A preparation method for an aqueous simulated lunar soil profile sample

Abstract

The present invention provides a method for preparing a water-containing simulated lunar soil profile sample, belonging to the field of preparing simulated lunar soil profile samples. It solves the problem that the existing samples will expand during preparation and cannot maintain the density of the samples. It includes Step 1: placing the sample in a stress aging barrel; Step 2: placing the upper stress aging device above the sample and applying a uniform pressure to the sample in the stress aging barrel to compress the volume of the sample; Step 3: when the volume of the sample is compressed to a certain position, stop pressurizing, and the upper stress aging device enters a pressure-holding state; Step 4: transferring the stress aging barrel loaded with the sample to a low-temperature environmental chamber for low-temperature storage. It is mainly used for the preparation of water-containing simulated lunar soil profile samples.

Description

Technical Field

[0001] The present invention belongs to the field of preparation of simulated lunar soil profile samples, and particularly relates to a method for preparing a water-containing simulated lunar soil profile sample. Background Art

[0002] During the preparation of a large number of profile samples for engineering tests, after the in-situ frozen samples are broken, the particles are granular between each other, and the strength of the whole sample cannot be guaranteed. The samples are densified again through stress aging strengthening to endow the samples with strength. After completing the first-level sample preparation task, the samples need to be placed in refrigerators at different levels for gradient refrigeration. However, when the samples were refrigerated in the past, due to the principle of frost heaving, the samples would expand. At this time, the required sample density for engineering tests could not be maintained, and cracks were likely to occur during the expansion of the samples, changing the mechanical properties of the profile water ice samples, and accurate mechanical parameters could not be obtained during the subsequent drilling and shoveling tests. Summary of the Invention

[0003] In view of this, the present invention aims to provide a method for preparing a water-containing simulated lunar soil profile sample to solve the problem that the existing samples will expand during preparation and cannot maintain the sample density.

[0004] To achieve the above object, the present invention adopts the following technical solutions: A method for preparing a water-containing simulated lunar soil profile sample, which comprises the following steps:

[0005] Step 1: Place the sample in a stress aging barrel;

[0006] Step 2: Place the upper stress aging device above the sample, apply a uniform pressure to the sample in the stress aging barrel, and compress the volume of the sample;

[0007] Step 3: When the volume of the sample is compressed to a certain position, stop pressurizing, and the upper stress aging device enters a pressure holding state;

[0008] Step 4: Transfer the stress aging barrel loaded with the sample to a low-temperature environmental chamber for low-temperature preservation.

[0009] Furthermore, when applying a uniform pressure to the sample in the stress aging barrel in Step 2, the temperature and pressure of the sample are monitored by a monitoring device.

[0010] Furthermore, when the sample is stored at low temperature in Step 4, the temperature and pressure of the sample are monitored by a monitoring device.

[0011] Furthermore, in Step 4, the low-temperature environmental chamber performs gradient cooling refrigeration, and the temperature drops by a certain amount at the same interval.

[0012] Further, the starting temperature of the gradient cooling refrigeration is -30°C, and after maintaining for 30 minutes, it is reduced to -86°C.

[0013] Further, in step 1, the stress aging barrel is pre-cooled and then the sample is loaded. In step 2, the upper stress aging device is pre-cooled and then placed above the sample.

[0014] Further, the pre-cooling temperature of the stress aging barrel and the upper stress aging device is -180°C or lower.

[0015] Further, in step 3, after the sample volume is compressed to a certain position, a plastic film is put on the stress aging barrel.

[0016] Further, in step 2, the upper stress aging device rotates and compacts the sample.

[0017] Further, in step 4, the low-temperature preservation time is 24 hours, and the low-temperature preservation temperature in step 4 is -86°C.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention is mainly applied to the preparation of simulated lunar soil water ice profile samples for engineering tests in the model task stage. During the gradient refrigeration process of the profile sample of the present invention, the sample is continuously subjected to upper pressure and circumferential compressive pressure, so that the strength of the broken sample particles meets the test requirements, which inhibits the expansion performance of the sample during the freezing process, keeps the density of the sample unchanged during this process, always meets the requirements of the engineering test for the sample density, and does not crack or break the sample, avoiding sample scrapping, and providing guarantee for the sample conditions required in the subsequent test process.

[0019] The present invention provides a method for stress aging of profile lunar soil with simple structure, easy operation, controllable temperature and high precision, which can solve problems such as freezing expansion and crack generation during the gradient refrigeration of primary samples, avoid damage to the sample density and sample integrity, and make the prepared samples meet the requirements of subsequent tests.

[0020] The pressure real-time monitoring step proposed by the present invention can accurately monitor the stress inside the lunar soil in the ultra-low temperature environment, display the condition parameters inside the sample through the intuitive indication on the display, can comprehensively monitor each part of the ice-containing sample, and give the relationship between the lunar soil density and the internal compressive stress of the lunar soil to judge the end position of compaction.

[0021] The present invention can detect the ultra-low temperature environment below -180°C, judge the internal temperature of the sample environment in real time, adjust the temperature inside the environmental chamber in time according to the change of temperature, and strictly control the sample.

[0022] The aging strengthening environment proposed by the present invention requires gradient refrigeration, and the temperature difference is adjusted downward correspondingly within the same time interval, which can avoid frosting of the sample in the sudden cooling environment and affect the moisture content of the sample.

[0023] The method of the present invention performs long-term pressure holding on the ice-containing particle sample, which can effectively prevent the sample from cracking in the low-temperature environment and can minimize the rebound of the sample after the pressure application ends. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0025] Figure 1 is a flowchart of a method for preparing a water-containing simulated lunar soil profile sample according to the present invention;

[0026] Figure 2 is a schematic diagram of the stress loading stage according to the present invention;

[0027] Figure 3 is a schematic diagram of the aging strengthening stage according to the present invention.

[0028] 1 - sample, 2 - stress aging barrel, 3 - monitoring device, 4 - low-temperature environment chamber. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0030] Refer to Figures 1-3 To illustrate this embodiment, a method for preparing a water-containing simulated lunar soil profile sample requires

[0031] conditions such as a pre-cooled stress aging barrel 2 and an upper stress aging device, a low-temperature environment chamber 4 for creating an ultra-low temperature environment, and a real-time sample pressure and temperature monitoring device 3.

[0032] The preparation includes the following steps:

[0033] Step 1: Place the sample 1 in the stress aging barrel 2;

[0034] Step 2: Place the upper stress aging device above the sample 1, apply a uniform pressure to the sample 1 in the stress aging barrel 2, so that each part of the sample is uniformly stressed, and compress the volume of the sample 1;

[0035] Step 3: When the volume of Sample 1 is compressed to a certain position, stop applying pressure, and the upper stress aging device enters the pressure-holding state;

[0036] Step 4: Transfer the stress aging barrel 2 loaded with Sample 1 to the low-temperature environmental chamber 4 for low-temperature storage.

[0037] When applying a uniform pressure to Sample 1 in the stress aging barrel 2 in Step 2, monitor the temperature and pressure of Sample 1 through the monitoring device 3. When performing low-temperature storage on Sample 1 in Step 4, monitor the temperature and pressure of Sample 1 through the monitoring device 3. Obtain the sample parameters in an intuitive reading manner.

[0038] In Step 4, the low-temperature environmental chamber 4 performs gradient cooling refrigeration, and the temperature drops by a certain amount at the same interval. The starting temperature of the gradient cooling refrigeration is -30°C, and it drops to -86°C after maintaining for 30 minutes.

[0039] In Step 1, pre-cool the stress aging barrel 2 and then load Sample 1. In Step 2, pre-cool the upper stress aging device and then place it above Sample 1. The pre-cooling temperature of the stress aging barrel 2 and the upper stress aging device is -180°C or lower. The pre-cooling method uses liquid nitrogen pre-cooling.

[0040] In Step 3, after the volume of Sample 1 is compressed to a certain position, put a plastic film on the stress aging barrel 2.

[0041] In Step 2, the upper stress aging device performs rotary compaction on Sample 1.

[0042] In Step 4, the low-temperature storage time is 24 hours, and the low-temperature storage temperature in Step 4 is -86°C.

[0043] As Figure 1 shown, the preparation method includes installing a stress loading tooling, rotary compaction, sample transfer, and ultra-low temperature storage. Among them, the stress loading tooling and rotary compaction belong to the stress loading stage. The stress loading tooling includes the stress aging barrel 2 and the upper stress aging device. Transferring to the gradient refrigeration environment for low-temperature storage for 24h belongs to the aging strengthening stage. During the rotary compaction process, the temperature and pressure need to be monitored in real time, and the temperature and pressure also need to be monitored during the low-temperature storage stage.

[0044] As Figure 2 shown, the principle of the stress loading stage is to apply a downward pressure to the ice-containing sample particles in the stress aging barrel 2. At this time, the ice-containing sample particles are restricted by the downward uniform pressure and the confining pressure of the stress aging barrel 2, and the density gradually increases. The strength and hardness of the sample gradually increase. At this time, it is necessary to monitor the pressure and temperature of Sample 1 in real time, calculate the relative density of the ice-containing particle sample at this time according to the volume compression amount and mass of Sample 1, and stop applying pressure when the density reaches the requirement.

[0045] As Figure 3 shown, the principle of the aging strengthening stage is that after the pressurization of the ice-containing particle sample 1 is completed, the sample 1 needs to be stored under high pressure for a long time in a low-temperature environment. The entire sample and the tooling are transferred into a gradient refrigeration environment for storage, and the temperature is reduced by a corresponding amount every same time period. The storage duration is 24 hours. The long-term stress loading can ensure the density and strength of the sample for a long time, avoid the rebound phenomenon and frost heave cracks after the stress loading of the sample stops, and prevent the density and integrity of the sample from changing again.

[0046] This embodiment can be applied to the preparation of simulated lunar regolith water ice profile samples for engineering tests in the model mission stage. During the gradient refrigeration process of the profile sample, the sample 1 is continuously subjected to the upper pressure and the circumferential confining pressure, so that the strength of the crushed sample particles meets the test requirements, the expansion performance of the sample 1 during the freezing process is inhibited, the density of the sample 1 remains unchanged during this process, and always meets the requirements of the engineering test for the sample density, and no cracks or sample breakage will occur, avoiding the scrapping of the sample 1 and providing guarantee for the sample conditions required in the subsequent test process.

[0047] This embodiment can solve problems such as frost heave and crack generation during the gradient refrigeration of the primary sample, avoid the destruction of the sample density and sample integrity, and make the prepared sample meet the subsequent test requirements. Through real-time pressure monitoring, the stress inside the lunar regolith in the ultra-low temperature environment can be accurately monitored. The condition parameters inside the sample are displayed through the intuitive indication on the display, and all parts of the ice-containing sample can be monitored in all directions, and the relationship between the lunar regolith density and the internal compressive stress of the lunar regolith is given to judge the end position of the compaction.

[0048] The embodiments of the present invention disclosed above are only used to help explain the present invention. The embodiments do not describe all the details in detail, nor limit the invention to the specific embodiments described. According to the content of this specification, many modifications and changes can be made. These embodiments are selected and specifically described in this specification to better explain the principle and practical application of the present invention, so that those skilled in the art in the relevant technical field can understand and utilize the present invention well.

Claims

1. A preparation method for an aqueous simulated lunar soil profile sample, characterized in that: It includes the following steps: Step 1: Place the sample (1) inside the stress aging barrel (2); Step 2: Place the upper stress aging device above the sample (1), apply a uniform pressure to the sample (1) inside the stress aging barrel (2), and compress the volume of the sample (1); Step 3: When the volume of the sample (1) is compressed to a certain position, stop pressurizing, and the upper stress aging device enters the pressure-holding state; Step 4: Transfer the stress aging barrel (2) loaded with the sample (1) to the low-temperature environmental chamber (4), and store the sample (1) under low temperature and high pressure for a long time in the low-temperature environment; 2. The preparation method of a water-containing simulated lunar soil profile sample according to claim 1, characterized in that: When applying the uniform pressure to the sample (1) inside the stress aging barrel (2) in Step 2, monitor the temperature and pressure of the sample (1) through the monitoring device (3); 3. The preparation method of a water-containing simulated lunar soil profile sample according to claim 1, characterized in that: When storing the sample (1) at low temperature in Step 4, monitor the temperature and pressure of the sample (1) through the monitoring device (3); 4. The preparation method of a water-containing simulated lunar soil profile sample according to claim 1, characterized in that: In Step 4, the low-temperature environmental chamber (4) performs gradient cooling refrigeration, and drops a certain temperature at the same interval of time; 5. The preparation method of a water-containing simulated lunar soil profile sample according to claim 4, characterized in that: The starting temperature of the gradient cooling refrigeration is -30°C, and it drops to -86°C after maintaining for 30 minutes; 6. The preparation method of an aqueous simulated lunar soil profile sample according to claim 1, wherein: In Step 1, pre-cool the stress aging barrel (2) and then load the sample (1). In Step 2, pre-cool the upper stress aging device and then place it above the sample (1); 7. A method for preparing a water-containing simulated lunar soil profile sample according to claim 6, characterized in that: The pre-cooling temperature of the stress aging barrel (2) and the upper stress aging device is -180°C or lower; 8. A method for preparing a water-containing simulated lunar soil profile sample according to claim 1, characterized in that: After the volume of the sample (1) is compressed to a certain position in Step 3, put a plastic film on the stress aging barrel (2); 9. The preparation method of a water-containing simulated lunar soil profile sample according to claim 1, wherein: In Step 2, the upper stress aging device rotates and compacts the sample (1); 10. The preparation method of a water-containing simulated lunar soil profile sample according to claim 1, characterized in that: The low-temperature storage time in Step 4 is 24 hours.

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