A grouting body surface roughness measuring device and measuring method

Abstract

The application discloses a kind of grouting surface roughness measuring equipment and measuring method, and the equipment includes sample forming device, which includes sample forming box;Liquid injection device, which includes liquid injection container and connecting pipe, both ends of connecting pipe are connected to sample forming box and liquid injection container respectively, and first liquid is loaded in liquid injection container;Measuring device, which includes measuring container and balance, and balance detects weight change of measuring container, and second liquid is loaded in measuring container;Cooling device is connected with sample forming box and transfers cold quantity.By injecting first liquid and using cooling condensation method, the process of actual grouting and waiting for grout solidification is simulated, the condensation time is shorter to save experimental time, and the sample can be melted and recovered after the experiment to repeat multiple experiments, reducing the waste of materials during the experimental process.Moreover, the second liquid is used instead of traditional sand, and the second liquid can flow into various fine gaps, thereby having higher detection accuracy.

Description

Technical Field

[0001] This invention relates to the field of grouting inspection technology, and in particular to a grouting body surface roughness measuring device and measuring method. Background Technology

[0002] Grouting technology is now widely used, and soil grouting can serve functions such as reinforcement and seepage prevention. After grouting, a grout body of a certain size is often formed. The shape of the grout body is usually simplified to a cylinder or sphere for ease of calculation. For fine-grained soils, this simplification has little impact. However, for coarse-grained soils, especially larger gravelly soils, due to the larger particle size, when the overall size of the grout body is small, the surface roughness of the grout body is large. The uneven surface interlocks with the surrounding soil particles. In this case, simplifying the surface of the grout body to a cylindrical or spherical surface to analyze its interfacial mechanical behavior with the soil often leads to significant errors. It is necessary to consider the influence of the grout body surface roughness on its interfacial mechanical behavior. The first step in analyzing the influence of surface roughness is to quantitatively measure the surface roughness.

[0003] Surface roughness measurement involves two steps: first, preparing a representative sample; and second, measuring the surface roughness of the sample. For sample preparation, due to the large particle size of coarse soil, larger samples are required to be representative, thus consuming more material. Furthermore, if samples are prepared by grouting and solidifying under actual working conditions, the resulting samples can only be used for a single measurement and are subsequently discarded, resulting in significant material waste.

[0004] The most widely used method for measuring surface roughness is the sand-filling method. First, a baffle is used to surround the structure. Then, standard sand is laid on the surface up to the highest point. The surface of the sand is leveled, and the sand is collected and its volume is measured. The roughness is calculated by dividing the sand volume by the area of ​​the surface to which the sand was laid. However, because sand has difficulty penetrating some tiny pores, the volume measured by the sand-filling method has a relatively large error, which is not conducive to accurate measurement of surface roughness. Summary of the Invention

[0005] The present invention aims to at least solve one of the aforementioned technical problems existing in the prior art. To this end, this application proposes a grout surface roughness measuring device, which can save the materials consumed in sample preparation and improve the measurement accuracy of grout surface roughness.

[0006] This application also proposes a measurement method based on the above-mentioned grout surface roughness measuring device.

[0007] The grout surface roughness measuring device according to the first aspect of this application includes:

[0008] A sample preparation device, comprising a sample preparation box containing a sample;

[0009] The liquid injection device includes a liquid injection container and a connecting tube, the two ends of which are respectively connected to the sample box and the liquid injection container, and the liquid injection container is filled with a first liquid;

[0010] A measuring device comprising a measuring container and a balance, the measuring container having an outlet facing the sample box, the balance detecting weight changes in the measuring container, the measuring container being filled with a second liquid;

[0011] A cooling device, which is connected to the sample container and the liquid injection container and transfers cold energy;

[0012] Wherein, the solidification temperature of the second liquid is lower than that of the first liquid, the first liquid in the injection container can enter the sample box through the connecting pipe, the cooling device can solidify the first liquid, and the second liquid can flow onto the sample and the solidified first liquid for surface roughness measurement.

[0013] The grout surface roughness measuring device according to the embodiments of this application has at least the following beneficial effects: by injecting a first liquid and using a cooling and solidification method, the actual grouting process is simulated, and the solidification time is shorter, saving experimental time. Moreover, after the experiment, the sample can be heated to melt and recovered for repeated experiments, reducing material waste during the experimental process. Furthermore, by using a second liquid instead of traditional sand, the second liquid can flow into various fine gaps, thereby achieving higher detection accuracy.

[0014] According to some embodiments of this application, the freezing temperature of the second liquid is at least 4°C lower than the freezing temperature of the first liquid.

[0015] According to some embodiments of this application, the sample forming device further includes a base disposed at the bottom of the sample forming box, the base being capable of leveling the sample forming box.

[0016] According to some embodiments of this application, the sample preparation device further includes a level detector connected to the sample preparation box to detect whether the sample preparation box is placed horizontally.

[0017] According to some embodiments of this application, there are multiple horizontal detectors installed on the side of the sample collection box, and each horizontal detector maintains the same height.

[0018] According to some embodiments of this application, a valve is installed on the connecting pipe to control the flow rate of the connecting pipe.

[0019] According to some embodiments of this application, the valve includes an inlet valve and an outlet valve, with the inlet valve disposed near the sample box and the outlet valve disposed near the injection container.

[0020] According to some embodiments of this application, the connection position of the connecting tube to the sample box is close to the bottom of the sample box, and the first liquid first flows into the bottom of the sample box.

[0021] According to some embodiments of this application, the measuring device further includes a support, the measuring container is mounted to the support, and the support is placed on the balance.

[0022] The measurement method according to the second aspect of this application, which is based on the above-described grout surface roughness measuring device, includes the following steps:

[0023] S100. Prepare a soil sample according to the experimental requirements to form a specimen, fill the specimen into the specimen box and compact it so that the specimen reaches the predetermined height in the specimen box.

[0024] S200. Check whether the sample box is leveled;

[0025] S300. Inject the first liquid in the injection container into the sample box until the liquid level of the first liquid reaches a predetermined height;

[0026] S400. Turn on the cooling device to freeze all the first liquid in the sample box;

[0027] S500. Remove the unbonded particles located above the first liquid freezing surface from the sample box;

[0028] S600. Zero the reading of the balance and record the current mass M1 of the measuring container;

[0029] S700. The second liquid in the measuring container is injected into the sample box until the liquid level of the second liquid reaches the highest point of the sample;

[0030] S800. Record the reading of the balance and record the current mass M2 of the measuring container;

[0031] S900. It can be known that the injected mass of the second liquid is M=M1-M2, and the surface roughness is R=M / ρ / A, where ρ is the density of the second liquid at the temperature applied by the cooling device, and A is the cross-sectional area of ​​the sample box;

[0032] S1000. Turn off the cooling device, the frozen body of the first liquid is heated and melted, and the sample is dried;

[0033] S1100. Repeat steps S100 to S1000 above to obtain at least three sets of surface roughness and obtain the average value from them.

[0034] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0035] The accompanying drawings are used to provide a further understanding of the technical solutions disclosed in this application and form part of the specification. They are used together with the embodiments disclosed in this application to explain the technical solutions of this application and do not constitute a limitation on the technical solutions disclosed in this application.

[0036] Figure 1 This is a schematic diagram of the structure of the grout surface roughness measuring device according to the first aspect of this application;

[0037] Figure 2 This is a schematic diagram of the condensation of the first liquid in the measurement method of the second aspect embodiment of this application;

[0038] Figure 3 This is a schematic diagram of the measurement method in the second aspect of this application when the second liquid is placed.

[0039] Reference numerals: 100-Sample preparation device, 110-Sample box, 120-Base, 130-Level detector, 200-Injection device, 210-Injection container, 220-Connecting pipe, 230-Valve, 231-Inlet valve, 232-Outlet valve, 300-First liquid, 400-Measuring device, 410-Measuring container, 420-Balance, 430-Support, 500-Second liquid, 600-Cooling device, 700-Sample. Detailed Implementation

[0040] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0041] In the description of this application, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0042] In the description of this application, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0043] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0044] In the description of this application, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0045] Grouting technology is now widely used, and soil grouting can serve functions such as reinforcement and seepage prevention. After grouting, a grout body of a certain size is often formed. The shape of the grout body is usually simplified to a cylinder or sphere for ease of calculation. For fine-grained soils, this simplification has little impact. However, for coarse-grained soils, especially larger gravelly soils, due to the larger particle size, when the overall size of the grout body is small, the surface roughness of the grout body is large. The uneven surface interlocks with the surrounding soil particles. In this case, simplifying the surface of the grout body to a cylindrical or spherical surface to analyze its interfacial mechanical behavior with the soil often leads to significant errors. It is necessary to consider the influence of the grout body surface roughness on its interfacial mechanical behavior. The first step in analyzing the influence of surface roughness is to quantitatively measure the surface roughness.

[0046] Surface roughness measurement involves two steps: first, preparing a representative sample; and second, measuring the surface roughness of the sample. For sample preparation, due to the large particle size of coarse soil, larger samples are required to be representative, thus consuming more material. Furthermore, if samples are prepared by grouting and solidifying under actual working conditions, the resulting samples can only be used for a single measurement and are subsequently discarded, resulting in significant material waste.

[0047] The most widely used method for measuring surface roughness is the sand-filling method. First, a baffle is used to surround the structure. Then, standard sand is laid on the surface up to the highest point. The surface of the sand is leveled, and the sand is collected and its volume is measured. The roughness is calculated by dividing the sand volume by the area of ​​the surface to which the sand was laid. However, because sand has difficulty penetrating some tiny pores, the volume measured by the sand-filling method has a relatively large error, which is not conducive to accurate measurement of surface roughness.

[0048] To address this issue, this application proposes a surface roughness measuring device for grout. By injecting a first liquid and employing a cooling and solidification process, it simulates the actual grouting process and the subsequent solidification of the grout. This results in a shorter solidification time, saving experimental time. Furthermore, the sample can be heated and melted after the experiment, allowing for repeated testing and reducing material waste. Moreover, by using a second liquid instead of traditional sand, the second liquid can better penetrate into various minute gaps, thus achieving higher detection accuracy.

[0049] In addition, this application also proposes a measurement method based on the above-mentioned grout surface roughness measuring device.

[0050] Reference Figure 1 The surface roughness measuring device for grout in the first aspect of this application includes a sample preparation device 100, a liquid injection device 200, a first liquid 300, a measuring device 400, a second liquid 500, and a cooling device 600. The sample preparation device 100 is used to place the sample 700 and primarily performs surface roughness measurement. The liquid injection device 200 injects the first liquid 300 into the sample preparation device 100. The first liquid 300 solidifies under the action of the cooling device 600, thereby simulating the grouting and solidification process. The measuring device 400 adds the second liquid 500 to the sample preparation device 100. The second liquid 500 fills the space above the frozen surface of the first liquid 300, and the surface roughness of the current sample 700 can be calculated by detecting the mass of the second liquid 500.

[0051] Specifically, the sample preparation device 100 includes a sample preparation box 110, which contains a sample 700. The liquid injection device 200 includes a liquid injection container 210 and a connecting tube 220, with both ends of the connecting tube 220 connected to the sample preparation box 110 and the liquid injection container 210, respectively. The liquid injection container 210 contains a first liquid 300. Thus, when the connecting tube 220 is connected, the first liquid 300 can flow from the liquid injection container 210 into the sample preparation box 110.

[0052] The measuring device 400 includes a measuring container 410 and a balance 420. The measuring container 410 is provided with an outlet facing the sample container 110. The balance 420 detects the weight change of the measuring container 410, which contains a second liquid 500. Thus, the second liquid 500 can enter the sample container 110 from the outlet of the measuring container 410. Notably, the freezing temperature of the second liquid 500 is lower than that of the first liquid 300, so that when the first liquid 300 reaches its freezing point and freezes, the second liquid 500 can remain liquid.

[0053] The cooling device 600 is connected to the sample box 110 and the liquid injection container 210 and transfers cold energy, so that the first liquid 300 in the sample box 110 cools down and condenses, while the second liquid 500 also reaches the same temperature to prevent the frozen body of the first liquid 300 from re-melting due to the temperature difference when the second liquid 500 comes into contact with the first liquid 300.

[0054] The first liquid 300 in the injection container 210 can enter the sample box 110 through the connecting pipe 220, and the cooling device 600 can solidify the first liquid 300. The second liquid 500 can flow onto the sample 700 and the solidified first liquid 300 for surface roughness measurement.

[0055] The working principle of this grout surface roughness measuring device is as follows: After the sample 700 is loaded into the sample box 110, the first liquid 300 enters the sample box 110 through the connecting pipe 220 to simulate the grouting process. When the first liquid 300 reaches a predetermined liquid level, it is cooled and solidified by the cooling device 600 to simulate the grout solidification process. Then, the second liquid 500 is placed into the sample 700 and the solidified first liquid 300, just enough to submerge the exposed sample 700. The surface roughness of the sample 700 after grouting can be obtained by dividing the volume of the second liquid 500 by the cross-sectional area of ​​the sample box 110.

[0056] The above method of measuring the surface roughness of the grout body has two advantages. First, the use of the first liquid 300 to cool and freeze simulates the solidification of the grout, which can save solidification time and speed up the experimental process. Second, after the frozen body of the first liquid 300 melts, the sample 700 can be recovered and the experiment can continue, which reduces the material loss in the surface roughness measurement experiment and lowers the experimental cost.

[0057] Specifically, the sample collection box 110 can be a cuboid, cube, or cylinder, or it can be a fully enclosed or open-top structure. In this embodiment, the sample collection box 110 is a cuboid structure with an open top, and the outlet of the measuring container 410 is located above the open top of the sample collection box 110.

[0058] Furthermore, the freezing temperature of the second liquid 500 is at least 4°C lower than that of the first liquid 300. This ensures that when the temperature drops to the freezing temperature of the first liquid 300, the second liquid 500 remains liquid, preventing it from cooling and condensing after entering the sample container 110, which would affect the normal operation of the measurement. Regarding the specific types of the first liquid 300 and the second liquid 500, in this embodiment, the first liquid 300 is water, and the second liquid 500 is a 10% sodium chloride solution. It is easily understood that other liquids that meet the above requirements can also be used, and these will not be elaborated upon here.

[0059] Furthermore, the sample preparation device 100 also includes a base 120, which is disposed at the bottom of the sample preparation box 110. The base 120 can level the sample preparation box 110 so that the liquid surface inside the sample preparation box 110 is parallel to the horizontal plane. Specifically, the base 120 is provided with multiple support feet whose height can be adjusted individually. By adjusting the height of each support foot, the tilt of the sample preparation box 110 can be adjusted.

[0060] Furthermore, the sample preparation device 100 also includes a level detector 130, which is connected to the sample preparation box 110 to detect whether the sample preparation box 110 is placed horizontally. In some embodiments, the level detector 130 is an electronic level with a built-in gyroscope, which is in close contact with the sample preparation box 110 and detects the tilt angle when the sample preparation box 110 tilts. In other embodiments, the level detector 130 is specifically a physical level with a built-in bubble level. There are multiple level detectors 130, which are installed on the side of the sample preparation box 110, and each level detector 130 maintains the same height. When the bubble level in the level moves away from the central range to one side, it can be determined that the sample preparation box 110 is tilted, and the base 120 is adjusted accordingly to level the sample preparation box 110.

[0061] Furthermore, a valve 230 is installed on the connecting pipe 220 to control the flow rate of the connecting pipe 220, thereby controlling the flow rate of the first liquid 300 from the injection container 210 to the sample collection box 110. Specifically, the valve 230 includes an inlet valve 231 and an outlet valve 232. The inlet valve 231 is located near the sample collection box 110, and the outlet valve 232 is located near the injection container 210. Only when the inlet valve 231 and the outlet valve 232 are opened simultaneously can the first liquid 300 be injected into the sample collection box 110 through the connecting pipe 220.

[0062] Furthermore, the connection point between the connecting pipe 220 and the sample box 110 is close to the bottom of the sample box 110. The first liquid 300 first flows into the bottom of the sample box 110, and the liquid level gradually rises as the liquid is continuously injected, simulating the grouting process in real-world situations.

[0063] Furthermore, the measuring device 400 also includes a support 430, to which the measuring container 410 is mounted, and the support 430 is placed on the balance 420. Thus, the support 430 can elevate the measuring container 410 so that it is positioned above the sample container 110, and the second liquid 500 inside the measuring container 410 can fall naturally into the sample container 110 after being discharged from the outlet.

[0064] Furthermore, in some embodiments, the cooling device 600 is a low-temperature constant temperature chamber, in which the sample preparation device 100, the liquid injection device 200 and the measuring device 400 are all placed, thereby avoiding temperature fluctuations of the sample preparation device 100 caused by the external environment, keeping the first liquid 300 and the second liquid 500 at the same temperature, and making it easier to maintain a constant temperature environment to ensure that the first liquid 300 is in a condensed state.

[0065] The measurement method in the second aspect embodiment of this application, which is based on the above-mentioned grout surface roughness measuring device, includes the following steps:

[0066] S100. Prepare a soil sample according to the experimental requirements to form a specimen 700. Fill the specimen 700 into the specimen box 110 and compact it so that the specimen 700 reaches the predetermined height in the specimen box 110. The predetermined height of the specimen can be selected according to the actual situation.

[0067] S200. Check whether the sample box 110 is level. The base 120 can be adjusted based on the level detector 130, or leveling can be assisted by other means.

[0068] S300. The first liquid 300 in the injection container 210 is injected into the sample box 110 until the liquid level of the first liquid 300 reaches a predetermined height. The predetermined height can be selected according to the actual situation, and is generally located at 1 / 3 to 2 / 3 of the height of the sample box 110.

[0069] S400. Turn on the cooling device 600 to freeze all the first liquid 300 in the sample box 110. The cooling temperature of the cooling device 600 is about 2°C lower than the freezing point of the first liquid 300.

[0070] S500. Remove the unbonded particles above the freezing surface of the first liquid 300 in the sample box 110 to expose the top surface of the frozen body of the first liquid 300 and the bonded particles that are exposed from the surface of the frozen body.

[0071] S600. Zero the reading of the balance 420 and record the current mass M1 of the measuring container 410;

[0072] S700. Inject the second liquid 500 in the measuring container 410 into the sample box 110 until the liquid level of the second liquid 500 reaches the highest point of the sample 700; when the liquid level of the second liquid 500 is close to the highest point of the sample 700, the valve can be adjusted or a pipette or dropper can be used to make the final liquid level flush with the highest point of the sample 700.

[0073] S800. Record the reading of the balance 420 and record the current mass M2 of the measuring container 410;

[0074] S900. It can be seen that the injected mass of the second liquid 500 is M=M1-M2, and the surface roughness is R=M / ρ / A, where ρ is the density of the second liquid 500 at the temperature applied by the cooling device 600, and A is the cross-sectional area of ​​the sample box 110.

[0075] S1000. Turn off the cooling device 600, the frozen body of the first liquid 300 is heated and melted, and the sample is dried 700;

[0076] S1100. Repeat steps S100 to S1000 above to obtain at least three sets of surface roughness and obtain the average value from them.

[0077] Specifically, when the error between the three roughness values ​​and the average value is no greater than 5%, the average value of the three values ​​is taken as the surface roughness value under that gradation and density. If the error is too large, the number of measurements needs to be increased, outlier data needs to be removed, and then the average value is taken as the surface roughness value under that gradation and density.

[0078] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application. Furthermore, unless otherwise specified, the embodiments and features described in the embodiments of this application can be combined with each other.

Claims

1. A cast body surface roughness measuring apparatus characterized by, The application relates to a surface roughness measuring device, comprising: a sample forming device comprising a sample forming box, wherein a sample is loaded in the sample forming box; a liquid injection device comprising a liquid injection container and a connecting pipe, wherein two ends of the connecting pipe are connected to the sample forming box and the liquid injection container respectively, and the liquid injection container is loaded with a first liquid; a measuring device comprising a measuring container and a balance, wherein the measuring container is provided with a water outlet facing the sample forming box, the balance detects the weight change of the measuring container, and the measuring container is loaded with a second liquid; a cooling device connected to the sample forming box and the liquid injection container and capable of delivering cold energy; wherein the freezing temperature of the second liquid is lower than that of the first liquid, the first liquid in the liquid injection container can enter the sample forming box through the connecting pipe, the cooling device can freeze the first liquid, and the second liquid can flow onto the sample and the frozen first liquid to perform surface roughness measurement.

2. The grout surface roughness measuring apparatus according to claim 1, characterized by: The freezing temperature of the second liquid is at least 4 DEG C lower than that of the first liquid.

3. The grout surface roughness measuring apparatus of claim 1, wherein: The sample forming device further comprises a base arranged at the bottom of the sample forming box, and the base can level the sample forming box.

4. The grout surface roughness measuring apparatus of claim 3, wherein: The sample forming device further comprises a level detector connected to the sample forming box to detect whether the sample forming box is placed horizontally.

5. The grout surface roughness measuring apparatus of claim 4, wherein: The level detector has a plurality of level detectors installed on the side of the sample forming box, and each level detector has the same height.

6. The grout surface roughness measuring apparatus of claim 1, wherein: A valve is installed on the connecting pipe to control the flow of the connecting pipe.

7. The grout surface roughness measuring apparatus of claim 6, wherein: The valve comprises a water inlet valve and a water outlet valve, the water inlet valve is arranged close to the sample forming box, and the water outlet valve is arranged close to the liquid injection container.

8. The grout surface roughness measuring apparatus of claim 1, wherein: The connecting pipe is connected to the sample forming box close to the bottom of the sample forming box, and the first liquid first flows into the bottom of the sample forming box.

9. The grout surface roughness measuring apparatus of claim 1, wherein: The measuring device further comprises a support, the measuring container is installed on the support, and the support is arranged on the balance.

10. A measurement method based on the measurement apparatus for the surface roughness of a cast body according to any one of claims 1 to 9, characterized by, The application relates to a surface roughness measuring device, comprising: S100. A soil sample is configured according to experimental requirements to form a sample, the sample is filled into the sample forming box and compacted, so that the sample reaches a predetermined height in the sample forming box; S200. The sample forming box is checked to see whether it is leveled; S300. The first liquid in the liquid injection container is injected into the sample forming box until the liquid surface of the first liquid reaches a predetermined height; S400. The cooling device is started to freeze the first liquid in the sample forming box; S500. The unconsolidated particles above the frozen surface of the first liquid in the sample forming box are removed; S600. The reading of the balance is zeroed, and the current mass M1 of the measuring container is recorded; S700. The second liquid in the measuring container is injected into the sample forming box until the liquid surface of the second liquid reaches the highest point of the sample; S800. The reading of the balance is recorded, and the current mass M2 of the measuring container is recorded; S900. The injection mass of the second liquid is M=M1-M2, and the surface roughness R is M / ρ / A, wherein rho is the density of the second liquid under the temperature applied by the cooling device, and A is the cross-sectional area of the sample forming box. S1000. The cooling device is turned off, the frozen body of the first liquid is warmed and melted, and the sample is dried; S1100. The steps S100 to S1000 are repeated to obtain at least three groups of surface roughness, and an average value is obtained therefrom.

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