LU501810B1 - Frost heaving test system for ice lens observation - Google Patents
Frost heaving test system for ice lens observation Download PDFInfo
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- LU501810B1 LU501810B1 LU501810A LU501810A LU501810B1 LU 501810 B1 LU501810 B1 LU 501810B1 LU 501810 A LU501810 A LU 501810A LU 501810 A LU501810 A LU 501810A LU 501810 B1 LU501810 B1 LU 501810B1
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- soil sample
- frost heaving
- thermal insulation
- insulation cover
- soil
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N25/00—Investigating or analyzing materials by the use of thermal means
- G01N25/02—Investigating or analyzing materials by the use of thermal means by investigating changes of state or changes of phase; by investigating sintering
- G01N25/04—Investigating or analyzing materials by the use of thermal means by investigating changes of state or changes of phase; by investigating sintering of melting point; of freezing point; of softening point
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/24—Earth materials
Abstract
The invention comprises an incubator, a thermal insulation cover, a soil sample frost heaving experiment device and an image acquisition device; the thermal insulation cover is arranged in the incubator, and the soil sample frost heaving experiment device is arranged in the thermal insulation cover; the thermal insulation cover comprises a soil sample peripheral thermal insulation cover and a soil sample photo collection area thermal insulation cover; the soil sample peripheral thermal insulation cover is provided with an observation area, and the soil sample photo collection area thermal insulation cover is movably arranged in the observation area to cover or expose the observation area; an observation window is arranged on the surface of the incubator and at a position corresponding to the observation area; the image acquisition device is arranged outside the observation window.
Description
DESCRIPTION LU501810
TECHNICAL FIELD The invention relates to the technical field of geological observation, and in particular to a frost heaving test system for ice lens observation.
BACKGROUND Frozen soil is widely distributed in China, with seasonal frozen soil and permafrost accounting for about 75% of China's land area. In the vast frozen soil area, there are abundant natural resources and a large number of people living there. With the rapid development of China's economy, people's demands for living environment, travel and resources are increasing year by year, and it is urgent to build a large number of railways, highways, civil buildings and energy projects in the vast permafrost regions. The construction will involve a lot of problems in the field of frozen soil, such as frost heaving of soil in low temperature environment is a typical problem, and the research on this problem is of great significance to the construction of projects in cold regions, disaster prevention and the development of related theories of frozen soil.
In the process of soil freezing, water freezes into ice, forming ice lens, and the growth of ice lens promotes the increase of frost heaving. The segregation and development of ice is a complex dynamic process; in the rapid freezing stage, there is no external moisture migration, and the soil is of integral structure, and there is no segregation ice; in the transition section, the moving speed of freezing front slows down, and there is a small amount of external moisture migration, which will form a small amount of discontinuous segregated ice. When the freezing front is stable, the external moisture has enough time to move to the freezing front, which promotes the rapid growth of the ice lens. This stage is the main stage of frost heaving. Therefore, it is of great significance to be able to observe the moisture migration in the experiment at different time periods in the frost heaving experiment.
At present, there are several methods to observe the ice lens: first, after the soil sample frost heaving experiment is completed, remove the thermal insulation material wrapped around the soil samples, collect photos of the frozen soil samples by taking photos, and analyze the distribution of the ice lens by binarizing the photo images; secondly, the sample cylinder is made of transparent material, and the soil sample is placed in the transparent sample cylinder; during the freezing process of the soil sample, photographic acquisition is carried out from the outsidé}501810 of the soil sample cylinder, and the distribution of ice lens is analyzed with binary analysis. The evaluation of the above two methods is as follows: the first method has an advantage of simple operation, but the operation of removing the thermal insulation material around the soil sample requires opening the door of the incubator and manually removing the thermal insulation material, which has a great influence on the environmental temperature of the soil sample, and the ice is easily affected by the temperature and melts, so the test accuracy is low; in addition, this operation is the final operation after the frost heaving test, and only the distribution of ice lens in the final soil sample can be measured, but the formation process of ice lens can not be photographed. The second one can observe the distribution of ice in the soil from the outside in real time, and observe the progress of the frozen edge and the formation process of the ice lens. However, it is difficult to ensure the control of the temperature around the soil sample in the frost heaving test without taking heat preservation measures. In addition to being transferred from the top to the bottom of the soil sample, the cooling energy will also spread to the outside of the sidewall of the sample cylinder, which can't realize unidirectional freezing. As far as the frost heaving test itself is concerned, the temperature control is inaccurate, which leads to the inaccuracy of the test results. And because of the need of shooting, the camera is often placed in a low-temperature room for shooting, and fog will appear on the camera lens, and the influence of lighting in the low-temperature room will lead to the shooting not achieving the best effect.
SUMMARY (I) Technical problems to be solved The objective of the embodiment of the invention is to provide a frost heaving test system for ice lens observation, so as to solve the technical problems of complicated operation and low test accuracy of the ice lens observation method in the prior art.
(IT) Technical scheme In order to solve the above technical problems, the embodiment of the invention provides a frost heaving test system for ice lens observation, which comprises an incubator, a thermal insulation cover, a soil sample frost heaving experiment device and an image acquisition device; the thermal insulation cover is arranged in the incubator, and the soil sample frost heaving experiment device is arranged in the thermal insulation cover, among them, the thermal insulation cover comprises a soil sample peripheral thermal insulation cover and a soil sampléJ501810 photo collection area thermal insulation cover; the soil sample peripheral thermal insulation cover is provided with an observation area, and the soil sample photo collection area thermal insulation cover is movably arranged in the observation area to cover or expose the observation area, an observation window is arranged on the surface of the incubator at a position corresponding to the observation area; and the image acquisition device is arranged outside the observation window.
The system also comprises a first cold bath box and a second cold bath box; the soil sample frost heaving experiment device comprises a top plate and a bottom plate, which are respectively located at the top and bottom of the soil sample frost heaving experiment device; heat exchange tubes are respectively arranged inside the top plate and the bottom plate; the surface of the top plate is provided with top plate cold bath interfaces communicated with the interior of the top plate, and the surface of the bottom plate is provided with bottom plate cold bath interfaces communicated with the interior of the bottom plate; the first cold bath box is connected with the top plate cold bath interfaces through a supercooled liquid pipe, and the second cold bath box is connected with the bottom plate cold bath interfaces through a supercooled liquid pipe.
The soil sample frost heaving experiment device also includes a fixed rod and a fixed plate, wherein the fixed plate is arranged in the circumferential direction of the top plate, and the fixed rod is vertically arranged, and one end of the fixed rod is fixed with the fixed plate and the other end is fixed with the bottom plate.
The system also includes a temperature acquisition device for monitoring the temperature change during the soil freezing process, and a plurality of temperature acquisition interfaces are vertically arranged on the sidewall surface of the soil sample frost heaving experiment device, and the temperature acquisition device is respectively connected to the temperature acquisition interfaces for monitoring the temperature change during the soil freezing process.
The system also comprises a Markov bottle and a water replenishing pipeline, wherein the bottom of the soil sample frost heaving experiment device is provided with a water replenishing port, and the Markov bottle is communicated with the water replenishing port through the water replenishing pipeline.
Among them, the soil sample peripheral thermal insulation cover and the soil sample phot&501810 collection area thermal insulation cover both comprise a polytetrafluoroethylene layer, an aerogel felt layer and a polystyrene board which are nested in sequence from inside to outside.
Among them, the system also comprises a lifting device and a driving device, wherein the driving device is connected with the soil sample photo collection area thermal insulation cover, and the lifting device comprises a rail and a sliding part, wherein the rail is vertically fixed, and the sliding part is arranged on the rail in a liftable manner and fixedly connected with the soil sample photo collection area thermal insulation cover.
Among them, the system also comprises a soil sample frost heaving deformation measuring device, which is arranged inside the soil sample frost heaving experiment device and located at the top of the soil sample frost heaving experiment device and used for monitoring the frost heaving deformation in the freezing process.
Among them, the soil sample frost heaving experiment device comprises a transparent plexiglass barrel.
(3) Beneficial effects According to the frost heaving test system for ice lens observation provided by the embodiment of the invention, when the formation process of the ice lens needs to be observed, the soil sample photo collection area thermal insulation cover is removed from the observation area, and the frost heaving situation of the soil in the soil sample frost heaving experiment device is monitored through the observation window and the observation area by using the image acquisition device, so that the image acquisition of the image acquisition device is clear; during the experiment, moving the soil sample photo collection area thermal insulation cover just completely covers the gap, forming a complete thermal insulation cover, which has a good thermal insulation effect and avoids the change of soil sample temperature. According to the invention, through the image acquisition device, it is easier to observe the freezing process of water in the soil into ice and the formation and change process of the ice lens, and the unidirectional freezing of the soil can be guaranteed to the greatest extent, and the frost heaving test result of the soil temperature will not be influenced by shooting. The system has the advantages of low cost, high test accuracy, clear and reliable observation results, and the test results clearly and intuitively show the formation process of ice lens in frozen soil, which has important theoretical and practical significance for the research of frost heaving theory of soil 501810 cold regions and the prevention and control of engineering frost damage.
BRIEF DESCRIPTION OF THE FIGURES FIG. 1 is a structural schematic diagram of a frost heaving test system for ice lens observation according to an embodiment of the present invention; FIG. 2 is an exploded view of the frost heaving test system for ice lens observation according to an embodiment of the present invention; FIG. 3 is a schematic structural diagram of an incubator according to an embodiment of the present invention; FIG. 4 is a structural schematic diagram of a soil sample frost heaving experiment device according to an embodiment of the present invention; FIG. 5 is a bottom view of the soil sample frost heaving experiment device according to an embodiment of the present invention; FIG. 6 is a schematic structural diagram of a lifting device, a driving device and a thermal insulation cover according to an embodiment of the present invention; FIG. 7 is a structural schematic diagram of a soil sample peripheral thermal insulation cover according to an embodiment of the present invention; FIG. 8 is a top view of the soil sample peripheral thermal insulation cover according to an embodiment of the present invention; FIG. 9 is a partial detail view of the fixed end of the lifting device according to the embodiment of the present invention; FIG. 10 is a partial detail view of a linear bearing according to an embodiment of the present invention; FIG. 11 is a schematic structural diagram of a soil sample frost heaving deformation measuring device according to an embodiment of the present invention; FIG. 12 is a schematic structural diagram of a temperature acquisition device according to an embodiment of the present invention; FIG. 13 is a schematic view of the longitudinal section of the incubator according to an embodiment of the present invention.
Reference number:
1: thermal insulation cover; 101: soil sample peripheral thermal insulation cover; 102: sdiU501810 sample photo collection area thermal insulation cover; 103: geared motor; 104: pulley; 1011: roof; 1012: the fifth hole; 1013: the third hole; 1014: the sixth hole; 1015: the seventh hole; 1016: polytetrafluoroethylene layer; 1017: aerogel felt layer; 1018: polystyrene board; 1019: the eighth hole; 1021: fixed end; 1022: rail; 1023: linear bearing; 1024: screw; 1025: backing plate; 2: soil sample frost heaving experiment device; 201: top plate; 202: bottom plate; 203: fixed rod; 204: transparent plexiglass barrel, 205: temperature acquisition interface; 206: top plate cold bath interface; 207: fixed plate; 208: bottom plate cold bath interface; 209: simulated groundwater inlet; 3: incubator; 301: observation window; 302: the first hole; 303: the second hole; 4: the first cold bath box; 401: supercooled liquid pipe; 5: the second cold bath box; 6. temperature acquisition device; 602: thermistor sensor; 601: data acquisition instrument; 603: temperature sensor circuit; 7: Markov bottle; 701: water replenishing pipeline; 8. soil sample frost heaving deformation measuring device; 801: displacement sensor; 802: displacement sensor line; 803: data acquisition device; 9: driving device; 10: image acquisition device.
DESCRIPTION OF THE INVENTION The specific embodiments of the present invention will be described in further detail below with reference to the drawings and embodiments. The following embodiments are used to illustrate the invention, but not to limit the scope of the invention.
In the description of the present invention, it should be noted that the terms "installation", "connected" and "connection" should be broadly understood, for example, they can be fixed connection, detachable connection or integral connection; they can be mechanically connected or electrically connected; they can be directly connected, can also be indirectly connected through an intermediate medium, and can be the internal communication of two elements. For ordinary technicians in the field, the specific meanings of the above terms in the present invention can be understood in specific situations.
As shown in FIG. 1 to FIG. 13, the invention discloses a frost heaving test system for ice lens observation, which comprises an incubator 3, a thermal insulation cover 1, a soil sample frost heaving experiment device 2 and an image acquisition device 10; the thermal insulation cover 1 is arranged in the incubator 3, and the soil sample frost heaving experiment device 2 is arranged in the thermal insulation cover 1; among them, the thermal insulation cover 1 comprises a soil sample peripheral thermal insulation cover 101 and a soil sample photo collection aré4)501810 thermal insulation cover 102; the soil sample peripheral thermal insulation cover 101 is provided with an observation area, and the soil sample photo collection area thermal insulation cover 102 is movably arranged in the observation area to cover or expose the observation area; an observation window 301 is arranged on the surface of the incubator 3 at a position corresponding to the observation area; and the image acquisition device 10 is arranged at the observation window 301.
Specifically, in the embodiment of the invention, the thermal insulation cover 1 is used to keep the temperature of the soil sample inside the soil sample frost heaving experiment device 2, and the incubator 3 outside the soil sample frost heaving experiment device 2 has the function of controlling the temperature of the soil sample. In this embodiment, the low-temperature incubator 3 is adopted, and the frost heaving test of soil samples is ensured to be carried out at low temperature by the temperature control device; this device has good temperature control, heat preservation and heat insulation performance, and its temperature control accuracy is +0.5°C.
In this embodiment, the observation area constructed by the soil sample peripheral thermal insulation cover 101 is a gap; during the experiment, the moving soil sample photo collection area thermal insulation cover 102 just completely covers the gap to form a complete thermal insulation cover 1, which has a good thermal insulation effect and avoids the change of the temperature of the soil sample; when it is necessary to observe the formation process of the ice lens, the soil sample photo collection area thermal insulation cover 102 is removed from the gap, and the image acquisition device 10 is used to monitor the soil frost heaving in the soil sample frost heaving experiment device 2 through the observation window 301 and the observation area, so as to ensure that the image acquisition by the image acquisition device 10 is clear.
The main body of the soil sample frost heaving experiment device 2 is a transparent plexiglass barrel 204, the interior of which is used to hold the experimental soil.
The image acquisition device 10 can use two cameras and a stereo microscope; when the device is used, it can observe the microstructure in the freezing process through the observation window 301, observation area and transparent plexiglass barrel 204 of the incubator 3 at a certain frequency. Through the combination of stereo microscope and scientific camera, and the organic combination with the movable soil sample photo collection area thermal insulation covet)501810 102, microstructure observation and real-time shooting can be realized, and then the formation process of ice lens during soil sample frost heaving can be clearly observed.
According to the invention, through the image acquisition device 10, the freezing process of water in the soil into ice and the formation and change process of the ice lens can be easily observed, and the unidirectional freezing of the soil can be guaranteed to the greatest extent, and the frost heaving test result of the soil temperature will not be influenced by shooting. The system has the advantages of low cost, high test accuracy, clear and reliable observation results, and the test results clearly and intuitively show the formation process of ice lens in frozen soil, which has important theoretical and practical significance for the research of frost heaving theory of soil in cold regions and the prevention and control of engineering frost damage.
Among them, as shown in FIG. 2, FIG. 4, FIG. 5 and FIG. 13, the system also includes a first cold bath box 4 and a second cold bath box 5; the soil sample frost heaving experiment device 2 includes a top plate 201 and a bottom plate 202, which are located at the top and bottom of the soil sample frost heaving experiment device 2 (i.e., transparent plexiglass barrel 204) respectively; heat exchange tubes are respectively arranged inside the top plate 201 and the bottom plate 202; the surface of the top plate 201 is provided with top plate cold bath interfaces 206 communicated with the interior of the top plate 201, and the surface of the bottom plate 202 is provided with bottom plate cold bath interfaces 208 communicated with the interior of the bottom plate 202; the first cold bath box 4 is connected with the top plate cold bath interfaces 206 through a supercooled liquid pipe 401, and the second cold bath box 5 is connected with the bottom plate cold bath interfaces 208 through a supercooled liquid pipe 401. Specifically, in this embodiment, the top plate 201 and the bottom plate 202 are made of copper with excellent thermal conductivity, and an annular heat exchange tube structure is arranged in the top plate 201 and the bottom plate 202, so that the path of the cold bath liquid in the plate is lengthened and the temperature control efficiency is improved. The temperature control accuracy of the cold bath box is £0.01; the supercooled liquid pipe 401 passes through a second hole 303 in the sidewall of the incubator 3, and connects the first cold bath box 4 with the top plate 201 and the second cold bath box 5 with the bottom plate 202 through fifth holes 1012 and sixth holes 1014 of the thermal insulation cover 1, respectively, so that the cold bath liquid can be circulated in the passage through the pressurizing device in the cold bath box, thereby achieving accurate contrblU501810 of the soil.
Among them, as shown in FIG. 4, the soil sample frost heaving experiment device 2 further comprises a fixed rod 203 and a fixed plate 207; the fixed plate 207 is arranged in the circumferential direction of the top plate 201, and the fixed rod 203 is vertically arranged, and one end of the fixed rod 203 is fixed with the fixed plate 207 and the other end is fixed with the bottom plate 202. Specifically, one end of the fixed rod 203 is connected with the bottom plate 202 through threading, and the other end of the fixed rod 203 is fixed with a fixed plate 207 through a bolt, so as to prevent the transparent plexiglass barrel 204 from moving when the sample is frost heaving.
Among them, as shown in FIG. 4 and FIG. 12, the system also includes a temperature acquisition device 6 for monitoring the temperature change during the soil freezing process, and a plurality of temperature acquisition interfaces 205 are arranged on the sidewall surface of the soil sample frost heaving experiment device 2 in the vertical direction, and the temperature acquisition device 6 is respectively connected to the temperature acquisition interfaces 205 for monitoring the temperature change during the soil freezing process. In this embodiment, the temperature acquisition device 6 uses a thermistor sensor 602 to connect with a data acquisition instrument 601 through a temperature sensor circuit 603, and the temperature sensor circuit 603 is inserted into the sample soil through a first hole 302 in the sidewall of the incubator 3, third holes 1013 in the soil sample peripheral thermal insulation cover 101 and the temperature acquisition interfaces 205 reserved on the transparent plexiglass barrel 204, and the freezing depth of the soil can be determined by collecting data of the temperature field during freezing.
Among them, as shown in FIG. 3, the system also includes a Markov bottle 7 and a water replenishing pipeline 701; the bottom of the soil sample frost heaving experiment device 2 is provided with a water replenishing port, and the Markov bottle 7 is communicated with the water replenishing port through the water replenishing pipeline 701. In this embodiment, the Markov bottle 7 is used to connect its water outlet to a simulated groundwater inlet 209 at the bottom of the soil sample frost heaving experiment device 2 through the second hole 303 of the incubator 3 and seventh holes 1015 of the thermal insulation cover 1 through the water replenishing pipeline 701 for simulated water replenishment. The simulation effect is that by adjusting the height of the Markov bottle 7, the tip of the Markov bottle 7 is on a horizontal line with the bottom of théJ501810 soil sample frost heaving experiment device 2, the test soil sample will absorb the water on the base when frost heaving begins, and then the water in the Markov bottle 7 will be replenished immediately, so as to simulate the phenomenon of groundwater replenishment.
Among them, as shown in FIG. 7 and FIG. 8, the soil sample peripheral thermal insulation cover 101 and the soil sample photo collection area thermal insulation cover 102 both include a polytetrafluoroethylene layer 1016, an aerogel felt layer 1017 and a polystyrene board 1018 which are nested in sequence from inside to outside. Specifically, the polytetrafluoroethylene layer 1016 of the first layer has good properties, such as high temperature resistance, corrosion resistance, non-adhesion, self-lubrication, excellent dielectric properties and low friction coefficient; its smooth surface reduces the friction force when the soil sample photo collection area thermal insulation cover 102 rises and falls, making the whole rising and falling process stable and fast. The aerogel felt layer 1017 of the second layer is nano-scale, which has excellent thermal insulation performance, and the thermal insulation effect is 2-5 times that of ordinary thermal insulation materials, and a small thickness can obtain a good thermal insulation effect. The polystyrene board 1018 of the third layer has good thermal insulation performance and certain strength, and the gap between it and polytetrafluoroethylene layer 1016 is filled with nano aerogel felt, and the soft nano aerogel felt is connected to the inner ring wall of polystyrene board 1018 and the outer ring wall of PTFE by rubber-plastic thermal insulation glue. The roof 1011 of the soil sample peripheral thermal insulation cover 101 and the soil sample photo collection area thermal insulation cover 102 also has three layers, and the composition materials and connection methods of each layer from inside to outside are the same as those described above. The polytetrafluoroethylene layer 1016 of the roof 1011 and the polytetrafluoroethylene layer 1016 of the sidewall are integrated, so no other connection is needed. Through this multi-stage thermal insulation treatment, the unidirectional freezing of soil samples is guaranteed to the maximum extent.
As shown in FIG. 6, FIG. 9 and FIG. 10, the system also includes a lifting device and a driving device 9, and the driving device 9 is connected with the soil sample photo collection area thermal insulation cover 102; the lifting device includes a rail 1022 which is vertically fixed, and a sliding member which is arranged on the rail 1022 in a liftable manner and fixedly connected with the soil sample photo collection area thermal insulation cover 102. Specifically, the drivit&501810 device 9 in this embodiment can adopt a geared motor 103, which is an integrated body of a geared motor and a motor (motor); the controller of the geared motor 103 and the motor itself are both outside the incubator 3; one end of the nylon rope is connected with the geared motor 103, and the other end is connected with the incubator 3 through a pulley 104 and the connecting plate of the soil sample photo collection area thermal insulation cover 102. By controlling the operation of the geared motor 103, the nylon rope is retracted, thereby adjusting the lifting of the closing part. Specifically, the nylon rope connected with the geared motor 103 is tied and connected with the soil sample photo collection area thermal insulation cover 102 through the top connecting plate, so that the geared motor 103 controls the nylon rope to lift and drive the soil sample photo collection area thermal insulation cover 102 to lift. The soil sample photo collection area thermal insulation cover 102 falls through the rail 1022 to make it coincide with the observation area to form a closed cover again; the soil sample photo collection area thermal insulation cover 102 rises during shooting and remains closed at other times to reduce the disturbance of temperature to the sample. This semi-automatic way makes it unnecessary to open the door of the incubator 3 during the whole experiment, and there is no gas exchange between the environment of the sample and the external environment during the whole experiment, thus reducing the influence of temperature disturbance on the experiment.
The opening and closing state of the observation area can be adjusted by the controller that controls the geared motor 103 outside the incubator 3; after the geared motor 103 controls the soil sample photo collection area thermal insulation cover 102 to rise, the observation area faces the observation window 301 of the incubator 3, and a light path is formed in the micro camera lens, the observation window 301 and the observation area, so that the micro camera system can clearly observe the frozen structure of the soil sample. In the early stage of the experiment, the ice lens was not formed, so a longer photo collection interval could be adopted; in the middle and later stage of the experiment, after the freezing front is stabilized, the external moisture has enough time to move to the freezing front, which promotes the rapid growth of the ice lens; this stage 1s the main stage that causes frost heaving, and in this stage, the samples are observed once every half hour. The formation process of the ice lens is recorded by this multi-period observation with different frequencies. When shooting is finished, start the motor to make the soil sample photo collection area thermal insulation cover 102 descend, and form a closed whol&J501810 with the thermal insulation cover 1 around the soil body to realize constant temperature.
Further, the sliding part can be a sliding block, a linear bearing 1023 or a screw mechanism; take linear bearing 1023 as an example; as shown in Figs. 9 and 10, an upper fixed end 1021 of the rail 1022 is fixed with the soil sample peripheral thermal insulation cover by screws 1024 and backing plates 1025, and the end of the rail 1022 is threaded and screwed into the fixed end 1021 through the round holes on the fixed end 1021. The connection mode of linear bearing 1023 is as follows: the screws pass through the fourth holes on the soil sample photo collection area thermal insulation cover 102 through threading and are welded with the linear bearing 1023, so as to ensure the smooth movement of the soil sample photo collection area thermal insulation cover 102 on the rail 1022. The rail 1022 provides a sliding support for the lifting of the soil sample photo collection area thermal insulation cover 102, so that the soil sample photo collection area thermal insulation cover 102 can be lifted stably.
Further, the top of the pulley 104 is connected with a bolt, which is bolted with the bolt hole on the top of the incubator 3 to fix the pulley 104 in the incubator 3. The function of the pulley 104 is to provide a reasonable path for the movement of the nylon rope, so that the nylon rope can be vertically connected with the connecting plate of the soil sample photo collection area thermal insulation cover 102, thereby achieving the purpose of low friction and smooth opening and closing of the soil sample photo collection area thermal insulation cover 102 during the lifting process.
Among them, as shown in FIG. 11, the system also includes a soil sample frost heaving deformation measuring device 8, which is arranged inside the soil sample frost heaving experiment device 2 and located at the top of the soil sample frost heaving experiment device 2, and is used for monitoring the frost heaving deformation during freezing. Specifically, the soil sample frost heaving deformation measuring device 8 in this embodiment uses a displacement sensor 801, which is in contact with the top of the soil sample frost heaving experiment device 2; a displacement sensor line 802 is introduced into the incubator 3 through an eighth hole 1019 in the roof 1011 of the soil sample peripheral thermal insulation cover 101, and passes through the first hole 302 of the incubator 3 and is connected to the data acquisition device 803 outside the incubator 3 to measure the frost heaving deformation during freezing.
The invention firstly determines the freezing depth of the soil by collecting data of th&J501810 temperature field during the freezing process, and combines the frost heaving deformation of the soil, photographs the frozen soil samples in different periods, and then analyzes the formation process of the ice lens; and the research results will provide a basis for the related analysis and numerical calculation of the frost heaving of the soil. The system realizes the experimental design that integrates groundwater recharge simulation of frost heaving experimental soil, temperature reduction and thermal insulation of soil samples, frost heaving deformation measurement of soil samples, observation and microscopic photography of soil samples with ice lens; the test system has the characteristics of simple operation, high automation, small temperature fluctuation, high test accuracy and strong practicability; besides observation of frozen soil samples, the system can also observe other samples with strict temperature control requirements in real time. According to the invention, under the condition of ensuring the minimum influence of the surrounding temperature, the observation of the ice lens in the unidirectional freezing process is carried out; the whole experimental process does not affect the temperature around the soil sample and does not destroy the structure of the sample, and the formation process including the freezing front and the segregated ice can be effectively observed, and the microstructure in the formation process of the ice lens can be dynamically observed, and meanwhile, the unidirectional freezing of the soil can be ensured to the greatest extent. The experimental results are of great significance to the analysis of frost heaving mechanism and numerical simulation of frost heaving.
The above description is only the preferred embodiment of the present invention, and it is not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of protection of the present invention.
Claims (9)
1. À frost heaving test system for ice lens observation, which 1s characterized by comprising an incubator, a thermal insulation cover, a soil sample frost heaving experiment device and an image acquisition device; the thermal insulation cover is arranged in the incubator, and the soil sample frost heaving experiment device is arranged in the thermal insulation cover; among them, the thermal insulation cover comprises a soil sample peripheral thermal insulation cover and a soil sample photo collection area thermal insulation cover; the soil sample peripheral thermal insulation cover is provided with an observation area, and the soil sample photo collection area thermal insulation cover is movably arranged in the observation area to cover or expose the observation area; an observation window is arranged on the surface of the incubator at a position corresponding to the observation area; and the image acquisition device is arranged outside the observation window.
2. The frost heaving test system for ice lens observation according to claim 1, which is characterized by further comprising a first cold bath box and a second cold bath box; the soil sample frost heaving experiment device comprises a top plate and a bottom plate, which are respectively located at the top and bottom of the soil sample frost heaving experiment device; heat exchange tubes are respectively arranged inside the top plate and the bottom plate; the surface of the top plate is provided with top plate cold bath interfaces communicated with the interior of the top plate, and the surface of the bottom plate is provided with bottom plate cold bath interfaces communicated with the interior of the bottom plate; the first cold bath box is connected with the top plate cold bath interfaces through a supercooled liquid pipe, and the second cold bath box is connected with the bottom plate cold bath interfaces through a supercooled liquid pipe.
3. The frost heaving test system for ice lens observation according to claim 2, which is characterized in that the soil sample frost heaving experiment device further comprises a fixed rod and a fixed plate, wherein the fixed plate is arranged in the circumferential direction of the top plate, the fixed rod is vertically arranged, and one end of the fixed rod is fixed with the fixed plate, and the other end is fixed with the bottom plate.
4. The frost heaving test system for ice lens observation according to claim 1, which k&/501810 characterized by further comprising a temperature acquisition device for monitoring the temperature change during soil freezing, wherein the sidewall surface of the soil sample frost heaving experiment device is provided with a plurality of temperature acquisition interfaces in the vertical direction, and the temperature acquisition device is respectively connected to the temperature acquisition interfaces.
5. The frost heaving test system for ice lens observation according to claim 1, which is characterized by further comprising a Markov bottle and a water replenishing pipeline, wherein the bottom of the soil sample frost heaving experiment device is provided with a water replenishing port, and the Markov bottle is communicated with the water replenishing port through the water replenishing pipeline.
6. The frost heaving test system for ice lens observation according to claim 1, which is characterized in that the soil sample peripheral thermal insulation cover and the soil sample photo collection area thermal insulation cover both comprise a polytetrafluoroethylene layer, an aerogel felt layer and a polystyrene board which are nested in sequence from inside to outside.
7. The frost heaving test system for ice lens observation according to claim 1, which is characterized by further comprising a lifting device and a driving device, wherein the driving device is connected with the soil sample photo collection area thermal insulation cover, and the lifting device comprises a rail and a sliding part, wherein the rail is vertically fixed, and the sliding part is arranged on the rail in a liftable manner and fixedly connected with the soil sample photo collection area thermal insulation cover.
8. The frost heaving test system for ice lens observation according to claim 1, which is characterized by further comprising a soil sample frost heaving deformation measuring device, wherein the soil sample frost heaving deformation measuring device is arranged inside the soil sample frost heaving experiment device and located at the top of the soil sample frost heaving experiment device for monitoring the frost heaving deformation during freezing.
9. The frost heaving test system for ice lens observation according to claim 1, which is characterized in that the soil sample frost heaving experiment device comprises a transparent plexiglass barrel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| LU501810A LU501810B1 (en) | 2022-04-05 | 2022-04-05 | Frost heaving test system for ice lens observation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| LU501810A LU501810B1 (en) | 2022-04-05 | 2022-04-05 | Frost heaving test system for ice lens observation |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| LU501810B1 true LU501810B1 (en) | 2022-10-05 |
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Effective date: 20221005 |