the bottom of the rock crack, and then fill the crack in the sample with water to ensure that the crack is saturated;

③ Place the distributed membrane pressure sensor 10 in the sealed bag 19 and fix all the Dupont wires 22. After the distributed membrane pressure sensor 10 and its Dupont wires 22 are arranged, use a sealing cover to insulate and seal the wire opening;

④ Turn on the ice-containing crack frost heave pressure monitoring system 3, convert the pressure signal received in the sensing area into an electrical signal and transmit it to the ice-containing crack frost heave pressure monitoring system 3 through the Dupont line 22. The monitoring system 3 will generate this electrical signal. The pressure signal is again converted into the pressure data analysis module of the total control analysis system 1, and then the frost heave pressure evolution curve inside the ice-containing crack during the freeze-thaw cycle is obtained.

The operation process of the rock damage detection system 5 is as follows:

①Put the specific rock sample into the transmission crawler 15 in the freezing and thawing chamber;

② After the specified number of freeze-thaw cycles, push the rock sample through the transmission crawler 15 onto the weighing instrument 14 in the drying chamber 12 for drying;

④ During the drying process, the damage data analysis module of the total control analysis system 1 records the quality of the rock sample in real time. When the quality of the rock sample no longer changes with time, the rock sample is considered to have been dried;

⑤After the drying process is completed, the dried rock sample is pushed into the saturated area 16 in the saturated chamber 13 through the transmission crawler 15;

⑥When the drying treatment of each rock sample after the specified number of freeze-thaw cycles is completed, perform saturated treatment in the water-saturated area 16;

⑦After the water saturated treatment of all specific rock samples is completed, they are pushed onto the weighing instrument 14 in sequence through the transmission crawler 15 to measure the saturated mass.

This embodiment proposes a rock freeze-thaw cycle test equipment and method capable of real-time monitoring of frost heave pressure and freeze-thaw damage in ice-containing fissures. It is intended to carry out rock freeze-thaw cycle tests while simultaneously quantifying ice-containing fissures in real time, automatically and accurately. The evolution process of frost heave pressure, and dual parameters (mass loss and porosity) are used to quantitatively characterize rock freeze-thaw damage.

The porosity n is calculated as follows:

In the formula, m _sat is the mass of saturated rock, m _dry is the mass of dry rock, ρ _w is the density of water, and V is the volume of the rock sample.

The calculation of the mass damage rate M is characterized by the dry mass of the sample:

In the formula, m ₁ is the mass of the dry rock sample before the freeze-thaw cycle, and m ₂ is the mass of the dry rock sample after the freeze-thaw cycle.

Freeze-thaw damage variable S based on sample porosity n:

In the formula, S _i is the damage variable of the rock sample after i freeze-thaw cycles; n _i and n ₀ are respectively the porosity of the rock sample after i freeze-thaw cycles and the porosity of the rock sample that has not experienced freeze-thaw cycles. Porosity.

The above-described embodiments only express specific implementations of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the patent scope of the present invention. It should be noted that, for those of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention.

Claims (8)

1. A rock freeze-thaw cycle test equipment for monitoring frost heave pressure and freeze-thaw damage, which is characterized by including a total control analysis system, a visual freeze-thaw environment box, an ice-containing crack frost heave pressure monitoring system, and a temperature acquisition system , rock damage detection system and water level control system; the total control analysis system is used to control the entire freeze-thaw test process and integrate and analyze all data; the visual freeze-thaw environment box includes a stainless steel box, located in the stainless steel The stainless steel sample rack in the box, the double-layer insulated glass cover located on the top of the stainless steel box and the heating and cooling assembly located at the bottom of the stainless steel box can be used to test the placed rocks in a visible freeze-thaw environment. The sample is subjected to freeze-thaw cycle processing; the ice-containing crack frost heave pressure monitoring system monitors the frost heave pressure of ice-containing cracks during the freezing and thawing process in real time through a distributed membrane pressure sensor located inside the visible freeze-thaw environment box; so The above-mentioned temperature acquisition system collects temperature signals throughout the visual freezing and thawing environment box in real time through a temperature sensor installed inside the visual freezing and thawing environment box during the freezing and thawing process; the rock damage detection system transmits a series of quality data through a weighing instrument. To quantitatively analyze the degree of freeze-thaw damage of the sample in the total control analysis system; the water level control system includes a water storage chamber and a water level sensor located in the water storage chamber, used to control the water replenishment inside the visible freeze-thaw environment box and return water level. 2. The rock freeze-thaw cycle test equipment for monitoring frost heave pressure and freeze-thaw damage according to claim 1, characterized in that the total control analysis system includes a parameter control module, a pressure data analysis module, and a temperature curve display module. Damage data analysis module and water level control module; including: The parameter control module is used to pre-set freeze-thaw cycle related parameters, and is connected to the power control end of the heating and refrigeration component to control the work of the heating and refrigeration component; The pressure data analysis module is connected to the signal output port of the ice-containing fissure frost heave pressure monitoring system, and is used to display the evolution curve of the ice-containing fissure frost heave pressure over time in real time; The temperature curve display module is connected to the port of the temperature acquisition system for real-time display of the temperature curve of each control point inside the visual freeze-thaw environment box; The damage data analysis module is connected to the signal output port of the weighing instrument in the rock damage detection system, and is used to collect the dry mass m _dry and saturated mass m _sat of the rock sample, and automatically calculate the pores of the rock sample based on this. rate n, mass loss rate M and damage variable S; The water level control module is connected to the control port of the water level control system. When the water level control module switches to the air-frozen water thawing mode, the water level control system will be in an open state, that is, the water in the water storage chamber is being heated during the thawing process. Then it will be extracted into the visible freezing and thawing environment box. On the contrary, when the water level control module switches to the air-freezing, air-thawing and freezing-thawing mode, the water level control system is in a closed state, so that the air-freezing, water-thawing or air-freezing and thawing mode can be set as needed. Two freezing and thawing modes: freeze and gas thawing. 3. The rock freeze-thaw cycle test equipment for monitoring frost heave pressure and freeze-thaw damage according to claim 2, characterized in that the porosity n is calculated as follows: In the formula, m _sat is the mass of saturated rock, m _dry is the mass of dry rock, ρ _w is the density of water, and V is the volume of the rock sample; The calculation of mass loss rate M is characterized by the dry mass of the sample: In the formula, m ₁ is the mass of the dry rock sample before the freeze-thaw cycle, and m ₂ is the mass of the dry rock sample after the freeze-thaw cycle; Freeze-thaw damage variable S based on sample porosity n: In the formula, S _i is the damage variable of the rock sample after i freeze-thaw cycles; n _i and n ₀ are respectively the porosity of the rock sample after i freeze-thaw cycles and the porosity of the rock sample that has not experienced freeze-thaw cycles. Porosity. 4. The rock freeze-thaw cycle test equipment for monitoring frost heave pressure and freeze-thaw damage according to claim 1, characterized in that the stainless steel sample rack is divided into three layers: upper, middle and lower, and is placed in a visible freeze-thaw environment. The middle part of the box is composed of columns and partitions. The partitions are hollow partitions to facilitate the circulation of water in the mode of air freezing and water thawing. 5. The rock freeze-thaw cycle test equipment for monitoring frost heave pressure and freeze-thaw damage according to claim 1, characterized in that the heating and refrigeration assembly is composed of a heating machine and a refrigeration compressor, and the heating machine is used for heating. The water inside the water storage chamber reaches the designated melting water temperature, and the refrigeration compressor is used to reduce the temperature in the freezing and thawing chamber to the designated freezing temperature; the heating and refrigeration components are connected to the parameter control module of the total control analysis system, and freeze according to the set The relevant parameters of the fusion cycle are used to control the operation of the heating machine and refrigeration compressor. 6. The rock freeze-thaw cycle test equipment for monitoring frost heave pressure and freeze-thaw damage according to claim 1, characterized in that the distributed film pressure is located in a sealed bag and installed on the surface of the rock sample to be tested, The sealed bag is pasted on the crack surface of the rock sample, converts the pressure signal received in the sensing area into an electrical signal and transmits it to the ice-containing crack frost heave pressure monitoring system through Dupont line. The bottom of the crack in the rock sample is equipped with waterproof and heat insulation Material. 7. The rock freeze-thaw cycle test equipment for monitoring frost heave pressure and freeze-thaw damage according to claim 1, characterized in that the rock damage detection system includes a drying chamber and a saturated chamber; the drying chamber includes a transmission crawler and a weighing instrument. The transmission crawler is used to transport rock samples after a specified number of freeze-thaw cycles from the freezing and thawing chamber to the drying chamber of the damage detection system. The weighing instrument is used to weigh the frozen and thawed samples dried in the drying chamber in real time. The quality of the water-saturated chamber includes a transmission crawler and a saturated area. The transmission crawler is used to transport the dried rock samples from the drying chamber to the saturated chamber. The saturated area is used to wait for different freeze-thaw cycles. After drying, the frozen-thawed rock samples were saturated with water according to specifications. 8. A rock freeze-thaw cycle test method for monitoring frost heave pressure and freeze-thaw damage, characterized in that the rock freeze-thaw cycle for monitoring frost heave pressure and freeze-thaw damage as described in any one of claims 1-7 is used Test equipment; the method described includes the following steps: ①Set the relevant parameters of the freeze-thaw cycle on the operating system and whether to monitor the frost heave pressure of ice-containing cracks and detect freeze-thaw damage; ②Put the sample to be tested into the sample rack in the freezing and thawing chamber; ③ If you want to monitor the frost heave pressure of ice-containing cracks, install the distributed film pressure sensor on the surface of the sample to be tested before starting the freeze-thaw cycle test; ④ If you want to conduct freeze-thaw damage detection, place the sample on the transmission track; ⑤ According to the set freeze-thaw cycle test plan, carry out freeze-thaw cycle tests on rocks, frost heave pressure monitoring of ice-containing fissures, and freeze-thaw damage detection tests.